Canadian International Matriculation Programme
Sunway University College
[SCH4U] CHEMISTRY FINAL EXAMINATION
Date:
Wednesday, Nov. 28, 2007
Time:
2:30 p.m. – 4:30 p.m.
Length:
2 Hours
Lecturer:
Ms Kimberley Gagnon
Student Name: __________________________Section/Period: _______
INSTRUCTIONS TO STUDENTS:
Check that your examination has 15 typed pages, including the cover page.
Answer all questions in the spaces provided.
Marks are indicated in the right-hand margin in brackets.
You may use a scientific calculator.
You may use a dictionary.
Chemistry Tables are provided on pages 12 to 15. Please tear them off now for easier
referral.
7. There are four sections to the exam. Read instructions to each part carefully.
1.
2.
3.
4.
5.
6.
STRUCTURE/EVALUATION
PART A
PART B
PART C
PART D
Knowledge/Understanding
Communication
Inquiry
Making Connections
TOTAL
40 marks, allow 25 minutes
10 marks, allow 15 minutes
45 marks, allow 60 minutes
15 marks, allow 20 minutes
110 marks, 2 hours
2
Part A: Knowledge/Understanding: (40 marks, allow 25 minutes)
Multiple Choice: On the line to the left of the question, identify the letter of the choice that best completes the
statement, or answers the question. Note: Each question is worth 2 marks.
____
1. Which substance is the strongest reducing agent?
a. Na
b. Na+
c. H+
d. Mg
e. Mg2+
____
2. A voltaic cell has a solid lead electrode in a solution of 1.0 mol/L Pb(NO3)2 and a solid zinc electrode in a
solution of 1.0 mol/L Zn(NO3)2. What reactant will be reduced?
a. Zn2+
b. Pb2+
c. Pb
d. Zn
e. NO3−
____
3. Given the following standard reduction potentials, which statement is correct?
K+ + e → K(s)
E° = –2.931 V
Fe2+ + 2e → Fe(s)
E° = –0.447 V
2H+ + 2e → H2(g)
E° = 0.000 V
2+
Cu + 2e → Cu(s)
E° = 0.342 V
a.
b.
c.
d.
e.
The best oxidizing agent is K+.
The most easily oxidized substance is Cu.
H+ has no tendency to form H2.
The reaction Cu2+ + Fe → Fe2+ + Cu has a standard cell potential of 0.789 V.
The hydrogen gas is produced at a temperature of absolute zero.
____
4. Which change does not increase the voltage of the following electrochemical cell?
2Ag+(aq) + Cu(s) → 2Ag(s) + Cu2+(aq)
a. increasing the concentration of nitrate ions in the copper half-cell
b. increasing the concentration of silver ions in the silver half-cell
c. decreasing the concentration of copper ions in the copper half-cell
d. adding solid silver nitrate to the silver half-cell
e. All of these actions increase the voltage of this cell.
____
5. Which pair of half-cells, when connected, results in the highest possible voltmeter reading?
a. Fe and Cu
b. Mg and Au
c. Fe and Au
d. Mg and Cu
e. They all have the same voltmeter reading.
3
____
6. A strip of copper is placed in a 1.0 mol/L solution of Cu(NO3)2. A strip of silver is placed in a 1.0 mol/L
solution of silver nitrate. The two solutions are connected by a voltmeter, and a salt bridge is used. Then
the voltmeter is removed, and the two electrodes are connected by a wire. Which observation is not
made?
a. Electrons flow in the external circuit from the copper electrode to the silver electrode.
b. There is a net general movement of silver ions through the salt bridge to the copper halfcell.
c. The silver electrode increases in mass as the cell operates.
d. Negative ions pass through the salt bridge from the silver half-cell to the copper half-cell.
e. All of the above will occur.
____
7. Consider the following balanced equation.
2Au3+(aq) +3Mg(s) → 2Au(s) + 3Mg2+(aq) E°cell = 3.870 V
What is the cell potential for the reaction below under the following concentrations?
Mg(s) │Mg2+(aq)(0.010M)║Au3+(aq)(0.200M) │Au(s)
Given: Ecell = E°cell - 0.0257V ln Q
n
a.
b.
c.
d.
e.
