Chemical Equilibrium – Ch16 | Organized Test Bank – 15e

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Package Title: Hein Test Bank

Course Title: Hein 15e

Chapter Number: 16

Question Type: Multiple Choice

1. The main reason for the increase in the rate of reaction as temperature increases is

A. molecules can be closer together to react.

B. the number or frequency of collisions between molecules increases.

C. molecules have less energy to move away from each other.

D. more energy is available to overcome the activation energy.

Difficulty: easy

Learning Objective 1: List the factors that affect the rate of a chemical reaction.

Section Reference: Section 16.1

2. A chemical reaction A B is said to be in equilibrium when complete conversion of A to B has taken place

1. conversion of A to B is only 50% complete
2. only a fraction of conversion of A to B has taken place
3. the rate of transformation of A to B is equal to the rate of transformation of B to A in the system

Difficulty: easy

Learning Objective 1: Define a reversible chemical reaction and explain what is occurring in a chemical system of equilibrium.

Section Reference: Section 16.2

3. According to Le Châtelier’s principle, decreasing the temperature at which the following reaction takes place will

N₂O₄(g) + 58.6 kJ 2NO₂(g)

A. shift the equilibrium to the left.

B. shift the equilibrium to the right.

C. have no effect on the equilibrium.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

4. A catalyst accelerates the rate of a chemical reaction by

A. raising the enthalpy of the products.

B. lowering the enthalpy of the products.

C. lowering the activation energy.

D. raising the activation energy.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

5. Equilibrium is reached in a chemical reaction when

A. the reactants are completely consumed.

B. the concentrations of all reactants and products become equal.

C. the rates of the opposing reactions become equal.

D. the forward and reverse reactions stop.

Difficulty: easy

Learning Objective 1: Define a reversible chemical reaction and explain what is occurring in a chemical system of equilibrium.

Section Reference: Section 16.2

6. A solution in which equilibrium is reached between dissolved and undissolved solute is

A. saturated.

B. unsaturated.

C. supersaturated.

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

7. In which direction will the point of equilibrium shift when the pressure is decreased in the following equilibrium?

N₂ (g) + 3 H₂ (g) 2 NH₃ (g)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

8. For the given exothermic reaction, the favorable conditions for the formation of NH₃ will be

N₂ (g) + 3 H₂ (g) 2 NH₃ (g)

A. low temperature and high pressure

B. low temperature and pressure

C. high temperature and low pressure

D. high temperature and pressure

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

9. In which direction will the point of equilibrium shift when the pressure is decreased in the following equilibrium?

H₂ (g) + Cl₂ (g) 2 HCl (g)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

10. In which direction will the point of equilibrium shift when volume is decreased in the following equilibrium?

2 NO (g) + O₂ (g) 2 NO₂ (g)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

11. In which direction will the point of equilibrium shift when solid KCl is added to the following equilibrium?

KCl(s) K⁺ (aq) + Cl^– (aq)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

12. In which direction will the point of equilibrium shift when the volume of the reaction vessel increases in the following equilibrium?

2 HI (g) H₂ (g) + I₂ (g)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

13. For the following reaction, the yield of SO₃ will be maximum if

2 SO₂ (g) + O₂ (g) 2 SO₃ (g) + 188 kJ

A. Temperature is increased and pressure is kept constant

B. Temperature is decreased and pressure is increased

C. Both temperature and pressure are increased

D. Both temperature and pressure are decreased

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

14. In which direction will the point of equilibrium shift when the volume of the reaction vessel decreases in the following equilibrium?

2 SO₃ (g) 2 SO₂ (g) + O₂ (g)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

15. In which direction will the point of equilibrium shift when the concentration of chloride ion

increases in the following equilibrium?

NaCl (s) Na⁺ (aq) + Cl^– (aq)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

16. In which direction will the point of equilibrium shift when NaOH is added to the following

equilibrium? Note: Fe⁺³ precipitates with OH^-.

