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CCC 202 2 page 3 of 4
16) Which of the following elements forms a stable +4 ion with the following
shorthand electron configuration: [noble gas] (n-1) d3?
A) Mn B) Co C) Pb D) V E) Ti
17) For the hypothetical reaction, 2 A + 3 B → A 2B3,
when the initial [A] = 0.100 mol L-1 and the initial [B] = 0.100 mol L-1,
the reaction rate is 1.4 x 10-1 mol L-1 s-1, Which experiment in the table
below would be consistent with the rate law, rate = k[A][B]2?
Experiment Initial [A]
(mol L-1) Initial [B]
(mol L-1) Reaction Rate
(mol L-1s-1)
A) 0.200 0.200 4.48 x 100
B) 0.200 0.300 1.68 x 100
C) 0.300 0.200 1.68 x 100
D) 0.300 0.300 1.13 x 101
E) 0.200 0.400 2.24 x 100
18) Which statement about this electrochemical cell setup is incorrect ?
A) The v oltmeter reading would be 2.71 V
B) The direction of electron movement is correct in the diagram
C) The direction of the salt bridge ion movement is correct in the diagram
D) The cathode half-cell reaction is correct in the diagram
E) The magnesium electrode would become lighter as the cell operated
19) When the following redox reaction is balanced with the lowest possible
integer coefficients , what is the sum of the coefficients of all reactants and
products?
Cr2O72- + H+ + Fe2+ → Fe3+ + Cr3+ + H 2O
A) 6 B) 18 C) 26 D) 30 E) 36
20) A chemist performs a Karl Fischer titration to calculate the water content of
a 26.0 mg unknown sample of a powder. Assume all of the water in the
unknown sample reacts. If 11.2 mg of I 2 were consumed during the
titration, use the following balanced equation for the Karl Fischer reaction
to determine the percent water content by mass in the unknown sample.
H2O + SO 2 + I2 → SO 3 + 2HI
A) 1.70 % B) 3.06 % C) 4.42 % D) 6.12 % E) 21.5 %
21) 1.0 mol of sulfur dioxide and 1.0 mol of oxygen gas react and establish an
equilibrium as follows:
O2 (g) + 2 SO2 (g) ⇌ 2 SO 3 (g) Keq >1
Which addition of reactants to the equilibrium reaction system will cause
the greatest increase in the amount of sulfur trioxide? Assume both the
volume and the temperature of the reaction mixture remain constant.
Moles of O 2 (g) added Moles of SO2 (g) added
A) 0.8 1.2
B) 0.9 1.1
C) 1.0 1.0
D) 1.1 0.9
E) 1.2 0.8
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CCC 202 2 page 4 of 4
22) A 25.00 mL sample of 0.800 M sodium acetate was titrated to equivalence
with 15.00 mL of hydrochloric acid solution. Which of the following
represents the calculations needed to determine the pH of the final solution?
(acetic acid K a = 1.8 x 10-5)
A)
B)
C)
D)
E)
23) The green chemistry metric called process mass intensity (PMI) allows a
chemist to calculate the total material used to synthesize a certain amount of
desired product in a chemical reaction:
PMI = [(mass of all input materials) / (actual mass of desired product)]
Consider the following laboratory procedure used to synthesize benzocaine,
a local anesthetic used to treat oral ulcers:
0.0144 moles of 4 -aminobenzoic acid hydrochloride (formula: C 7H8ClNO 2)
was dissolved in 20.0 mL of ethanol (d ensity: 0.790 g/mL) and 1.1 mL
concentrated H 2SO 4 (density: 1.82 g/mL) was added. The mixture was then
rapidly stirred and heated vigorously for two hours. After cooling to room
temperature, the reaction mixture was neutralized with 20.0 mL of a 10%
aqueou s sodium carbonate solution (density: 1.10 g/mL) and transferred to a
separatory funnel. Extraction of the product was performed with 30.0 mL of
dichloromethane (density: 1.325 g/mL) and the dichloromethane was
subsequently dried with 6.0 g of anhydrous so dium sulfate. Removal of this
drying agent and evaporation of the dichloromethane left 0.0102 moles of
pure benzocaine (formula: C 9H11NO 2).
The PMI for this reaction is
A) 46.6 B) 48.8 C) 50.9 D) 51.2 E) 52. 3
24) Consider the table below with the relative strength of acids and bases .
Assuming all reactant species have the same concentration , which of the
following equilibria would you expect to have the lowest Keq value?
A) CH 3COOH (aq) + NH 3(aq) ⇌ CH 3COO-(aq) + NH 4+(aq)
B) H2S(aq) + H2O(l) ⇌ HS-(aq) + H3O+(aq)
C) HCl(aq) + H2O(l) → H3O+(aq) + Cl-(aq)
D) HF(aq) + H2O(l) ⇌ H3O+(aq) + F-(aq)
E) HCN(aq) + NH3(aq) ⇌ CN-(aq) + NH4+(aq)
Strongest Acid HCl Cl- Weakest Base
H2SO 4 HSO 4-
H3O+ H2O
H2SO 3 HSO 3-
HF F-
CH 3COOH CH 3COO-
H2CO 3 HCO 3-
H2S HS-
HCN CN-
NH 4+ NH 3
Weakest Acid H2O OH- Strongest Base
25) For a reaction that is spontaneous at -100C but non -spontaneous at 200 C.
what must be true about the reaction ?
A) The reaction is endothermic and Keq < 0
B) The reaction is exothermic and Keq > 0
C) The reaction is endothermic and decreases entropy
D) The reaction is exothermic and increases entropy
E) H < 0 and S < 0
End of Part A of the contest
Go back and check your work
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THE CANADIAN CHEMISTRY CONTEST 2022
for high school and CEGEP students
PART C: CANADIAN CHEMISTRY OLYMPIAD
Final Selection Examination 2022
(120 minutes)
This segment has five (5) questions. While students are expected to attempt all questions for a
complete examination in 2 hours, it is r ecognized that backgrounds will vary and students will not be
eliminated from further competition becaus e they have missed parts of the paper.
Your answers are to be written in th e spaces provided on this paper. All of the paper, is to be returned
immediately by upload.
— PLEASE READ —
1. BE SURE TO COMPLETE THE INFORMATION REQUESTED AT THE
BOTTOM OF THIS PAGE BEFORE BEGINNING PART C OF THE
EXAMINATION.
2. STUDENTS ARE EXPECTED TO ATTEMPT ALL QUESTIONS OF
PART A AND PART C . CREDITABLE WORK ON A LIMITED
NUMBER OF THE QUESTIONS MAY BE SUFFICIENT TO EARN AN
INVITATION TO THE NEXT LEVEL OF THE SELECTION PROCESS.
3. IN QUESTIONS WHICH REQUIR E NUMERICAL CALCULATIONS, BE
SURE TO SHOW YOUR REASONING AND YOUR WORK.
4. ONLY NON-PROGRAMMABLE CALCULATORS MAY BE USED ON
THIS EXAMINATION.
5. PART A DATASHEET IS THE ONLY DATASHEET THAT MAY BE
USED ON THIS EXAMINATION.
PART A ( )
Correct Answers
25 x 1.6 = ......... /040
PART C
1. .................... /012
2. .................... /012
3. .................... /012
4. .................... /012
5. .................... /012
TOTAL ............. /100
Name _____________________________ School ____________________________
(LAST NAME, Given Name; Print Clearly)
City & Province _____________________________ Date of Birth __________________
E-Mail ____________________________
Home Telephone ( ) - _________________
Years at a Canadian high school ___ No. of chemistry courses at a Québec CÉGEP ___
Male Canadian Citizen Landed Immigrant Visa Student
Female Passport valid until February 2023 Nationality of Passport ___________
Teacher __________________________ Teacher E-Mail_______________________
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Page 2 of 16
1. ORGANIC CHEMISTRY
a) Starting with pyridine and any non-cyclic organic reagents with 6 or less carbon atoms, devise a
synthesis of nicotine without stereochemistry. You may use any inorganic reagents you wish.
Clearly draw the entire scheme containing reagents and intermediates. 6 marks
Official answer (other correct answers may also be accepted)
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Page 3 of 16
b) Starting with hexan-1,5-diol and any organic and inorganic reagents you wish, devise a synthesis
of menthol without stereochemistry. Clearly draw the entire scheme containing reagents and
intermediates. 4 marks
Hint: here’s a reaction that may be useful; a gilman reagent is a lithium dialkyl cuprate salt that can
perform conjugate addition reactions like so:
Where R, R 1 and R 2 are different alkyl groups.
Official answer (other correct answers may also be accepted)
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Page 4 of 16
c) The following structures are all stereoisomers of menthol. Assuming that all these structures are
in their most stable conformations, circle the most stable stereoisomer. 2 marks
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Page 5 of 16
2. ANALYTICAL CHEMISTRY
Colorless crystal A undergoes a thermal decomposition reaction to produce two gases B and
C. When gas B is further heated to a higher temperature and then cool ed down to the original
temperature, the volume the gases increase by 50%. Although A is commonly used in agriculture
as a fertilizer, it nevertheless is an oxidizing agent. A dissolve easily in water and causes the
temperature of the solution to de crease noticeably and the re sulting solution is slightly acidic (pH
between 4.5 and 5.0). Heating equal moles of A and solid NaOH produces a gas D with
unpleasant odor and a white solid E. When gas D is introduced into a AgNO3 solution, a dark
brown solid F is formed. However, when gas D is continuously introduced, a colorless solution is
obtained. Heating solid E produces colorless gas G which is essential for combustion reaction
and a white solid H. When H is treated with concentrated nitric ac id, a brown color gas is evolved.
a) Based on information given, please identify A, B, C, D, E, F, G and H.
4 marks (0.5 each)
A: NH 4NO 3 B: N2O C: H2O
D: NH 3 E: NaNO 3 F: Ag2O
G: O2 H: NaNO 2
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Page 6 of 16
b) Write the chemical reaction equations for the following
4 marks (0.6 each, 0.4 last question)
Reaction to produce B & C
NH 4NO 3(s) → N2O(g) + H2O(g)
Reaction for heating B to increase the volume by 50%
2N2O(g) → 2N 2(g) + O 2(g)
Reaction to produce D & E
NH 4NO 3(s) + NaOH(s) → NH 3(g) +NaNO 3(s) + H 2O(g)
Reaction to produce F
2Ag+(aq) + 2NH 3(g) + H 2O(l) → Ag 2O(s) + 2NH 4+(aq)
Reaction of F to produce the colorless solution
2Ag 2O(s) + 4NH 3(aq) + H 2O(l) → 2[Ag(NH 3)2]+ + 2OH-(aq)
Reaction of E to produce G and H
2NaNO 3(s) → 2NaNO 2(s) + O 2(g)
Reaction of H to produce the brown color gas
NaNO 2(s) + 2HNO 3(aq, concentrated) → NO 2(g) + 2NaNO 3(aq) + NO(g) + H 2O(l)
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Page 7 of 16
Leucine (CH 3)2CHCH 2CH(NH 2)COOH is on the top list of e ssential amino acids for human
body. Leucine contains a carboxylic acid f unctional group and an amine functional group and
has a pK a = 2.36 and pK b = 4.40. Leucine has been used in the food industry and as healthy
supplement.
c) Using your knowledge of Charge Balance and/or Mass Balance, calculate the pH of a
0.100M aqueous Leucine solution. Show your detailed work to earn full marks.
2.5 marks
Leucine will dissolve and form Zwitterion (CH 3)2CHCH 2CH(NH 3+)COO‐
Charge balance
[A‐] + [OH‐] = [A+] + [H+] (1.0 point)
Ka = [A‐][H+] / [A]
[A‐] = Ka[A] / [H+]
Kb = [A+][OH‐] / [A]
[A+] = Kb[A] / [OH‐]
Approximation
Since [A+] >> [H+] and [A‐] >> [OH‐]
[A+] ≈ [A‐] (0.5 points)
Kb[A] / [OH‐] = Ka[A] / [H+]
Kb[A][H+] / kw = Ka[A] / [H+]
[H+]2 = Ka[A] * Kw / Kb[A]
[H+] = ( Ka * Kw / Kb )1/2 (0.5 points)
pH = 5.98 (0.5 points)
Any correct final pH value with in an error of ±0.02 will get 0.5 points.
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Page 8 of 16
In a lab, there are 0.100M NaOH, 0, 120M HCl, oxalic acid primary standard (H 2C2O4•2H 2O,
126.07g/mol), Potassium Hydrogenpht halate primar y standard (KHC 8H4O4, 204.22 g/mol),
Tris(hydroxymethyl)-ami nomethane primary standard ( Tris. (HOCH 2)3CNH 2, kb = 1.15×10−6,
121.14g/mol), Sodium Car bonate primary standard (Na 2CO 3, 155.99g/mol), and three
indictors, Phenolphthalein (pK a = 9.4), methyl orange (pK a = 3.4) and methyl red (pK a = 4.95).
d) The purity of Leucine, which is going to be used in making dietary supplement, is to be
determined by titration. A 2.000g of Leucine is taken to make a 250.00mL aqueous solution.
Which of the afore listed chemicals would you use as the titrant? Which would you use as
the indicator?
0.5 mark
Since the solution is acidic, so NaOH would be chosen as the titrant and Phenolphthalein
would be chosen as the indicator.
(0.25 points for each correct answer)
e) Which of the primary standards would you use to standardize your titrant?
0.5 mark
To standardize NaOH, either Oxalic Acid primary standard or Potassium Hydrogenphthalate
primary standard will be chosen .
(either one gets full points)
f) If 14.94mL of the titrant is required to reach the equivalence point for a 25.00mL aliquot of
the analyte, what is the purity of the Leucine sample?
0.5 mark
0.01494 * 0.100 * 10 *131.17 / 2.000 = 97.98%
(97.48 ~ 98.48% gets full points)
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Page 9 of 16
3. INORGANIC CHEMISTRY
The Monsanto process is a famous industria l catalytic cycle. The process is presented
below:
Please answer the following questions pertaining to the Monsanto process:
a) Write the overall balanced equation for the Monsanto process.
1 mark
CH 3OH + CO CH 3COOH
b) For complex A, state which of its ligands are weak field and which are strong field, and also
state whether the complex is a cis or trans isomer.
1 mark
iodide is weak field and CO is strong field (0.25 points each). The complex is in cis
conformation (0.5 points).
c) For complex B, draw its crystal field splitting diagram, making sure to fill in the electrons and
label each d orbital. Hint: complex B is diamagnetic.
2 marks 𝑒 𝑑௫మି௬మ ,𝑑௭మ
𝑡
ଶ 𝑑௫௬ ,𝑑௫௭,𝑑௬௭
This is just a typical low spin octahedral CFT diagram, with 6 electrons filling the t 2g set. 1 point for
the d-orbital splitting, 0.5 points for labelling the orbitals correctly, and 0.5 points for filling in the
electrons properly.
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Page 10 of 16
d) For complex C, state its geometry and coordination number.
1 mark
the geometry is square pyramidal (0.5 points) and the coordination number is 5 (0.5 points).
e) For complex D, state the metal’s oxidation state and d-electron count.
1 mark
the oxidation state is +3 (0.5 points) a nd the d-electron count is 6 (0.5 points).
Rhodium, the metal used in the Monsanto proce ss, crystallizes into the face centered cubic
structure as shown below:
The lattice parameter (unit cell le ngth) of the cryst al is 0.380 nm.
f) State the number of atoms present in the unit cell.
0.5 mark 4
g) State the coordination number of Rh in the crystal.
0.5 mark 12
h) Calculate the density of Rh in g cm−3.
2 marks
mass/volume: (4x102.9)/(6.02214x1023x(0.380x10-7)3) = 12.5 g cm−3
1 point for general mass/volume expressi on, 0.5 points for correct answer,
0.5 points for correct units.
i) Calculate the volume of empty space in the unit cell of Rh in nm3.
Hint: the volume of a sphere with radius r is given by: 𝑉ൌସ
ଷ𝜋𝑟ଷ
3 marks
Rh atomic radius = 0.380x √2/4 = 0.134 nm (1.5 points)
volume occupied by atoms: 4ൈସ
ଷ𝜋ൈ 0.134ଷ = 0.0406 nm3 (0.5 points)
volume of unit cell: 0.3803 = 0.0549 nm3 (0.5 points)
volume of empty space: 0.0549 – 0.0406 = 0.0143 nm3 (0.5 points)
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Page 11 of 16
4. ORGANIC CHEMISTRY and NMR spectroscopy
a) The total synthesis of Gymnomitrol combines a wide variety of synthesis techniques. In step 1, only one
side is reacted. Over the reaction sequence, a Michael addition and enolate attack are performed consecutively. Later in the sequence, an aldol addition is us ed to further cyclize the molecule. Given starting
compound A and the following reaction sequence, identify compounds C, D, F, G, I, J and K. Structures L
1
and L2 are both possible products from precursor K. Draw them both and note which one reacts to form
Gymnomitrol.
9 marks
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Page 12 of 16
b) Step 2 in the synthesis of Gymnomitrol is known as a Wolff-Kishner Reduction. Draw
the complete reaction mechanism.
1 mark
1 point; 0.5 points for hydrazone formation, 0.5 points for deprotonation and condensation
c) The selected hydrogen atoms all appear in the condensed H-NMR spectrum. Fill in the
table with the hydrogen atoms’ corresponding H-NMR peaks.
2 marks
Chemical shift options for peaks:
5.00, 3.72, 1.65 and 2.53 ppm
Hydrogen
atom Chemical shift of peak
(ppm)
a. 3.72
b. 1.65
c. 2.53
d. 5.00
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Page 13 of 16
5. PHYSICAL CHEMISTRY
The following 2nd-order reaction: 𝐴ሺ𝑔ሻ → 2𝐵ሺ𝑔ሻ was carried out at T = 27 °C in a reaction
vessel of constant volume. At the beginning of the reaction, only A( g) at P = 1 atm was
present. After 100 minutes of reac tion, the total pressure P in the vessel reaches 1.5 atm.
Assume that both A(g) and B(g) are ideal gases.
a) Determine the half-life t 1/2 and the rate constant k of the reaction at 27 °C. State your
units in atmosphere and minutes.
3 marks
A → 2B 𝑃
I 1 atm 0 1 atm
C -x +2x +0.5
E 1-x 2x 1.5 atm
1െ𝑥 2𝑥ൌ 1.5
1𝑥ൌ 1.5
𝑥ൌ 0.5 𝑎𝑡𝑚
𝑃ሺ100 𝑚𝑖𝑛ሻൌ1െ0.5ൌ0.5 𝑎𝑡𝑚
Or:
𝑃
ൌ2ሺ1െ𝑃ሻ
𝑃𝑃ൌ1.5⇒
𝑃2ሺ1െ𝑃ሻൌ1.5 𝑎𝑡𝑚 𝑎𝑡 100 𝑚𝑖𝑛
𝑃2െ2𝑃ൌ1.5
2െ1.5ൌ𝑃
𝑃ሺ100 𝑚𝑖𝑛ሻൌ0.5 𝑎𝑡𝑚 1 mark
𝑃ሺ100 𝑚𝑖𝑛ሻൌ0.5ൈ𝑃ሺ0 𝑚𝑖𝑛ሻ⟹
𝑡భ
మൌ100 𝑚𝑖𝑛 1 mark
2ௗ 𝑜𝑟𝑑𝑒𝑟 𝑘ൌଵ
௧భ
మಲሺ ሻൌଵ
ଵൈଵൌ0.01 𝑎𝑡𝑚ିଵ𝑚𝑖𝑛ିଵ 1 mark
Remove 0.5 mark for missing or wrong units
b) Give the rate constant k using moles, litres and seconds for the units.
1 mark
ሾ𝐴ሿൌ𝑛
𝑉ൌ𝑃ሺ0 𝑚𝑖𝑛ሻ
𝑅𝑇ൌ1
0.08206ൈ300ൌ0.0406𝑚𝑜𝑙
𝐿
𝑜𝑟 ൌ101325
8.314ൈ300ൈ1000𝐿/𝑚ଷൌ0.0406𝑚𝑜𝑙
𝐿
𝑡ଵ
ଶൌ100 𝑚𝑖𝑛 ൌ 6000 𝑠
𝑘ൌ1
𝑡
ଵ
ଶሾ𝐴ሿൌ1
6000ൈ0.0406ൌ4.1ൈ10ିଷ 𝑚𝑜𝑙ିଵ𝐿𝑠ିଵ 𝑜𝑟 0.0041 𝑚𝑜𝑙ିଵ𝐿𝑠ିଵ
Remove 0.5 mark for missing or wrong units
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Page 14 of 16
Consider a closed container of fixed size in contact with its surroundings maintained at a
temperature of 298 K. The inside of this container is partitioned by a frictionless, movable
wall into two compartments labeled 1 and 2, with initial volumes of 𝑉ଵൌ5𝐿 and 𝑉ଶൌ1𝐿,
respectively. In compartment 1, there is a gaseous equili brium mixture of molecules 𝐴
and 𝐵 with a total pressure of 1 atm. In compar tment 2, there is a gas of only compound
𝐶 also with a pressure of 1 atm. A piece of metal catalyst of negligible volume is then
introduced into compartment 2 which causes gas 𝐶 to decompose into gaseous product
𝐷 in an equilibrium reaction. This pushes the wall against compartment 1, which increases
𝑉ଶ and decreases 𝑉ଵ, also shifting the 𝐴⇌𝐵 equilibrium as according to Le Chatelier’s
principle. The wall is pushed until the reacti ons in both compartmen ts reach a new state
of equilibrium. The standard c hanges in Gibbs free energies for the two equilibria are:
𝐴ሺ𝑔ሻ⇌2𝐵ሺ𝑔ሻ ∆𝐺ଵൌെ 5.183 𝑘𝐽/𝑚𝑜𝑙
𝐶ሺ𝑔ሻ⇌3𝐷ሺ𝑔ሻ ∆𝐺ଶൌെ 5.636 𝑘𝐽/𝑚𝑜𝑙
Assume all gases are ideal.
c) Calculate the initial number of moles for C.
