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Chemistry 12
Multiple Choice Exam Review
**Questions taken from old Chemistry 12 Provincial Exams
Name:
1. Which phase change results in the release of energy?
A. H2O(g)  H2O(l)
B. H2O(l)  H2O(g)
C. H2O(s)  H2O(l)
D. H2O(s)  H2O(g)
2. A 10.0 g sample of a substance has 34.8 J of energy added to it and its temperature increases by 25.0°C. What is the
specific heat capacity of the substance?
A. 0.139 J/g°C
B. 0.338 J/g°C
C. 0.718 J/g°C
D. 0.870 J/g°C
3. If the ΔH for a reaction is positive, which of the following statements is true?
A. The kinetic energy is decreasing in the system.
B. The potential energy is decreasing in the system.
C. The products have less potential energy than the reactants.
D. The reactants have less potential energy than the products.
4. In experiments that use a simple calorimeter, what assumption is made?
A. Distilled water is always used.
B. Heat is not transferred to the surroundings.
C. The final temperature is above room temperature.
D. The starting temperature is at room temperature.
5. At its boiling point, 20.7 kJ of heat is required to vaporize 53.2 g of sulfur dioxide, SO 2(l). What is the enthalpy of
vaporization for SO2(l)? (SO2 = 64.1 g/mol)
A. 5.39 kJ/mol
B. 17.2 kJ/mol
C. 20.7 kJ/mol
6. Using only the information given below, which valid interpretation can be made?
K(s) + ½Br2(l)  KBr(s) ΔH = -393.8 kJ
D. 24.9 kJ/mol
A. The decomposition of KBr(s) is an endothermic process.
B. The dissolving of KBr(s) is an exothermic process.
C. The equation represents a phase change.
D. KBr(s) is less stable than its constituent elements.
7. What is the enthalpy change for the following reaction? 2SO2(g) + O2(g)  2SO3(g)
A. -198 kJ
B. -99 kJ
C. 99 kJ
D. 198 kJ
8. How much heat is required to raise the temperature of 250.0 g of H 2O(l) from 10.8°C to 31.1°C?
A. 21.2 kJ
B. 43.8 kJ
C. 274 kJ
D. 523 kJ
9. Which statements are true?
i) A thermochemical equation must include the physical states of all substances.
ii) The coefficients in a themochemical equation are interpreted as moles.
iii) The sign of ΔH for an endothermic reaction is negative.
A. i) and ii)
B. i) and iii)
C. ii) and iii)
D. i), ii), and iii)
10. Which one of the following processes is endothermic?
A. C(s) + O2(g)  CO2(g)
B. 2H2(g) + O2(g)  2H2O(g)
C. H2O(g)  H2O(s)
D. H2O(s)  H2O(l)
11. What is the ΔHºf of hydrogen fluoride?
H2(g) + F2(g)  2HF(g) + 542 kJ
A. –542 kJ
B. –271 kJ
C. +271 kJ
D. +542 kJ
12. What is the specific heat capacity of a substance if 167 J are needed to change the temperature of 15.0 g of it from
25.0ºC to 33.0ºC?
A. 0.19 J/g•ºC
B. 0.34 J/g•ºC
C. 0.72 J/g•ºC
D. 1.4 J/g•ºC
13. Which process involves the largest enthalpy change?
A. combustion of CH4(g)
C. formation of HCl(g)
B. condensation of H2(g)
D. fusion of H(g)
14. Which represents an exothermic process?
A. 2CO(g) + O2(g)  2CO2(g)
ΔH = –566 kJ
B. 2H2O(l)  H2O2(l) + H2(g)
ΔH = 384 kJ
C. N2(g) + O2(g) + 180 kJ  2NO(g)
D. This diagram:
15. If the heat of formation for the chemical reaction S 8(s) + 12O2(g)  8SO3(g), is –395.7 kJ/mol of SO3, how can the
equation be rewritten to include the heat term?
A. S8(s) + 12O2(g)  8SO3(g) + 3166 kJ
B. S8(s) + 12O2(g)  8SO3(g) – 395.7 kJ
C. S8(s) + 12O2(g) 
8SO3(g) + 395.7 kJ
D. S8(s) + 12O2(g) + 3166 kJ 
8SO3(g)
16. Use the equations to answer the question below.
2A + B  A2B ΔH = –377.7 kJ
2A + BC  A2B + C ΔH = –475.6 kJ
What is the value of ΔH for the reaction B + C  BC?