Fe³⁺ (aq) + SCN^– (aq) Fe(SCN)²⁺ (aq)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: hard

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

17. In which direction will the point of equilibrium shift when temperature is increased in the following equilibrium?

2 SO₃ (g) + 188 kJ 2 SO₂ (g) + O₂ (g)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

18. In which direction will the point of equilibrium shift when temperature is decreased in the following equilibrium?

2 NO (g) + O₂ (g) 2 NO₂ (g) + 113 kJ

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

19. In which direction will the point of equilibrium shift when a catalyst is added to the following equilibrium system?

2 C (s) + O₂ (g) 2 CO (g) + 110 kJ

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

20. In which direction will the point of equilibrium shift when a catalyst is added to the following equilibrium system?

KNO₃(s) + 34.7 kJ K⁺ (aq) + NO₃^– (aq)

A. shift to the right

B. shift to the left

C. no shift

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

21. In the following equilibrium, when chloride ion is added, the concentration of sodium ion will

NaCl(s) Na⁺ (aq) + Cl^– (aq)

A. increase.

B. decrease.

C. remain the same.

Difficulty: medium

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

22. In the following equilibrium, when sodium ion is removed, the concentration of chloride ion will

Na⁺ (aq) + Cl^– (aq) NaCl (s)

A. increase.

B. decrease.

C. remain the same.

Difficulty: medium

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

23. In the following equilibrium, when Fe⁺³ ion is added, the concentration of Fe(SCN)²⁺ ion will

Fe³⁺ + SCN^– Fe(SCN) ²⁺

A. increase.

B. decrease.

C. remain the same.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

24. Which is/are the spectator ion(s) when hydrochloric acid is added to a saturated solution of sodium chloride?

A. hydrogen ion

B. chloride ion

C. sodium ion

D. sodium ion and chloride ion

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

25. Which K_eq value indicates the greatest concentration of reactants at equilibrium assuming similar stoichiometry?

A. 6.7 10⁵

B. 3.2 10⁹

C. 1.4 10^–3

D. 3.2 10^–7

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

26. Which K_eq value indicates the greatest concentration of products at equilibrium assuming similar stoichiometry?

A. 6.7 10⁵

B. 3.2 10⁹

C. 1.4 10^–3

D. 3.2 10^–7

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

27. Which K_eq value indicates the reaction goes farthest to completion assuming similar stoichiometry?

A. 1.0 10²

B. 10

C. 1.4 10^–2

D. 1

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

28. Which acid ionization constant would indicate the strongest acid?

A. 3.5 10^–4

B. 9.5 10^–8

C. 1.5 10^–2

D. 1.3 10^–13

Difficulty: easy

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

29. Which acid ionization constant would indicate the weakest acid?

A. 3.5 10^–4

B. 1.8 10^–5

C. 4.6 10^–4

D. 1.5 10^–2

Difficulty: easy

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

30. According to the given data, which salt is the most soluble salt?

A. AgCl, K_sp= 1.7 10^–10

B. AgBr, K_sp= 5.2 10^–13

C. BaSO₄, K_sp= 1.5 10^–9

D. CuS, K_sp= 8.5 10^–45

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

31. According to the given data, which salt is the least soluble salt?

A. AgCl, K_sp= 1.7 10^–10

B. AgBr, K_sp= 5.2 10^–13

C. BaSO₄, K_sp= 1.5 10^–9

D. CuS, K_sp= 8.5 10^–45

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

32. In the following, as P₄ (s) is added, the concentration of H₂ (g) will

P₄ (s) + 6 H₂ (g) 4 PH₃ (g)

1. increase.
2. decrease.
3. remain the same.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

33. The equilibrium SO₂Cl₂ (g) SO₂ (g) +Cl₂ (g) is attained at 25 ^oC in a closed container. When the concentration of Cl₂ is increased keeping the temperature constant, which of the following statements are correct?

1. Concentration of SO₂ is increased
2. Concentration of SO₂Cl₂ is decreased
3. Concentration of SO₂ is decreased
4. None of the above

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

34. In the following equilibrium; as H₂(g) is removed, the concentration of

HI (g) will

H₂ (g) + I₂ (g) 2 HI (g)

A. increase.

B. decrease.

C. remain the same.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

35. In the following equilibrium; as I₂(g) is added, the concentration of

HI (g) will

H₂ (g) + I₂ (g) 2 HI (g)

A. increase.

B. decrease.

C. remain the same.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

36. In the following equilibrium, as HNO₃ is added, the concentration of CrO₄^2– ion will

2 CrO₄^2– (aq) + 2 H⁺ (aq) Cr₂O₇^2– (aq) + H₂O (l)

A. increase.

B. decrease.

C. remain the same.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

37. According to the given data, which salt is the most soluble salt in water?

A. AgCl, K_sp= 1.7 10^–10

B. CaF₂, K_sp= 3.9 10^–11

C. BaSO₄, K_sp= 1.5 10^–9

D. Mg(OH)₂, K_sp= 2.0 10^–13

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

38. In the following equilibrium, as volume of the reaction vessel decreases, the point of equilibrium will

N₂O₄ (g) 2 NO₂ (g)