____
3.825 V
3.870 V
3.883 V
3.915 V
4.006 V
8. An electrochemical cell involves the following reaction. If the silver-copper cell is run long enough for a
change of 1.08 g at the silver electrode, what will the change in mass at the copper electrode be?
2Ag+(aq) + Cu(s) → 2Ag(s) + Cu2+(aq)
a.
b.
c.
d.
e.
____
1.08 g loss
1.08 g gain
0.32 gain
0.63 g gain
0.32 g loss
9. Consider the following half-reactions.
Pb2+(aq) + 2e− → Pb(s)
Ag+(aq) + e− → Ag(s)
E° = –0.1262 V
E° = 0.800 V
What is the standard cell potential for the reaction below?
2Ag(s) + Pb2+(aq) → Pb(s) + 2Ag+(aq)
a.
b.
c.
d.
e.
−0.926 V
0.674 V
−0.674 V
0.926 V
0.463 V
4
____ 10. Which redox reaction is not spontaneous under standard conditions?
a. 2Fe + 3Br2 → 2Fe3+ + 6Br−
b. 2Fe3+ + 3Ni → 2Fe + 3Ni2+
c. Fe2+ + Ni → Fe + Ni2+
d. 2Fe3+ + Ni → 2Fe2+ + Ni2+
e. All of these reactions are spontaneous.
____ 11. Which statement about electrolytic cells is not correct?
a. Electrons always flow from the anode.
b. The standard cell potential of an electrolytic cell is negative.
c. In an electrolytic cell, electroplating occurs at the cathode.
d. Reduction occurs at the cathode.
e. Oxidation occurs at the cathode.
____ 12. Which situation must be true for two electrons to occupy the same orbital?
a. The electrons must have the same principal quantum number, but the other quantum
numbers must be different.
b. The electrons must have the same spin.
c. The electrons must have identical sets of quantum numbers.
d. The electrons must have low energy.
e. The electrons must have the opposite spin.
____ 13. An electron has the following set of quantum numbers: n = 3, l = 1, ml = 1, ms =
. In which orbital is
this electron found?
a. 3s
b. 3p
c. 3d
d. 3f
e. 4p
____ 14. Which element contains a full 3s orbital?
a. B
b. Na
c. Mg
d. Be
e. Ne
____ 15. Which element has the ground state electron configuration [Ne] 3s23px13py1 for its valence electrons?
a. Mg
b. Al
c. Si
d. P
e. S
____ 16. How many p orbitals are in each energy level, except n = 1?
a. 1
b. 3
c. 5
d. 6
e. 7
5
____ 17. Which pair of atoms and/or ions is isoelectronic (same number of electrons)?
a. O2− and Cl−
b. Ca2+ and Cl−
c. F− and N2−
d. Li+ and Na+
e. K+ and Kr
____ 18. How does atomic radius change from left to right across a period in the periodic table?
a. It increases.
b. It decreases.
c. It stays the same.
d. It increases and then decreases.
e. It decreases and then increases.
____ 19. What is the shape of a molecule of antimony(III) fluoride, SbF3?
a. linear
b. trigonal planar
c. trigonal pyramidal
d. tetrahedral
e. angular
____ 20. Predict the shape of a phosphate ion, PO43−.
a. seesaw
b. trigonal planar
c. trigonal pyramidal
d. tetrahedral
e. square planar
Part B: Communication: (10 marks, allow 15 minutes)
For the following questions, write the most appropriate answer in the space provided.
21. Define the standard molar enthalpy of formation. Give an example.
(3 marks)
22. What are the two major requirements for a chemical reaction to occur?
(2 marks)
6
23.
Define Le Châtelier’s principle. Give an example to show how Le Châtelier’s principle can be used.
(3 marks)
24.
Describe two ways that a buffer solution can be made.
(2 marks)
Part C: Inquiry: (45 marks, allow 60 minutes)
For the following questions, write the answer in the space provided. Use complete sentences in your
answer. If the question requires mathematical calculations, show all of your work. Write a final statement
that gives your solution. Answer all questions with the correct number of significant figures (digits).