1 mark
𝑛ൌ𝑃𝑉
𝑅𝑇ൌ1ൈ1
0.08206 ൈ298ൌ0.0409 𝑚𝑜𝑙
𝑜𝑟 ൌ101325ൈ0.001
8.3145ൈ298ൌ0.0409 𝑚𝑜𝑙
Remove 0.5 mark for missing or wrong units
d) Calculate the equilibrium constant for reaction 1 and 2.
1 mark
∆𝐺ൌെ 𝑅 𝑇 𝑙 𝑛 ሺ𝐾ሻ⇒lnሺ𝐾ሻൌെ∆𝐺
𝑅𝑇⟹
𝐾ଵൌ𝑒ି∆ಸభ
ೃൌ𝑒ఱభఴయ
ఴ.యభరఱൈమవఴൌ8.10 0.5 mark
𝐾ଶൌ𝑒ି∆ಸమ
ೃൌ𝑒ఱలయల
ఴ.యభరఱൈమవఴൌ9.72 0.5 mark
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Page 15 of 16
e) Calculate the initial number of moles for A and B.
2 marks
𝐾ଵൌ𝑃ଶ
𝑃ൌ8.1 𝑎𝑛𝑑 𝑃𝑃ൌ1 𝑎𝑡𝑚
𝑃ଶ
𝑃ൌ𝑃ଶ
1െ𝑃ൌ8.1 ⟹ 𝑃ଶൌ8.1െ8.1𝑃⟹𝑃ଶ8.1𝑃െ8.1ൌ0
𝑢𝑠𝑒 𝑞𝑢𝑎𝑑𝑟𝑎𝑡𝑖𝑐 𝑒𝑞𝑢𝑎𝑡𝑖𝑜𝑛 𝑡𝑜 𝑠𝑜𝑙𝑣𝑒 𝑤𝑖𝑡ℎ 𝑎ൌ 1,𝑏ൌ 8.1 𝑎𝑛𝑑 𝑐ൌെ 8.1
ඥ𝑏ଶെ4𝑎𝑐ൌ9.9 𝑡ℎ𝑒 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑖𝑠: 𝑃ൌെ8.19.9
2ൌ0.9 𝑎𝑡𝑚
(The other root gives a negative pressure.)
𝑃ൌ1െ0.9ൌ0.1 𝑎𝑡𝑚
𝑛ൌ𝑃𝑉
𝑅𝑇
𝑛ൌ𝑃𝑉
𝑅𝑇ൌ0.1ൈ5
0.08206 ൈ298ൌ0.0204 𝑚𝑜𝑙 𝑜𝑟 0.1ൈ101325ൈ0.005
8.3145ൈ298ൌ0.0204 𝑚𝑜𝑙
𝑛ൌ𝑃𝑉
𝑅𝑇ൌ0.9ൈ5
0.08206 ൈ298ൌ0.184 𝑚𝑜𝑙 𝑜𝑟 0.9ൈ101325ൈ0.005
8.3145ൈ298ൌ0.184 𝑚𝑜𝑙
Remove 0.5 mark for missing or wrong units
We know that 𝑉ଶ will increase and 𝑉ଵ will decrease. To get a better idea of how the system
may evolve we can define 𝑉௫, the maximum volume of compartment 2 and 𝑉 the
minimum volume of compartment 1. To answer f) and g) assu me that both compartments
are independent from one another and the sum of their vo lumes is not restricted.
f) Calculate the value of 𝑉௫, the maximum volume of compartment 2 at 1 atm.
1 mark
𝐼𝑛𝑖𝑡𝑖𝑎𝑙 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐶,𝑛ൌ0.0409 𝑚𝑜𝑙
𝐶→ 3𝐷 ,𝑡ℎ𝑒𝑟𝑒𝑓𝑜𝑟𝑒 𝑖𝑓 𝑡ℎ𝑒 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 𝑖𝑠 𝑐𝑜𝑚𝑝𝑙𝑒𝑡𝑒 𝑛ൌ3𝑛ൌ3ൈ0.0409ൌ0.1227 𝑚𝑜𝑙
𝑉௫ൌ𝑛𝑅𝑇
𝑃
𝑎𝑡 1 𝑎𝑡𝑚 𝑎𝑛𝑑 298 𝐾,𝑉௫ൌ0.1227ൈ0.08206ൈ298
1ൌ3 𝐿
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g) Calculate the value of 𝑉, the minimum volume of compartment 1 at 1 atm.
1 mark
𝐼𝑛𝑖𝑡𝑖𝑎𝑙 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐴 𝑎𝑛𝑑 𝐵,𝑛ൌ0.0204 𝑚𝑜𝑙 𝑎𝑛𝑑 𝑛ൌ0.184 𝑚𝑜𝑙
2𝐵→𝐴 ,𝑡ℎ𝑒𝑟𝑒𝑓𝑜𝑟𝑒 𝑖𝑓 𝑡ℎ𝑒 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 𝑖𝑠 𝑐𝑜𝑚𝑝𝑙𝑒𝑡𝑒 𝑛ൌ0.0204𝑛
2ൌ0.1124 𝑚𝑜𝑙
𝑉ൌ𝑛𝑅𝑇
𝑃
𝑎𝑡 1 𝑎𝑡𝑚 𝑎𝑛𝑑 298 𝐾,𝑉ൌ0.1124ൈ0.08206ൈ298
1ൌ2.75 𝐿
h) Once a new state of equilibrium is reached the pressure of the system has changed and
the volume of compartment 1 reach 4L. Determine the value of the new equilibrium pressure in the container. 2 marks
𝑛ൌ0.02040.184െ𝑛
2ൌ0.04080.184െ𝑛
2 ൌ0.2248െ𝑛
2
𝑛ൌ𝑃𝑉ଵ
𝑅𝑇ൌ0.16357𝑃 𝑎𝑛𝑑 𝑛ൌ𝑃𝑉ଵ
𝑅𝑇ൌ0.16357𝑃
⟹0.16357𝑃ൌ0.2248െ0.16357𝑃
2
𝑃ൌ0.2248െ0.16357𝑃
0.32714
𝑠𝑢𝑏𝑠𝑡𝑖𝑡𝑢𝑡𝑒 𝑖𝑛 𝑃ଶ
𝑃ൌ8.1 ⟹ 0.32714𝑃ଶ
0.2248െ0.16357𝑃ൌ8.1
⟹0.32714𝑃ଶൌ1.82088െ1.324917 𝑃⟹0.32714𝑃ଶ1.324917 𝑃െ1.82088
𝑎ൌ 0.32714
𝑏ൌ 1.324917
𝑐ൌെ 1.82088
√𝑏ଶെ4𝑎𝑐ൌ2.034
𝑃ൌିଵ.ଷଶସଽଵାଶ .ଷସ
ଶൈ .ଷଶଵସൌ1.084 𝑎𝑡𝑚
𝑃ൌಳమ
଼.ଵൌ0.145 𝑎𝑡𝑚
𝑃ൌ𝑃𝑃ൌ1.23 𝑎𝑡𝑚
(Give 1 mark for 1.084 or 0.145 atm. 2 marks for 1.23 atm)
-END OF PART C-
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Potential
Energy (kJ) THE CANADIAN CHEMISTRY CONTEST 2021
PART A – MULTIPLE CHOICE QUESTIONS (60 minutes)
All contestants should attempt this part of the conte st before proceeding to Part B and/or Part C .
The only reference material allowed is the CIC/CCO Periodic Table provided. You must complete answers on the Scantron Sheet provided . Students
may use a scientific calculator. No phones or communication device s are allowed.
1) What mass of cobalt (II) chloride hexahydrate must be used in order to make
500.0 mL of a solution that has a chloride ion concentration of [Cl-] = 0.300
mol L-1?
A) 9.74 g B) 17.8 g C) 35.7 g D) 143 g E) 150 g
2) Which of the following statements are TRUE about reactions 1 and 2?
Reaction 1: N
2 (g) + 3H 2 (g) → 2NH 3 (g)
Reaction 2: NaOH (aq) + HCl (aq) → H 2O (l) + NaCl (aq)
i) Reaction 1 is a redox reaction
ii) Reaction 2 is a redox reaction
iii) Hydrogen is the reducing agent in both reaction 1 and 2
iv) One of the products in each reaction has a bond angle of < 109.5°
A) i, ii and iii B) i, ii and iv C) ii and iv
D) i and iv E) i, ii, iii and iv
3) A student combines 25.00 mL of a 0.125 mol L-1 solution of potassium
iodide KI with 10.00 mL of a 0.250 mol L-1 solution of lead (II) nitrate
Pb(NO 3)2. What mass of precipitate will be formed?
A) 0.316 g B) 0.720 g C) 0.980 g D) 1.15 g E) 1.44 g
4) Respiration i s an example of a catabolic process in which energy is released.
Which statement best explains why energy is released in this reaction ?
C6H12O6 (s) + 6 O2 (g) → 6 CO 2 + 6 H 2O
A) Breaking the bonds in glucose releases energy
B) Burning calories converts molecules into energy
C) Bond formation in carbon dioxide and water is highly exothermic
D) The larger a molecule is, the more potential energy it contains.
E) Kinetic energy is converted into potential energy in this reaction.
5) The following reaction diagram represents a two step reaction. Which of the
statements about this reaction are correct?
i) The rate determining step is endothermic.
ii) The overall reaction enthalpy is negative.
iii) Producing reaction intermediates releases energy.
A) i only B) ii only C) iii only D) i and iii E) i, ii and iii
6) Some air is evacuated from a 400.0 mL Erlenmeyer f lask at 25 .0°C.
Assuming Ideal Gas Law behaviour, what is the partial pressure of O 2 inside
the container if 1.21 x 10–2 mol gas remain in the
container, consisting of 9.44 x 10–3 mol N2,
1.17 x 10–4 mol Ar and O 2 is the only other gas
in the container?
A) 75.0 kPa B) 63.9 kPa C) 47.1 kPa D) 39.3 kPa E) 15.8 kPa
Gas
evacuation
tube
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7) Scientists have discovered that one of the twenty- eight artificially created
zirconium isotopes, zirconium -88, had an unusually high affinity for
neutrons. In zirconium -88, a proton absorbs an atomic electron, forming a
neutron and emitting a neutrino. Wha t is the correct notation for the atom that
forms as a result of this transition?
A) 𝑌𝑌3988 B) 𝑌𝑌3989 C) 𝑍𝑍𝑍𝑍3989 D) 𝑍𝑍𝑍𝑍4088 E) 𝑁𝑁𝑁𝑁4189
8) The COVID- 19 pandemic triggered an intense effort worldwide to screen
existing “small -molecule” drugs in the development of a treatment. The
structure s of two such compounds of interest are shown below. What is the
difference in the molecular weight of the compounds in g mol-1?
NO
NO
N O
NH2
FH
A) 14.1 B) 26.1 C) 27.1 D) 28.1 E) no difference
9) Which statement is TRUE for the two compounds in Question 8 ?
A) only one compound contains one amide functional group
B) both compounds have the same number of lone pair electrons
C) both compounds contain one amide functional group
D) both compounds contain a benzene ring
E) only one compound contains one amine functional group
10) The kinetic molecular theory describ es the behaviour of ideal gases. Which
of the following aspects of the partic le theory of matter does not correspond
to the kinetic molecular theory?
A) Particles are always moving.
B) Different substances are made of different particles.
C) Particles move faster at higher temperatures.
D) Particles are all attracted to each other .
E) Identical substances are made of identical particles 11) Arrange the following compounds in order of increasing volatility
A) IV, I, II, III D) IV, I, III, II
B) I, III, II, IV E) III, II, IV, I
C) I, IV, II, III
12) For the titration of a weak base with a strong acid, which of the following
indicators would be best to visualize the equivalence point?
A) Cresol red (pKa = 1.0) D) Phenolphthalein (pKa = 9.4)
B) Methyl red (pKa = 5.0) E) Alizarin yellow (pKa = 11.2)
C) Thymol blue (pKa = 8.9)
13) Methylamine is a weak base with a pKb of 3.36. What is the pH of a 0.500 M solution of methylamine?
A) 1.84 B) 10.08 C) 12.16 D) 12.32 E) 13.70
14) An acid -base titration is performed using formic acid (HCOOH) and
sodium hydroxide (NaOH) as the titrant, according to the equation below:
HCOOH (aq) + NaOH (aq) → H 2O (ℓ) + NaHCOO (aq)
If 15.00 mL of 0.400 M sodium hydroxide solution was required to neutralize
a 30.00 mL sample of formic acid, what will be the pH at the equivalence
point of this titration? The K a of formic acid is 1.77 × 10-4.
A) 5.562 B) 7.000 C) 8.438 D) 11. 686 E) 13.651
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15) Tums® tablets contain the active ingredient calcium carbonate, which eases
the symptoms of acid -indigestion by neutralizing hydrochloric acid in the
stomach and inhibiting peptic activity. The standard dose f or the treatment
of acid -indigestion with Tums® is two tablets , which each contain 1000 mg
of calcium carbonate. Suppose an individual with a stomach volume of 1 L
and pH of 1.64 ingests the recommended dose of Tums®. What will be the
resulting pH of the contents of the stomach once the reaction is complete?
A) 2.53 B) 1.78 C) 2.8 7 D) 2.72 E) 1.89
16) The α amino acid pyrrolysine is absent in humans, but found in some
methanogenic bacteria and archeobacteria for synthesis of proteins. The
structure of pyrrol ysine is shown below:
What are the approximate values of the bond angles labelled 1, 2, and 3,
respectively?
A) 120°, 120°, 120° D) 109.5°, 109.5°, 109.5°
B) 109.5°, 109.5°, 120° E) 120°, 109.5°, 120°
C) 109.5°, 120° , 120°
17) An equimo lar mixture of two amino acids, glycine and valine, ( structures
below) underwent a condensation reaction. How many dipeptide products
were formed which have different atom connectivity?
H2NO
OH
glycine valin eNH2
OHO
A) 2 B) 3 C) 4 D) 5 E) 6 18) The organic substance below is a component of a variety of essential oils
and belongs to a family of compounds known as “rose ketones”.
O
Which of the following compounds is NOT an isomer of this substance?
19) The human body is approximately 60% water ( specific heat capacity of
water, c = 4.184 J g
-1 K-1). When not dressed properly on a 5 ℃ day, body
temperature drops at 2.0 ℃ h-1. For a 60.0 kg person, w hat mass of glucose
(C6H12O6, 𝚫𝚫Hc = -2880 kJ mol-1) must be bur ned per hour to maintain a
constant body temperature ?
A) 9.4 g B) 16 g C) 19 g D) 31 g E) 47 g
20) An ice calorimeter measures the heat released in a reaction using the mass
of ice melted during a chemical process. The heat of fusion of ice (ΔH
fus) is
333 J g-1. Assu ming there is some energy lost in the process, if 1.75 g of ice
melt when 0.250 g of an unknown metal react with excess hydrochloric acid to produce the metal chloride XCl
2 and hydrogen gas. In a separate
experiment, the volume of hydrogen gas e volved in the reaction of excess
hydrochloric acid and 0.250 g of the metal was 0.0850 L at 0° C and 101.3
kPa. What is the approximate enthalpy of this reaction?
A) 154 kJ B) 198 kJ C) 258 kJ D) 396 kJ E) 761 kJ
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21) The “atom economy” of a chemical reaction is the fraction of starting
material atoms that end up in a desired product. It is important for both sustainable development and economic reasons to use reactions with
high atom economy as much as possible.
Which of the following three reactions occur with 1 00% atom
economy, based on forming the desired product shown?
Br
BrBr2(i)
(ii)heat+
Cl
Cl2(iii)
light
A) i only B) ii only C) iii only D) i and ii E) i, ii & iii
22) Consider the following galvanic
cell for Questions 22 -24
𝑬𝑬𝑪𝑪𝒖𝒖𝟐𝟐+/𝑪𝑪𝒖𝒖𝒐𝒐= +𝟎𝟎.𝟑𝟑𝟑𝟑 𝑽𝑽
𝑬𝑬𝒁𝒁𝒏𝒏𝟐𝟐+/𝒁𝒁𝒏𝒏= −𝟎𝟎.𝟕𝟕𝟕𝟕 𝑽𝑽
Which of the statements is true about [𝐶𝐶𝑙𝑙−] at the anode and the
cathode after the cell has operated for 5 minutes?
A) [𝐶𝐶𝑙𝑙−]=0 𝑀𝑀 in both half cells.
B) Both half cells contain [𝐶𝐶𝑙𝑙−]=0.1 𝑀𝑀 due to diffusion.
C) [𝐶𝐶𝑙𝑙−] is greatest at the cathode. A precipitate forms at the anode.
D) [𝐶𝐶𝑙𝑙−] is greatest at the cathode as the ions migrate to make the
cell work.
E) [𝐶𝐶𝑙𝑙−] is greatest at the anode as ions move to neutralize the
charge difference. 23) If the anode and cathode were connected with a wire with constant
resistance, which would be the expected graph of voltage of the cell
vs. time?
24) Assuming no energy is lost in the system, how much work can the cell
do at 298 K if the re are 2 mols of 𝐶𝐶 𝑢𝑢2+ at the cathode and 2 mols of
𝑍𝑍𝑛𝑛2+ at the anode? The potential of the cell is 1.10 𝑉𝑉 .
A) 1.10 J B) 2.20 J C) 106.15 kJ D) 212.3 kJ E) 424. 5 kJ
25) The Ksp value for SrSO 4 is 7.6 × 10–7, and the Ksp value for SrF 2 is
7.9×10–10. Sr(NO 3)2(s) is added to 1.00 L of solution containing
0.020 mol F– and 0.20 mol of SO 4–2 with constant volume. Which salt
precipitates first , and what is the [Sr2+] in solution when the
precipitate forms?
End of Part A of the contest
Go back and check your work A) SrF 2 and SrSO 4 both precipitate when [Sr2+] = 3.8 × 10–4 mol L-1
B) SrF 2 precipitates first, when [Sr2+] = 2.0 × 10–6 mol L-1
C) SrF 2 precipitates first, when [Sr2+] = 1.6 × 10–7 mol L-1
D) SrSO 4 precipitates first, when [Sr2+] = 7.7 × 10–8 mol L-1
E) SrSO 4 precipitates first, when [Sr2+] = 5.3 × 10–9 mol L-1
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THE CANADIAN CHEMISTRY CONTEST 2020
PART A – MULTIPLE CHOICE QUESTIONS (60 minutes)
All contestants should attempt this part of the conte st before proceeding to Part B and/or Part C .
The only reference material allowed is the CIC/CCO Periodic Table provided . You must complete answers on the Scantron Sheet provided . Students
may use a scientific calculator. No phones or communication device s are allowed.
1) 15 mL of 0.25 mol L-1 aqueous silver nitrate reacts with 0.10 g of zinc as
follows:
2 AgNO 3 (aq) + Zn (s) → 2 Ag (s) + Zn(NO 3)2 (aq)
What mass of silver metal should the reaction produce?
A) 0.16 g B) 0.20 g C) 0.33 g D) 0.40 g E) 0.81 g
2) Two elements X and Y form a covalent compound. X has six valence
electrons and Y has seven valence electrons. Which of the options ( I-IV)
given below, represent possible formulae and shapes of covalent compounds
of X and Y based on VSEPR theory and Lewis structures?
I) XY 4 II) XY 6 III) bent IV) see -saw (or distorted tetrahedral )
A) I and III only B II and IV only C) I and IV only
D) I, II and III only E) I, II, III and IV
3) A student combines 100 mL of two clear, equimolar, colourless solutions
and observes a solid white precipitate form at the bottom of the beaker. A
representation of the resultant particles in the beake r is in the diagram below .
Which combination of reactants would best align with the information
provided and diagram of resultant particles in the beaker?
A) lead (II) nitrate (aq) + potassium chloride (aq)
B) zinc nitrate (aq) + sodium phosphate (aq)
C) nickel (II) nitrate (aq) + lithium bromide (aq)
D) copper (II) nitrate (aq) + sodium hydroxide (aq)
E) silver nitrate (aq) + magnesium sulfate (aq)
4) A student drew structural diagrams fo r some of the isomers of a molecule
and wrote down each isomer’s boiling point (b.p.) . There is an error in the
student’s work. For which structure did the student incorrectly record the
boiling point?
A) b.p. 129°C B) b.p. 116°C
C) b.p. 126°C D) b.p. 106°C
E) b.p. 109°C
5) In which of the following substances does sulfur have the lowest oxidation
state?
A) S8 B) Na 2S2O3 C) Na2SO 4 D) H2S E) SO 2
6) Given the graph of the successive ionization energies for two unknown
atoms, which combination provides the m ost likely identity of X and Y?
Unknown: X Y
A) Al Si
B) Kr Rb
C) Cl Ar
D) Se Br
E) Rb Sr
020000400006000080000
1st
2nd
3rd
4th
5th6th7th8th9th
10th
11th
12th
13th
14thIonization Energy (kJ mol-1)
Electron removed from the unknown elementSuccessive ionization energies of 2 elements
Unknown X Unknown Y
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7) The structure below is a substance found in the skin of certain species of
amphibians . In large quantities , the substance can have a psychoactive effect
on humans , changing brain function and altering behaviour. What is the correct
molecu lar formula of the substance ?