A. shift to the right.

B. shift to the left.

C. not shift.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

39. In the following equilibrium, as volume of the reaction vessel decreases, the point of equilibrium will

2A(g) + 3B(g) 3A(g) + 2B(g)

A. shift to the right.

B. shift to the left.

C. not shift.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

40. In the following equilibrium, as pressure of the reaction vessel increases, the point of equilibrium will

2 HF (g) H₂ (g) + F₂ (g)

A. shift to the right.

B. shift to the left.

C. not shift.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

41. In the following equilibrium; as HI(g) is added, the concentration of

H₂ (g) will

H₂ (g) + I₂ (g) 2 HI (g)

A. increase.

B. decrease.

C. remain the same.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

42. In the following equilibrium, as temperature increases, the point of equilibrium will

CO₂ (g) + 2 H₂O (g) + 890 kJ CH₄ (g) + 2 O₂ (g)

A. shift to the right.

B. shift to the left.

C. not shift.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

43. For the following reaction:

K_eq = 7.6 × 10^–4. COCl₂ is introduced in a closed container until its concentration is 0.890 M.

What will be the concentration of Cl₂(g) once the reaction has reached equilibrium?

A.

B.

C.

D.

Difficulty: hard

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

44. Calculate the value of K_eq for the following equilibrium when [ H₂ ] = 0.228 M,

[ I₂ ] = 0.228 M, and [ HI ] =1.544 M.

H₂ (g) + I₂ (g) 2 HI (g)

A. 29.7

B. 0.0337

C. 0.0219

D. 45.9

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

45. Calculate the value of K_eq for the following equilibrium when [ PCl₅ ] = 0.010 M,

[PCl₃ ] = 0.020 M, and [Cl₂ ] =0.020 M.

PCl₅ (g) PCl₃ (g) + Cl₂ (g)

A. 29.7

B. 0.0337

C. 0.0219

D. 0.040

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

46. What is the [H⁺¹] in a 0.0001 M solution of HCl?

A. 1 10^–14 M

B. 1 10^–10 M

C. 1 10^–4 M

D. 1 10^–7 M

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

47. What is the [OH^–] in a 0.0001 M solution of HCl?

A. 1 10^–14 M

B. 1 10^–10 M

C. 1 10^–4 M

D. 1 10^–7 M

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

48. What is the pH in a 0.0001 M solution of LiOH?

A. 1 10^–3

B. 1 10^–11

C. 3

D. 10

Difficulty: medium

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

49. What is the [H⁺] in a 0.01 M Ba(OH)₂ solution?

A. 1 10^–2 M

B. 5 10^–13 M

C. 1 10^–7 M

D. 1 10^–12 M

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

50. What is the [OH^–] in a 0.01 M KOH solution?

A. 1 10^–2 M

B. 1 10^–14 M

C. 1 10^–7 M

D. 1 10^–12 M

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

51. What is the pH of a 0.10 M KOH solution?

A. 1.00

B. 7.00

C. 13.00

D. 14.00

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

52. What is the pH of a 0.050 M NaOH solution?

A. 1.30

B. -1.30

C. 12.7

D. 0.0500

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Reference: Section 16.5

53. What is the pH of a 0.001 M HCl solution?

A. 1.0 × 10^–3

B. 3.0

C. 11

D. 4.0

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

54. What is the [OH^–] of a solution with pH 3?

A. 1.0 × 10^–11

B. 1.0 × 10^–7

C. 1.0 × 10^–3

D. 1.0 × 10^–14

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

55. What is the pH of a 0.14 M HCl solution?

A. 0.85

B. 13.20

C. 0.14

D. 3.66

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

56. Hydrocyanic acid, HCN, is a weak acid whose K_a value is 4.0 10^–10. What is the [H⁺] in

a 0.10 M solution of HCN?

