15967_Chapter 14 Questions

1. Which of the following is equal for the forward and reverse reactions at equilibrium?A) concentrationB) ratesC) rate constants

2. All chemical equilibria are _____ in nature.A) dynamicB) equalC) staticD) kinetic

3. An example of a physical equilibrium is _____.A)

B)

C)

D)

4. Which of the following is not a physical equilibrium?A) meltingB) allotropic transformationC) vaporizationD) rusting

5. An example of heterogeneous equilibrium is _____.A)

B)

C) Enzyme-catalyzed reactions

6. Which of the following statements is always correct?A) chemical equilibria are homogeneousB) physical equilibria are homogeneousC) physical equilibria are heterogeneousD) chemical equilibria are heterogeneous

7. The expression for Kp for the reaction

is _____.A)

B)P

C)/ P

D)· P

8. The expression for Kp for the reaction

is _____.A)

2P + PB)

P2 · PC)

P + PD)

2P / P

9. The equilibrium constant Kp is not applicable for the reaction _____.A)

B)

C)

D)

10. The equilibrium constant Kc for the reaction

is given by _____.A)

B)

C)

D)

11. The equation relating Kp and Kc is _____.A) Kp = Kc (RT)n

B) Kp = Kc RTn

C) Kc = Kp RTn

D) Kc = Kp (RT)n

12. Kp will be equal to Kc if _____.A) n = 1B) n = 0C) RT = 0D) n =

13. Kp will be less than Kp if _____.A) H = negativeB) n = positive

C) n = negativeD) n = 0

14. The equilibrium constants for the reactions

and are x and y, respectively. The equilibrium constant for the reaction

is _____.A)

B) x + yC) x – yD) xy

Use the following to answer questions 15-16:

The equilibrium constant for the reaction

is x.

15. The equilibrium constant for the reaction

is _____.A) –xB) xC) 1/xD) 2x

16.The equilibrium constant for the reaction is _____.A) 2xB) xC) x/2D) x2


is 4.17 . The equilibrium constant for the reaction

isA) –4.17 B) 4.17 1031

C) 2.40 1030

D) 2.40 10-33

18. The number of moles of H2, S2, and H2S present at the equilibrium for the reaction

are 2.50, 1.35 10-5 and 8.70 moles respectively in a 12 L flask. The equilibrium constant, Kc for the reaction is _____.A) 1.08 107

B) 1.08 10-7

C) 5.6 103

D) 7.2 10-5

19. Kc for the reaction

is 2.24 1022 at 1273 ºC. Kp for the reaction at the same temperature is _____.A) 7.16 10-18

B) 1.76 1020

C) 5.12 10-15

D) 3.12 1019

20. The equilibrium partial pressures of N2, O2 and NO in the reaction

are 0.15, 0.33 and 0.050 atm, respectively at 2200°C. The value of Kp for the reaction is _____.A) 5.1B) 0.51C) 51D) 0.051

21. The equilibrium concentrations of NH3, N2 and H2 are 0.25 M, 0.11 M and 1.91 M, respectively. The equilibrium constant Kc for the reaction

is _____.A) 0.082B) 8.2 10-3

C) 8.2D) 0.82

22. The equilibrium constant, Kc, for the reaction

is 0.082. What is Ka for

A) 0.164B) 0.041C) 0.29D) 1.64

23. The equilibrium constant, Kc , for the reaction

is 3.8 10-5 at 727°C. The value of Kp for the equilibrium

at the same temperature is _____.A) 648B) 320C) 32.0D) 6.48

24. The equilibrium pressure for the reaction

is 0.105 atm at 350°C. Kp for the reaction is _____.A) 0.105B) 0.210C) 1.05D) 10.5

25. Kp for the reaction

at 350oC is 0.105. Kc for the reaction at the same temperature is _____.A) 4.21 103

B) 0.105C) 3.05 10-4

D) 2.05 10-3

26. The equilibrium constant, Kp, for the reaction

is 1.05 at 250°C. The reaction is started with PCl5, PCl3 and Cl2 at 0.177, 0.223 and 0.111 atm at 250°C. When the reaction comes to equilibrium, the pressure of _____.A) PCl3 must have decreasedB) Cl2 must have decreasedC) PCl5 must have decreasedD) PCl5 must have increased

27. Starting with only the solid, the total pressure of NH3 and CO2 was found to 0.363 atm

for the equilibrium at 40°C. The equilibrium constant, Kp isA) 7.1 10-3

B) 2.5 10-2

C) 5.3 10-4

D) 3.6 10-6

28. 1.05 moles of Br2 in a 0.980 L container undergo 1.2% dissociation. The equilibrium

constant, Kc for the reaction is _____.A) 2.5 10-5

B) 1.8 10-3

C) 6.2 10-4

D) 5.9 10-6

29. Kp = Kc for the reaction _____.A)

B)

C)

D)

30. 3.00 10-2 mol of phosgene gas, COCl2, was heated in a 1.50 L container at 800 K. At equilibrium the pressure of CO was found to be 0.497 atm. The equilibrium constant, Kp

for the reaction is _____.A) 3.30B) 9.80C) 2.75D) 5.61

31. The equilibrium constant, Kp for the reaction

at 2200°C is 0.051. The equilibrium constant, Kc for the same reaction is _____.A) 0.102B) 0.051C) 2.5 10-3

D) 1.02 104


At equilibrium, nitrosyl bromide in the reaction

is 34% dissociated at 25°C and the total pressure is 0.25 atm.

32. The value of Kp for the reaction is _____.A) 9.6 10-3

B) 1.39 10-5

C) 3.8 10-4

D) 6.7 10-6

33. The value of Kc for the above reaction is _____.A) 1.6 10-6

B) 2.7 10-5

C) 3.9 10-4

D) 4.5 10-7

34. 2.50 mole of NOCl was heated in a 1.50 L vessel at 400°C.At equilibrium it was found that 28.0% of the NOCl had dissociated. The equilibrium constant, Kc of the reaction

is _____.A) 0.0353B) 3.53 102

C) 3.53 10-4

D) 3.53

35. The ionization constants Kc' and Kc” for

were found to be 9.5 10-8 and 1.0 10-19 respectively. The equilibrium constant for the reaction

is _____.A) 9.5 10-8

B) 1.0 10-19

C) 9.5 10-27

D) 1.05 10-12

36. The equilibrium constant, Kc = 4.0 × 10-6 for the reaction

.If the equilibrium constant, Kc= 6.5 10-2 for the reaction

,the equilibrium constant for

is _____.A) 4.0 10-6

B) 6.1 10-5

C) 1.6 104

D) 6.5 10-2


The following equilibrium constants were measured for the reactions:


is _____.A) xyB) x + yC) xy2

D) x + y2

38. The equilibrium constants K1 and K2 for the reactions above are 1.3 1014 and 6.0 10-3, respectively. The equilibrium constant for the reaction

is _____.A) 4.7 109

B) 1.0 1014

C) 1.0 1026

D) 3.6 1018

39. The equilibrium constants K1 K2 and K3 for the reactions below are

K1 = 4.2 1052

K2 = x

K3 = 5.6 1023. The value of K2 is _____.A) 9.8 1028

B) 9.8 10128

C) 6.7 1012

D) 2.6 1075

40. The equilibrium constant in terms of rate constants for the forward reaction, kf, and the reverse reaction, kr, is given as _____.A)