A) C12H16N2O B) C 10H12N2O C) C 11H14N2O
C) C
12H18NO E) C 12H14N2O
8) How many constitutional isomers and how many stereoisomers does the
organic molecule with the formula C
3H9N have?
9) Consider the following equilibrium in a sealed container
2NO(g) + 5H 2(g) ⇋ 2NH 3(g) + 2H 2O(g) ΔH = -756.4 kJ mol-1
Which of the following changes would most likely shift the equilibrium
position towards reactants?
A) Increasing the temperature D) Adding nitrogen monoxide gas
B) Adding argon gas E) Removing ammonia
C) Decreasing the volume of the
sealed container
10) When a sample of an unknown compound with a formula of C
xHy
combusts with an excess amount of oxygen, the reaction produces
132.001 g of carbon dioxide and 72.064 g of water. Based on the
information given, this unknown compound is :
A) methane B) ethane C) propane D) butane E) octane 11) Hydr ogen peroxide decomposes to form oxygen gas and water via the
following chemical equation:
2 H 2O2 (aq) → 2 H 2O (l) + O 2 (g) ΔH = -392 kJ
The density of 30% hydrogen peroxide is 1.11 g mL-1. If 50.0 mL of a 30%
by mass hydrogen peroxide solution decomposes, what is the accompanying
change in energy?
A) 96 kJ released B) 117 kJ absorbed C) 173 kJ released
D) 192 kJ released E) 392 kJ absorbed
12) A mixture of ethanol and nitric acid , called nital, is an industrial etching
agent . A student prepared a 20.0 mL solution of n ital using 0.70 mL of nitric
acid of unknown concentration and 19.3 mL of 98% ethanol. The student
determined by titration that the final concentration of nitric acid in the nital
etching agent was 4.0 % by mass . The density of 98% ethanol was 0.79 g
mL-1 and the density of the unknown concentration of aqueous HNO 3 was
1.4 g mL-1. What was the original concentration of HNO 3, in w/w, in the
0.70 mL reagent the student used for the nital solution preparation ?
A) 63% B) 66% C) 70% D) 73% E) 93%
13) A student placed 3 identical metal cubes into an oven and heated them to the
same final temperature. The student entirely submerged each of the 3 cubes
in separate beakers as shown in the d iagram below. All solutions had
approximately the same density and all were at room temperature before
adding the metal cubes. The maximum tem perature compared as follows:
Tmax beaker B > T max beaker A > T max beaker C.
Which of the following is true about the relationship of the spe cific heat
capacities of solutions A, B and C?
A) cA > c C > c B
B) cC > c B > c A
C) cC > c A > c B
D) cB > c A > c C
E) cB > c C > c A
constitutional
isomers stereoisomers constitutional
isomers stereoisomers
A) 2 2 D) 4 0
B) 3 2 E) 3 0
C) 4 2
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14) The organic compound below is a local anesthetic developed over one
hundred years ago to treat pain. What is the correct IUPAC name of the
compound?
A) methyl 4 -hydroxy -5-aminobenzoate
B) methyl 3 -hydroxy -4-aminobenzoate
C) methyl 3 -aminophenolate
D) methyl 3 -amino -4-hydroxybenzoic aci d
E) methyl 3 -amino -4-hydroxybenzoate
15) Given the following standard reduction po tentials.
Which of th e following statement(s ) is/are true?
I. Na is the most easily oxidized
II. Cu is the best reducing agent.
III. Cu
2+ cann ot be spontaneously reduced by Al
IV. Na+ has a greater attraction for electrons than Al3+
A) I only B) I and II only C) I, II and III only
D) II and IV only E) II, III, and IV only
16) Which of the following should have the same electron arrangement as BF 4–
around the central atom?
A) IF4– B) XeCl 4 C) C lF4+ D) SF 4 E) CCl 4
17) A student adds t wo moles of liquid water initially at 273 K to three moles
of liquid water at 363 K in a perfectly insulated co ntainer. The total volume
of water remains co nstant . Assume that the molar heat capacity of liquid
water is constant and independent of temperature. What is the final
equilibrium temperature of the water?
A) 298 K B) 309 K C) 318 K D) 327 K E) 358 K
18) One mole of uranium -238 deca ys slowly. If uranium -238 decays according
to first order kinetics , after how many half -lives is there likely only one
atom of uranium -238 left?
A) 85 B) 10 C) 238 D) 41 E) 79
19) Consider the structures and associated pKa values in the table below.
Which statement below the table best explains the pKa values observed ?
A) The electron density on the ionizable proton is diminished by
induction , which increases the strength of the acid
B) The presence of electron -donating alkyl groups increases the stability
of the conjugate base, increasing the strength of the acid
C) Resonance stabilization of the conjugate base increases the strength of
the acid
D) The presence of el ectronegative atoms decreases the stability of the
conjugate base, decreasing the strength of the acid
E) Resonance stabilization of the conjugate base decreases the strength of
the acid
Cu2+ + 2 e– → Cu Eo = + 0.34 V
Al3+ + 3 e– → Al Eo = – 1.66 V
Na+ + e– → Na Eo = – 2.71 V
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20) H2PO 4–(aq) + H 2O(l) ⇌ HPO 42–(aq) + H 3O+(aq) Ka = 6.2 x 10–8
H3PO 4 (aq) + H 2O(l) ⇌ H2PO 4–(aq) + H 3O+(aq) Ka = 7.9 x 10–3
H3COOH (aq) + H 2O(l) ⇌ CH 3COO–(aq) + H 3O+(aq) Ka = 1.8 x 10-5
Using the equilibria below , determine which of the following combinations
of solutions will generate a buffer with a pH of approximately 5?
A) 50 mL of 0.10 mol L–1 Na2HPO 4 + 100 mL of 0.10 mol L–1 NaH 2PO 4
B) 100 mL of 0.1 0 mol L–1 NaCH 3COO + 100 mL of 0.10 mol L–1 NaOH
C) 100 mL of 0.1 0 mol L–1 NaH 2PO 4 + 100 mL of 0.1 0 mol L–1 HCl
D) 100 mL of 0.1 0 mol L–1 NaH 2PO 4 + 100 mL of 0.1 0 mol L–1 NaOH
E) 100 mL of 0.1 0 mol L–1 CH 3COOH + 50 mL of 0.1 0 mol L–1 NaOH
21) The reaction mass efficiency (RME) helps a student determine how much
reactant material a product contains at the end of a chemical reaction. RME
is calculated as follows:
mass of desired product
(total input mass - mass of recycled material)reaction mass
efficiencyx 100%=
0.205 moles of phenylboronic acid (C 6H7BO 2) was reacted with 0.205 moles
of 4-iodophenol (C 6H5IO) and 0.615 moles of potassium carbonate to form
0.185 moles of 4 -phenylphenol (shown below). 300 mg of catalytic
palladium o n carbon was used and completely recycled.
A) 18.4 % B) 20.3 % C) 24.2 % D) 25.5% E) 35.1 %
22) The crossover temperature for a r eaction is the temperature at which a
chem ical reaction changes from occurring spontaneous ly to being non -
spontaneous . For a particular chemical reactio n, the entropy change is
-157 J mol
-1·K-1 and the enthalpy change is -82 kJ mol-1. What is the
crossover temperature for the reaction?
A) 0 K B) 75K C) 239 K D) 522K E) There is no
crossover temperature
for this
reaction 23) One source of oxygen in chemical oxygen generators for emergencies in
submarines and aircraft is potassium perchlorate, which decomposes as
follows:
KClO 4 (s)→ KCl (s) + 2 O 2 (g)
Assume ideal gas behaviour for the reaction, a temperature of 25 .0°C and a
pressure of 1 .00 bar. If 138.5 g rams of potassium perchlorate decompose
inside an oxygen generato r, what volume of oxygen does the reaction
generate if there is a 78 .0% yield ?
A) 9.65 L B) 19.3 L C) 24.8 L D) 38.6 L E) 49.6 L
24) Metal sulfides have considerable applications in industry, including their
use as componen ts of semiconducting materials. Consider the following
equilibrium, where M represents a transition metal:
MS(s) ⇋ M2+(aq) + S2-(aq)
S2- ions liberated in solution readily react and form HS- and OH- according
to the following equilibrium:
S2-(aq) + H 2O(l) ⇋ HS-(aq) + OH-(aq)
Which of the followin g will increase the solubility of the metal sulfide?
A) Increasing the concentration of OH– by adding a strong base
B) Adding a strong acid
C) Increasing the amount of the metal sulfide present
D) Diluting the solution present
E) Adding MCl 2
25) The thermochemical reaction for the formation of water vapour is:
H
2 (g) + ½ O 2 (g) → H 2O (g) ΔH f° = –241 .8 kJ mol-1
The thermochemic al reaction of diatomic element X with oxygen is :
X2 (g) + O 2 (g) → 2X O (g) ΔH° = +180.8 kJ mol-1
If the enthalpy of the reaction of of the tri -hydride of element X with oxygen is:
4 XH3 + 5 O 2 (g) → 4 XO (g) + 6 H 2O (g) ΔH ° = –904.4 kJ mol-1
What is the enthalpy (in kJ ) of the synthesis of 2 mols of the tri- hydride of
element X from the reaction of X 2 (g) and hydrogen gas?
A) –996.8 B) –391.2 C) –513.2 D) – 92.4 E) – 964.4
End of Part A of the contest
Go back and check your work
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THE CANADIAN CHEMISTRY CONTEST 201 9
PART A – MULTIPLE CHOICE QUESTIONS (60 minutes)
All contestants should attempt this part of the conte st before proceeding to Part B and/or Part C .
The only reference material allowed is the CIC/CCO Periodic Table provided . You must complete answers on the Scantron Sheet p rovided . A
scientific calculator is allow ed. No phones or any devices tha t can be used for communication are allowed.
1) A solution is 0.0240 mol L-1 KI and 0.0146 mol L-1 MgI 2. What volume of
water should be added to 100. 0 mL of this solution to produce a
solution with [I-] concentration of 0.0500 mol L-1?
A) 106.4 mL B) 53.2 mL C) 26.6 mL D) 13.3 mL E) 6.4 mL
.
2) The boiling points of the compounds acetic acid (CH 3COOH), 1 -pentanol
(C5H11OH), dibutyl ether (C 8H18O) and dodecane (C 12H26) increase in
that order. Which of the following statements provides the best
explanation for this increase?
A) The London dispersion forces increase
B) The hydrogen bonding increases
C) The dipole -dipole forces increase
D) The chemical reactivity increases
E) The number of carbon atoms increases
3) Health Canada recommends th at women between the ages of 12 and 45
consume 400 micrograms of folic acid (C 19H19N7O6) per day, which
reduces the risk of neural tube defects during pregnancy. How many
moles of folic acid are equivalent to 400 micrograms?
A) 1.10 mmol B) 0.177 mol C) 0.906 mol
D) 0 .906 mmol E) 9.06 x 10-7 mol
4) An unknown amino acid contains 9.5 % nitrogen by mass as determined
by elemental analysis . Which of the following could be the unknown
amino acid ?
A) arginine C 6H14N4O2 B) cysteine C 3H7NO 2S
C) histidine C 6H9N3O2 D) glutamic acid C 5H9NO 4
E) glycine C 2H5NO 2
5) The melting point of CaS is higher than that of KCl. Explanations for this
observation include which of the following?
I. Ca2+ is more positively charged than K+.
II. S2– is more negatively charged tha n Cl–.
III. The K+ ion is smaller than the Ca2+ ion.
A) II only B) I and II only C) I and III only
D) II and III only E) I, II, and III
6) Fluorine is the most electronegative element on the periodic table. As a
result it always forms polar bonds with other non -metals. Despite this,
which of the following fluorine containing compounds would be a non -
polar molecule?
A) SF4 B) PF 3 C) IF 5 D) BrF 3 E) XeF 4
7) Ronald James Gillespie, who developed Valence Shell Electron Pair
Repulsion (VSEPR) theory, isolated the superacid fluorosulfuric acid
(HSO 3F) when he combined fluorinated compounds with concentrated
sulfuric acid, creating brightly coloured solutions. Which of the
following best describes the molecular shape of fluorosul furic acid, as
predicted by VSEPR theory?
A) See saw B) Trigonal bipyramidal C) Tetrahedral
D) Square planar E) Trigonal pyramidal
8) Vinegar used as a cooking ingre dient, or in pickling, is a solution of 5%
acetic acid (CH 3COOH) by mass in solution with water. The pKa = 4.76
for acetic acid at 25C. E valuate the pH of vinegar at 25 C.
A) 4.80 B) 4.15 C) 2.92 D) 2.4 2 E) 2.24
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9) The ionization energies for period 3 element X are listed in the table
below.
Ionization Energies for element X (kJ mol-1)
First Second Third Fourth Fifth
580 1,815 2,740 11,600 14,800
Based on the data, which statement about element X is FALSE ?
A) Its most common oxidation state is +3
B) It is displaced from aqueous solution by copper metal
C) It is the most abundant metal in the Earth’s crust
D) Its oxide is insoluble in water
E) It is a lustrous metal
10) Stavzor (structure below) is a medication primarily used to treat epilepsy and
bipolar disorder.
O HO
Stavzor
A well -known substance with a characteristic odour of bananas ( A) is a
constitutional isomer of Stavzor. Which of the following is a possible
structure for A?
O
O
O
OO O O OH
O O(a) (b) (c)
(d) (e)
11) Given the following electrochemical cell data:
Cell 1 Cd(s) | Cd2+ (1.0M) || Cu2+ (1.0M) | Cu(s) Eo = +0.74 V
Cell 2 Zn(s) | Zn2+ (1.0 M) || Cu2+ (1.0 M) | Cu(s) Eo = +1.10 V
Cell 3 Zn(s) | Zn2+ (1.0 M) || Cd2+ (1.0 M) | Cd(s)
Determine the standard cell potential for Cell 3.
A) – 0.36 V B) 0.36 V C) –1.84 V
D) –0.18 V E) 0.18 V
12) Lead (II) sulfate can decompose into lead (II) sulfite and oxygen gas
when he ated. If the reaction generates 2.25 g of oxygen gas , wh at mass
of lead (II) sulfate reacted? Assume 100% yield in this reaction.
A) 42.6 g B) 21.3 g C) 20.2 g D) 10.7 g E) 4.50 g
13) A stud ent combines 75 mL of 0.500 mol L-1 hydrochloric acid with
55 mL of 0.125 M KOH. What is the pH of the resulting solution?
A) 0.30 B) 0.39 C) 0.63 D) 1.51 E) 7.00
14) A system undergo es a reversible cyclic process and proceeds through
a series of thermodynamic processes, exchanging heat and work with
its surroundings and ultimately returning to its original state . Which
one of the following statements is true? Assume that the surroundings
are muc h, much larger than the system .
A) Ssurroundings > 0 B) q > 0 C) q < 0 D) q = w = 0 E) S > 0
15) The thermite reaction is the reaction of aluminum metal and iron (III)
oxide:
2 Al (s) + Fe 2O3 (s) Al2O3 (s) + 2 Fe (s) H = –852 kJ
A teacher does a demonstration with 1.00 mol of iron (III) oxide and
2.00 m ol of aluminum metal both initially at 25 .0 C. If the combined
specific heat of the products is 0.800 J g-1 C-1 over a wide range of
temperatures, what is the final temperature of the products?
A) 3550C B) 4960 C C) 5010 C D) 6470 C E) 6500C
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16) The compound acetanilide is important in the industrial synthesis of
several dyes. Acetanilide (mol. wt. = 135.16) can be made in the
laboratory by a reaction between aniline and excess acetic anhydride
which has a yield of 61.5%:
aniline acetic anhydrideNH2
O O
O
acetanilideO
N
H+
Aniline and acetic anhydride are both liquids which have densities of
1.219 g mL-1 and 1.082 g mL-1 respectively.
What volume of aniline was used in this reaction if the recorded mass of
acetanilide product was 7.14 g?
A) 4.03 mL B) 9.75 mL C) 4.92 mL
D) 5.99 mL E) 6.56 mL
17) One of the Twelve Principles of Green Chemistry is that “synthetic
methods should be designed to maximize the incorporation of all
materials used in the process into the final product”. One way to
consider this is to calculate the atom economy (AE) of a ch emical
reaction where AE is defined as follows:
𝑎𝑡𝑜𝑚 𝑒𝑐𝑜𝑛𝑜𝑚𝑦 =𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑑𝑒𝑠𝑖𝑟𝑒𝑑 𝑝𝑟𝑜𝑑𝑢𝑐𝑡
𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑎𝑙𝑙 𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠×100%
The ato m economy of the reaction in the previous question (#16) is:
A) 61.5% B) 69.2% C) 100% D) 68.9% E) 74.4%
18) Given the following set of equilibria and their respective constants
NH 4+ ⇌ H+ + NH 3 Ka = 5.6 x 10–10
H2CO 3 ⇌ H+ + HCO 3– Ka1 = 4.2 x 10–7
HCO 3–⇌ H+ + CO 32– Ka2 = 2.4 x 10–8
what would the equilibrium constant be for the reaction below?
H2CO 3 + 2 NH 3 ⇌ (NH 4)2CO 3 K = ?
A) 1.8 x 10–5 B) 4.4 x 10–7 C) 9.0 x 10–6
D) 3.2 x 104 E) 3.1 x 10–5
19) The subshell filling order used for the quantum mechanical model of
the atom is an approximation of th e relative subshell energies, which
assumes the energies remain fixed. However, there are exceptions to
the Aufbau Principle . Which of the following is the correct ground state
configuration of an element found on the periodic table ?
A) [Ar] 4s1 3d5 B) [Ar] 4s2 3d4 C) [Ar] 4s2 4d4
D) [Ar] 4s2 4p4 E) [Ar] 4s1 4p5
20) A vessel contains 2.50 mol of O 2 gas, 0.50 mol of N 2 gas and 1.00 mol of
CO 2 gas. The total pressure is 200 kPa. The partial pressure exerted by
the O 2 in the mixture is:
A) 25 kPa B) 50 kPa C) 100 kPa D) 125 kPa E) 150 kPa
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21) The O 2 (g) produced in the decomposition of 3.275 g mixture of
potassium chlo rate and potassium chloride which is 65.82% KClO 3 by
mass is collected over water at 21.0 C. Assume ideal gas conditions. I f
atmospheric pressure is 753.5 mmHg, water vapour pressure at 21.0 C
is 18.7 mmHg, once the pressure in the gas collection vessel was
equalized with atmospheric pressure , how many milliliters of O 2 gas
would be produced according t o the reaction:
2 KClO 3 (s) 2 KCl (s) + 3 O 2 (g)
A) 130 mL B) 439 mL C) 563 mL
D) 658 mL E) 1320 mL
22) The equilibrium CO (g) + NO 2 (g) ⇌ CO 2(g) + NO (g) is established in
four different, but identical containers . Each container started with a
different composition as follows :
Container CO (mol) NO 2 (mol) CO 2 (mol) NO (mol)
1 1 1 0 0
2 1 0 1 1
3 1 1 1 0
4 0 1 1 1
5 1 1 1 1
After equilibrium is established, which container would have the largest
concentration of CO (g)
A) 1 B) 2 C) 3 D) 4 E) 5 23) For the reaction H 2 (g) + I 2 (g) ⇌ 2 HI (g) H = +52.96 kJ.
Which of the following statement(s) is/are correct?
I. The heat of formation of 1 mol of HI is +26.48 kJ
II. As the temperature increases, the reaction will proceed to the
right
III. As the pressure increases, the reaction will proceed to the
right
A) I only B) I and II only C) I, II and III
B) II and III only E) III only
24) Calculate G at 25 C for the reaction given the data below
4 HCl (g) + O 2 (g) 2 Cl 2 (g) + 2 H 2O (g) H = –114.4 kJ
𝑆𝐶𝑙2𝑜= 223. 0 J mol-1 K-1 𝑆𝐻2𝑂𝑜= 188 .7 J mol-1 K-1,
𝑆𝑂2𝑜= 205 .0 J mol-1 K-1 𝑆𝐻𝐶𝑙𝑜= 186.8 J mol-1 K-1
A) + 14.4 kJ B) –111.18 kJ C) + 3105.6 kJ
D) + 38 kJ E)– 76.0 kJ
25) For the reaction 2 NO (g) + Cl 2 (g) 2 NOCl (g) the t able below
provide s experimental data for 3 different reactions.
Experiment [NO] (mol L-1) [Cl 2] (mol L-1) Initial Rate
(mol L-1s-1)
1 0.0125 0.0128 1.14 x 10-5
2 0.0125 0.0511 4.55 x 10-5
3 0.0250 0.0255 9.08 x 10-5
What is the rate constant for the reaction?
A) 140 L mol-1 s-1 B) 0.0714 L mol-1 s-1 C) 5.70 L2 mol-2 s-1
D) 0.562 L mol-1 s-1 E) 1. 39 L2 mol-2 s-1
End of Part A of the contest
Go back and check your work
KClO 3
O2
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THE CANADIAN CHEMISTRY CONTEST 2017
PART A – MULTIPLE CHOICE QUESTIONS (60 minutes)
All contestants should attempt this part of the conte st before proceeding to Part B and/or Part C
The only reference material allowed is the CIC/CCO Periodic Table provided . You must complete answers on the Scantron Sheet p rovided . A
scientific calculator is allow ed. No phones or any devices tha t can be used for communication are allowed.
1) Which of the following metals should be label led with the WHMIS symbol
for flammable substances ?