A. 1 10^–4

B. 6.3 10^–6

C. 4.0 10^–9

D. 1.0 10^–11

Difficulty: hard

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

57. Hydrocyanic acid, HCN, is a weak acid whose K_a value is 4.0 10^–10. What is the pH of a

0.10 M solution of HCN?

A. 1.0

B. 5.2

C. 9.4

D. 10.

Difficulty: hard

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

58. If a 0.2 M solution of HCOOH is 3.2% ionized, the ionization constant for HCOOH is

A. 9.6 10^–3

B 2.1 10^–4

C. 1.3 10^–6

D. 4.8 10^–5

Difficulty: hard

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

59. A 0.050 M solution of a weak acid has [H⁺] = 3.8 10^–7 M. What is the K_a for this acid?

A. 7.5 10^–3

B. 2.9 10^–12

C. 7.0 10^–7

D. 3.8 10^–-8

Difficulty: hard

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

60. Lactic acid has a K_a value of 8.3 10^–4. What is the percent ionization of a 0.35 M solution

of lactic acid?

A. 1.1%

B. 2.2%

C. 4.9%

D. 8.9%

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

61. If a 0.1 M solution of HCN is 0.01% ionized, the ionization constant for HCN is

A. 1.0 10^–9

B 1.0 10^–7

C. 1.0 10^–5

D. 1.0 10^–3

Difficulty: hard

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

62. The K_sp of silver iodide is 8.3 10^–17. What is the solubility of silver iodide in g/L?

A. 2.1 10^–6 g/L

B. 1.6 10^–30 g/L

C. 1.9 10^–14 g/L

D. 6.1 10^–21 g/L

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

63. The K_sp of silver bromide is 5.0 10^–13. What is the solubility of silver bromide in g/L?

A. 4.7 10^–23 g/L

B. 3.0 10^-11 g/L

C. 1.3 10^–4 g/L

D. 9.4 10^–11 g/L

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

64. The solubility of AgCl at 20 ^oC is 1.4 10^–5 moles/L. The solubility product of AgCl is

A. 1.0 10^–5

B. 2.0 10^–10

C. 1.4 10^–5

D. 1.1 10^–6

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

65. HCl is added to a saturated AgCl solution until the [Cl^–] is 0.010 M. What is the [Ag⁺] remaining in the solution? The K_sp of AgCl is 1.8 10^–10.

A. 1.8 10^–10 M

B. 1.8 10^–8 M

C. 1.8 10^–12 M

D. 0.010 M

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

66. AgNO₃ is added to a saturated AgI solution until the [Ag⁺] is 0.050 M. What is the [I^–]

remaining in the solution? The K_sp of AgI is 8.3 10^–17.

A. 0.050 M

B. 4.2 10^–18 M

C. 1.7 10^–15 M

D. 8.3 10^–17 M

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

67. What is the solubility in mol/L of CaF₂ in water? K_sp= 3.9 10^–11

A. 6.2 10^–6 M

B. 2.7 10^–4 M

C. 2.1 10^–4 M

D. 3.8 10^–2 M

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section: 16.7

68. If the concentration of a saturated solution of Ag₂SO₄ is 2.5 10^–2 M, solubility product will be

A. 6.3 10^–4

B. 6.3 10^–5

C. 6.3 10^–6

D. 6.3 10^–7

Difficulty: hard

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

69. The pH of an aqueous solution is 3.2. What is the [] in the same solution?

A. M

B. M

C. M

D. 10.8 M

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

70. In aqueous solution the [H⁺] is 1.4 10^–4 M. The [OH^–] in the same solution is

A. 1.4 10^–2 M

B. 1.4 10^–7 M

C. 1.0 10^–7 M

D. 7.1 10^–11 M

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

71. In aqueous solution the [OH^–] is 3.0 10^–6 M. The [H⁺] in the same solution is

A. 1.0 10^–7 M

B. 3.3 10^–9 M

C. 3.0 10^–6 M

D. 3.0 10⁸ M

Difficulty: easy

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

72. If HCl (aq) is added to a saturated NaCl solution, the [Na⁺] will

A. increase.

B. decrease.

C. remain the same.

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

73. The equilibrium constant can change significantly with a change in

A. concentration.

B. catalyst.

C. temperature.

D. pressure.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

74. A 0.30 M solution of formic acid, HCHO₂, is 2.4% ionized. The acid ionization constant, K_a, for formic acid is

A. 1.7 10^–4.

B. 7.2 10^–3.

C. 2.4 10^–-2.

D. 1.6 10^–-5.

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

75. A 0.50 M solution of hydrofluoric acid, HF, is 3.6% ionized. The acid ionization constant, K_a, for hydrofluoric acid is