A. +853.3 kJ
B. +97.9 kJ
C. –97.9 kJ
D. –853.3 kJ
17. Which of the following would produce a precipitate when equal volumes of 0.5 mol/L aqueous solutions of each are
mixed? (Refer to the Data Booklet)
A. AgNO3 and NaCl
B. BaCl2 and KNO3
C. NaOH and H2CO3
D. (NH4)2CO3 and K2SO4
18. Solubility data for four different salts in water are shown in the table below.
Salt
(i)
Solubility in Water at 60°C
10 g in 50 mL of H2O
(ii)
20 g in 60 mL of H2O
(iii)
30 g in 120 mL of H2O
(iv)
40 g in 80 mL of H2O
A. i
B. ii
C. iii
D. iv
19. Which compound is least soluble in water at 25°C? (Refer to the Data Booklet)
A. Ca(OH)2
B. Na3PO4
C. SrCO3
D. (NH4)2SO4
20. What mass of H3BO3(s) is required to prepare 4.00 L of a 0.500 mol/L solution of H 3BO3(aq)? (H3BO3 = 61.8 g/mol)
A. 2.00 g
B. 30.9 g
C. 61.8 g
D. 124 g
21. Which statement explains what happens when an ionic solid is added to a polar, liquid solvent?
A. They will dissolve because both solid and solvent particles are uncharged.
B. They will dissolve because neither particles are gaseous.
C. They will dissolve because the particles of the solid and liquid have similar polarity.
D. They will dissolve because the particles in the solid are uncharged.
22. 35.0 mL of a solution is diluted by the addition of water to a final volume of 62.0 mL. The diluted solution has
concentration of 1.65 mol/L. What was the concentration of the original solution?
A. 1.56 mol/L
B. 1.96 mol/L
C. 2.92 mol/L
D. 3.16 mol/L
23. When a mixture of solid KNO3 and water is prepared, what is the KNO3 called?
A. precipitate
B. solute
C. solution
D. solvent
24. What is the concentration of a solution if 3.4 g of NH 3 is dissolved in enough water to make 500 mL of solution?
–4
–3
A. 4.0 x 10 mol/L
B. 6.8 x 10 mol/L
C. 0.40 mol/L
D. 6.8 mol/L
25. What is the concentration of a solution of sulphuric acid that is prepared by the dilution of 150 mL of 5.00 mol/L
H2SO4 to 2.00 L?
A. 0.150 mol/L
B. 0.375 mol/L
C. 0.500 mol/L
D. 0.750 mol/L
26. Combining which solutions would result in a precipitate? (See the Solubility Table)
A. Ca(NO3)2(aq) and NaClO3(aq)
C. Pb(NO3)2(aq) and NaClO3(aq)
B. Ca(NO3)2(aq) and NaI(aq)
D. Pb(NO3)2(aq) and NaI(aq)
27. What is the definition of molarity of a solution?
A. moles of solute per kilogram of solution
C. moles of solute per litre of solution
B. moles of solute per kilogram of solvent
D. moles of solute per litre of solvent
28. Which combinations of solid and liquid would likely form a solution?
I. ionic solid and nonpolar liquid
III. nonpolar solid and nonpolar liquid
II. ionic solid and polar liquid
IV. nonpolar solid and polar liquid
A. I and III
B. I and IV
C. II and III
D. II and IV
29. The equation for the decomposition of baking soda is: 2NaHCO3(s) + energy  Na2CO3(s) + CO2(g) + H2O(g)
Which of the following would increase the quantity of CO2(g) produced?
A. decreasing the temperature
B. decreasing the volume
30. Consider the following reactions at 25ºC.
C. increasing the pressure
D. increasing the temperature
+
-
I Ag (aq) + Br (aq) AgBr(s)
II 4Fe(s) + 3O2(g)  2Fe2O3(s)
Which of the following statements best describes the relative rates of the two reactions?
A. I and II are both fast.
C. I is faster than II
B. I and II are both slow.
D. II is faster than I
31.
32. On the activation energy diagram shown, which letter labels the activated complex for the reaction?
A. a
B. b
C. c
D. d
33. According to the collision theory, what must happen in order for a reaction to occur?
I. Molecules must collide
II. Molecules must collide with the correct orientation
III. The collisions of molecules must occur with enough energy
A. I and II
B. I and III
C. II and III
D. I, II, and III
34. The decomposition of hydrogen peroxide to produces oxygen and water is used in some contact lens cleaning
procedures.