B) K = kf + kr

C)

D) K = kf kr

41. The concentration of H+ in pure water at 25°C is _____.A) 10-14 MB) 10-7 MC) 10-10 MD) 10-8 M

42. The equilibrium constant of a reaction is 12.6. If the rate constant of the reverse reaction is 5.1 10-2, the rate constant for the forward reaction is _____.A) 0.32B) 0.16C) 0.64D) 0.08

43. Which of the following statements can be correct with respect to reaction quotient, Q and equilibrium constant, K?A) Q < KB) Q = KC) Q > KD) all the above

44. The value of Kc for the equilibrium

is 5.6 104 350°C. The initial pressures of SO2 and O2 in a mixture are 0.350 atm and 0.762 atm. The total pressure at equilibrium will be _____ atm.A) less than 0.350B) less than 0.741C) less than 1.112D) equal to 1.112

45.The value of Kc for the reaction is 1.2 . The reaction is started with [H2 ]0 = 0.76 M, [N2]0 = 0.60 M and [NH3]0= 0.48 M. Which of the following is correct as the reaction comes to equilibrium?A) The concentration of N2will increaseB) The concentration of H2will decreaseC) The concentration of NH3will decreaseD) The concentration of both N2and H2will increase


For the reaction

Kc = 0.534 at 700°C

46. Calculate the number of moles of H2 present at equilibrium if a mixture of 0.300 moles of CO and 0.300 moles of H2O is heated to 700°C in a 10.0 L container.A) 0.432 molB) 0.273 molC) 0.577 molD) 0.173 mol

47. Which statement is correct with respect to the above equilibrium when 0.30 moles of CO and 0.30 moles of H2O are heated to 700°C and allowed to reach equilibrium.A) [H2O] = [CO2]B) [CO2] = [CO]C) [H2O] = [CO]D) [H2O] = [H2]

48. Which of the following statements is correct?A) All concentrations are equalB) Kp = Kc

C) Kp < Kc

D) Kp > Kc

49. Kp is 158 for the equilibrium

Starting with NO2 (g) only, the partial pressure of O2 at equilibrium is 0.25 atm. Calculate the partial pressure of NO2 at equilibrium.A) 0.020 atmB) 0.20 atmC) 3.1 atmD) 0.035atm

50. The partial pressure of NO in the above equilibrium is _____ atm.A) 0.125B) 0.50C) 0.25D) 0.02

51.The equilibrium constant Kc for the reaction is 2.18 106. Starting with 3.20 moles of HBr in a 12.0L container, the concentration of HBr at equilibrium is _____.A) 0.167 MB) 0.0267 MC) 1.6 MD) 0.267 M

52.Kc is 3.8 10-5 at 1000K for the equilibrium Starting with 0.0456 moles of I2 in a 2.30 L flask, at 1000 K, the equilibrium concentration of I2 at is:A) 1.94 MB) 0.0194 MC) 0.12 MD) 0.012 M


Kc for the reaction is 4.63 10-3 at 527°C .

53. Starting with pure phosgene, COCl2, at 0.760 atm, the equilibrium partial pressure of CO is _____.A) 0.352 atmB) 0.0416 atmC) 0.0352 atmD) 0.416 atm

54. Starting with pure phosgene, COCl2, at 0.760 atm, the equilibrium partial pressure of COCl2 is _____.A) 0.173 atmB) 0.204 atmC) 0.302 atmD) 0.408 atm

55.What is the value of Kc for the reaction when the equilibrium concentrations of CO, H2, CO2 and H2O are 0.050 M, 0.045 M, 0.086 M and 0.040 M respectively?A) 0.074B) 0.52C) 0.063D) 0.24


The equilibrium constant Kp for the reaction is 1.52 and the total pressure at equilibrium is 4.50 atm.

56. The equilibrium partial pressure of CO is _____ atm.A) 0.86B) 1.62C) 1.96D) 1.31

57. The equilibrium partial pressure of CO2 is _____ atm.A) 2.54 atmB) 0.98 atmC) 1.27 atmD) 0.72 atm


The equilibrium constant, Kc for the reaction is 4.2. Initially 0.80 mole of H2 and 0.80 mole CO2 are placed in a 5.0 L flask.

58. The concentration of H2 at equilibrium is _____.A) 0.054 MB) 0.025 MC) 0.15 MD) 0.029 M

59. At equilibrium, the concentration of H2 is equal to the concentration of _____.A) H2OB) COC) CO2

D) H2O + CO2

60. The concentration of CO at equilibrium is _____.A) 0.22MB) 0.056MC) 0.021MD) 0.11M

61. Le Châtelier's principle can help to predict how to maximize _____.A) Reaction yieldB) Equilibrium constantC) TemperatureD) Rate constant

62. Which can alter the value of the equilibrium constant?A) CatalystB) ConcentrationC) PressureD) Temperature

63. The equilibrium position of the reaction

can be shifted in the forward direction by _____.A) Removing SO2

B) Adding Cl2

C) Removing Cl2

D) Removing SO2 and Cl2


The equilibrium constant Kc for the equilibrium

is x.


is _____.A) x/2B) x1/2

C) x2

D) 2x

65. The equilibrium constant for the reaction is _____.A) x2

B)

C) x–2

D) –2x

66. Which of the following equilibria is not affected by pressure?A)

B)

C)

D)

67. The equilibrium

, can be shifted toward more product formation by _____. H = 92.5 kJ.A) Increasing temperatureB) Increasing pressureC) Decreasing temperatureD) Increasing the concentration PCl3

68. The equilibrium

can shifted to the reactant side by _____. H = –198.2 kJA) Decreasing temperatureB) Decreasing volume

C) Decreasing pressureD) Increasing the concentration of SO2

69. The equilibrium pressure of NO2 in the equilibrium is 1.56 atm. Its pressure on the addition of a catalyst will be _____.A) 1.06 atmB) 0.75 atmC) 1.56 atmD) 2.71 atm

70.The position of the equilibrium can be shifted to the left by the addition of _____ at constant pressure.A) COB) HeC) O2

D) KCl

71.The addition of He to the equilibrium at constant volume _____.A) Shifts the equilibrium to the leftB) Increases Kc

C) Shifts the equilibrium to the rightD) Has no effect

72. Which of the following will shift the equilibrium

to the right?A) Decrease of temperatureB) Addition of KClC) Addition of CO2

D) Addition of NaOH solution

73.The equilibrium can be shifted to the right by _____.A) increasing temperatureB) decreasing pressureC) removing some CO2

D) all of the above


Pure NOCl gas was heated to 240 °C in a 1.00-L container. At equilibrium the total pressure was 1.00 atm and the NOCl pressure was 0.64 atm.