A) Al B) Ni C) Mg D) Pb E) Hg
2) A reaction AB + C, undergoes a single displacement reaction . Which of the
following would be a product of the reaction if A is a group 2 metal and C
is a group 1 metal?
A) CA 2 B) B C) CB D) A 2 E) C 2B
3) In which of the following situations could hydrogen bonding occur
between H2O and the solute ?
A) ammoni a gas dissolved in water
B) hydrogen gas dissolved in water
C) carbon dioxide gas in water
D) methane gas dissolved in water
E) hydrogen sulfide gas dissolved in water
4) The exothermic thermite reaction between iron (III) oxide and aluminum
metal occurs as follows:
Fe2O3 (s) + 2Al (s) 2Fe (s) + Al 2O3 (s)
If 8.0 g of iron (III) oxide is combined with 5.4 g of aluminum metal, what
mass of iron metal will be produced?
A) 2.8 g B) 5.6 g C) 8.0 g D) 11 g E) 14 g
5) Which of the following molecules has a molecular dipole?
A) XeF 4 B) SeF 4 C) CF 4 D) SiF 4 E) KrF 2
6) Given the following heats of formation, what is the enthalpy of combustion
for toluene shown in the following equation?
C7H8 (l) + 9 O 2 (g) 7 CO 2 (g) + 4 H 2O (l)
Substance Hf (kJ mol–1) Substance Hf (kJ mol–1)
C7H8 (l) +12.0 H2O (l) -286
CO 2 (g) -394 O2 (g) 0
A) 680 kJ mol–1 B) 692 kJ mol–1 C) –692 kJ mol–1
D) –389 0 kJ mol–1 E) –3914 kJ mol–1
7) Artificial photosynthesis involves splitting water with solar energy. This
clean energy reaction is: 2 H2O (l) 2 H2 (g) + O 2 (g)
Which of the following statements about the splitting of water is incorrect :
A) The oxidation state of hydrogen in water is +1
B) The oxidation state of hydrogen gas is 0
C) Water is the oxidizing and reducing agent
D) The oxidation state of oxygen in water is – 1
E) The oxygen atoms are oxidized in this process
8) Cows are one of the most significant sources of methane (CH 4) emitted
into the atmosphere . The average cow produces 259 grams of methane
per day. The lower explosive limit (LEL) is the lowest concentration at
which there is a risk of an explosion . For methane , the LEL at SATP is 5.0%
v/v. Assuming a constant rate of methane emission from cow s, how long
would it be safe to keep a n average cow in a 10.0 m3 enclosed space at
25C and 100 kPa before there is a risk of explosion? The molar volume of
a gas at SATP is 24.8 L.
A) 30 hours B) 60 hours C) 90 hours D) 60 0 hours E) 900 hours
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9) Predict the conditions maximizing the rate of hydrogen gas production in
the steam methane reforming reaction:
CH 4 (g) + H2O (g) ⇌ CO(g) + 3H 2 (g) ∆H = +206 kJ mol-1
A) Low temperature, high pressure and a catalyst
B) Low temperature, low pressure and a catalyst
C) Low temperature, high pressure and no catalyst
D) High temperature, high pressure and a catalyst
E) High temperature, low pressure and a catalyst
10) The molality (m) of a solution is defined as the number of moles of solute
per kilogram of solvent. Lauryl alcohol (C 12H26O) is prepared from coconut
oil and is used to make sodium lauryl sulfate, a synthetic detergent. What is
the molality of a solution of 17.1 g lauryl alcohol dissolved in 3.21 moles of
ethanol (C 2H6O)?
A) 0.310 m B) 0. 621 m C) 0.842 m D) 1.41 m E) 2.52 m
11) The following data were taken for the addition of solid barium fluoride to
enough water to make 100.0 mL of solution. What is the K sp of barium
fluoride :
BaF 2 (s) ⇌ Ba2+(aq) + 2 F–(aq) ?
Mass of solid
added (g) Mass of solid
dissolved (g) Mass of solid
undissolved (g)
0.100 0.100 0
0.200 0.200 0
0.300 0.300 0
0.400 0.319 0.081
A) 1.30 x 10–1 B) 3.25 x 10–2 C) 2.41 x 10-5
D) 6.03 x 10–6 E) 6. 03 x 10–9
12) The electron configuration 1s22s22p63s23p64s23d8 corresponds to which
of the following?
A) Ni B) Ni2+ C) Fe D) Fe2+ E) Zn2+
13) What is the correct relationship between the following two organic
substances?
A) non -superimposable mirror images
B) identical
C) Structural , non -geometric isomers
D) hydrocarbons with different molecular formulae
E) geometric isomers
14) Canada is a world -leader in the producti on of radionuclides such as
technetium -99m (99mTc), which is used to diagnose bone diseases. 99mTc
has a relat ive atomic mass of 98.91 amu and exhibits first -order
radioactive decay with a half -life of 6.00 hours . If 8.62x10-12 mol of sodium
pertechnetate (Na99mTcO 4) is injected into a 75 kg adult patient, what
mass of 99mTc would remain after 24 hours?
A) 1.46x10-9 g B) 2.13x10-10 g C) 3.66x10-11 g
D) 5.33x10-11 g E) 9.15x10-11 g
15) The f irst electron affinity (EA) for any element X is represented by the
equation: X (g) + e– X– (g) + EA 1. Negative values for electron affinity
indicate that energy is released when an atom gains an electron. Most
highschool textbooks teach the trend that electron affinity increases
across a period. According to the table below, which of the following
statemen t(s) is/are true?
Element Li Be B C N O F Ne
EA (kJ mol–1)
–59.6 0 –26.7 –153.9 –7 –141 –328 0
I. The absolute value of the energy released when an atom gains an
electron is always lower for metals than non -metals
II. Metals cannot form anions
III. Neutral atoms with complete subshells do not release energy
during anion formation
A) I only B) II only C) III only
D) I and II only E) I and III only
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16) When aqueous magnesium chloride is added to a solution of silver nitrate,
silver chloride is precipitated according to the following unbalanced
chemical equation:
AgNO 3 (aq) + MgCl 2 (aq) AgCl (s) + Mg(NO 3)2 (aq)
If excess magnesium chloride is added to the silver nitrate solution, which
of the following diagrams best depicts the balanced chemical reaction after
it has gone to completion?
17) The process mass intensity (PMI) allows chemists to calculate how much
material is used when generating a target amount of product in a chemical
reaction. PMI is expressed as follows:
PMI = [(mass of all input mat erials) / (mass of desired product)]
To synthesize moclobemide, an anti -depressant pharmaceutical,
0.00381 moles of 4 -(2-aminoethyl)morpholine (C 6H14N2O) is dissolved in
20.0 mL of triethylamine (density: 0.726 g mL–1) and 0.00384 moles of
4-chlorobenzo yl chloride (C 7H4Cl2O) is added. After rapid stirring for
30 minutes, 10.0 mL (density: 1.00 g mL–1) of water is added followed by
10.0 mL of dichloromethane (density: 1.325 g mL–1) and then the mixture
transferred to a separatory funnel. After extraction, the dichloromethane is
dried with 5.0 g of magnesium sulfate. At the end of the process, 0.826 g of
pure moclobemide is recovered.
The PMI for this reaction is:
A) 43.8 B) 47.1 C) 49.3 D) 53.2 E) 55.9 18) A closed 600.0 mL flask contains solid mercuric oxide and air initially at
21.0C and 101.3 kPa. When heated, mercuric oxide decomposes
completely according to the reaction:
2 HgO (s) 2 Hg (s) + O 2 (g)
After heating, the flask is at a temperature of 75.2C and has a
pressure of 205.5 kPa . What mass of mercury metal is in the flask
when the reaction is complete?
A) 7. 11 g B) 4.33 g C) 3. 56 g D) 17. 1 g E) 8. 66 g
19) When you do extreme exercise, your body converts glucose to l actic acid
(HCH 3H5O3). Lactic acid has a K a= 1.38 x 10-4. Buffer systems maintain the
pH of yo ur blood at 7.4 during exercise. Without buffers, what would your
blood pH range be at equilibrium if 4.00 x 10-3 mol L-1 of lactic acid
dissociated according to the equation:
HCH 3H5O3 (aq) + H 2O(l) ⇌ CH 3H5O3–(aq) + H 3O+(aq)
A) 2<pH<3 B) 3<pH<4 C) 4<pH<5 D) 5<pH<6 E) 6<pH<7
20) Molecular hydrogen is an essential feedstock for the industrial production
of ammonia. Due to the impracticality of transporting molecular hydrogen,
it is produced at the site of ammonia production through steam methane
reforming , as follows:
H2O (g) + CH 4 (g) ⇌ CO (g) + 3 H2 (g)
Given a starting steam (H 2O) to methane (CH 4) mole ratio of 2.5:1.0, an
initial pressure of 28 atm, no starting carbon monoxide or molecular
hydrogen , determine the Kp if 62.5% of the initial methane is converted to
products. Assume ideal gas behaviour.
A) 1.7 x 100 B) 1.4 x 101 C) 2.1 x 102
D) 3.8 x 102 E) 5.6 x 103
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21) If the rate law for an equation A + B + C ABC is
Rate= k [A]0[B][C]2 and the reactant concentration of all of the reactants
doubles, by what factor does the rate of reaction increase?
A) 3 B) 4 C) 6 D) 8 E) 10
22) When solid tin is added to a solution of silver nitrate, a single
displacement reaction occurs to generate si lver metal.
If 1.2 g of tin is added to 50 mL of 0.20 M silver nitrate solution, which of
the following diagrams best describes the reaction once it has gone to
completion?
23) Hypophosphatemia is a condition of abnormally low phosphate
concentration in the human blood stream, occurring in 2% of hospitalized
patients. The treatment includes administration of intravenous phosphate
buffer to increase blood phosphate concentration. However, since
phosphoric acid is a weak acid, care needs to be taken to maintain blood
pH at 7.4. Given the data below, and assuming similar concentrations of
both species of the acid -base conjugate pair , determine the most e ffective
buffer combination to achieve a pH o f 7.4.
H3PO 4–; Ka = 7.2 x 10-3 H2PO 4–; Ka = 6.3 x 10-8 HPO 42–; Ka = 4.2 x 10-13
A) H3PO 4 and H 2PO 4– B) H 3PO 4 and HPO 42– C) H 2PO 4– and HPO 42–
D) H2PO 4– and PO 43– E) HPO 42– and PO 4
24) Dopamine is a neurotransmitter found in the human brain that is involved
in motor control. The IUPAC name for dopamine is 4 -(2-
aminoethyl)benzene -1,2-diol. Which of th e following structures represents
a molecule of dopamine?
NH2 HOHOA)
HOHO
NH2NH2 HO
OH
HOHO
NH2NH2 HOHO
B) C)
D) E)
25) Given the following half reactions and galvanic cell diagram
K+ (aq) + e– K (s) E = –2.93 V
Cu2+ (aq) + 2e– Cu (s) E = +0.34 V
Cr3+ (aq) + 3e– Cr (s) E = –0.74 V
what is the theoretical potential of the cell?
A) 0.40 V B) 1.08 V
C) 1.85 V D) 2.19 V
E) 2.50 V
End of Part A of the contest
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THE CANADIAN CHEMISTRY CONTEST 201 8
PART A – MULTIPLE CHOICE QUESTIONS (60 minutes)
All contestants should attempt this part of the conte st before proceeding to Part B and/or Part C .
The only reference material allowed is the CIC/CCO Periodic Table provided . You must complete answers on the Scantron Sheet p rovided . A
scientific calculator is allow ed. No phones or any devices tha t can be used for communication are allowed.
1) Sodium hydroxide (NaOH) is commonly used in high school labs.
NaOH is a WHMIS category 1 health hazard causing severe eye,
skin and respiratory tract effects . NaOH is hygroscopic and
readily absorbs moisture from the ai r. Any prepared solution of
NaOH should be standardized to determine its precise concentration .
You have the glassware V, W, X, Y, Z below and solid pellets of NaOH .
V W X Y Z
Which of the choices provides the safest, most efficient method of
preparing exactly 100.0 mL NaOH of approximately 1M before
standardizing the solution with 0.500 M oxalic acid (C 2O4H2)? Assume
the NaOH solution is mixed thoroughly once prepared.
A) Filling V with approximately 50 mL water, add ing 4.0 g NaOH ,
dilut ing to precisely 100 mL in V .
B) Filling W with approximately 50 mL water, add ing 4.0 g NaOH and
dilut ing to 100 mL in W .
C) Placing 4.0 g NaOH in X then a dding 100 mL of water to X using Y.
D) Placing 4.0 g NaOH in W then a dding 100 mL of water to W using Z .
E) Filling X with precisely 50 mL of water using Z, adding 4.0 g of NaOH
and adding an additi onal 50 mL of water using Z.
2) Vitamin C (C 6H8O6) supplements often come in 500 mg tablets. If a
person consumes one 500 mg tablet of Vitamin C, how many moles of
Vitamin C would they be consuming?
A) 2.84 x 10-3 B) 8.81 x 10-2 C) 1.00
D) 2.84 E) 88.1
3) What is the mole percent of a solution of ethanol (C2H5OH) which
consists of 71.0 g of ethanol for every 12.8 g of water present?
A) 2.17 % B) 12.3 % C) 31.6 %
D) 68.4 % E) 84.7 %
4) A 2.0 L balloon initially holds 3.0 mol of helium. When 3.0 mol of helium
are added , the volume of the balloon increase s to 4.0 L and the
temperature remains unchanged. Which expression correctly
describes the final pressure of the system in terms of the initial
pressure, P? Assume Ideal Gas behaviour.
A) P B) 2P C) 3P D) 4P E) 6P
5) A compound is composed of element X and hydrogen. Analysis shows
the compound to be 79.89 % X by mass, with three times as many
hydrogen atoms as X atoms per molecule. Which element is element X?
A) He B) C C) N D) P E) S
6) To increase strength and hardness when forging knives and blades, hot
steel can be quenched by rapidly cooling in water. A 454 g steel blade is
heated to a uniform temperature, and then quenched in 2000 mL of
25.0 oC water. If the steel blade loses 173.7 k J of heat during the
quenching process, what is the final temperature of the water? The
specific heat capacity of water is 4.18 J g–1 oC–1. Assume no water
evaporates during the quenching process.
A) 16.9 oC B) 20.7 oC C) 41.9 oC D) 45.8 oC E) 91.5 oC
100 mL 100 mL
10 mL 50 mL
125 mL
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7) Table 1: Successive Ionization Energies of 3rd Period Elements
Element IE1
(kJ –1 mol –1) IE2
(kJ –1 mol –1) IE3
(kJ –1 mol –1) IE4
(kJ –1 mol –1) IE5
(kJ –1 mol –1)
V 787 1577 3231 4356 16091
W 738 1451 7733 10540 13630
X 1251 2297 3822 5158 6540
Y 496 4562 6912 9543 13353
Z 578 1817 2745 11575 14830
Based on this information, which of the following statements is FALSE ?
A) Y is sodium B) X has the smallest radius
C) W is an alkali ne earth metal D) Z forms the largest cation
E) V is a semi -metal
8) Hydrofluoric aci d reacts with potassium hydroxide according to the net
ionic equation :
HF (aq) + OH– (aq) F– (aq) + H 2O (l)
If 5.0 mL of 1.0 M KOH are added to 25.0 mL of 2.0 M HF, what is the pH
of the resulting solution? The K a of HF is 7.2 x 10–4.
A) 1.42 B) 1.4 8 C) 1.66 D) 2.19 E) 2. 84
9) For a reaction A + B —> Products, the rate law is : rate= k[A][B]2. For
containers with the same volume, which mixture would have the
highest rate of reaction according to this rate law? The legend indicates
which molecule is A and which is B.
A) B) C) D) E)
10) Tigan (structure below) is an antiemetic drug used to prevent nausea
and vomiting. It is often prescribed for patients with gastroenteritis ,
medication -induced nausea, and other illnesses.
O
O
O
ON
H
ON
Tigan
Which of the following functional groups are present within Tigan?
A) amine, ether, amide B) amine, ketone, ether, alcohol
C) ether, aldehyde, amine D) alcohol, amine, ether, amide
E) ketone, amine, ether
11) How many carbon (C) and hydrogen (H) atoms are present in a
molecule of Tigan?
A) 21 C and 28 H atoms B) 21 C and 27 H atoms
C) 16 C and 28 H atoms D) 20 C and 28 H atoms
E) 21 C and 29 H atoms
12) Which of the following would increase the K eq of the reaction below?
HCO 3– (aq) + H 3O+(aq) ⇌ H2CO 3(aq) + H 2O(l)
A) Increasing the pH B) Decreasing the pH C) Adding water
D) Adding H2CO 3 E) None of the options
provided
13) In 1962, at the University of British Columbia, Neil Bartlett shattered
conventional chemistry wisdom and synthesize d xenon tetrafluoride ,
the first binary compound of a noble gas. Which of the following
statements is/are true about a molecule of xenon tetrafluoride?
I) The molecule has no lone pairs on the central atom
II) The molecule has a tetrahedral geometr y
III) The molecule has no net molecular dipole
A) I only B) II only C) III only D) II and III E) I, II and III Legend
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14) For the titration of HNO 3
with KOH , which of the
following receiving flasks
best depicts the ions present
at the endpoint as indicated
on this titration curve ?
A) B) C) D) E)
15) What is the pH of a solution created by mixing 1000.0 mL of 0.120 M
HNO 3 (aq) with 250.0 mL of 0.750 M HBr (aq)?
A) 1.268 B) 0.000 C) 0.060 D) 0.512 E) 0.609
16) The smell often associated with public swimming pools comes from
chloramines. The reaction of hypochlorous acid with ammonia from
human urine will produce monochloramine (NH 2Cl) as follows:
HOCl(aq) + NH 3(aq) ⇌ NH 2Cl(aq) + H 2O(l) Keq = 1.47 x 1011
One part per million (ppm) is a mg L–1. A typical public swimming
pool volume (750,000 L) contains 75.0 L of urine . The concentration
of ammonia in 1 L of urine is 0.200 M. If the concentration of
hypochlorous acid in pool water is 1.00 ppm, determine the
concentration (in ppm) of monochloramine (NH 2Cl) in a typical public
swimming pool. Assume the mass of 1 L of pool water is 1 kg.
A) 1.91 B) 1.64 C) 1.03 D) 1.00 E) 0.98 17) Use th e information provided below to calculate the enthalpy of
reaction when one mole of chlorine trifluoride gas decomposes into
one mole of chlorine monofluoride gas and one mole of gaseous
fluorine.
2 ClF(g) + O 2(g) Cl2O(g) + F 2O(g) ΔH = + 167.4 kJ
2 ClF 3(g) + 2 O 2(g) Cl2O(g) + 3 F 2O(g) ΔH = + 341.4 kJ
3 F 2O (g) 3 F 2(g) + 3
2 O2(g) ΔH = + 65.1 kJ
A) -217.4 kJ B) +25.0 kJ C) +68.4 kJ D) +108.7 k J E) 573.9 kJ
18) Consider the following reaction, where the starting compound is
treated with an unknown reagent over a catalytic surface to form the
product:
Which two terms can be used to describe this process?
A) hydrogenation, elimination B) hydration, addition
C) hydrogenation, substitution D) hydrogenation, addition
E) hydration, s ubstitution
19) A quantity of solid material weighing 6.445 g was obtained from a
hazardous waste facility. A 1.545 g sample of this material was
analyzed for barium content by dissolving in water and then adding
sodium sulfate. The insoluble barium sulfate precipitate was dried, and
a total of 73.8 mg of BaSO 4 was collected. What percentage by mass of
the sample is barium?
A) 0.281 % B) 0.674 % C) 2.81 % D) 4.02 % E) 6.74 %
20) Which of the following accurately represents a trend in atomic radius ?
A) F > Cl > Br B) F > O > N C) Cl- > Na+ > Mg2+
D) Ca2+ > K+ > Ca E) O2- > S2- > Cl
?
catalyst
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21) 96.5% of water available on Earth is sea water.
Desalination of seawater could provide a solution to the
global fresh water crisis. There are many challenges
that chemist s face in achieving desalination. Given the
half reactions below and the setup of the electrolytic
cell to the right, what would happen with an
applied potential difference from the power
source?
Na+ (aq) + e– Na (s) E = –2.71 V
2H 2O (l) + 2e– H2 (g) + 2OH– (aq) E = –0.83 V
O2 (g) + 4H+ (aq) + 4e– 2H 2O (l) E = +1.23 V
Cl2 (g) + 2e– 2Cl– (aq) E = +1.36 V
A) With 1.35 V, the cell produces Na at the cathode and Cl 2 at the
anode
B) With 1.35 V, the cell produces Na at the anode and Cl 2 at the
cathode
C) With 4.07 V, the cell produces Na at the cathode and Cl 2 at the
anode
D) With 2.06 V, the cell produces H 2 at the anode and H 2O at the
cathode
E) With 2.06 V, the cell produces H 2 at the cathode and O 2 at the
anode
22) The market for lab -made diamonds is growing. Chemist s can create
diamonds identical to mined diamonds by using chemical vapour
deposition in which methane decomposes in the presence of a
hydrogen catalyst and plasma. If t his methane decomposition reaction
were possible at 298 K, what would be the Gibbs Free Energy ( G) of
the lab -made diamond synthesis process indicated b elow (in kJ mol-1)?