2H2O2 (aq)  2H2O(l) + O2(g)
A small piece of platinum is used as a catalyst for purpose of the platinum catalyst?
A. to change the equilibrium concentrations
B. to decrease the time required to reach equilibrium
C. to shift the equilibrium toward the product side
D. to shift the equilibrium toward the reactant side
35.
36. The equilibrium constant of the following reaction equals 10.8 at a certain temperature.
2NO2 (g)  N2O4 (g)
If the concentration of NO2 is 0.0191M, what is the concentration of N2O4?
A. 0.206 mol/L
B. 4.21 x 10-2 mol/L
C. 3.94 x 10-3 mol/L
D. 1.77 x 10-3 mol/L
37. This reaction is allowed to come to equilibrium: 2NO(g) + 2CO(g) N2 (g) + 2CO2(g)
Additional NO(g) is then injected into the reaction chamber, and equilibrium is restored. Which statement is true?
A. All concentrations remain the same.
B. A new equilibrium is reached such that[CO] decreases.
C. A new equilibrium is reached such that [N2] decreases.
D. The numerical value of the equilibrium constant increases
38. In this reaction, the concentrations of Ag+(aq) and Cl-(aq) are both equal to 1.3 x 10-5 mol/L.
AgCl(s) Ag+(aq) + Cl-(aq)
What is the value of the equilibrium constant for this reaction?
A. 1.7 x 10-10
B. 2.6 x 10-10
C. 1.3 x 10-5
D. 3.6 x 10-3
39. Assume that the following system has reached equilibrium in a closed container. Which of the following changes will
produce a greater yield by shifting the equilibrium to the right?
S8 (s) + 12 O2 (g) 8 SO3 (g)
ΔH = -3166 kJ
A. add a catalyst
C. increase the temperature
B. increase the pressure
D. remove O2 (g)
40. What effect does a catalyst have?
A. increases the reaction rate by decreasing the heat of reaction
B. increases the reaction rate by increasing the activation energy of the reverse reaction
C. increases the reaction rate by lowering the activation energy of the forward reaction only
D. increases the reaction rate by providing an alternative pathway with a lower activation energy.
41. The rate of a chemical reaction may depend upon which factors?
I. concentration of reactants
II. nature of reactants III. temperature
A. I and II
B. I and III
C. II and III
D. I, II, and III
42. Which statement concerning an equilibrium is true?
A. It cannot exist between a liquid and its vapour.
B. It does not exist when the temperature is constant.
C. It exists in a closed system.
D. It occurs in all chemical reactions.
43. Which would definitely increase the concentration of NO2(g) present at equilibrium in this reaction?
2NO(g) + O2(g) 2NO2(g) + 113 kJ
A. adding a catalyst
B. adding NO(g) C. increasing the volume D .increasing the temperature
44. The potential energy diagram for the reaction, Br + H2 HBr + H, is:
What is the heat of reaction for the forward reaction?
A. –117 kJ/mol B. –105 kJ/mol C. +105 kJ/mol D. +117 kJ/mol
45. Which of these equilibriums will shift to the left as a result of a decrease in volume?
A. H2(g) + Cl2(g) 2HCl(g)
C. 2SO3(g) 2SO2(g) + O2(g)
B. N2(g) + 3H2(g) 2NH3(g)
D. 4Fe(s) + 3O2(g) 2Fe2O3(s)
46. Which will cause an increase in the numerical value of the equilibrium constant for this reaction?
C(s) + 2H2(g) CH4(g) + 75 kJ
A. decreasing the temperature
B. decreasing the volume
C. finely powdering the C(s)
D. increasing [H2]
47. At equilibrium in this gaseous system
2A + B 2C + D
[A] = 2.00, [B] = 1.20, [C] = 3.00, and [D] = 0.600. What is the numerical value of the equilibrium constant?
A. 4.32
B. 1.33
C. 1.12
D. 0.889
6
48. Which statement is true for this reaction if its equilibrium constant equals 1.6 x 10 ?
2CO(g) + O2(g) 2CO2(g)
A. It produces mostly products.
B. It goes only in one direction.
C. It does not take place to a significant extent.
D. It takes place very rapidly.
49. What is the equilibrium constant expression for the reaction: CaCO3 (s)  CaO(s) + CO2 (g)
50. The equilibrium: CO(g) + H2O(g) CO2 (g) + H2 (g) Kc = 0.50
is established in a one litre container. If 2.0 mol of CO and 3.0 mol of H2O are in equilibrium with 4.0 mol of H2, how much
CO2 is present?