74. The partial pressure of NO at equilibrium in the reaction

is _____ atm.A) 0.24B) 0.12C) 0.34D) 0.17

75. The partial pressure of Cl2 in the equilibrium

is _____ atm.A) 0.36B) 0.09C) 0.12D) 0.18

76. Kp for the equilibrium

is _____.A) 1.7B) 0.12C) 0.17D) 0.017


Kp is 2.9 10-11 at 530°C for the reaction

.

77. What is the partial pressure of NO at equilibrium when the equilibrium partial pressures of N2 and O2 are 3.0 atm and 0.012 atm, respectively?A) 1.0 10–6 atmB) 1.6 10–3 atmC) 1.6 10–2 atmD) 0.16 atm

78. What is the partial pressure of NO at equilibrium under atmospheric conditions where the partial pressures of N2 and O2 are 0.78 atm and 0.21 atm at 25°C? Kp for the reaction is 4.010-31 at 25 °C.A) 1.12 10-12 atm

B) 2.6 10-16 atmC) 1.3 10-8 atmD) 1.45 10-4 atm

79. The thermal decomposition of NaHCO3(s) is favored by _____.A) decreasing temperatureB) increasing temperatureC) increasing pressureD) adding CO2

80. Kp < Kc at 25 °C for which of the reactions below?A)

B)

C)

D)

81. The condition for maximum yield of NOCl2 in the reaction

is _______. ( of NOCl = 51.7 kJ/mol,

of NO = 90.4kJ/mol.)A) high pressure, high temperatureB) low pressure, low temperatureC) low pressure, high temperatureD) high pressure, low temperature

82. For the reaction

PA = 0.60 atm and PB = 0.60 atm at equilibrium at some temperature. Kp for the reaction is _____.A) 1B) 0.5C) 1.7D) 0.6

83. For the reaction

at equilibrium, the PA=0.60 atm and PB=0.60 atm and the total pressure is 1.2 atm. What is the PA when the total pressure is increased to 1.5 atm?A) 0.69 atmB) 0.81 atmC) 0.75 atmD) 0.91 atm

84. The equilibrium mixture in the reaction

consists of 0.020 mole O2, 0.040 mole NO and 0.96 mole NO2. What is Kp for the reaction at 430°C and at a total pressure of 0.20 atm?A) 1.5 105

B) 7.2 104

C) 8.1 10–3

D) 5.6 10–6

85. Ammonium carbamate decomposes at a certain temperature .The equilibrium pressure of the reaction

is 0.318 atm. Kp for the reaction is _____.A) 5.92 10-5

B) 1.26 10-4

C) 3.12 10-6

D) 4.76 10-3


A mixture of 0.47 moles of H2 and 3.59 moles of HCl is heated to 2800°C and allowed to reach equilibrium. The total pressure at equilibrium is 2.00 atm.

Kp = 193 at 2800°C.

86. The equilibrium pressure of H2 is _____ atm.A) 0.56 atmB) 0.28 atmC) 0.049 atmD) 1.67 atm

87. The partial pressure of Cl2 in the above equilibrium is _____ atm.A) 0.28 atmB) 0.049 atmC) 0.56 atmD) 0.49 atm

88. The partial pressure of HCl in the above equilibrium is _____ atm.A) 1.28 atmB) 1.01 atmC) 2.06 atmD) 1.67 atm

89. Initially 1 mole of N2O4 is placed in a vessel and allowed to reach equilibrium. The relation between the degree of dissociation , total pressure P and Kp for the reaction

is _____.A)

B)

C)

D)

90. One mole of N2 and three moles of H2 are placed in a flask and allowed to reach equilibrium. T = 375 ºC. The mole fraction of NH3 at equilibrium is found to be 0.21. What is the total pressure of the system at equilibrium?

A) 50 atmB) 5 atmC) 500 atmD) 0.5 atm

91. What is [S2] at equilibrium in the following reaction if [H2S] = 4.84 10-3 M and [H2] = 1.50 10-3 M at equilibrium?

Kc = 2.25 10-4

A) 2.34 10-2

B) 0.234 MC) 2.34 10-3MD) 2.34 10-4M

92. 6.75 g of SO2Cl2 was placed in a 2.00L flask. At 648 K 0.0345 moles of SO2 was

present. Kc for the reaction is _____.A) 3.83 10-2

B) 4.71 10-3

C) 1.12 10-2

D) 6.12 10-4


Kp for the reaction at 375°C is 4.31 10-4. The reaction is started with 0.373 atm of H2 and 0.862 atm of N2 in a constant volume vessel.

93. The partial pressure of N2 at equilibrium is _____ atm.A) 0.260B) 0.760C) 0.860D) 0.960

94. The partial pressure of H2 at equilibrium is _____ atm.A) 0.366B) 0.166C) 0.266D) 0.566

95. The partial pressure of NH3 at equilibrium is _____ atm.A) 4.40 10-3

B) 1.12 10-2

C) 7.20 10-4

D) 2.70 10-5


A 0.244 M fructose solution was prepared and it was found that at equilibrium the fructose concentration had decreased to 0.113 M.

96.The equilibrium constant for the reaction is _____.A) 2.06B) 5.16C) 4.27D) 1.16

97. The percentage of fructose converted into glucose in the equilibria

is _____.A) 53.7%B) 83.1%C) 21.7%D) 63.2%


The equilibrium pressure of oxygen for the reaction is 0.49 atm .

98. Kp for the reaction is _____.A) 0.49B) 2.5 10-3

C) 0.98D) 4.9

99. The fraction of CuO that will decompose if 0.16 mole of CuO is placed in a 2.0 L vessel at 1024°C is _____.A) 0.15B) 0.71C) 0.23D) 0.47

100. 3.9 moles of NO and 0.88 moles of CO2 are allowed to react as

At equilibrium 0.11 moles of CO2 was present. Kc for the reaction is _____.A) 0.27B) 1.7C) 3.14D) 6.03


For the reaction at 430°C, Kc = 54.3.Initially 0.714 moles of H2 and 0.984 moles of I2 and 0.886 moles of HI are placed in a 2.40 L vessel.

101. The equilibrium concentration of H2 is _____.A) 0.070 MB) 0.182 MC) 0.152 MD) 0.012 M

102. The equilibrium concentration of I2 is _____.A) 0.112B) 0.082C) 0.182D) 0.116

103.A gaseous compound, A, dissociates as follows: . A was heated until equilibrium was reached. The pressure of A at equilibrium was 0.14P,where P is the total pressure. Kp for the reaction is _____.A) 0.13PB) 1.3PC) 0.013PD) 13P


For the reaction Kc = 1.2 at 375°C.