CH 4 (g) ⇌ C (diamond) + 2H 2 (g)
Compound CH 4 (g) C (diamond) H2 (g)
Hf (kJ mol-1) -74.87 1.897 0
S (J K-1 mol-1) 186. 1 2.377 130.6
A) -23.0 B) 23. 0 C) 53.7 D) -53.7 E) 92.6 23) Another way to make diamonds in the lab is by converting graphite to
diamond. At 2000 K and 200 000 atm:
C (graphite) ⇌ C (diamond); ΔG = −10 kJ mol-1, ΔS = −10 J K−1 mol−1
Which of the following is a good approximation of the equilibrium
temperature for the reaction at 200 000 atm if enthalpy and entropy
are assumed to be temperature independent ?
A) T eq = 2000 K B) Teq = 3000 K C) T eq = 1000 K
D) T eq = 4000 K E) T eq = 100 K
24) Over 80% of global methanol (CH 3OH) production is converted into
further synthetic chemicals. Conseque ntly, methanol is an economically
significant chemical compound. Methanex , a Vancouver -based company,
is the world’s largest producer and distributor of methanol. Methanol is
produced according to the following balanced chemical reaction:
CO(g) + 2H 2 (g) ⇌ CH 3OH (g)
Given initial partial pressures of PCO = 26 bar and PH2 = 65 bar , and an
equilibrium partial pressure of PCH3OH = 16 bar, determine Kp. Assume
constant container volume and ideal gas behaviour .
A) 1.5 x 10-4 B) 6.7 x 10-4 C) 1.5 x 10-3
D) 3.3 x 10-2 E) 4.8 x 10-2
25) A chemist creates one litre of buffer solution by mixing unequal
volume s of 1.0 M acetic acid (Ka = 1.74 x 10-5)
and 1.0 M sodium hydroxide to obtain a
solution with the ratio of solution particle s in
the diagram to the right. What is the pH of
the buffer solution?
A) 4.33 B) 4.54 C) 4.76
D) 4.98 E) 5.19
End of Part A of the contest
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THE CANADIAN CHEMISTRY CONTEST 2016
PART A – MULTIPLE CHOICE QUESTIONS (60 minutes)
All contestants should attempt this part of the conte st before proceeding to Part B and/or Part C
The only reference material allowed is the CIC/CCO Periodic Table provided . You must complete answers on the Scantron Sheet p rovided . A
scientific calculator is allow ed. No phones or any devices tha t can be used for communication are allowed.
1) WHMIS 2015 is the updated labelling system whic h conforms to the
new international standard of classifying hazardous materials. Although all
of the compounds below would require some labelling for other
characteristics, which compound would NOT require the oxidizer
label shown to the right ?
A) potassium permanganate B) sodium chlorate
C) ethanol D) nitric acid
E) hydrogen peroxide
2) A 0.48 g piece of magnesium metal is placed in hydrochloric acid.
Assuming the hydrochloric acid is in excess and the magnesium reacts
completely, how many grams of hydrogen gas are produced?
A) 0.01 0 g B) 0.040 g C) 0.080 g
D) 0.48 g E) 0.96 g
3) If the total pressure increases in each of the reaction mixtures below, f or
which reaction would the product yield remain unchanged at equilibrium?
A) CO (g) + H 2O (g) ⇋ CO2 (g) + H 2 (g)
B) 2 NO (g) + Cl 2 (g) ⇋ 2 NOCl (g)
C) 2 H2S (g) ⇋ 2 H2 (g) + S2 (g)
D) 2 H2 (g) + O 2 (g) ⇌ 2 H2O (g)
E) 3 H2 (g) + CO (g) ⇌ CH4 (g) + H 2O (g)
4) Which of the following compounds has the smallest bond angle?
A) BF 3 B) CF 4 C) NF 3 D) OF 2 E) ClF 3
5) After a chemist stirs the contents of a beaker, the rate of a reaction
between reactants A and B increases by a factor of four. Use the diagrams
below to help you to determine the main reason why the rate of reaction
increases.
A) Reaction surface are a increases B) Activation energy increases
C) Reactant concentrations increase D) Total kinetic energy increases
E) Average kinetic energy increases
6) The limit for lead in drinking water is 0.015 ppm according to t he
Environmental Protection Agency ( EPA ). A 100.0 mL sample of well water
tested for dissolved Pb2+ with a satur ated potassium iodide solution
produced 1.7 mg of yellow lead iodide precipitate . How many times higher
than the EPA limit was the concentration of lead in the well water?
A) 110 times B ) 1100 times C) 510 times D) 700 times E) 51 times
7) A common method for cleaning up an acid spill is to spread sodium
carbonate over the spill to neu tralize it. If 50.0 mL of 0.75 mol L–1HCl
spilled on the countertop, what is the minimum amount of sodium
carbonate required to neutralize the spill?
A) 1.6 g B) 1.9 g C) 2.0 g D) 3.1 g E) 4.0 g
8) Which element would h ave its highest energy valence electron correspond to
the following quantum numbers? n= 4, l = 2
A) Sc B) Y C) K D) Zn E) Ga
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9) The 1st and 3rd ionization energies of aluminum are 577.5 kJ mol–1 and
2744.8 kJ mol–1 respectively. What data best match es the 2nd and 4th
ionization energies of aluminum ?
2nd ionization energy
(kJ mol–1) 4th ionization energy
(kJ mol–1)
A) 700 3500
B) 700 5000
C) 700 11000
D) 1800 11000
E) 1800 5000
10) Levobunolol (structure below) is used topically to treat glaucoma, an
eye disorder which causes damage to the optic nerve.
O
OOH
N
Hlevobunolol
Which of the following functional groups are contained within the structure
of levobunolol?
A) amine, ketone, ether, phenol B) amide, ketone, ether, alcohol
C) amine, ketone, ester, alcohol D) amine, ketone, ether, alcohol
E) amine, aldehyde, ether, alcohol
11) Penicillamine is an important organic compound used in the treatment
of rheumatoid arthritis. One molecule of penicillamine contains a single
sulfur atom and the weight percentage of sulfur in penicillamine is 21.49%.
What is the molecular weight of penici llamine in g mol–1?
A) 85.4 0 B) 101.3 C) 125.2 D) 137.6 E) 149.2
12) For a spontaneous reaction, which relationship below is always true?
A) ΔG⁰ rxn > 0 B) S universe > 0 C) S universe < 0
D) ΔH⁰ rxn > 0 E) ΔH⁰ rxn < 0 13) A student performs the follo wing reaction to make solid sulfur:
Na 2S2O3 (aq) + 2 HCl (aq) 2 NaCl (aq) + S (s) + SO 2 (g) + H 2O (l)
The student records the following data at the start of the reaction :
Concentration (mol L–1) Volume (mL)
Na 2S2O3 (aq) 0.45 130
HCl (aq) 0.15 400
If the student recovers 0 .89 g of solid sulfur from the experiment, what is
the % yield of the reaction?
A) 46% B) 48% C) 75% D) 89% E) 93%
14) A student places 0.75 0 g of solid sodium hydroxide (NaOH) in to
20.0 0 mL of water at 25.0 C inside a coffee cup calorimeter. The final
temperature of the calorimeter contents is 34.6 C. The density of water is
1.0 g mL–1. Assume the specific he at capacity of the solution approximates
that of water at 4.184 J g –1 C–1 and the calorimeter has 1 00% efficiency.
What is the ΔH rxn for the dissolution reaction below?
NaOH (s) NaOH (aq)
A) –42.8 kJ mol–1 B) – 44.4 kJ mol–1 C) – 803 J mol–1
D) –833 J mol–1 E) – 1070 J mol–1
15) Canadian cities began adding fluoride to their drinking water in the
mid -1950s, as a means to reducing dental caries (cavities) in children.
Sodium fluorosilicate (Na 2SiF6), a by -product of the industrial proc essing
of phosphate minerals, can be added to d rinking water to pro duce free
fluoride ions. A drinking water analysis for a Canadian city revealed the
following data:
pH = 7.6 0 [F–] = 3.2 x 10–5 mol L–1
Given that the pKa of hydrofluoric acid (HF) is 3.17, determine the
concentration of HF in t he drinking water of this Canadian city. Assume a
water temperature of 25°C.
A) 5.4 x 10–2 mol L–1 B) 3.2 x 10–5 mol L–1 C) 6.4 x 10–5 mol L–1
D) 1.9 x 10–8 mol L–1 E) 1.2 x 10–9 mol L–1
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16) The transition metal rhenium (Re), is among the rarest elements in the
earth’s crust. The precursor to the pure metal, ammonium perrhenate, is
produced during the refinement of molybdenum ores. The principal
application of rhenium is as an alloy with nickel, used in je t engine
components. Consider the unbalanced chemical equation for the hydrogen
reduction of ammonium perrhenate:
__ NH 4ReO 4 + __ H2 __ Re + __H2O + _ _ NH 3
Assume the oxidation number of nitrogen in the reactants an d products is
unch anged. Determine the sum of the smallest integer coefficients for the
stoichiometrically balanced chemical equation.
A) 5 B) 14 C) 18 D) 20 E) 21
17) The metric known as reaction mass efficiency (RME) provides a way to
assess how much reactant material ends up in a desired product at the end
of a chemical reaction. One way of expressing RME is as follows:
reaction mass efficiency =mass of desired product
(total input mass −mass of recycled material )
0.115 moles of cholesterol (C 27H46O) was reacted with 0.365 moles of
molecular bromine to form 0.102 moles of dibromocholesterol in an
addition reaction (shown below). It was possible to recover and recycle
0.151 moles of molecular bromine from the reaction mixture.
HOHH
HBr2
HOHH
H
Br
Brcholesterol
What is the percentage reaction mass efficiency for this process?
A) 43.3 % B) 54.3% C) 70.9% D) 84.6 % E) 89.1% 18) Solid lead carbonate precipitate can be formed from mixing aqueous
lead nitrate and sodium carbonate:
Pb(NO 3)2 (aq) + Na 2CO3 (aq) PbCO 3(s) + 2 NaNO 3 (aq)
If 360 mL of 0.15 mol L–1 sodium carbonate w as
combined with 45 mL of 0.60 mol L–1 lead nitrate,
which of the following diag rams best describes the
system once it has gone to completion? A
19) Naphthalene is a white crystalline solid, traditionally used as the
primary ingredient in mothballs. It has the chemical
formula C 10H8, and its structure is shown to the right.
Rank the solubility of naphthalene in the following
solvents from most to least soluble.
I. water II. hexane III. ethanol IV. hexanol
A) II > IV > III > I B) IV > II > III > I C) I > III > II > IV
D) II > III > IV > I E) IV > III > II > I
20) Vitamin -B3, or Niacin, is an essential nutrient for humans. Its
molecular structure is shown on the right. A 0.005 0 mol L–1
solution of Niacin in water has a pH of 3.56 . What is the
percentage ionization of niacin in water ?
A) 1.4 % B) 2.8 % C) 3.6 % D) 5.5 % E) 7.8 %
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21) 2- propanol reacts with oxygen as follows:
2 C3H7OH (l) + 9 O2 (g) 6 CO2 (g) + 8 H2O (g)
If 0.500 moles of 2 -propanol react in the presence of 4.00 moles of oxy gen,
how many kilojoules of heat would be absorbed or released? A table of
average bond energies is given below.
Bond Type Bond Energy
(kJ mol–1) Bond Type Bond Energy
(kJ mol–1)
C-H 413 O=O 495
O-H 467 C=O 799
C-O 358 C-C 347
A) – 1890 kJ B) + 1890 kJ C) – 1680 kJ
D) – 946 kJ E) + 473 kJ
22) For the cell depicted, the half -reactions are:
Zn2+ (aq) + 2e– → Zn(s) E° = –0.76 V
Cu2+ (aq) + 2e– → Cu(s) E° = +0.34 V
Which o f the following is true for the spontaneous cell reaction?
A) Zn is the anode ; the electron flow is from anode to cathode ; anions
migrate through the salt bridge from the Zn/Zn2+ to the Cu/Cu2+
half-cell and cations migrate in the opposite direction.
B) Zn is the cathode ; the electron flow is from anode to cathode ;
anions migrate through the salt bridge from the Zn/Zn2+ to the
Cu/Cu2+ half-cell and cations migrate in the opposite direction.
C) Zn is the anode ; the electron flow is from cathode to anode ; anions
migrate through the salt bridge from the Zn/Zn2+ to the Cu/Cu2+
half-cell and cations migrate in the opposite direction.
D) Zn is the cathode ; the electron flow is from anode to cathode ;
cations migrate through the salt bridge from the Zn/Zn2+ to the
Cu/Cu2+ half-cell and anions migrate in the opposite direction.
E) Zn is the anode ; the electron flow is from anode to cathode ;
cations migrate through the salt bridge from the Zn/Zn2+ to the
Cu/Cu2+ half-cell and anions migrate in the opposite direction. 23) A gaseous anesthetic with an unknown molecular formula is 85.63%
carbon and 14.37% hydrogen by mass. What is the molecular formula of
the unknown if 0.45 L of the compound combusts with excess oxygen at
120 .0C at 72.93 kPa to form 2.70 L of an equimolar mixture of carbon
dioxide and water vapour?
A) C 3H6 B) C 4H8 C) C 5H10 D) C 6H12 E) C7H14
24) Given the following data table for the reaction 2 A + B2 → 2 AB
[A] mol L–1 [B2] mol L–1 Rate of Reaction (mol L–1 s–1)
0.10 0 0.10 0 0.117
0.20 0 0.10 0 0.468
0.20 0 0.20 0 0.936
What is the rate of reaction in mol L–1 s–1 if [A] = [B 2] = 0.30 0 mol L–1?
A) 1.87 B) 2.81 C) 3.02 D) 3.16 E) 3.51
25)
Both Flask 1 and Flask 2 have a volu me of exactly 2.0 L, KE is the average
kinetic energy, and P is pressure . Which statement below is TRUE ?
A) P 1 = P 2
B) the KE of the particles in flask 1 < the KE of the particles in flask 2
C) the number of particles in flask 1 > the number of particles in flask 2
D) the number of collisions in flask 1 = number of collisions in flask 2
E) 2 P 1 = P 2
End of Part A of the contest
Go back and check your work
Flask 1
2.0 g of H 2
gas at 25C
and P 1 Flask 2
16.0 g of O 2
gas at 25C
and P 2
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THE CANADIAN CHEMISTRY CONTEST 2015
PART A – MULTIPLE CHOICE QUESTIONS (60 minutes)
All contestants should attempt this part of the conte st before proceeding to Part B and/or Part C
The only reference material allowed is the CIC/CCO Periodic Table provided . You must complete answers on the Scantron Sheet p rovided . A scientific
calculator is allow ed. No phones or any devices tha t can be used for communication are allowed.
1. Through the Workplace Hazardous Materials Information System
(WHMIS), l abs use eight labels to identify the dangers chemists
encounter from the six classes of hazardous materials. Using your
knowledge of the properties of chemical substances , identify the list
below which contains three chemicals that should ALL be identified wit h
the flammable materials label?
A) Copper wire, sodium chloride and helium
B) Hydrogen, magnesium wire, ethanol
C) Platinum wire , iron (III) oxide, carbon dioxide
D) Neon, potassium iodide, silver wire
E) Liquid m ercury, calcium bromide, nitrogen
2. What is the correctly balanced form of the chemical reaction depicted in
the figure below?
A) 4 A + 6 B → A 4B6
B) A4 + B 6 → A 4B6
C) A4 + 3 B 2 → 2 A 2 + 2 B 3
D) A4 + 3 B 2 → 2 A 2B3
E) 4 A + 3 B 2 → 2 A 2B3
3. One component of gastric (stomach) fluid is hydrochloric acid (HCl).
Baking soda (NaHCO 3) will neutralize HCl according to the reaction:
NaHCO 3 (aq) + HCl (aq) → NaCl (aq) + H 2O (l) + CO 2 (g)
How many grams of CO 2 are produced when 300 mL of 1.22 mol L–1
HCl react with 175 mL of 1.55 mol L–1 NaHCO 3?
A) 9.89 g B) 10.5 g C) 11.9 g D) 14.4 g E) 16.1 g 4. When dissolved in aqueous solution, Al3+ forms a six coordinate complex with
water that can undergo dissociation according to the following equation:
Al(OH 2)63+(aq)+ H 2O (l) ⇌ Al(OH 2)5(OH)2+(aq) + H 3O+(aq) Ka = 1.0 x 10–5
If the initial concentration of Al(OH 2)63+ is 0.10 mol L–1 , what is the
approximate pH of the solution?
A) 1.00 B) 3.0 0 C) 4.00 D) 5.00 E) 7.0 0
5. Dapsone is the active ingredient in Aczone™ gel, a treatment for adult acne.
Each gram of Aczone gel contains 50 mg of dapsone (molecular weight 248.3 g
mol–1). The dapsone content of a 10.0 g sample of Aczone was analyzed and
found to be composed of 290.3 mg carbon, 64.5 mg sulphur, 56.4 mg nitrogen
and 24.4 mg hydrogen with the remaining mass being oxygen. What is the
molecular formula of dapsone?
A) C12H10NOS 2 B) C10H8N4O2S C) C11H8N2O3S
D) C 13H14NO 2S E) C 12H12N2O2S
6. Given a fixed mass of gas in a closed, expanda ble container at constant
pressure, which graph shows the variation in the volume of gas (y -axis) versus
the temperature in degrees Kelvin (x-axis)?
A) B) C)
D) E)
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7. Assuming the oxidation number of chlorine is – 1, the oxidation numbers
of iodine and antimony in the compound [ICl 2]+[SbCl 6]– are respectively
A) +2 and +6 B) +2 and +5 C) +1 and +7
D) +3 and+5 E) +3 and +7
8. Water and carbon tetrachloride (CCl 4) are immiscible liquids. If a student
adds solid iodine to a beaker containing water and car bon tetrachloride,
stirs vigorously to dissolve the iodine and allows the mixture to settle,
which particulate d iagram best describes the physical change that occurs?
Answer: B
9. Potassium iodate, KIO 3, has applications as both source of dietary iodine
in table salt and as protection against the accumulation of radioactive
iodine in the human thyroid gland. The following reaction produces
potassium iodate:
2KClO 3(s) + I 2(s) → 2KIO 3(s) + Cl 2(g)
What is the theoretical yield of KIO 3 if the limiting reactant is 51.0 g I 2?
A) 43.0 g B) 46.2 g C) 86.0 g D) 172 g E) 185 g
10. The first ionization energy of phosphorus is lower than that of :
A) chlorine B) silicon C) sodium D ) barium E) bismuth 11. In w hich of t he following four compounds is intermolecular hydrogen -
bonding present ?
(I) 2-propanol, (CH 3)2CHOH
(II) triethylamine, (C 2H5)3N
(III) dimethyl ether, (CH 3)2O
(IV) n-butylamine, CH 3CH 2CH 2CH 2NH 2
A) (I), (III) and (IV) B) (I) and (III) C) (II) and (IV)
D) (I) only E) (I) and (IV)
12. A student sets up two 1.00 L gas bulbs at 25 .0 oC connected by a glass
tube. The combined volume of one bulb and half of the tube is 1.00 L.
The student opens the valve and allows 0.0400 moles of A 2 (g) and 0.0400
moles of B (g) to mix . The reaction form s AB (g). What is the final
pressure (kPa) in the 2.00 L system if the reactio n proceeds to
completion and the temperature remains constant ?
A2 (g) + 2B (g) → 2AB (g)
A) 198 kPa B) 149 kPa C) 99.1 kPa D) 74.3 kPa E) 49.6 kPa
13. The combustion of acetylene, C 2H2, provides the hottest flame
temperature of all commercially available fuels. The average bond e nergy
(ΔH) data table and the balanced chemical equation are below .
2 C 2H2 (g) + 5 O2 (g) → 4 CO 2 (g) + 2 H2O (g)
Bond type ΔH (kJ mol–1) Bond type ΔH (kJ mol–1)
C–H +411 C=O +799
C–C +346 O=O +494
C≡C +835 O–H +459
What is the enthalpy of combustion for 1 mol e of acetylene?
A) + 3422 kJ mol–1 B) + 2444 kJ mol–1 C) – 611 kJ mol–1
D) – 1222 kJ mol–1 E) – 3422 kJ mol–1
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14. Which particulate diagram best represents a dilute aqueous solution of
magnesium chloride (solubility = 59.2 g/100 mL). Answer : A
15. Assuming all orbitals in a given sublevel have equivalent energy, i n which
type of orbital(s) would the highest energy electron (s) in the Sc3+ be
found ? The neutral eleme nt scandium has an atomic number of 21.
A) i B) ii C) ii or iii D) iv E) iv or v
16. Levobunolol (structure below) is used topically to treat glaucoma, an eye
disorder which causes damage to the optic nerve.
O
OOH
N
Hlevobunolol
Which of the following functional groups are contained within the
structure of levobunolol?
A) amine, ketone, ether, phenol
B) amide, ketone, ether, alcohol
C) amine, ketone, ester, alcohol
D) amine, aldehyde, ether, alcohol
E) amine, ketone, ether, alcohol
17. What is the smallest F —Xe—F bond angle in XeF 4?
A) <90o B) 90o C) 104.5o D) 109.5o E) 120o 18. A student titrated a queous ethanoic acid with sodium hydroxide and
recorded the change in pH on the graph below . Using the curve,
estimate the pH at the equivalence point for this titration.