A. 3.6 10^–2.

B. 1.8 10^–2.

C. 3.2 10^–4.

D. 6.5 10^–4.

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

76. A 0.20 M solution of the weak acid HA has a [H⁺] = 1.4 10.^-4 M. The acid ionization constant, K_a, for this acid is

A. 9.8 10^–8.

B. 1.8 10^–5.

C. 2.0 10^–8.

D. 7.0 10^–4.

Difficulty: easy

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

77. What is the pH of a 0.00500 M solution of barium hydroxide?

A. 11.70

B. 12.00

C. 2.00

D. 2.30

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

78. The solubility of silver chromate, Ag₂CrO₄, is 0.0287g/L. What is the K_sp for silver chromate?

A. 9.5 10^–6

B. 2.4 10^–5

C. 2.6 10^–12

D. 6.8 10^–13

Difficulty: hard

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: 16.7

79. Which of the following solutions will have the highest pH?

A. 0.1 M HNO₂

B. 0.1 M HCl

C. 0.1 M KOH

D. 0.1 M NH₄Cl

Difficulty: easy

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

80. What will be the [H⁺] in a 0.50 M solution of HClO? The K_a of HClO = 3.5 10^–8.

A. 1.8 10^–8 M

B. 7.0 10^–8 M

C. 1.3 10^–4 M

D. 1.9 10^–4 M

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

81. What is the pH of 0.50 M HClO solution? The K_a of HClO is 3.5 10^–8.

A. 0.30

B. 7.5

C. 7.8

D. 3.9

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

82. The magnitude of K_eq depends on

A. initial concentration of reactants.

B. presence of a catalyst.

C. temperature.

D. volume of reaction vessel.

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

83. The solubility of silver bromide is 7.1 10^–7 M. The K_sp of silver bromide is

A. 7.1 10^–5

B. 5.0 10^–5

C. 5.0 10^–13

D. 5.0 10^–15

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

84. The solubility of CaF₂ is 2.14 10^–4 M. The K_sp of CaF₂ is

A. 3.92 10^–11

B. 4.58 10^–8

C. 9.80 10^–12

D. 2.14 10^–8

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

85. In the following equilibrium; as the pressure is increased, the amount of NO₂ formed will

N₂ (g) + 2 O₂ (g) 2 NO₂ (g)

A. increase.

B. decrease.

C. remain the same.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

86. The concentration of hydroxide ions,, in an aqueous solution is M. The pH of the solution is

A. 1.00.

1. 4.50.
2. 9.50.
3. 3.17.

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

87. The mathematical expression for the equilibrium constant of the following reaction is shown in which of the choices?

A.

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

88. Calculate the percent ionization of a 0.050 M aqueous solution of HF having a pH of 3.15.

A. 1.4%

1. 4.9%
2. 1.6%
3. 6.3%

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

89. Calculate the percent ionization of a 0.200 M aqueous solution of HNO₂ having a pH of 2.80.

A. 7.1%

1. 1.4%
2. 2.0%
3. 0.79%

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

90. Calculate the pH of a 0.250 M aqueous solution of HNO₂. The acid dissociation constant, K_a, for HNO₂ is .

A. 1.97

1. 2.74
2. 3.35
3. 3.95

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

91. Which is a buffer solution?

1. CH₃COOH + CH₃COONa
2. HCl + CH₃COONH₄
3. CH₃COOH + NH₃Cl
4. NaOH + HCl

Difficulty: easy

Learning Objective 1: Describe the function of a buffer solution.

Section Reference: Section 16.8

92. Which is a buffer solution?

1. NaOH + CH₃COONa
2. NaOH + Na₂SO₄
3. K₂SO₄ + H₂SO₄
4. NH₄OH + CH₃COONH₄

Difficulty: easy

Learning Objective 1: Describe the function of a buffer solution.

Section Reference: Section 16.8

True/False

93. If the K_a of acetic acid is 1.8 10^–5, and the K_a for nitrous acid is 4.5 10^–4, then at equal concentrations, the acetic acid solution will be more acidic.

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

94. The value of the equilibrium constant is temperature dependent.

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

95. An aqueous solution containing both Na₃PO₄ and Na₂HPO₄ will act as a buffer.

Difficulty: easy

Learning Objective 1: Describe the function of a buffer solution.

Section Reference: Section 16.8

96. Adding more solid silver chloride to a saturated aqueous solution of silver chloride will shift the equilibrium to the right.