104. Kp for the reaction is _____.A) 4.2 10-2

B) 1.2 102

C) 3.1 10-3

D) 4.2 10-4

105. Kc for the reaction is _____.A) –1.2B) 0.83C) 0.38D) 0.012

106. Kc for the formation of one mole of NH3 from H2 and N2 is _____.A) 0.6B) 1.1C) 1.2D) 2.2


The vapor pressure of water at 20°C is 0.0231 atm.

107.Kp for the process is _____.A) 0.0231B) 2.31 10-6

C) 2.31D) 100

108. Kc for vaporization of water is_____.A) 1.8 10-2

B) 2.3 10-5

C) 9.6 10-4

D) 3.6 10-3


The density of a mixture of the gases, NO2 and N2O4, is 2.3 g/L at 74°C and 1.3 atm.

109. The partial pressure of NO2 in the mixture is _____ atm.A) 1.2B) 0.12C) 0.012D) 0.24

110. The partial pressure of N2O4 the mixture is _____ atm.A) 0.62B) 0.12C) 0.062D) 0.63

111. What is Kp for the reaction when the total pressure at equilibrium is 2.2 atm?A) 1.1B) 1.2C) 2.2D) 2.1


For the equilibrium , the equilibrium partial pressures of NO2 and N2O4 are 0.15 and 0.20 atm at 25°C.

112. What is the equilibrium partial pressure of NO2 when the volume is doubled?A) 1.0atmB) 0.10atmC) 10atmD) 0.01atm

113. The equilibrium partial pressure of N2O4 when the volume is doubled will be _____ atm.A) 0.88B) 0.44C) 0.044D) 0.088

114. Kp for the equilibrium at 25°C is _____.A) 1.13B) 0.113C) 11.3D) 1.13 104

115. The vapor pressure of mercury is 0.0020 mmHg at 26°C. Kc for the process

, is _____.A) 1.1 10-7

B) 2.2 104

C) 1.1 10-3

D) 4.4 10-2

Answer Key

1. B2. A3. C4. D5. A6. C7. D8. B9. B

10. C11. A12. B13. C14. D15. C16. D17. C18. A19. B20. D21. A22. C23. B24. A25. D26. C27. A28. C29. D30. A31. B32. A33. C34. A35. C36. B37. C38. A39. B40. C41. B42. C43. D44. C45. B46. D47. C48. B49. A50. B

51. D52. B53. A54. D55. B56. C57. A58. A59. C60. D61. A62. D63. B64. B65. C66. A67. A68. C69. C70. B71. D72. D73. D74. A75. C76. D77. A78. B79. B80. A81. D82. C83. A84. A85. D86. B87. B88. D89. A90. A91. C92. A93. C94. A95. A96. D97. A98. A99. C

100. B101. A102. C

103. B104. D105. B106. B107. A108. C109. A110. B111. B112. B113. D114. B115. A

Chapter 14 Chemical Equilibrium

Student: ___________________________________________________________________________

1. Which is the correct equilibrium constant expression for the following reaction?Fe2O3(s) + 3H2(g) 2Fe(s) + 3H2O(g)

A. Kc = [Fe2O3] [H2]3/[Fe]2[H2O]3 B. Kc = [H2]/[H2O] C. Kc = [H2O]3/[H2]3 D. Kc = [Fe]2[H2O]3/[Fe2O3] [H2]3 E. Kc = [Fe] [H2O]/[Fe2O3] [H2]

2. The equilibrium constant expression for the reaction 2BrF5(g) Br2(g) + 5F2(g) is

A. Kc =[Br2] [F2]/[BrF5] B. Kc = [Br2] [F2]5/[BrF5]2 C. Kc = [Br2] [F2]2/[BrF5]5 D. Kc = [BrF5]2/[Br2][F2]5 E. Kc = 2[BrF5]2/([Br2] 5[F2]5)

3. The following reactions occur at 500 K. Arrange them in order of increasing tendency to proceed to completion (least greatest tendency).

A. 2 < 1 < 3B. 1 < 2 < 3C. 2 < 3 < 1D. 3 < 2 < 1E. 3 < 1 < 2

4. Consider the two gaseous equilibria

The values of the equilibrium constants K1 and K2 are related by

A. K2 = K12

B. K22 = K1

C. K2 = 1/K12

D. K2 = 1/K1 E. none of these

5. Carbon tetrachloride reacts at high temperatures with oxygen to produce two toxic gases, phosgene and chlorine. CCl4(g) + (1/2)O2(g) COCl2(g) + Cl2(g), Kc = 4.4 109 at 1,000 K

Calculate Kc for the reaction 2CCl4(g) + O2(g) 2COCl2(g) + 2Cl2(g).

A. 4.4 109 B. 8.8 109 C. 1.9 1010 D. 1.9 1019 E. 2.3 10-10

6. The equilibrium constant for the reaction Ni(s) + 4CO(g) Ni(CO)4(g) is 5.0 104 at 25ºC. What is

the equilibrium constant for the reaction Ni(CO)4(g) Ni(s) + 4CO(g)?

A. 2.0 10-5

B. 2.5 109

C. 5.0 104

D. 5.0 10-4

E. 2.0 10-3

7. Which of these statements is true about chemical equilibria in general?

A. At equilibrium the total concentration of products equals the total concentration of reactants, that is, [products] = [reactants].

B. Equilibrium is the result of the cessation of all chemical change.C. There is only one set of equilibrium concentrations that equals the Kc value.D. At equilibrium, the rate constant of the forward reaction is equal to the rate constant for the reverse

reaction.E. At equilibrium, the rate of the forward reaction is equal to as the rate of the reverse reaction.

8. The following reactions occur at 500 K. Arrange them in order of increasing tendency to proceed to completion (least completion greatest completion).

A. 2 < 1 < 3 < 4 B. 3 < 1 < 4 < 2 C. 3 < 4 < 1 < 2 D. 4 < 3 < 2 < 1 E. 4 < 3 < 1 < 2

9. When the following reaction is at equilibrium, which of these relationships is always true? 2NOCl(g) 2NO(g) + Cl2(g)

A. [NO][Cl2] = [NOCl] B. [NO]2[Cl2] = [NOCl]2 C. [NOCl] = [NO] D. 2[NO] = [Cl2] E. [NO]2[Cl2] = Kc[NOCl]2

10. Calculate Kp for the reaction 2NOCl(g) 2NO(g) + Cl2(g) at 400C if Kc at 400C for this reaction is

2.1 10-2.

A. 2.1 10-2

B. 1.7 10-3

C. 0.70D. 1.2E. 3.8 10-4

11. On analysis, an equilibrium mixture for the reaction 2H2S(g) 2H2(g) + S2(g) was found to contain

1.0 mol H2S, 4.0 mol H2, and 0.80 mol S2 in a 4.0 L vessel. Calculate the equilibrium constant, Kc, for this reaction.

A. 1.6B. 3.2C. 12.8D. 0.64E. 0.8

12. 2.50 mol NOCl was placed in a 2.50 L reaction vessel at 400ºC. After equilibrium was established, it was found that 28% of the NOCl had dissociated according to the equation 2NOCl(g) 2NO(g) + Cl2(g).