A) 3.0 B) 7.0 C) 8.8 D) 11 .0 E) 12.5
19. At a lab at the Universi ty of Toronto in 1929, Dr. Vely en Henderson and
Dr. George Lucas were the first to discover the use of cyclopropane as a
general an esthetic. Cyclopropa ne undergoes slow molecular
rearrangement to propene. From the data below, determine the rate law
for the reaction :
Initial concentrati on of
cyclopropane (mol L–1 ) Rate of f ormation of propene
(mol L–1s–1 )
0.050 2.95 × 10–5
0.100 5.90 × 10–5
0.150 8.85 × 10–5
A) Rate = 5.9 × 10–4 s–1 × [cyclopropane]
B) Rate = 1.2 × 10–2 L mol–1 s–1 × [cyclopropane]2
C) Rate = 2.4 × 102 mol L–1 s–1 × [cyclopropane]2
D) Rate = 1.7 × 103 s–1 × [cyclopropane]
E) Rate = 2.4 × 10–1 mol L–1 s–1 × [cyclopropane]2
02468101214
0 2 4 6 8 10 12 14 16pH
Volume of NaOH (mL )
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+
`
–
`
20. Joseph Priestl ey discovered sweet -smelling, colourless laughing gas,
nitrous oxide (N2O), in 1763. N 2O has been widely used as an anesthetic
for medical and dental applications. Nitrogen dioxide (NO 2) is a toxic
reddish brown gas that is the major component of smog. Nitrogen oxide
(NO) is a colourless, non -toxic gas that readily oxidizes to nitrogen
dioxid e in the presence of oxygen. Using the reactions:
4 NO (g) → 2 N 2O (g) + O 2 (g) G = – 139.56 kJ
2 NO (g) + O 2 (g) → 2 NO 2 (g) G = – 69.70 kJ
calculate the Gibbs Free Energy released or required when 2 moles of
nitrous oxide combine with three moles of oxygen to produce four moles
of nitrogen dioxide.
A) – 209.26 kJ B) – 139.86 kJ C) – 69.86 kJ
D) + 0.16 kJ E) +139.72 kJ
21. Which of the following statements about the electrolysis of a solution of
magnesium iodide , as depicted in the diagram, is false ?
A) If the negative and positive terminals of the cell are reversed,
magnesium would begin to plate on electrode B.
B) The reaction is non -spontaneous without an applied power source .
C) An acid -base indicator could be used to detect a product
formed at electrode A.
D) I2 forms at the anode.
E) A gas is formed at the cathode.
I2(s) + 2 e– → 2 I−(aq) E° = + 0.54 V
Mg2+(aq) + 2 e–→ Mg(s) E° = − 2.37 V
O2(g) + 4 H+(aq) + 4e– → 2 H 2O(l) E° = + 1.23 V
2H2O(l) + 2 e− → H2(g) + 2 OH−(aq) E° = − 0.83 V
22. Milk of magnesia is sold at drugstores in Canada to treat
indigestion or mild constipation . The active ingredient in milk of
magnesia is magnesium hydroxide , Mg(OH) 2. The solubility of Mg(OH) 2
is 7.05 x 10–3 g L–1. What is the Ksp of magnesium hydroxide?
A) 1.99 x 10–4 B) 1.40 x 10–6 C) 3.50 x 10–7
D) 1.46 x 10–8 E) 7.06 x 10–12
23. Consider the following half -cell reactions in aqueous, acid conditions:
Cl2(aq) + 2e– ⇌ 2Cl–(aq) E° = +1.36 V
MnO 4–(aq) + 8H+(aq) + 5e– ⇌ Mn2+(aq) + 4H2O(l) E° = +1.49 V
Assuming correct stoichiometric ratios of reactants, which of the following
represents the products from the spontaneous cell reaction? (H+ and H2O have been
omitted for clarity ) Answer: B
24. Which of the following would cause the precipitation of more silver in
the equilibrium which is exothermic in the forward direction.
Ag+(aq) + Fe2+(aq) ⇌ Ag(s) + Fe3+(aq)
A) Increasing the temperature
B) Increasing the volume of water
C) Removing some of the solid silver precipitate
D) Increasing the concentration of Fe3+ ions
E) Increasing the concentration of Fe2+ions
25. Given the following equilibria,
NH 3(aq) + H 2O(l) ⇌ NH 4+(aq) + OH–(aq) Kb=1.8 x 10–5
CH 3COOH(aq) + H 2O(l) ⇌ CH 3COO–(aq) + H 3O+(aq) Ka=1.8 x 10–5
HCN (aq) + H 2O(l) ⇌ CN–(aq) + H3O+(aq) Ka=6.2 x 10–10
Which salt is the most alkaline from among the options below?
A) NaCN B) NaCH 3COO C) NH 4Cl D) NH 4CH 3COO E) NH 4CN
End of Part A of the contest
Go back and check your work
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THE CANADIAN CHEMISTRY CONTEST 2014
PART A – MULTIPLE CHOICE QUESTIONS (60 minutes)
All contestants should attempt this part of the conte st before proceeding to Part B and/or Part C
The only reference material allowed is the CIC/CCO Periodic Table provided . Answers must be completed on the Scantron Sheet Provided
A scientific calculator is allow ed. No phones or any devices tha t can be used for communication are allowed.
1. To safely and efficiently prepare 1.0 L of a 1.0 mol L–1 solution of HCl
from a 12.0 mol L–1 stock so lution of HCl, what should a chemist add to a
1 L volumetric flask first?
A) 500 mL of distilled water with a beaker
B) 120.0 mL of 12.0 mol L–1 HCl w ith a graduated cylinder
C) 83.3 mL of 12.0 mol L–1 HCl with a graduated cylinder
D) 12.0 mL of 12.0 mol L–1 HCl with a graduated cylinder
E) 10.0 mL of distilled water with a graduated cylinder
2. According to the Aufbau Principle in quantum mechanics, which of the
following is the highest energy electron sublevel?
A) 7s B) 6p C) 6d D) 5f E) 5p
3. In their solid form, w hich of the following is made up of discrete particles
(either atoms, ions or molecules) that only have London Dispersion forces
of attraction between them?
A) Ag B) CO 2 C) C, graphite D) KCl E) NH 3
4. Removing all lone pairs of electrons on the central atom of ClF 3 would
change the geometry
A) from trigonal pyramidal to trigonal planar
B) from T–shaped to trigonal planar
C) from trigonal bipyramidal to trigonal pyramidal
D) from trigonal bipyramidal to trigonal planar
E) minimally. The shape would remain trigonal planar.
5. Select the arrangement below that lists the bonds in order of increasing
polarity (least polar to most polar):
A) C–F, O–F, Be –F B) O–F, C–F, Be–F C) Be–F, O–F, C–F
D) Be–F, C–F, O–F E) O –F, Be –F, C–F 6. The top diagram represents the initial state of a mixture of diatomic gas A
and diatomic gas B in a closed reaction flask. Which of the diagrams under
the answer choices represen ts the contents of the flask if the reaction goes
to completion ? The balanced chemical equation is: A 2 + 3 B2 → 2 AB 3
A) B) C) D) E)
7. Calcium fluoride, CaF 2, occurs in nature principally as the mineral fluorite
and is the primary source of industrial hydrogen fluoride. Determine the
concentration of fluoride ions in a saturated solution of calcium fluoride
with [Ca2+] = 0.025 0 mol L–1. Ksp for calcium fluoride is 3.45 x 10–11.
A) 1.38 x 10–9 mol L–1 B) 2.76 x 10–9 mol L–1 C) 5.87 x 10–6 mol L–1
D) 3.71 x 10–5 mol L–1 E) 1.85 x 10–5 mol L–1
8. A closed 2.0 L container initially holds 4.0 mol of oxygen and 2.0 mol of
nitrogen at temperature T. If the pressure remains constant when 2.0 mol of
oxygen a re removed, which express ion correct ly describes the final
temperature of the system in terms of the initial temperature, T ? Assume
Ideal Gas behaviour.
A) 𝟑𝐓/𝟐 B) 2T C) 2T/3 D) 3T E) T
B2 molecule
A2 molecule
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9. In the television series Breaking Bad , Walter White and Jesse Pinkman
synthesize methamphetamine ( N–methyl –1–phenyl –2–propanamine) which
is mark eted as methamphetami ne hydrochloride, or “crystal me th”.
methamphetamine
hydrochloride
N
H H+Cl-
What is the molecular formula of methamphetamine hydrochloride?
A) C8H16ClN B) C10H10ClN C) C 10H16ClN
D) C10H14ClN E) C 9H16ClN
10. Referring to question #9 , in the structure of methamphetamine
hydrochloride, how many non-bonding valence shell electrons are there ?
Lone valence electrons are single valence electrons that are not involved in
covalent bonds.
A) 4 B) 6 C) 7 D) 8 E) 10
11. What is the final temperature of a mixture of 50.0 g of Cu (specific heat
capacity = 0.3845 J g–1 o C–1) initially at 135.0oC and 150.0 mL o f water
(specific heat capacity = 4.184 J g–1 o C–1) initially at 21.0 oC? Assume that
there is no loss of heat and the container has a negligible heat capacity.
A) 17.4C B) 22.5C C) 24.4C D) 35.2C E) 78.0C
12. Consider the following potential energy diagram for the reaction
AB + C AC + B.
What is/are the reaction intermediate(s) in this reaction?
A) AB and C B) B C) AC and B
D) A, B and C E) A 13. In the emergency oxygen system on commercial passenger aircraft, s odium
chlorate undergoes thermal decompos ition to produce oxygen gas:
2 NaClO 3 (s) 2 NaCl (s) + 3 O 2 (g)
On average a human under stress consumes 38 .0 L of O 2 through
respiration every 15 minutes. Determine the minimum mass of sodium
chlorate required to deliver this volume of O 2 (assume P= 100 kPa and T=
273.15 K)
A) 65.0 g B) 119 g C) 178 g D) 267 g E) 356 g
14. The reaction to convert iron (II) oxide to iron (III) oxide is as follows:
4 FeO (s) + O 2 (g) 2 Fe2O3 (s) ΔH rxn = – 564 kJ mol–1
If the enthalpy of formation ( ΔH°f) of rust (Fe2O3(s)) is – 826 kJ mol–1,
what is the enthalpy of formation of FeO in kJ mol–1?
A) – 554 B) – 272 C) + 272 D) – 262 E) +262
15. The chemical rea ction that takes place when 1.30 g of pure zinc is mixed
with 400 mL of a 0.100 mol L–1 copper (II) chloride solution is :
Zn (s) + CuCl 2 (aq) Cu (s) + ZnCl 2 (aq)
Which dia gram best represents the system after the r eaction has gone to
completion? Answer: Flask D
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16. Iron(III) is readily hydrated in aqueous solution and subsequently
undergoes hydrolysis according to the following equations:
Fe3+ + 6 H2O Fe(H 2O)63+
Fe(H 2O)63+ ⇌ Fe(H 2O)5(OH)2+ + H+ pKa =2.2; ∆ H° =+42.7 kJ mol–1
Predict the effect of an increase in temperature on the pKa and the [H+] of
the solution.
A) pKa increases, [H+] decreases B) pKa increases, [H+] increases
C) pKa decreases, [H+] decreases D) pKa decreases, [H+] increases
E) pKa unchanged, [H+] unchanged
17. One of the Twelve Principles of Green Chemistry is that “synthetic
methods should be designed to maximize the incorporation of all materials
used in the process into the final product”. One way to consider this is to
calculate the atom economy (AE) of a ch emical reaction where AE is defined
as follows:
molecular mass of desired product
molecular mass of all reactantsatom economy = x 100%
1,4–Dimethoxybenzene is an organic compound with an intensely sweet
floral odour and used in the perfumery industry. It can be synthesized in the
laboratory by the reaction shown below:
1,4-dimethoxybenzeneOCH3 H3CO OH HO +2 NaOH+2 CH3Br+2 NaBr
+2 H2O
mol. wt. = 110.11
What is the percentage atom economy for this reaction?
A) 46.1% B) 36.3% C) 56.4% D) 67.4% E) 20.6%
18. The reaction 2 A + B 2 2 AB is first order in [B 2] and zero order in [A].
The half–life for the overall reaction is 2 minutes. If 0.100 moles of A and
0.0300 moles of B 2 are dissolved in 100.0 mL of solvent, what will [A] be ,
6.00 minutes after the reaction begins?
A) 0.001 25 mol L–1 B) 0.12 5 mol L–1 C) 0.003 75 mol L–1
D) 0.738 mol L–1 E) 0.47 5 mol L–1
19. A galvanic cell is created for the following reaction:
Zn(s) + 2 Cu2+ Zn2+ + 2 Cu(s) Ecell = 1.10 V, H= –217 kJ/mol
A light bulb is connected to the cell and allowed to glow until it dies out.
Doubling the mass of the electrodes and volumes of solutions will have
which of the following effects?
I. The light bulb will glow twice as bright.
II. Twice as much heat will be generated.
III. The light bulb will glow twice as long.
A) II only B) I and II C) I and III D) II and III E) I, II, and
III
20. To create a nickel –plated electrode using a 1.5 V battery, what are the most
appropriate choices for A, B, and C in the diagram of the electrolytic cell
below?
Ni 2+ + 2 e– Ni E = – 0.25 V
Cu 2+ + 2 e– Cu E = + 0.34 V
Al 3+ + 3 e– Al E = – 1.66 V
A B C
A) Ni Cu CuSO 4
B) Ni Cu NiSO 4
C) Cu Ni NiSO 4
D) Ni Al Al2(SO 4)3
E) Al Ni NiSO 4
– +
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21. Hemoglobin is the iron -containing protein in red blood cells that transports
oxygen to cells and tissues . Four oxygen molecule s bond with e ach
hemoglobin molecule to form oxygenated hemoglobin, Hb(O 2)4. The
production of oxygenated hemoglobin can be depicted by the following
equilibrium: Hb (aq) +4 O 2 (g) ⇌ Hb(O 2)4 (aq)
At high altitudes , the total atmospheric pressure decreases and thu s the
partial pressure of oxygen decreases. With insuffici ent oxygenated
hemoglobin, a person will feel light -headed and eventually lose
consciousness. Which of the following statements is TRUE about the
hemoglobin equilibrium reaction as a person climbs to a high altitude ?
A) The concentration of the products increases
B) The rate of the reverse reaction increases
C) The reaction quotient (Q) will increase
D) The concentrations of the aqueous solutions will not change
E) The value of the equilibrium constant increases
22. Given the following standard reference values at 25C and 100 kPa , which
of the following combination of thermodynamic values describes a reaction
that is endothermic and spontaneous at 200 0 C? Assume enthalpy and
entropy values are not temperature dependent.
H(kJ mol–1) S (J mol–1 K–1) G(kJ mol–1)
A) 217.0 115.0 182.7
B) – 230.0 – 11.0 – 226.7
C) 52.0 10.0 49.0
D) – 363.0 249.0 – 437.2
E) 268.6 – 88.0 294.8
23. To determine the concentration of 10.00 mL of a solution of H2SO3 of
unknown concentration, a 10.00 mL sample of the unknown H2SO3 is
diluted to 100.00 mL and 25.00 mL of the diluted H2SO3 is titrated with
0.1178 mol L1sodium hydroxide . The complete neutralization of the
unknown H2SO3 requires 32.45 mL of t he NaOH solution . What is the
concentration of the original H 2SO3 solution?
A) 0.01529 mol L–1 B) 0.07645 mol L–1 C) 0.1529 mol L–1
D) 0.7645 mol L–1 E) 1.529 mol L–1 24. Which diagram best depicts a n aqueous solution of dilute hydrofluoric acid ?
A) B) C) D) E)
25. The following is a titration curve of a weak acid by a strong base . What is
the [ H 3O+] in mol L–1 at equivalence?
A) 1.6 x 10 –9 B) 8.8 x 10 –8 C) 1.0 x 10–7 D) 0.010 E) 0.94
End of Part A of the contest.
Now go back and check your work 2.884.164.584.94
5.365.636.148.7911.4211.8912.1
12.3712.52
12.6212.7
02468101214
0 10 20 30 40 50 60pH
VOLUME OF 0.200 MOL L-1NaOH ADDED (mL)T I T RAT I ON C U RV E OF 50. 0 mL OF 0. 1 00 M OL L-1
W E AK AC I D W I T H 0. 200 M OL L-1S T RON G B AS EH+ H+
H+
F–
H+
H+ F–
H+
H+
HF
H+
H+ HF
H+
H+
HF
H+
H+ HF
H+
H+
HF
H+
H+ HF
H+
H+
H2O
H+
H+ H2O
H+
H+ H2O
H+
H+ H+
H2O
H+
H+
H+
H+ HF
H+
H+ H2O
F–
H+
H+
H+
H+ F–
F–
H+
H+
H+
H+ F–
H+
H+ H+ HF
H+
H+
F–
H+
H+ HF
H+
H+ H+
H2O
H+
H+ H2O
H+
H+ F–
H+
H+ F–
H+
H+ H2O
H+
H+ H2O
H+
H+ F–
H+
H+ H+
H2O
H+
H+
H+
H+ H2O
H+
H+ H2O
H+
H+
H2O
H+
H+ H+
F–
H+
H+ H2O
H+
H+ H2O
H+
H+
H+ HF
H+
H+
H2O
H+
H+ H2O
H+
H+ H2O
H+
H+
H2O
H+
H+
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Round 1 - Level A
INSTRUCTIONS TO CANDIDATES:
(1). Do not turn this page until you are told to do so
(2). This paper consists of fifteen (1 5) numbered pages
(3). There are sixty (60) multiple choice questions. The duration of this exam in 1 hour and 30
minutes .
(4). Answer all questions. There is no negative marking.
(5). In addition to this question paper, you should also have an answer sheet.
(6). Each question has four (4) options - (A), (B), (C ), (D). Only one is the correct answer.
(7). On you r answer sheet, completely shade your choice.
(8). The use of non -programmable calculators is allowed.
(9). A Periodic Table will not be provided.
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1. In order to neutralize 50 mL of 1 M NaOH, which of the following acid solutions will be
required in the highest volume?
(A). 1 M H 2SO4
(B). 1 M HCl
(C). 1 M HNO 3
(D). 1 M CH 3COOH
Solution:
- The weaker the acid the greater will be the volume required for neutralization.
- A, B, and C represent mineral acids that are described as strong acids.
- D is an organic acid , and is weak.
D is the correct answer.
2. Which of the following processes can be described as Osmosis?
(A). Liquid bromine placed at the base of a measuring cylinder giving rise to brown vapours at
the top
(B). A crystal of iodine placed at the base of a measuring cylinder giving rise to brown vapours
at the top
(C). Your fingers becoming wrinkled after spending some time in the sea
(D). A drop of ink placed on the middle of filter paper gradually spreading outward
Solution:
- Osmosis is the movement of solvent ( not solute, not only water) particles across a semi -
permeable membrane from a less concentrated solut ion to a more c oncentrated one.
- The sol ute particles do not move from one compartment to the next.
- This process continues until the solute concentration in both compartments is the same.
- A: does not involve a semi -permeable membrane, this is diffusion
- B: is also diffusion. Note that at at mospheric pressure, iodine undergoes sublimation, not
vapourization like bromine.
- C: skin is a semi -permeable membrane. The concentration of salts (solute particles) in the sea is
much higher than that in human cells. Water from within the cells moves ou t into the external
environment creating the physical change observed. (Note that recent research has suggested that
a different mechanism/explanation has been proposed for the phenomenon of wrinkling in non -
salt water)
- D: This is movement along the stat ionary phase. This can be an example of paper
chromatography: the components of the ink will be separated as a function of their different
affinity for the paper.
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D is the correct answer.
3. An antiproton has the same mass as a proton, but opposite charge. Which of the following
describes the properties of an antiproton?
Relative Charge Relative Mass
(A). + 1 0
(B). + 1 1
(C). - 1 1
(D). - 1 0
Solution:
- A proton has a charge of + 1, and a relative mass of 1.
- A: This is an antielectron (positron)
- B: This is a proton
- C: This has a charge opposite to that of a proton, but the same mass
- D: This is an electron
C is the correct answer.
Questions 4 - 7 refer to the following properties of different pure substances :
State at RTP Electrical Conductivity at RTP
(A). Gas No
(B). Liquid No
(C). Solid No
(D). Solid Yes
Which of the above properties most likely represents the following substances?
Solution:
- Significant information about the structure and boding within a substance can be gleaned from
examining its physical properties
- Strength of intermolecular forces: solid >> liquid > gas
- To conduct an electric current requires the presence of species capable of carrying charge: free
electrons, mobile ions
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4. H 2S
A is the correct answer
5. H 2O
B is the correct answer
6. NaCl
C is the correct answer
7. Graphite
D is the correct answer
8. An atom, M, lost its 3 valence electrons to form an ion, N. Which of the following statements is
true?
(A). N has more neutrons than M
(B). N has less neutrons than M
(C). N has more protons than M
(D). N is positively charged
Solution:
- When an atom loses electrons (oxidation), the protons and neutrons are not affected.
- Electrons are negatively charged, and when a species has more protons than electrons, it is
positively charged.
D is the correct answer.
9. Diamond is best described as having this type of structure:
(A). Ionic
(B). Macromolecular
(C). Metallic
(D). Simple covalent
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Solution:
- Diamond is a covalent substance, but is the hardest naturally occurring substance. This is not
representative of a substance with a simple covalent framework.
- Diamond does not conduct electricity in any state, nor does it dissolve in water. This not
representative of an ionic or metallic structure.
B is the correct answer.
10. Consider the formula: Na 2SO4.5H 2O (s). This represents:
(A). An aqueous solution of Na 2SO4
(B). That there are 5 molecules of water of crystallization per molecule of Na 2SO4
(C). A mixture of Na2SO4 and ice
(D). Molten Na 2SO4
Solution:
- A: This will be represented as Na 2SO 4 (aq)
- B: Some ionic salts trap water in their lattice (often when recrystallized from aqueous
solutions) and these are represented as: ionic salt . number of moles of water of crystallization
- C: This will be represented as Na 2SO 4 (s) + H 2O (s)
- D: This will be represented as Na 2SO 4 (l)
B is the correct answer.