A. 0.33 mol
B. 0.75 mol
C. 2.0 mol
D. 3.0 mol
51. A 0.025 mol/L aqueous solution of a pure substance has a pH = 12 .4. How would this substance be classified?
A. strong acid
B. weak acid
C. strong base D. weak base
52. Citric acid, which is extracted from citrus fruits and pineapple waste, is extensively used in the manufacture of candy
and soft drinks. Which of the following is a characteristic of citric acid solution?
A. a bitter taste B. a sour taste C. the ability to neutralize vinegar D. the ability to turn litmus from red to blue
53. According to the Brønsted-Lowry theory what what does an acid do?
A. acts as a proton acceptor in any system
C. decrease [H+] in an H2O solution
B. acts as a proton donor in any system
D. increases [H+] in an H2O solution
54. What could be the pH of acid rain?
A. 5.0
B. 7.0
C. 9.0
D. 11.0
55. Which characteristic is true of an Arrhenius base?
A. accepts OH- in solution
C. donates protons in solution
B. accepts protons in solution
D. releases OH- in solution
56. Consider the following equilibrium:
CH3COOH(aq) + OCl- (aq) HOCl(aq) + CH3COO- (aq)
Identify the stronger acid and predict whether reactants or products are favoured at equilibrium.
A. CH3COOH stronger, products favoured.
C. HOCl stronger, products favoured
B. CH3COOH stronger, reactants favoured
D. HOCl stronger, reactants favoured
57. Which statement is true for the following reaction? HCN(aq) + H2O(l)  CN-(aq) + H3O+
A. HCN is an acid and CN- is its conjugate base
C. H2O is an acid and HCN is its conjugate base
B. HCN is an acid and H2O is its conjugate base
D. H2O is an acid and H3O+ is it s conjugate base
58. What volume of 1.20 mol/L HBr(aq) is required to neutralize 50.0 mL of 0.350 mol/L KOH?
A. 42.9 mL
B. 15.6 mL
C. 14.6 mL
D. 5.25 mL
59. The pH of a 0.10 mol/LK HCl is about 1.0 and the pH of a 0.10 mol/L H3PO4 is about 1.6. Which following of the
following best explains the difference?
A. HCl is more ionized than H3PO4 in water
C. H3PO4 is amphiprotic in water
B. HCl is a weaker acid than H3PO4.
D. H3PO4 has more hydrogen atoms
60. Which statements are true for an aqueous solution of an acid?
I. conducts electricity
II. reacts with zinc forming hydrogen gas III. turns red litmus blue
A. I and II
B. I and III
C. II and III
D. I, II, and III
61. According to the Arrhenius theory, what does a base do?
+
A. accepts H ions from an acid
B. ionizes completely when dissolved in water
–
C. ionizes in aqueous solutions to produce hydronium ions
D. produces OH ions when dissolved in water.
62. What is true for an amphoteric (amphiprotic) substance?
A. behaves as a weak acid in solution
C. behaves as a weak acid or a weak base in solution
B. behaves as a weak base in solution
D. has a very low pH in solution
63. What is a Brønsted-Lowry acid?
A. an electron acceptor B. an electron donor
C. a proton acceptor
D. a proton donor
64. What is one of the acid-base conjugate pairs in this equilibrium?
–
–
CN (aq) + H2O(l)  HCN(aq) + OH (aq)
A. HCN, CN
–
B. HCN, H2O
C. HCN, OH
–
D. H2O, CN
–
65. A 0.1 mol/L solution of an electrolyte has a pH of 6. How may the electrolyte be described?
A. a strong acid
B. a strong base
C. a weak acid
D. a weak base
66. Which information indicates the most acidic solution?
+
A. [H3O ] = 10
–3
–
B. [OH ] = 10
–10
C. pH = 6
D. pOH = 12
–
67. What is the effect of adding CH3OO (aq) ions to a solution of acetic acid in water?
-
+
CH3COOH(aq) + H2O(l) CH3COO (aq) + H3O (aq)