Calculate the equilibrium constant, Kc, for the reaction.

A. 0.021B. 0.039C. 0.169D. 26E. 47

13. 1.25 moles of NOCl were placed in a 2.50 L reaction chamber at 427ºC. After equilibrium was reached, 1.10 moles of NOCl remained. Calculate the equilibrium constant, Kc, for the reaction 2NOCl(g)

2NO(g) + Cl2(g).

A. 3.0 10-4

B. 1.8 103

C. 1.4 10-3 D. 5.6 10-4

E. 4.1 10-3

14. The reaction A(g) + 2B(g) C(g) was allowed to come to equilibrium. The initial amounts of

reactants placed into a 5.00 L vessel were 1.0 mol A and 1.8 mol B. After the reaction reached equilibrium, 1.0 mol of B was found. Calculate Kc for this reaction.

A. 0.060B. 5.1C. 17D. 19E. 25

15. The brown gas NO2 and the colorless gas N2O4 exist in equilibrium, 2NO2 N2O4. In an experiment,

0.625 mole of N2O4 was introduced into a 5.00 L vessel and was allowed to decompose until equilibrium was reached. The concentration of N2O4 at equilibrium was 0.0750 M. Calculate Kc for the reaction.

A. 7.5B. 0.125C. 0.0750D. 0.10E. 0.050

16. Calculate Kc for the reaction 2HI(g) H2(g) + I2(g) given that the concentrations of each species at

equilibrium are as follows: [HI] = 0.85 mol/L, [I2] = 0.60 mol/L, [H2] = 0.27 mol/L.

A. 5.25 B. 0.22 C. 4.5 D. 0.19 E. 1.6 102

17. Phosgene, COCl2, a poisonous gas, decomposes according to the equationCOCl2(g) CO(g) + Cl2(g). Calculate Kp for this reaction if Kc = 0.083 at 900ºC.

A. 0.125B. 8.0C. 6.1D. 0.16E. 0.083

18. Kp for the reaction of SO2(g) with O2 to produce SO3(g) is 3 1024 . Calculate Kc for this equilibrium at 25ºC. (The relevant reaction is 2SO2(g) + O2(g) 2SO3(g).)

A. 3 1024

B. 5 1021

C. 2 1020

D. 5 1022

E. 7 1025

19. If one starts with pure NO2(g) at a pressure of 0.500 atm, the total pressure inside the reaction vessel when 2NO2(g) 2NO(g) + O2(g) reaches equilibrium is 0.674 atm. Calculate the equilibrium partial

pressure of NO2.

A. 0.152 atmB. 0.174 atmC. 0.200 atmD. 0.326 atmE. The total pressure cannot be calculated because Kp is not given.

20. Equilibrium is established for the reaction 2X(s) + Y(g) 2Z(g) at 500K, Kc = 100.

Determine the concentration of Z in equilibrium with 0.2 mol X and 0.50 M Y at 500K.

A. 3.2 MB. 3.5 MC. 4.5 MD. 7.1 ME. none of these

21. At 250ºC, the equilibrium constant Kp for the reaction PCl5(g) PCl3(g) + Cl2(g) is 1.80. Sufficient

PCl5 is put into a reaction vessel to give an initial pressure of 2.74 atm at 250ºC. Calculate the pressure of PCl5 after the system has reached equilibrium.

A. 1.50 atmB. 1.24 atmC. 4.24 atmD. 0.94 atmE. 1.12 atm

22. At 35ºC, the equilibrium constant for the reaction 2NOCl(g) 2NO(g) + Cl2(g) is

Kc = 1.6 10-5. An equilibrium mixture was found to have the following concentrations of Cl2 and NOCl: [Cl2] = 1.2 10-2 M; [NOCl] = 2.8 10-1 M. Calculate the concentration of NO(g) at equilibrium.

A. 1.0 10-4 MB. 1.0 10-2 MC. 2.8 10-1 MD. 2.4 10-2 ME. 1.6 10-3 M

23. For the reaction SO2(g) + NO2(g) SO3(g) + NO(g), the equilibrium constant is 18.0 at 1,200ºC. If 1.0

mole of SO2 and 2.0 moles of NO2 are placed in a 20. L container, what concentration of SO3 will be present at equilibrium?

A. 0.48 mol/LB. 0.11 mol/LC. 0.95 mol/LD. 2.22 mol/LE. 18 mol/L

24. Consider the reaction N2(g) + O2(g) 2NO(g), for which Kc = 0.10 at 2,000ºC. Starting with initial

concentrations of 0.040 M of N2 and 0.040 M of O2, determine the equilibrium concentration of NO.

A. 5.4 10-3 MB. 0.0096 MC. 0.011 MD. 0.080 ME. 0.10 M

25. Hydrogen iodide decomposes according to the equation 2HI(g) H2(g) + I2(g), for which Kc = 0.0156

at 400ºC. 0.550 mol HI was injected into a 2.00 L reaction vessel at 400ºC. Calculate the concentration of HI at equilibrium.

A. 0.138 MB. 0.220 MC. 0.550 MD. 0.275 ME. 0.0275 M

26. Hydrogen iodide decomposes according to the equation 2HI(g) H2(g) + I2(g), for which Kc = 0.0156

at 400ºC. 0.550 mol HI was injected into a 2.00 L reaction vessel at 400ºC. Calculate the concentration of H2 at equilibrium.

A. 0.275 MB. 0.138 MC. 0.0275 MD. 0.0550 ME. 0.220 M

27. At 400ºC, Kc = 64 for the equilibrium H2(g) + I2(g) 2HI(g). If 3.00 mol H2 and 3.00 mol I2 are

introduced into an empty 4.0 L vessel, find the equilibrium concentration of HI at 400ºC.

A. 0.15 MB. 1.2 MC. 2.4 MD. 4.8 ME. 5.8 M

28. Sodium carbonate, Na2CO3(s), can be prepared by heating sodium bicarbonate, NaHCO3(s).

2NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(g) Kp = 0.23 at 100ºC

If a sample of NaHCO3 is placed in an evacuated flask and allowed to achieve equilibrium at 100ºC, what will the total gas pressure be?

A. 0.46 atm B. 0.96 atm C. 0.23 atm D. 0.48 atm E. 0.11 atm

29. At 340 K, Kp = 69 for the reaction H2(g) + I2(g) 2HI(g). 50.0 g of HI is injected into an evacuated

5.00-L rigid cylinder at 340 K. What is the total pressure inside the cylinder when the system comes to equilibrium?


30. 15.00 g of solid ammonium hydrogen sulfide is introduced into a 500.-mL flask at 25C, the flask is sealed, and the system is allowed to reach equilibrium. What is the partial pressure of ammonia in this flask if Kp = 0.108 at 25C for NH4HS(s) NH3(g) + H2S (g)?