11. You wish to accurately measure out 25.00 mL of hexane. Which apparatus will allow you to
do so?
(A). 50 mL pipette
(B). 50 mL measuring cylinder
(C). 50 mL burette
(D). 50 mL beaker
Solution:
- Pay attention to the number of significant figures, which is representative of the accuracy of the
measurement and hence the equipment used.
- A: A bulb pipette (assumed unless specified as a graduated pipette, which can measure different
volumes accurately) cannot accurately measure any volume other than w hat it is specified for.
- B: A measuring cylinder is not suitable for accurate measurements
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- C: A burette can discriminate between xx.00 and xx.50 mL.
- D: A beaker is even less accurate than a measuring cylinder
C is the correct answer.
12. What is the pH of 0.01 M H 2SO4 (aq)?
(A). 0.01
(B). 1.7
(C). 1.0
(D). 2.0
Solution:
- pH = - log[H+] (logA = log 10A = lg10)
- H2SO 4 is (i) A diprotic acid and (ii) fully ionized in solution
1 (Answer C) mole H 2SO 4 = 2 (Answer D) moles H+
0.01 (Answer A) moles = 0.02 moles H+
0.01 M H 2SO 4 = 0.02 M H+
[H+] = 0.02 M
pH = - log (0.02) = - (-1.7) = 1.7
B is the correct answer.
13. When 1 mole of a strong acid is completely neutralized by 1 mole of a strong base, the
theoretical amount of energy released is 57.3 kJ mol-1. If 1 L of 1 M ethanoic acid is reacted with
1 L of 1 M NaOH (aq), what is a plausible enthalpy of neutralization?
(A). 0 kJ mol-1
(B). - 57.3 kJ mol-1
(C). + 57.3 kJ mol-1
(D). - 54 kJ mol-1
Solution:
- Ethanoic acid is a weak acid
- NaOH is a strong base
- The magnitude of the enthalpy of a neutralization reaction is a function of the extent of H+/OH
pairs available to freely undergo reaction. A weak acid will not contribute the same amount of
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H+ as a strong acid, of the same concentration, and therefore will be expected to release less
energy.
- A negative enthalpy represents energy being released to the environment (exothermic)
- A: indicates no enthalpy change (and no neutralization reacti on taking place)
- B: Same amount of energy released as a strong acid/strong base
- C: Endothermic process
- D: Less energy released than a strong acid/strong base
D is the correct answer.
14. NaOH (aq) was re acted with HCl (aq) to produce a solution wi th a mass of 400 g. The
temperature of the reaction increased by 3.5 °C. Given that the specific heat capacity of this
solution = 4.18 J K-1 g-1, how much heat was released by this reaction?
(A). 57.3 J
(B). 5.80 kJ
(C). 4.05 kJ
(D). 4.18 kJ
Solution:
- For a given substance, the relationship between the heat absorbed/released and the temperature
increase/decrease is given by the relationship:
Q = mcΔT
where Q = heat change; m = mass of substance; c = specific heat capacity of substance; ΔT =
change in temperature (1 °C = 1 K)
Note that the equation can also be represented as: Q = nc nΔT, where n = no. of moles of the
substance; c n = molar heat capacity
- Always pay attention units and convert if necessary (e.g. kg or g)
- Q = 400 x 4.18 x 3.5
= 5852
- Units Check: Q = g x J K-1 g-1 x K = J
- Q = 5852 J = 5852 / 1000 kJ ≈ 5.80 kJ (the more accurate approximation would be 5.9 kJ)
- A: correct value for molar heat of neutralization of HCl and NaOH, but incorrect unit
B is the correct answer.
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15. What volume of carbon dioxide is produced at STP, when 1.0 mole of CH 4 is completely
combusted?
(A). 1.0 dm3
(B). 2.0 dm3
(C). 22.4 dm3
(D). 24.0 dm3
Solution:
- At STP, the volume of 1 mole of an ideal gas = 22.4 dm3
- Questions of this nature require the balanced equation for the reaction:
- 1 mole of CH 4 = 1 mole of CO 2
- 1 mole of CO 2 = 22.4 dm3 at STP, assuming ideality
- D: the volume of an ideal gas at RTP
C is the correct answer.
16. If dry ice (CO 2(s)) is left at RTP, gaseous carbon dioxide will form. The process by which
this occurs is:
(A). Evaporation
(B). Boiling
(C). Condensation
(D). Sublimation
Solution:
- The process described is a solid to gas transition
- A: liquid to gas transition
- B: liquid to gas transition at a phase change temperature (boiling point)
- C: gas to liquid transition
D is the correct answer.
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17. Comparing distilled water to sea water:
(A). Sea water and distilled water will have the same boiling point
(B). Sea water will have a higher boiling point
(C). Sea water will boil at < 100 °C
(D). Sea water will have a higher freezing point
Solution:
- Sea water can be regarded as a solution of distilled water and dissolved salts and organic
matter.
- Sea water can be regarded as impure distilled water.
- A: An impure substance will not have the same boiling point as a pure one
- B: Impurities increas e the boiling point of a pure substance
- C: The boiling point of pure water is 100 °C
- D: Impurities decrease the freezing point of a pure substance
B is the correct answer.
18. Both oxygen and sulphur are in the same Periodic group, with sulphur being the heavier
atom.
At RTP, H 2O is a liquid, but H 2S is a gas. What is the reason for this?
(A). H 2S is heavier
(B). H 2O is lighter
(C). H 2O is ionic
(D). H 2O has extensive hydrogen bonding
Solution:
- Difference in physical properties such as state of existence at a given temperature and pressure,
is a function of the intermolecular forces of attraction. The greater these forces, the greater the
order of particles (solid > > liquid > gas)
- A and B: Both of these statements are correct. Neither is the correct reason.
- C: H 2O is a simple covalent molecule
- D: Oxygen is the 2nd most electronegative element, and the H -O system facilitates H -bonding.
D is the correct answer.
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19. What is the best technique to separate a homogeneous mixture of the following liquids:
I. water
II. methanol: boiling point = 65 °C, density = 0.792 gcm-3
III. propan -1-ol: boiling point = 98 °C, density = 0.803 gcm-3
(A). Simple distillation
(B). Filtration
(C). Use of a Separatory Funnel
(D). Fractional Distillation
Solution:
- A: I and III have very similar boiling points and hence simple distillation will not be effective
- B: Separation of a solid from a liquid
- C: Separation of immiscible liquids
- D: Separation of a mixture of liquids through repeated boiling/condensation cycles e.g. crude
oil distillation.
D is the correct answer.
20. Bronze is best described as what type of mixture?
(A). Solid in liquid solution
(B). Liquid in solid solution
(C). Solid and solid
(D). Liquid and liquid
Solution:
- Bronze is a mixture of copper and tin, and sometimes minor amounts of other elements.
- The components of bronze are solids at room temperature
C is the correct answer.
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21. Consider 1 g of Br 2 in different states of matter. Which particles have the greatest kinetic
energy?
(A). solid > liquid > gas
(B). liquid > solid > gas
(C). gas = liquid > solid
(D). gas > liquid > solid
Solution:
- The kinetic energy (K.E.) of a pa rticle is the energy it possesses due to its motion.
- K.E. = ½ mv2, where m = mass; v = velocity
- The greater the speed of the particles, the greater the K.E.
- Order of freedom of motion: solid << liquid < gas;
therefore speed of particles: solid << l iquid < gas
D is the correct answer.
22. Arrange the following elements in order of decreasing reactivity with water:
(A). K > Na > S > Li
(B). K > Na > Li > S
(C). S > Na > K > Li
(D). Na > K > Li > S
Solution:
- Each option has three Group I elements: Li, Na, K; and one Group VI element: S
- The metallic elements show trends of reactivity as follows: Group I > Group 2 > Group 3;
reactivity increases down the group . Reaction with water generates a metal hydroxide (alkaline
solution) and liberates H 2 (g)
- Typically, the non -metals do not react with water; except the Halogens (Group VII) : Cl 2, Br 2
and I 2 react with water to give solutions of varying bleaching power (Cl 2 > Br 2 > I2)
B is the correct answer.
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23. CaSO 4 is a salt that is sparingly soluble in water at room temperature . What is the best
method for purifying CaSO 4 from a mixture containing solid impurities that are insoluble in
boiling water?
(A). Fractional distillation
(B). Recrystallization
(C). Simple distillation
(D). Sublimation
Solution:
- A: Separation of a complex mixture of liquids
- B: Separation of a solid from impurities, utilizing the fact that solubility of a substance
increases with increasing temperature
- C: Separation of a few l iquids with significant differences in boiling points; and which do not
form azeotropes
- D: Used to purify a solid through the application of a vacuum, causing the substance to sublime
and then deposit on a cold surface. Requires specialized equipment.
B is the correct answer.
24. Arrange the following compounds in terms of increasing intermolecular forces of attraction:
(A). H2 < Cl 2 < I2 < Br 2
(B). H2 < Cl 2 < Br 2 < I2
(C). H 2 < I2 < Cl 2 < Br 2
(D). Cl2 < H 2 < Br 2 < I2
Solution:
- The physical state of the substance gives an indication of the relative strength of the prevalent
intermolecular forces of attraction
- Examining the structure of the molecule can assist in identification of the type of
intermolecular forces that exist
- H2: Predominantly van der Waals forces
- Halogens: Temporary dipoles exist
- At RTP: Cl 2 = gas; Br 2 = liquid; I 2 = solid
B is the correct answer.
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25. Which of the following pairs of substances are allotropes?
(A). Chlorine -35 and Chlorine -37
(B). Na and Li
(C). Red phosphorus and white phosphorus
(D). Na and Mg
Solution:
- Allotropes are the different forms of the same element, in a given physical state
- A: Isotopes
- B: Elements of the same Group
- C: P red and P white are both solids at RTP.
- D: Elem ents of the same Period
C is the correct answer.
26. What volume does 16 g of SO 2 occupy at RTP? Assume that SO 2 is an ideal gas.
Ar: S = 32; O = 16
(A). 6.0 dm3
(B). 12.0 dm3
(C). 24.0 dm3
(D). 48.0 dm3
Solution:
- At RTP, the volume of 1 mole of an ideal gas = 24.0 dm3
- Mr of SO 2 = (32 x 1) + (16 x 2) = 64
- 64 g SO 2 = 1 mole SO 2
- 16 g SO 2 = 0.25 mole SO 2
- 1 mole SO 2 = 24.0 dm3 at RTP
- 0.25 mole SO 2 = 6.0 dm3
A is the correct answer.
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27. 0.5 g of NaOH were dissolved in 100 mL of distilled water. What is the concentration of this
solution?
Ar: Na = 23; O = 16; H = 1
(A). 0.5 M
(B). 0.0125 M
(C). 0.125 M
(D). 40.0 M
Solution:
- Mr of NaOH = (23 x 1) + (16 x 1) + (1 x 1) = 40
- 40 g NaOH = 1 mole NaOH
- 0.5 g NaOH = 0.0125 mol e NaOH
- 100 mL water = 0.5 g NaOH = 0.0125 mole NaOH
- 1000 mL water = 0.125 mole NaOH
- Concentration of this solution = 0.125 mol dm-3
C is the correct answer.
28. A Cr3+ solution is electrolyzed, using a current of 7.60 A. What mass of Cr (s) is formed after
2 days? F = 96,500 C mol-1; Ar: Cr = 52
(A). 52 g
(B). 236 g
(C). 7.6 g
(D). 2 g
Solution:
- Write the half -cell equation showing the number of electrons gained or lost to form the atom or
ion:
- Q = It; where Q = charge delivered in Coulombs, I = current in Ampere, t = time in s
- 2 days = 2 x 24 hours = 2 x 24 x 60 minutes = 2 x 24 x 60 x 60 s = 172,800 s
- Q = 7.60 A x 1 72,800 s = 1,313,280 C
- Ar of Cr = 52, therefore 1 mole of Cr = 52 g
- F = 96,500 C mol-1, therefore 1 mole of e- = 96,500 C
- From the half equation:
3 mole e - = 1 mole Cr
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3 x 96,500 C = 52 g Cr
289,500 C = 52 g Cr
1,313,280 C = 236 g Cr
B is the correct answer.
29. How many molecules of CO 2 are present in 22 g of CO 2?
Ar: C = 12; O = 16
(A). 22
(B). 6.023 x 1023
(C). 3.01 x 1023
(D). 44
Solution:
- Mr of CO 2 = (12 x 1) + (16 x 2) = 44
- 44 g CO 2 = 1 mole CO 2
- 22 g CO 2 = 0.5 moles CO 2
- 1 mole CO 2 = N A (Avogadro's number) molecules CO 2
= 6.023 x 1023 molecules CO 2
- 0.5 moles CO 2 = 3.01 x 1023 molecules CO 2
C is the correct answer.
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Organic Chemistry is the Chemistry of Functional Groups. It is not the chemistry of
memorizing the reactions of individual molecules (of which the number is infinite); but
rather understanding the reactions of classes of molecules. Some useful guidelines:
(i) There are different ways of representing organic structures:
(ii) Focus on the functional group (s), not the rest of the molecule when considering simple
transformations. For example: Given that the following transformation occurs:
What would happen if cyclohexanol was reacted with PCl 3?
- In the above equation, the alcohol group is being replaced by a chlorine; the remainder of the
molecule (hydrocarbon portion/alkyl chain) is unaffected. It is reasonable then to predict that the
following will be the o utcome with cyclohexanol:
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30. Considering the homologous series of alkanes, arrange the following compounds in order of
increasing boiling point:
(A). CH 4 < C 3H8 < C 7H16 < C 8H18
(B). C 8H18 < C 7H16 < C 3H8 < CH 4
(C). CH 4 < C 7H16 < C 3H8 < C 8H18
(D). C 8H18 < C 3H8 < C 7H16 < CH 4
Solution:
- For a homologous series, as molecular size (molecular formula) increases , the intermolecular
forces of attraction will increase. This will therefore mean that more energy is required to
separate individual molecules from each other in a given phase, and hence boiling point (among
other properties) increases.
- Arrange the compounds in terms of increasing molecular size.
A is the correct answer.
31. How many structural isomer s exist, that possess the formula: C 4H10:
(A). 1
(B). 2
(C). 3
(D). 4
Solution:
- Structural isomerism is distinct from stereoisomerism.
- One approach is to draw the unbranched compound represented by the formula, and then use
that as the template to draw branched isomers
- Also consider if cyclic structural isomers can exist
B is the correct answer.
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32. Addition of a few drops of conc. H 2SO4 to the reaction between ethanol and ethanoic acid
increases the rate of product formation. What is the role of the H 2SO4 in this reaction?
(A). Oxidizing agent
(B). Reducing agent
(C). Inhibitor
(D). Promoter
Solution:
- The H 2SO 4 is not altering the identity of the products formed, and is therefore not a reactant,
eliminating options (A) and (B).
- The H 2SO 4 is chemically unchanged at the end of the reaction, is altering the rate of the
reaction, and is therefore a catalyst.
- The rate of this reaction is increased, and the specific type of catalytic activity is therefore
promotion.
D is the correct answer.
Questions 3 3 - 36 refer to the statement below:
KMnO 4/H+ is slowly added to compound A:
33. What is the oxidation number of the manganese in KMnO 4?
(A). 0
(B). + 2
(C). - 2
(D). + 7
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Solution:
- The oxidation numbers of: K = +1; O = -2
- KMnO 4 is a neutral compound, and therefore the sum of all charges of individual atoms present
in its structure must be equal to 0: (1 x K) + (1 x Mn) + (4 x O) = 0;
(1 x +1) + (1 x Mn) + (4 x -2) = 0
Mn = +7
D is the correct answer.
34. What will be observed when the KMnO 4/H+ mixes with A?
(A). The purple colour disappears
(B). No visible reaction
(C). The orange colour disappears
(D). A green solution is formed
Solution:
- KMnO 4/H+ is an oxidizing agent, and compound A is capable of undergoing oxidation ( primary
alcohol to carboxylic acid )
- The oxidizing agent will undergo reduction :
A is the correct answer.
35. What is the identity of the manganese species that is formed?
(A). Mn2+
(B). Mn7+
(C). Mn4+
(D). Mn
Solution:
- See explanation in Question 34.
A is the correct answer.
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36. What is the structure of the organic product that is formed?
Solution:
- See explanation in Question 34.
- A: No reaction
- B: Oxidation
- C: Dehydration
- D: Chain shortening by 1 Carbon
B is the correct answer.
37. What type of polymer is formed when B and C are reacted with each other?
(A). Polyester
(B). Polysaccharide
(C). Polyalkene
(D). Polyamide
Solution:
- An amine and an acid chloride will react to give an amide
- B is a diacid chloride and C is a diamine
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- A simple example of the reaction of a diacid and a diamine is that involved in the formation of
Nylon -6,6, a polyamide :
- Any diacid/diamine pair will be expected to react in a similar manner
D is the correct answer.
38. Compound D shown below, undergoes saponification with NaOH (aq) / Δ.
What are the product(s) of this reaction?
(A). C 4H9COOH and C 3H8O3
(B). C 4H9COO-Na+ and C 3H8O3
(C). C 4H9OH and C 3H8O3
(D). C 4H9 and C 3H8O3
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Solution:
- Saponification is the process by which triglycerides (fats/oils) are converted into a soap
(carboxylic acid salt) and alcohol, under the action of a base.
- At its simplest, it can be regarded as base -mediated hydrolysis of an ester linkage :
- There are three equivalent ester linkages present in D:
- A: Carboxylic acid and alcohol
- B. Salt of carboxylic acid and alcohol
- C. Two different alcohols
- D. Alkyl residue and alcohol
B is the correct answer.
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39. Consider a beaker in a dark room, to which liquid bromine and exc ess cyclohexane have
been mixed at RT.
Which of the following statements is true?
(A). If the mixture is exposed to sunlight, it will become colourless
(B). The mixture is colourless
(C). If the mixture is exposed to sunlight, no visible reaction will be observed
(D). The mixture alternates in colour between blue and colourless, over time
Solution:
- Cyclohexane is an alkane. Alkanes require a source of energy (heat or uv light) to react with
(and decolourize) halogens. At RT and in the dark, no reaction will occur and the orange/brown
colour of bromine will persist.
A is the correct answer.
40. Which of the fo llowing compounds, when fermented, will yield ethanol?
(A). C 3H7OH
(B). C 2H6
(C). CH 3COOH
Solution:
- Fermentation is the anaerobic reaction (absence of oxygen) of carbohydrates (glucose, fructose,
sucrose) to yield ethanol and carbon dioxide.
- A: Propan -1-ol
- B: Ethane
- C: Ethanoic acid
- D: Glucose
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- Note that even if the identity of the structure represented in choice (D) was unknown, by a
process of elimination, options (A) - (C) are invalid.
D is the correct answer.
41. Cyclohexene is reacted with chlorine gas at RT in the dark.
Which of the following are possible products, if any?
Solution:
- Alkenes possess a double bond, which is comprised of a π bond and a σ (single) bond. A π
bond is much weaker, and therefore more reactive, than a σ bond.
- Via their π bond, alkenes can therefore undergo reaction with halogens to yield a dihalide.
- A: No reaction
- B: Addition o f hydrogen chloride
- C: Addition of chlorine
- D: Substitution of a chlorine atom for a hydrogen atom
C is the correct answer.
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42. An organic compound, J, has four carbons, and shows mild effervescence with sodium metal.
Which of the following is a possible structure of J?
Solution:
- Among others, s odium metal undergoes reaction with alcohols and carboxylic acids, to y ield
hydrogen gas and the corresponding sodium salt.
- A: Alcohol
- B: Carbonyl
- C: Ether
- D: Ether
A is the correct answer.
43. You wish to perform the following reaction:
Which of the following will you employ?
(A). H 2 / Ni
(B). H 2O / Δ
(C). H 2SO4 / Δ
(D). HCl / Δ
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Solution:
- In this reaction, a double bond is being removed in the reactant, and a hydrogen atom is added
to each carbon (of the previous double bond).
- This is hydrogenation of an alkene, requiring hydrogen gas and a suitable catalyst
A is the correct answer.
44. Consider the following reaction that leads to the production of the polymer PTFE
(polytetrafluoroethylene), that is used in non -stick coatings:
What type of reaction best describes this process?
(A). Addition
(B). Substitution
(C). Condensation
(D). Fluorination
Solution:
In the context of a polymerization process:
- A: Reaction of two alkenes to give a dimer ( longer chain alkane )
- B: Replacement of one atom or group of atoms, by another
- C: Two monomers reacting to form a dimer and a small byproduct
- D: Incorporation of fluorine
A is the correct answer.
45. AgNO 3 (aq) was mixed with CoCl 2 (aq). What would be observed?
(A). A white precipitate is formed
(B). A colourless solution is formed
(C). A yellow precipitate is formed
(D). A yellow solution is formed
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Solution:
- When two aqueous solutions of different salts are mixed, ion exchange can occur:
- All common nitrates are soluble in water
- AgCl is a white solid
A is the correct answer.
46. KI (aq) is added to a solution of an unknown salt, and a yellow precipitate is formed. Which
of the following ions is most likely present?
(A). Na+
(B). Br-
(C). Cl-
(D). Pb2+
Solution:
- All common salts of Na+ and K+ are soluble in water.
- A: NaI will form
- B: KBr will form
- C: KCl will form
- D: PbI 2 will form
- PbI 2 is a yellow solid
D is the correct answer.