A. causes Ka of acetic acid to decrease
B. increases the concentration of CH3COOH molecules
C. increases the degree of ionization of acetic acid
D. reduces the pH of the solution
68. If the pH of an aqueous solution is 11, what is the hydroxide ion concentration?
–3
–7
–11
–14
A. 1 x 10 mol/L
B. 1 x 10 mol/L
C. 1 x 10 mol/L
D. 1 x 10 mol/L
69. When NaOH(aq) is titrated with HCl(aq), what is the pH at the equivalence point?
A. equal to 7
B. greater than 7
C. less than 7
D. undefined
+
70. What is the [H3O ] of seawater that has a pH of 8.10?
-9
–8
–6
A. 7.9 x 10 mol/L
B. 1.0 x 10 mol/L
71. Which is a strong acid as shown by Ka values?
A. H3BO3
B. H2CO3
–1
C. 1.3 x 10 mol/L
D. 8.0 x 10 mol/L
C. HNO2
D. HNO3
72. In the following reaction, which species is oxidized? 8NaI + 5H2SO4 4I2 + H2S + 4Na2SO4 + 4H2O
A. Na
B. I
C. S
D. O
73. What is the oxidation number of phosphorus in NaH2PO4 ?
A. -3
B. +1
C. +3
D. +5
74. In which compound does chlorine have the highest oxidation number?
A. NaClO
B. NaClO2
C. NaClO3
D. NaClO
75. In the following reaction, which species is the reducing agent?
3Cu(s) + 6H+(aq) + 2HNO3(aq)  3Cu2+(aq) + 2NO(g) + 4H2O(l)
A. Cu
B. H+
C. H in HNO3
D. O in HNO3
76. In what type of cell are the redox reactions made to occur by an externally applied electric current?
A. chemical cell
B. electrochemical cell
C. electrolytic cell
D. galvanic cell
77. Given the reaction: 2Al + 3Ni2+ 2Al3+ + 3Ni
What would be the net cell potential, Eº, for the reaction?
A. -1.94 V
B. 1.42 V
C 1.94
D. 2.58 V
78. In the oxidation-reduction reaction:
2–
–
3S + 2MnO4 + 4H2O  3S + 2MnO2 + 8OH
–
2–
2–
the S changes oxidation number to give the element S. Which statement is true?
2–
2–
A. S gains electrons
B. S has been oxidized
C. S has been reduced
79. Which species has the highest oxidation number for manganese?
A. MnO2
B. MnO4
–
C. Mn2O3
2–
D. S is an oxidizing agent
D. MnSO4
80. What does the oxidizing agent do in an oxidation-reduction reaction?
A. gains electrons from the reducing agent
C. is always oxidized
B. loses electrons to the reducing agent
D. is oxidized by the reducing agent
81. Which of the following species is the strongest oxidizing agent?
A. Br2
B. Cl2
C. F2
D. I2
82. Which of these chemical reactions is an oxidation-reduction reaction?
A. Ba(NO3)2 + Na2SO4 BaSO4 + 2NaNO3
C. CO2 + H2O H2CO3
B. Cl2 + 2NaBr Br2 + 2NaCl
D. HCl + NaOH NaCl + H2O
83. Which statement is true for an electrolytic cell?
A. Cations are attracted to the positive electrode.
B. Reduction occurs at the anode.
C. The cell operates on the energy of a power supply.
D. The charge is carried through the external circuit by ions.
4+
2+
3+
84. What is the Eº for an electrochemical cell with the reaction: 2Cr + 3Sn 3Sn + 2Cr
3+
–
4+
–
Cr + 3e Cr Eº = –0.74 V
2+
Sn + 2e Sn Eº = 0.15 V
A. 0.45 V
B. 0.59 V
C. 0.89 V
ANSWERS:
l. A
2. A
3. D
4. B
5. D
6. A
7. A
8. A
9. A
10. D
11. B
12. D
13. D
14. A
15. A
16. B
17. A
18. D
19. C
20. D
21. C
22. C
23. B
24. C
25. B
26. D
27. C
28. C
29. D
30. C
31. C
32. B
33. D
34. B
35. B
36. C
37. B
38. A
39. B
40. D
41. D
42. C
D. 1.93 V
43. B
44. C
45. C
46. A
47. C
48. A
49. A
50. B
51. C
52. B
53. B
54. A
55. D
56. A
57. A
58. C
59. A
60. A
61. D
62. C
63. D
64. A
65. C
66. D
67. B
68. A
69. A
70. A
71. D
72. B
73. D
74. D
75. A
76. C
77. B
78. B
79. B
80. A
81. C
82. B
83. C
84. C