31. For the nitrogen fixation reaction 3H2(g) + N2(g) 2NH3(g), Kc = 6.0 10-2 at 500C. If 0.250 M H2

and 0.050 M NH3 are present at equilibrium, what is the equilibrium concentration of N2?

A. 0.750 MB. 2.7 MC. 0.250 MD. 0.025 ME. 1.85 M

32. Consider the following reactions and their associated equilibrium constants:

For the reaction A + 2B D + E, having equilibrium constant Kc,

A. Kc = K1 + K2 B. Kc = K1/K2 C. Kc = K1 - K2 D. Kc = (K1)(K2) E. Kc = K2/K1

33. Consider the following equilibria:

Calculate the equilibrium constant for the reactionSO2(g) + NO3(g) SO3(g) + NO2(g).

A. 78 B. 1.3 10-2 C. 1.6 10-4 D. 3.2 10-10 E. 6.1 103

34. At 700 K, the reaction 2SO2(g) + O2(g) 2SO3(g) has the equilibrium constant Kc = 4.3 106, and the

following concentrations are present: [SO2] = 0.10 M; [SO3] = 10. M; [O2] = 0.10 M.

Is the mixture at equilibrium? If not at equilibrium, in which direction (as the equation is written), left to right or right to left, will the reaction proceed to reach equilibrium?

A. Yes, the mixture is at equilibrium.B. No, left to rightC. No, right to leftD. There is not enough information to be able to predict the direction.

35. At 700 K, the reaction 2SO2(g) + O2(g) 2SO3(g) has the equilibrium constant Kc = 4.3 106, and the

following concentrations are present: [SO2] = 0.010 M; [SO3] = 10.M; [O2] = 0.010 M.

Is the mixture at equilibrium? If not at equilibrium, in which direction (as the equation is written), left to right or right to left, will the reaction proceed to reach equilibrium?

A. Yes, the mixture is at equilibrium.B. No, left to rightC. No, right to leftD. There is not enough information to be able to predict the direction.

36. For the reaction H2(g) + I2(g) 2HI(g), Kc = 50.2 at 445ºC. If [H2] = [I2] = [HI] = 1.75 10-3 M at

445ºC, which one of these statements is true?

A. The system is at equilibrium, thus no concentration changes will occur.B. The concentrations of HI and I2 will increase as the system approaches equilibrium.C. The concentration of HI will increase as the system approaches equilibrium.D. The concentrations of H2 and HI will fall as the system moves toward equilibrium.E. The concentrations of H2 and I2 will increase as the system approaches equilibrium.

37. For the reaction PCl3(g) + Cl2(g) PCl5(g) at a particular temperature, Kc = 24.3. Suppose a system at

that temperature is prepared with [PCl3] = 0.10 M, [Cl2] = 0.15 M, and [PCl5] = 0.60 M. Which of these statements is true?

A. The reaction is at equilibrium.B. The reaction will proceed in the direction of forming more PCl5 until equilibrium is reached.C. The reaction will proceed in the direction of forming more PCl3 and Cl2 until equilibrium is reached.D. None of these statements is true.

38. For the following reaction at equilibrium, which choice gives a change that will shift the position of equilibrium to favor formation of more products?

2NOBr(g) 2NO(g) + Br2(g), Hºrxn = 30 kJ/mol

A. Increase the total pressure by decreasing the volume. B. Add more NO. C. Remove Br2. D. Lower the temperature. E. Remove NOBr selectively.

39. For the following reaction at equilibrium, which one of the changes below would cause the equilibrium to shift to the left?

2NOBr(g) 2NO(g) + Br2(g), Hºrxn = 30 kJ/mol

A. Increase the container volume. B. Remove some NO. C. Remove some Br2 . D. Add more NOBr. E. Decrease the temperature.

40. For the following reaction at equilibrium in a reaction vessel, which one of these changes would cause the Br2 concentration to decrease?

2NOBr(g) 2NO(g) + Br2(g), Hºrxn= 30 kJ/mol

A. Increase the temperature. B. Remove some NO. C. Add more NOBr. D. Compress the gas mixture into a smaller volume.

41. For the following reaction at equilibrium in a reaction vessel, which one of these changes would cause the Br2 concentration to increase?

2NOBr(g) 2NO(g) + Br2(g), Hºrxn= 30 kJ/mol

A. Lower the temperature. B. Remove some NO. C. Remove some NOBr. D. Compress the gas mixture into a smaller volume.

42. For the equilibrium reaction 2SO2(g) + O2(g) 2SO3(g), Hºrxn = -198 kJ/mol. Which one of these

factors would cause the equilibrium constant to increase?

A. Decrease the temperature.B. Add SO2 gas.C. Remove O2 gas.D. Add a catalyst.E. none of these

43. The reaction 2SO3(g) 2SO2(g) + O2(g) is endothermic. If the temperature is increased,

A. more SO3 will be produced.B. Kc will decrease.C. no change will occur in Kc .D. Kc will increase.E. the pressure will decrease.

44. For the reaction at equilibrium 2SO3 2SO2 + O2 (Hºrxn= 198 kJ/mol), if we increase the reaction

temperature, the equilibrium will

A. shift to the right.B. shift to the left.C. not shift.D. The question cannot be answered because the equilibrium constant is not given.

45. Which of these situations will result if some CH4(g) is removed from the reactionCO(g) + 3H2(g) CH4(g) + H2O(g) at equilibrium?

A. H2O will be consumed.B. More CH4 and H2O will be produced.C. Kp will decrease.D. More CO will be produced.E. No change will occur.

46. For the common allotropes of carbon (graphite and diamond), C(gr) C(dia) with equilibrium

constant K = 0.32. The molar volumes of graphite and diamond are, respectively, 5.30 cm3/mol and 3.42 cm3/mol; Hf of diamond is 1.90 kJ/mol. These data suggest that the formation of diamond is favored at

A. low temperatures and low pressures.B. high temperatures and low pressures.C. low temperatures and high pressures.D. high temperatures and high pressures.

47. In which of these gas-phase equilibria is the yield of products increased by increasing the total pressure on the reaction mixture?

A. CO(g) + H2O(g) CO2(g) + H2(g)

B. 2NO(g) + Cl2(g) 2NOCl(g)

C. 2SO3(g) 2SO2(g) + O2(g)

D. PCl5(g) PCl3(g) + Cl2(g)

48. Consider this gas phase equilibrium system: PCl5(g) PCl3(g) + Cl2(g) Hºrxn = +87.8 kJ/mol.

Which of these statements is false?

A. Increasing the system volume shifts the equilibrium to the right. B. Increasing the temperature shifts the equilibrium to the right. C. A catalyst speeds up the approach to equilibrium and shifts the position of equilibrium to the right. D. Decreasing the total pressure of the system shifts the equilibrium to the right. E. Increasing the temperature causes the equilibrium constant to increase.

49. The reaction 2NO(g) N2(g) + O2(g) is exothermic, Hºrxn = -180 kJ/mol.

Which one of these statements is true?