47. Which of the following compounds is expected to be insoluble at RT in water?
(A). Potassium chloride
(B). Strontium nitrate
(C). Lead nitrate
(D). Lead carbonate
Solution:
- All common salts of Na+ and K+ are soluble in water at RT
- All simple nitrates are soluble in water at RT
D is the correct answer.
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48. Which of the following gases will turn moist red litmus paper blue?
(A). HCl
(B). SO 2
(C). NH 3
(D). H 2S
Solution:
- Moist red litmus will be turned blue by an alkaline substance
- A: Acidic
- B: Acidic
- C: Basic
- D: Acidic
C is the correct answer.
49. A simple metal carbonate, MCO 3, is heated until it decomposes, Which of the following is
likely to be observed?
(A). Water vapour is produced
(B). No gas is evolved
(C). A yellow -green gas is produced
(D). A colourless gas w hich turns lime water milky, is produced
Solution:
- Metal carbonates undergo thermal decomposition as follows:
- CO 2 (g) is colourless and turns lime water milky
D is the correct answer.
50. Which of the following oxides is most likely to chemically react with 1 M HCl (aq)?
(A). Na 2O
(B). SO 2
(C). CO 2
(D). CO
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Solution:
- HCl (aq) is an acidic solution and will undergo reaction with those oxides that are basic in
nature, to yield a salt and water.
- Basic oxides typically are formed with metals, while acidic oxides tend to be formed with the
non-metals.
- A: Basic
- B: Acidic
- C: Weakly acidic
- D: Neutral
A is the correct answer.
51. Which of the following oxides is most likely to che mically react with 1 M NaOH (aq)?
(A). K 2O
(B). SO 2
(C). CaO
(D). BaO
Solution:
- NaOH (aq) is an acidic solution and will undergo reaction with those oxides that are acidic in
nature, to yield a salt and water.
- Basic oxides typically are formed with metals, while acidic oxides tend to be formed with the
non-metals.
- A: Basic
- B: Acidic
- C: Basic
- D: Basic
B is the correct answer.
52. Acid rain is likely to cause the most damage to buildings made from this substance:
(A). CaCO 3
(B). CaSO 4
(C). Clay
(D). Concrete
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Solution:
- Acidic substances will react with basic oxides (to yield a salt and water), carbonates (to yield a
salt, carbon dioxide and water), and metals (to yield a salt and hydrogen gas)
A is the correct answer.
53. Hydrated cop per sulphate, when heated, changes colour from blue to white. Why does this
occur?
(A). Loss of H 2O
(B). Loss of SO 2
(C). Loss of SO 2 and H 2O
(D). Loss of H 2O and CO 2
Solution:
- Heating a hydrated salt will drive off its water of crystallization, in a physical process ; which
may result in a colour change.
- The transformation taking place is:
A is the correct answer.
54. On heating, Cu(NO 3)2 yields a gas and a black solid. What is the identity of the gas?
(A). CO 2 (g)
(B). O 2 (g)
(C). NO 2 (g)
(D). NH 3 (g)
Solution:
- Heating nitrates yields an oxide, nitrogen dioxide, and oxygen
- The transformation taking place here is:
Either B or C is the correct answer.
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55. Copper carbonate reacts with hydrochloric acid according to the following balanced
equation:
What is the identity of X in the above equation?
(A). CuCl 2
(B). Cu 2Cl
(C). 2CuCl
(D). CuCl
Solution:
- Metallic oxides are typically basic, and will undergo reaction with acid to yield a salt, water,
and carbon dioxide
- No change in oxidation state of the metal is expected
- In CuCO 3, the oxidation state of Cu = +2
- A: Cu2+
- B: Cu0.5+ (cannot exist)
- C: Cu1+
- D: Cu1+
A is the correct answer.
56. What would be observed if NH 3 (aq) is slowly added to an aqueous solution of CuSO 4?
(A). The blue solution becomes lighter in colour
(B). The blue solution becomes colourless
(C). A pale blue precipitate is initially formed, which dissolves to form a deep blue solution upon
the further addition of NH 3 (aq)
(D). A pale blue precipitate is formed which is insoluble in excess NH 3 (aq)
Solution:
- The simplified transformation taking place is:
C is the correct answer.
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57. An orange solution was made by dissolving a metal salt in water. This solution gave a blood
red colouration with potassium thiocyanate (KSCN). What is the most likely identity of the cation
present:
(A). Fe3+
(B). Fe2+
(C). Ca2+
(D). Na+
Solution:
- Formation of a blood red solution with SCN- (aq) is a confirmatory test for the presence of Fe3+
A is the correct answer.
58. Arrange the following elements in terms of increasing metallic character:
(A). Na < Mg < P < Ar
(B). Mg < Na < P < Ar
(C). Ar < P < Mg < Na
(D). Ar < P < Na < Mg
Solution:
- Metallic character increases down a group, and from right to left on the Periodic Table
C is the correct answer.
59. An element, Y, has an electronic configuration: 2,8,8,1. Which of the following is likely to
describe its properties?
I. Reacts violently with water
II. Can be cut with a knife
III. Conducts electricity
IV. Volatile liquid at RT
(A). I only
(B). IV only
(C). I and IV only
(D). I, II and III only
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Solution:
- With one valence electron, element Y is a Group I element (alkali metal)
- (I), (II), and (III) are properties of Group I elements
- (IV) is not a characteristic of the Group I elements
D is the correct answer.
60. CaO (s) and HCl (aq) will react to give:
(A). CaCl and H 2O
(B). Ca(OH) 2 and Cl 2
(C). CaH and Cl 2
(D). CaCl 2 and H 2O
Solution:
- A metallic oxide will react with an acid to yield a salt and water
- The specific reaction occurring here is:
D is the correct answer.
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Round 1 - Level B
INSTRUCTIONS TO CANDIDATES:
(1). Do not turn this page until you are told to do so
(2). This paper consists of nineteen (19 ) numbered pages
(3). There are sixty (60) multiple choice questions. The duration of this exam in 1 hour and 30
minutes .
(4). Answer all questions. There is no negative marking.
(5). In addition to this question paper, you should also have an answer sheet.
(6). Each question has four (4) options - (A), (B), (C ), (D). Only one is the correct answer.
(7). On you r answer sheet, completely shade your choice.
(8). The use of non -programmable calculators is allowed.
(9). A Periodic Table will not be provided.
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1. Carbon -14 is the radioisotope of carbon with the longest half -life. It may be formed by the
following reaction:
What is the identity of X?
(A). e-
(B). 1H
(C). 13C
(D). 12C
Solution:
- Write in the atomic numbers for the different species:
- Consider the mass and atomic numbers as separate equations:
Mass Numbers:
14 + 1 = 14 + A
A = 1
Atomic Numbers:
7 + 0 = 6 + Z
Z = 1 = Hydrogen
- Therefore:
B is the correct answer.
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2. Argon consists of three stable isotopes:
Isotope Mass Abundance
Ar-36 35.968 0.334%
Ar-38 37.963 0.062%
Ar-40 39.963 99.604 %
What is the atomic mass of Argon?
(A). 38.000
(B). 37.965
(C). 37.963
(D). 39.948
Solution:
- Atomic mass = weighted contribution of the different isotopic masses
= (0.334% x 35.968) + (0.062% x 37.963) + (99.604% x 39.963)
= 39.948
- A: Average of mass numbers
- B; Average of isotopic masses, without consideration of relative abundance
- C: Middle isotope
D is the correct answer.
3. What is the name of the orbital shown below?
(A). s
(B). p z
(C). p z2
(D). d z2
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Solution:
- Examine (i) the shape of the orbital and (ii) the axis/axes it lies on
- A: Spherical orbital
- B: Dumbell shaped lobes lying along the z -axis
- C: Invalid orbital
- D: Dumbell shaped lobes lying alone the z -axis, with a "ring" around the centre
D is the correct answer.
Questions 4 and 5 refer to the following data:
You are utilizing red light at wavelength of 700 nm.
c = 3.0 x 108 ms-1; h = 6.63 x 10-34 J s
4. What is the frequency of this light?
(A). 2.84 x 10-19 Hz
(B). 2.84 x 10-28 Hz
(C). 4.29 x 1014 Hz
(D). 6.63 x 10-34 Hz
Solution:
- f (frequency) = c (speed of light) / λ (wavelength)
- It is imperative that the units match. One cannot divide a quantity with "m" by one with "nm".
- 1 nm = 1 x 10-9 m
- 700 nm = 700 x 10-9 m
- f = (3.0 x 108) / (700 x 10-9) = 4.29 x 1014
- Units Check: f = ms-1 / m = s-1 = Hz
C is the correct answer.
5. What is the energy of this light?
(A). 2.84 x 10-19 J
(B). 2.84 x 10-28 J
(C). 4.29 x 1014 J
(D). 3.0 x 108 J
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Solution:
- E (energy) = h (Planck's constant) x f (frequency)
= (6.63 x 10-34) x (4.29 x 1014)
= 2.84 x 10-19
- Units Check: E = Js x s-1 = J
A is the correct answer.
6. Consider the 1st Electron Affinity of the following atoms:
Atom j k l m
Energy released (kJ mol-1) 60 - 50 328 - 120
Which of these atoms would you expect to most readily form an ionic compound with Na?
(A). j
(B). k
(C). l
(D). m
Solution:
- Na ionizes with the release of an electron
- From the table, the greater the energy released, the more favourable is the process that is
depicted i.e. capture of an electron
- A negative sign for energy released in this case means that energy needs to be put into the
system to facilitate the transformation
- Order of favourability for electron capture:
m < k < j < l
C is the correct answer.
7. Con sider an element with electronic configuration: 1s2 2s2 2p5. What is the most likely
oxidation number of its ion?
(A). 0
(B). -1
(C). + 1
(D). - 5
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Solution:
- Atoms ionize in a manner which leads to 8 valence electrons
- This element has 7 valence electrons (2 x 2s and 5 x 2p), acquiring one more will complete the
octet
- A: 7 valence electrons
- B: 8 valence electrons
- C: 6 valence electrons
- D: 12 valence electrons
B is the correct answer.
8. Consider the ionization energies of element J:
Ionization energy (kJ mol-1) 1st 2nd 3rd 4th
578 1817 2745 11580
What is the likely formula of its oxide?
(A). JO
(B). J 2O
(C). JO 2
(D). J 2O3
Solution:
- The magnitude of ionization energies can be used to determine the number of valence electrons
- When there is a large increase in a particul ar ionization energy, this is indicative that an inner
shell has been broken into
- From the table, a large increase occurs with the 4th ionization energy
- Element J therefore has three valence electrons, and will likely ionize to form J3+
- Its compound with oxygen (O2-) will be J 2O3 (similar to Al 2O3 for Al)
D is the correct answer.
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9. Arrange the following intermolecular forces of attraction in terms of increasing strength:
(A). H -bonding < Van der Waals < Dipole -dipole < Electrostatic
(B). Van der Waals < H -bonding < Dipole -dipole < Electrostatic
(C). Van der Waals < Dipole -dipole < H -bonding < Electrostatic
(D). Van der Waals < H -bonding < Electrostatic < Dipole -dipole
Solution:
- Van der Waals dispersion forces: < 8 kJ mol-1
- Dipole -dipole: 8 - 25 kJ mol-1
- H-bonding: ≈ 40 kJ mol-1
- Electrostatic: > 200 kJ mol-1
Note that these values are averages, there are examples that can fall outside of the ranges listed.
C is the correct answer.
10. What is the shape of the methyl cation, +CH 3?
(A). Trigonal planar
(B). Tetrahedral
(C). Pyramidal
(D). Linear
Solution:
- A carbocation is sp2 hybridized and will therefore have a trigonal planar shape
A is the correct answer.
11. Arrange the following atoms in terms of increasing electropositivity:
(A). F < P < C < K
(B). K < C < P < F
(C). F < C < P < K
(D). K < P < C < F
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Solution:
- Electropositivity increases down a Group, and from left to right across a Period
C is the correct answer.
12. Consider the sy mmetrical molecule cyclopropane, in which the carbon -carbon bond angles
are 60°:
What is the hybridization of each carbon?
(A). sp
(B). sp2
(C). sp3
(D). Varies
Solution:
- This is a saturated system, with only C -C single bonds. Therefore , this is sp3 hybridization.
Note that typical sp3 hybridization results in bond angles of 109.5 °. The much smaller bond
angles in cyclopropane results in substantial ring strain for this molecule, and makes systems
based on it highly reactive.
C is the correct answer.
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13. Balance the following redox reaction in acidic conditions:
Solution:
Balancing a redox reaction is not the simple accounting for atomic stoichiometry (as presented in
options (A) and (D)). Additional steps are required in order to account for the oxidative and
reductive processes occurring:
- (i) Separate into half equations
- (ii) Balance non O and H atoms
- (iii) Balance the O atoms by adding H 2O to the relevant side
- (iv) Balance the H atoms by adding H+ to the relevant side
- (v) Balance the charges on both sides by adding the necessary number of electrons
- (vi) Ensure that the number of electrons in each half equation is the same
- (vii) Add the two half equations tog ether
- (viii) Remove excess species (cancel out common terms)
B is the correct answer.
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14. An iron nail is placed in beaker containing a solution of copper sulphate. What will you
observe over time?
(I). No visible reaction
(II). A reddish -brown solid appears
(III). A green solution forms
(IV). A blue solution forms
(A). I only
(B). II and III only
(C). II and IV only
(D). IV only
Solution:
- In the reactivity series of metals, iron is higher than copper. This means that iron will displace
copp er from a solution of its salt.
- The specific transformation taking place here is:
B is the correct answer.
15. Which of the following is not an assumption of the kinetic theory of gases?
(A). V total (gas) <<< V (container)
(B). Average kinetic energy of molecules 1/T
(C). Average kinetic energy = constant over time
(D). The intermolecular forces of attraction are negligible
Solution:
- The kinetic theory of gases states that gases consist of a large number of molecules tha t are in
constant random motion:
(i) The combined volume of all the individual gas molecules of a sample is negligible compared
to the volume of their container. - Option (A)
(ii) The attractive and repulsive for ces between gaseous molecules are negligible. - Option (D)
(iii) The average kinetic energy of the gaseous molecules at a given/ fixed tempera ture remains
constant over time. - Option (C)
(iv) The average kinetic energy of t he gaseous molecules is directly proportional to the absolute
temperature of the system. - i.e. Average kinetic energy of molecules T
B is the correct answer.
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16. 1.02 moles of a non -ideal gas occupy a container of volume 2.2 L at a temperature of 300 °C.
Which of the following is the most likely pressure exerted by this gas?
R = 0.0821 L atm mol-1 K-1
(A). 21.81 atm
(B). 20.84 atm
(C). 1.0 atm
(D). 22.78 atm
Solution:
- Consider the ideal gas equation: PV = nRT;
where P = pressure; V = volume = 2.2 L; n = number of moles = 1.02 mol; T = absolute
temperature = 300 + 273 = 573 K
- Rearranging and substituting into the equation:
P = nRT / V = (1.02 x 0.0821 x 573) / 2.2 = 21.81
- Units Check: P = (mol x L atm mol-1 K-1 x K) / L = atm
- Pideal = 21.81 atm
- Consider the differences between an ideal gas and a real gas. A real gas has attractive forces
between and among the gaseous molecules. This attraction will reduce the collisions of the
molecules with the walls of their container, and hence result in them exerting a slightly lower
pressure.
- i.e. P ideal > P real
- A: Preal = P ideal
- B: Preal < P ideal
- C: Too low
- D: Preal > P ideal
B is the correct answer.
17. An aqueous solution contains only the following ions:
Ion sodium sulphate magnesium
Concentration (mol dm-3) 1.0 0.8 c
What is the value of c?
(A). 0.2
(B). 0.5
(C). 0.8
(D). 0.3
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Solution:
- Each ion must be balanced by a counterion
- Cations = Na+ and Mg2+; Anion = SO 42-
- Electrically neutral salts: Na 2SO 4 and MgSO 4
- Given that all ions are in the same volume (same solution); concentration is representative of
the number of moles present
- For Na 2SO 4; 2 moles Na+ = 1 mole SO 42-
Therefore 1 mole Na+ = 0.5 mole SO 42-
- Moles of SO 42- remaining = 0.8 - 0.5 = 0.3
- For MgSO 4; 1 mole SO 42- = 1 mole Mg2+
Therefore 0.3 moles SO 42- = 0.3 moles Mg2+
D is the correct answer.
18. Given the following bond dissociation energies:
Cl-Cl = 242 kJ mol-1; F-F = 155 kJ mol-1; Cl-F = 253 kJ mol-1
What is the enthalpy of reaction for the formation of chlorine trifluoride?
(A). 144 kJ mol-1
(B). 811 kJ mol-1
(C). 406 kJ mol-1
(D). - 406 kJ mol-1
Solution:
(i) Write the balanced equation. Since this question is for the formation energetics of ClF 3, 1
mole of ClF 3 alone must be present
(ii) Draw the structures of each species in the reaction and identify the bonds broken (in the
reactants , requiring energy) and the bonds formed (in the products, releasing energy)
(iii) Assign values to the bonds broken and formed
(iv) Calculate the net energetic change
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(iv) Enthalpy change = Energy to break bonds - Energy released from bond formation
= 353.5 kJ mol-1 - 759 kJ mol-1
= - 405.5 kJ mol-1
D is the correct answer.
19. Which reaction is accompanied by the largest increase in entropy?
Solution:
- Entropy is a measure of the disorder in a system. Consider the freedom/restriction of motion of
molecules in different physical states, and the arrangement of disorder can be represented as:
solid < liquid <<< gas
- Consider each reaction shown, and determine which is associated with the biggest difference
between the products and reactants in terms of generation of disorder; based on the number and
states of the species present:
C is the correct answer.
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20. Consider the formation of CaF 2 (s) from Ca (s) and F 2 (g). Which of the following represent
exothermic reactions?
(A). I only
(B). I and IV only
(C). II and III only
(D). II, III and IV only
Solution:
- I: electron affinity - exothermic
- II: enthalpy of atomization - endothermic
- III: 1st Ionization energy - endothermic
- IV: Lattice energy - exothermic
B is the correct answer.
Questions 21 and 22 refer to the following information:
ΔrHϴ = - 566 kJ mol-1
CO (g) O2 (g) CO 2 (g)
Sϴ (J K-1 mol-1) 198 205 214
21. What is ΔrSϴ, the standard entropy change for the reaction?
(A). - 189 J K-1 mol-1
(B). - 173 J K-1 mol-1
(C). 189 J K-1 mol-1
(D). - 214 J K-1 mol-1
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Solution:
- Δreaction Sϴ = ΣΔ products Sϴ - ΣΔreactants Sϴ
= (2 x 214) - [(2 x 198) + (1 x 205)]
= -173
B is the correct answer.
22. At 25 °C, what is Δ rGϴ ?
(A). - 393 kJ mol-1
(B). - 739 kJ mol-1
(C). - 514 kJ mol-1
(D). - 562 kJ mol-1
Solution:
- Consider the Gibbs Free Energy equation: ΔG = ΔH - TΔS
- ΔrGϴ = Δ rHϴ - TΔ rSϴ
= - 566 kJ mol-1 - (298 K)( - 173 J K-1 mol-1)
= - 566 kJ mol-1 - (- 51554 J mol-1)
= - 566 kJ mol-1 + 51.554 kJ mol-1
= - 514.446 kJ mol-1
C is the correct answer
23. Which of the following compounds would you expect to have the highest boiling point?
(A). C 2H6
(B). CH 3OH
(C). CH 3COOH
(D). CH 3CH 2Cl
Solution:
- The relative magnitude of boiling points is a function the intermolecular forces of attraction.
- Greater intermolecular forces = higher boiling point.
- Van der Waals < Dipole -dipole < H -bonding < Electrostatic
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- Increasing boiling point: C 2H6 < CH 3CH 2Cl < CH 3OH < CH 3COOH
C is the correct answer.
24. The square planar complex Pt(NH 3)2Cl2 has two stereoisomers. The cis isomer is a potent
chemotherapy drug, while the other isomer is not. What is the structure of the ineffective isomer?
Solution:
- The ineffective isomer is the trans isomer
- A: cis
- B: cis
- C: trans
- D: tetrahedral , incorrect structure
C is the correct answer
25. Arrange the following 1 M solutions in terms of decreasing pH:
(A). KOH > CH 3CH 2NH 2 > H 3PO 4 > Phenol
(B). KOH > CH 3CH 2NH 2 > Phenol > H 3PO 4
(C). Phenol > H 3PO 4 > CH 3CH 2NH 2 > KOH
(D). Phenol > H 3PO 4 > KOH > CH 3CH 2NH 2
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Solution:
- Organic acids typically have a higher pH than mineral acids, therefore pH of: phenol > H 3PO 4
- Mineral bases typically have a higher pH than organic bases, therefore pH of KOH >
CH 3CH 2NH 2
B is the correct answer
26. Calculate the pH of 0.025 M CH 3CH 2COOH
pKa (propanoic acid) = 4.88
(A). 4.88
(B). 0.69
(C). 3.25
(D). 0.19
Solution:
- Propanoic acid a carboxylic acid, and is therefore not fully ionized in solution. The equilibrium
state has to be considered:
- pKa = - logK a
- - logK a = 4.88
- logK a = - 4.88
- Ka = 10-4.88
- Because propanoic acid is weakly ionized in solution: X is small,
0.025 >>> X
0.025 - X ≈ 0.025
- Ka = [CH 3CH 2COO-][H+] / [CH 3CH 2COOH] = (X)(X) / 0.025
- X2 = 0.025 x K a
- X = (0.025 x 10-4.88)1/2 = [H+]
- pH = - log[H+] = - log (0.025 x 10-4.88)1/2 = 3.25
C is the correct answer
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