(5 marks)
25. Complete the following table.
Reaction
Name of organic product(s)
3,4-dimethyl-2-pentene + bromine →
2-methylbutanal + K2Cr2O7 (alkaline)→
H SO
2
4 ( aq )
3-ethyl-3-octene + H20 (l) 

→
2,4-dibromopentanoic acid + ammonia
Heat

→
4-methylhexanol
H SO
/ 180 0 C
2
4 ( aq )



→
7
26. Complete the following table, based on the following equilibrium system.
Ni2+(aq) + 6NH3(aq) ⇔ Ni(NH3)62+(aq)
green
(5 marks)
blue
Stress
addition of nickel(II) nitrate
removal of ammonia
addition of water
addition of inert gas at constant pressure
removal of Ni(NH3)62+(aq)
Colour
27. a) Draw a graph to show the changes in [HI], [H2], and [I2] in the following equilibrium system, if the
(3 marks)
container initially contains 2.0 mol/L HI(g).
H2(g) + I2(g) ⇔ 2HI(g)
b) Draw a graph to show the change in equilibrium if the concentration of HI is increased.
(2 marks)
8
(5 marks)
28. Use the following diagram to answer the questions below.
a) Is the reaction exothermic or endothermic? Explain.
b) What letter represents the activation energy of the forward reaction?
c) What letter represents the heat of reaction?
d) What letter represents the activation energy of the reverse reaction?
________
________
________
29. The experimental data in the table below were collected for the following reaction of nitrogen monoxide
and hydrogen. What is the rate law for this reaction (include the value for the rate constant)?
(4 marks)
2NO(g) + 2H2(g) → N2(g) + 2H2O(g)
Trial
1
2
3
Initial concentration (mol/L)
[NO]
[H2]
0.10
0.10
0.10
0.20
0.20
0.10
Initial rate of disappearance of NO (mol/L•s)
1.23 × 10−3
2.46 × 10−3
4.92 × 10−3
9
30.
0.566 mol of NO2(g) is placed in a 1.00 L container. After the following equilibrium is established, the
container is found to contain 0.500 mol of NO. What is the equilibrium constant for this reaction?
(4 marks)
2NO2(g) ⇔
2NO(g) +
O2(g)
31. A salt solution of NaF(aq) has an initial concentration of 0.075 mol/L. What is the pH of the salt solution?
(4 marks)
10
32. The solubility of calcium fluoride is 1.6 × 10−2g/L at 20°C. Determine Ksp for calcium fluoride.
(4 marks)
33. A buffer solution is made by mixing 400.0 mL of 0.15 mol/L acetic acid with 325 mL of 0.20 mol/L
sodium acetate. What is the pH of the buffer solution?
(5 marks)
11
34. Use standard heats of formation to calculate the heat of reaction for the following equation.
(4 marks)
2H2S(g) + 3O2(g) → 2H2O(l) + 2SO2(g)
Part D: Making Connections: (15 marks, allow 20 minutes)
For the following questions, write the answer in the space provided. Use complete sentences in your
answer. If the question requires mathematical calculations, show all of your work. Write a final statement
that gives your solution.
(7 marks)
35. Ammonium nitrate is used in a cold pack.
NH4NO3(s) →
NH4+(aq)
+
NO3−(aq)
∆H = 26.2 kJ
a) 30.0 g of ammonium nitrate is used in a cold pack that contains 100.0 mL of water. What is the
temperature change of the water, assuming that all the heat absorbed by the reaction comes from
the water? Note: The specific heat capacity of water is 4.184 J/(g°C).
b) If the initial temperature of the water is 22.0°C, what is final temperature of the water?
12
c) Why is it important to make sure that the correct amount of the ammonium nitrate is used in the
cold pack?
36. A refrigerator keeps food fresh and stops it from spoiling. If food is left long enough in a refrigerator,
however, it goes bad. Explain.
(3 marks)
37.
Balance only ONE of the questions below.
FeSO4 + H2SO4 +
KMnO4 → Fe2(SO4)3 +
OR
NO3− + Bi → Bi3+ + NO2
(acidic)
(5 marks)
K2SO4 + MnSO4 + H2O