A. Kp at 1,000 K is less than Kp at 2,000 K. B. Kp at 1,000 K is larger than Kp at 2,000 K. C. The Kp's at 1000 K and 2000 K are the same. D. Kp depends on total pressure as well as temperature.

50. Consider this reaction at equilibrium: 2SO2(g) + O2(g) 2SO3(g), Hºrxn = -198 kJ/mol

If the volume of the system is compressed at constant temperature, what change will occur in the position of the equilibrium?

A. a shift to produce more SO2 B. a shift to produce more O2 C. no change D. a shift to produce more SO3

51. Consider this reaction at equilibrium at a total pressure P1:2SO2(g) + O2(g) 2SO3(g)

Suppose the volume of this system is compressed to one-half its initial volume and then equilibrium is reestablished. The new equilibrium total pressure will be

A. twice P1.B. three times P1.C. 3.5 P1.D. less than twice P1.E. unchanged.

52. For the reaction 2NOCl(g) 2NO(g) + Cl2(g), Kc = 8.0 at a certain temperature.

What concentration of NOCl must be put into an empty 4.00 L reaction vessel in order that the equilibrium concentration of NOCl be 1.00 M?

A. 1.26 MB. 2.25 MC. 2.50 MD. 3.52 ME. 11.0 M

53. The equilibrium constants (expressed in atm) for the chemical reactionN2(g) + O2(g) 2NO(g) are Kp = 1.1 10-3 and 3.6 10-3 at 2,200 K and 2,500 K, respectively.

Which one of these statements is true?

A. The reaction is exothermic, Hº < 0.B. The partial pressure of NO(g) is less at 2,200 K than at 2,500 K.C. Kp is less than Kc by a factor of (RT).D. The total pressure at 2,200 K is the same as at 2,500 K.E. Higher total pressure shifts the equilibrium to the left.

54. When the substances in the equation below are at equilibrium, at pressure P and temperature T, the equilibrium can be shifted to favor the products by

CuO(s) + H2(g) H2O(g) + Cu(s) Hºrxn = -2.0 kJ/mol

A. increasing the pressure by means of a moving piston at constant T. B. increasing the pressure by adding an inert gas such as nitrogen. C. decreasing the temperature. D. allowing some gases to escape at constant P and T. E. adding a catalyst.

55. 50.0 g of N2O4 is introduced into an evacuated 2.00 L vessel and allowed to come to equilibrium with its decomposition product, N2O4(g) 2NO2(g). For this reaction Kc = 0.133. Once the system has reached

equilibrium, 5.00 g of NO2 is injected into the vessel, and the system is allowed to equilibrate once again. Calculate the mass of NO2 in the final equilibrium mixture.

A. 17.8 gB. 12.4 gC. 14.7 gD. 19.7 gE. 15.5 g

56. 50.0 g of N2O4 is introduced into an evacuated 2.00 L vessel and allowed to come to equilibrium with its decomposition product, N2O4(g) 2NO2(g). For this reaction Kc = 0.133. Once the system has reached

equilibrium, 5.00 g of NO2 is injected into the vessel, and the system is allowed to equilibrate once again. Calculate the mass of N2O4 in the final equilibrium mixture.

A. 39.5 gB. 35.3 gC. 30.3 gD. 25.2 gE. 43.7 g

57. 75.0 g of PCl5(g) is introduced into an evacuated 3.00 L vessel and allowed to reach equilibrium at 250ºC. PCl5(g) PCl3(g) + Cl2(g)

If Kp = 1.80 for this reaction, what is the total pressure inside the vessel at equilibrium?


58. 75.0 g of PCl5(g) is introduced into a 3.00 L vessel containing 10.0 g of Cl2(g), and the system is allowed to reach equilibrium at 250ºC. PCl5(g) PCl3(g) + Cl2(g)

If Kp = 1.80 for this reaction, what is the total pressure inside the vessel at equilibrium?


59. 25.0 g of HI(g) is injected into a 4.00 L reaction vessel that contains 20.0 g of I2(g). When the system comes to equilibrium at 400ºC, what will be the total pressure inside the reaction vessel? 2HI(g) H2(g) + I2(g), Kc = 0.0156 at 400ºC


60. Solid ammonium hydrogen sulfide is introduced into a 2.00-L flask, and the flask is sealed. If this solid decomposes according to the equation NH4HS(s) NH3(g) + H2S(g), Kp = 0.108 at 25C,

what is the minimum mass of ammonium hydrogen sulfide that must be present in the flask initially if equilibrium is to be established at 25C?

A. 0.917 g B. 1.37 g C. 2.74 g D. 0.581 g E. 0.452 g

61. When the reaction 2H2S(g) 2H2(g) + S2(g) is carried out at 1065C, Kp = 0.012. Starting with pure

H2S at 1065, what must the initial pressure of H2S be if the equilibrated mixture at this temperature is to contain 0.250 atm of H2(g)?


62. If the reaction 2H2S(g) 2H2(g) + S2(g) is carried out at 1065C, Kp = 0.0120. Starting from pure H2S

introduced into an evacuated vessel at 1065C, what will the total pressure in the vessel be at equilibrium if the equilibrated mixture contains 0.300 atm of H2(g)?


63. A quantity of liquid methanol, CH3OH, is introduced into a rigid 3.00-L vessel, the vessel is sealed, and the temperature is raised to 500K. At this temperature, the methanol vaporizes and decomposes according to the reaction CH3OH(g) CO(g) + 2 H2(g), Kc= 6.90 10-2.

If the concentration of H2 in the equilibrium mixture is 0.426 M, what mass of methanol was initially introduced into the vessel?

A. 147 g B. 74.3 g C. 33.9 g D. 49.0 g E. 24.8 g

64. Describe why addition of a catalyst does not affect the equilibrium constant for a reaction.

65. Consider the reaction N2(g) + 3H2(g) 2NH3(g). If hydrogen gas is added to this system at

equilibrium, which direction will the reaction shift?

66. Consider the reaction N2(g) + 3H2(g) 2NH3(g). If nitrogen is added to the system at equilibrium,

what will happen to the ammonia concentration?

67. Consider the reaction N2(g) + 3H2(g) 2NH3(g). If nitrogen is removed from the system at

equilibrium, what will happen to the hydrogen (H2) concentration?

68. Consider the reaction N2(g) + 3H2(g) 2NH3(g). The production of ammonia is an endothermic

reaction. Will heating the equilibrium system increase or decrease the amount of ammonia produced?

69. Consider the reaction N2(g) + 3H2(g) 2NH3(g). If we use a catalyst, which way will the reaction

shift?

70. 5.00 mol of ammonia are introduced into a 5.00 L reactor vessel in which it partially dissociates at high temperatures. 2NH3(g) 3H2(g) + N2(g)

At equilibrium at a particular temperature, 1.00 mole of ammonia remains. Calculate Kc for the reaction.