Difficulty: easy

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

97. The presence of a catalyst will increase the yield of product present at equilibrium.

Difficulty: medium

Learning Objective 1: Use Le Châtelier’s principle to predict the changes that occur when concentration, temperature, or volume is changed in a system at equilibrium.

Section Reference: Section 16.3

98. The addition of a catalyst will change the value of K_eq in an equilibrium system.

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

99. If the concentration of hydronium ions in a solution is , the solution is acidic.

Difficulty: medium

Learning Objective 1: Calculate the concentrations of H+ OH- pH and pOH in a solution using the ion product constant for water.

Section Reference: Section 16.5

100. The buffer capacity of a solution is maximum when the molar ratio of salt to acid is close to one.

Difficulty: easy

Learning Objective 1: Describe the function of a buffer solution.

Section Reference: Section 16.8

Free Response

101. The K_sp for silver bromide is 5.0 10^–13. What is the molarity of the silver and the bromide ions in a saturated solution of silver bromide?

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

102. The K_sp of lead(II) chloride is 1.6 10^–5. What is the molarity of the lead(II) and chloride

ions in a saturated solution of lead(II) chloride?

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

103. A 7.5 L vessel contains 10.0 g of NO₂ (g) and 0.55 g of N₂O₄ (g) at equilibrium, as follows

2 NO₂ (g) N₂O₄ (g)

Calculate the value of the equilibrium constant for this reaction.

Difficulty: medium

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

104. In a closed reaction vessel the following equilibrium is established.

2 HI (g) H₂ (g) + I₂ (g)

The following concentrations were present at equilibrium: [HI] = 0.430 M, [ H₂ ] = 1.36 M,

[ I₂ ] = 1.36 M.

What is the value of K_eq for this equilibrium system?

Difficulty: easy

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

105. In a closed reaction vessel having a volume of 1.00 L, 1.25 g of N₂O₄ are allowed to undergo the following reaction.

N₂O₄ (g) 2 NO₂ (g) K_eq = 0.32

What will be the equilibrium concentrations of NO₂(g) and N₂O₄(g) in mol/L?

Difficulty: medium

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4

106. The ionization constant, K_a, for an acetic acid solution is 1.8 10^–5. For a 0.45 M solution

of acetic acid calculate the following:

A. [ H⁺ ]

B. pH

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

107. The acid ionization constant, K_a, of hydrosulfuric acid is 9.5 10^–8. For a 1.0 M solution of hydrosulfuric acid calculate the following:

A. [H⁺]

B. pH

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

108. The acid ionization constant, K_a, for ammonium chloride is 5.6 10^–5, which corresponds to the following equilibrium:

For a 0.350 M solution of ammonium chloride calculate the following:

A. [H⁺]

B. pH

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

109. Calculate the pH of a solution containing 50 mL of 0.2M acetic acid and 50 mL of 0.2 M sodium acetate. K_a = 1.85 10^–5

Answer : 4.7

Difficulty: medium

Learning Objective 1: Use the ionization constant of a reactant in an equilibrium expression to find the percent ionization of a substance in solution and to find the pH of a weak acid.

Section Reference: Section 16.6

110. The K_sp value for copper(II) sulfide is 8.5 10^–45. Calculate the solubility of copper(II) sulfide in grams per liter.

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

111. The K_sp value for barium sulfate is 1.5 10^–9. Calculate the solubility of barium sulfate in grams per liter.

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

112. The K_sp value for silver bromide is 3.3 10^–13. Calculate the solubility of silver bromide in grams per liter.

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

113. The solubility of Mg(OH)₂ is 8.352 10^–3 g/L. Calculate the K_sp value for Mg(OH)₂ .

Difficulty: easy

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

114. Some aqueous Na₂SO₄ is added to a saturated solution of barium sulfate until [] = 0.100 M.

What is the concentration of barium ions remaining in solution? The K_sp for barium sulfate is

.

Difficulty: medium

Learning Objective 1: Use the solubility product constant to calculate the solubility of a slightly soluble salt and to determine whether a precipitate will form in a solution.

Section Reference: Section 16.7

115. The following reaction takes place in a closed container:

The equilibrium constant for the reaction has a value of 0.5. Sketch the relative amounts of each species present at equilibrium in the box on the right if the starting conditions are those

shown on the left.

Answer :

Difficulty: hard

Learning Objective 1: Write the general expression for the equilibrium constant and calculate equilibrium constants.

Section Reference: Section 16.4