71. 4.2 mol of oxygen and 4.0 mol of NO are introduced to an evacuated 0.50 L reaction vessel. At a specific temperature, the equilibrium 2NO(g) + O2(g) 2NO2(g) is reached when [NO] = 1.6 M. Calculate Kc

for the reaction at this temperature?

72. 4.21 moles of S2Cl4 are introduced into a 2.0 L vessel. S2Cl4(g) 2SCl2(g)

At equilibrium, 1.25 moles of S2Cl4 are found to remain in the container. Calculate Kc for this reaction.

73. The data below refer to the following reaction:

Find the concentration of Br2 when the system reaches equilibrium.


Find the concentration of NOBr when the system reaches equilibrium.


Calculate Kc.

76. Consider the chemical reaction 2NH3(g) N2(g) + 3H2(g). The equilibrium is to be established in a 1.0

L container at 1,000 K, where Kc = 4.0 10-2. Initially, 1,220 moles of NH3(g) are present.

Estimate the equilibrium concentration of H2(g).



Estimate the equilibrium concentration of N2(g).



Calculate Kp for the reaction.

79. Hydrogen iodide decomposes according to the equation: 2HI(g) H2(g) + I2(g), Kc = 0.0156 at 400ºC

A 0.660 mol sample of HI was injected into a 2.00 L reaction vessel held at 400ºC.Calculate the concentration of H2 equilibrium.

80. Hydrogen iodide decomposes according to the equation: 2HI(g) H2(g) + I2(g), Kc = 0.0156 at 400ºC

A 0.660 mol sample of HI was injected into a 2.00 L reaction vessel held at 400ºC.Calculate the concentration of HI at equilibrium.

81. What conditions are used in the Haber process to enhance the yield of ammonia? Explain why each condition affects the yield in terms of the Le Châtelier principle.

82. The dissociation of solid silver chloride in water to produce silver ions and chloride ions has an equilibrium constant of 1.8 x10-18. Based on the magnitude of the equilibrium constant, is silver chloride very soluble in water? Why?

83. Consider the equilibrium equation C(s) + H2O(g) + 2296 J CO(g) + H2(g).What will happen to the

concentration of carbon monoxide if the temperature of this system is raised?

84. Consider the equilibrium equation C(s) + H2O(g) + 2296 J CO(g) + H2(g). If additional gaseous

water is added to this reaction mixture, what will happen to the temperature of the mixture?

85. Consider the equilibrium equation C(s) + H2O(g) + 2296 J CO(g) + H2(g).What will happen to the

mass of carbon if we add water to the system?

86. Consider the equilibrium equation C(s) + H2O(g) + 2296 J CO(g) + H2(g).Which way will the

reaction shift if the pressure on the system is increased?

87. Ethanol and acetic acid react to form ethyl acetate and water according to the equation C2H5OH + CH3COOH CH3COOC2H5 + H2O

When two moles each of ethanol and acetic acid are allowed to react at 100ºC in a sealed tube, equilibrium is established when two-thirds of a mole of each of the reactants remains. Calculate the equilibrium constant for this reaction.

88. 5.00 mol each of acetic acid and ethanol are allowed to react in a 1.00 L sealed container at 100ºC until equilibrium is established. How many moles of the ester and water are produced in this reaction? The equilibrium constant is 4.00 for the reaction C2H5OH + CH3COOH CH3COOC2H5 + H2O.

89. 5.00 mol each of acetic acid and ethanol are allowed to react in a 1.00 L sealed container at 100ºC until equilibrium is established. How many moles of ethanol and acid remain following equilibration? The equilibrium constant is 4.00 for the reaction, C2H5OH + CH3COOH CH3COOC2H5 + H2O.

90. What is the correct equilibrium constant expression for this reaction? 2HI(g) H2(g) + I2(g)

91. Consider the following equilibrium, 4NH3 + 3O2 2 N2 + 6H2O + 1531 kJ

State whether the concentration of each of the reactants would increase, decrease, or remain constant when the temperature is increased.


State whether the concentration of each of the products would increase, decrease, or remain constant when the temperature is increased.


State whether the concentration of each of the reactants would increase, decrease, or remain constant following the addition of 2 mol of ammonia to the system.


State whether the concentration of each of the reaction products would increase, decrease, or remain constant following the addition of 2 mol of ammonia to the system.

95. Kc for the reaction CO2(g) + H2(g) H2O(g) + CO(g) is 1.6 at about 990ºC. Calculate the number of

moles of carbon dioxide in the final equilibrium system obtained by initially adding 1.00 mol of H2, 2.00 mol of CO2, 0.750 mol of H2O, and 1.00 mol of CO to a 5.00 L reactor at 990ºC.


moles of hydrogen gas in the final equilibrium system obtained by initially adding 1.00 mol of H2, 2.00 mol of CO2, 0.750 mol of H2O, and 1.00 mol of CO to a 5.00 L reactor at 990ºC.


moles of water in the final equilibrium system obtained by initially adding 1.00 mol of H2, 2.00 mol of CO2, 0.750 mol of H2O, and 1.00 mol of CO to a 5.00 L reactor at 990ºC.


moles of carbon monoxide in the final equilibrium system obtained by initially adding 1.00 mol of H2, 2.00 mol of CO2, 0.750 mol of H2O, and 1.00 mol of CO to a 5.00 L reactor at 990ºC.

99. Two moles of PCl5 are placed in a 5.0 L container. Dissociation takes place according to the equation PCl5 (g) PCl3(g) + Cl2(g). At equilibrium, 0.40 mol of Cl2 are present. Calculate the equilibrium constant

(Kc) for this reaction under the conditions of this experiment.

100. The equilibrium constant expression for the reactionCuO(s) + H2(g) Cu(s) + H2O(g) is Kc = [H2]/[H2O].

True False

101. When the reaction 2O3(g) 3O2(g), for which Kp = 3.0 1026 at 773ºC, is at equilibrium, the mixture

will contain very little O2 as compared to O3.

True False

102. If the system 3H2(g) + N2(g) 2NH3(g) is at equilibrium and more N2 is added, a net reaction that

consumes some of the added N2 will occur until a new equilibrium is reached.

True False

103. Equilibrium constants are known for the following reactions:

Thus, for the reaction S(s) + O2(g) SO2(g), Kc = 4.4 1020.

True False

104. For the reaction H2(g) + I2(g) 2HI(g), Kp = Kc.

True False

Chapter 14 Chemical Equilibrium Key

1.C 2.B 3.C 4.C 5.D 6.A 7.E 8.C 9.E 10.D 11.B 12.A 13.D 14.C 15.A 16.B 17.B 18.E 19.A 20.D 21.B 22.B 23.A 24.C 25.B 26.C

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27.B 28.B 29.D 30.C 31.B 32.D 33.A 34.B 35.C 36.C 37.C 38.C 39.E 40.D 41.B 42.A 43.D 44.A 45.B 46.D 47.B 48.C 49.B 50.D 51.D 52.D 53.B 54.C 55.E 56.A 57.D

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58.B 59.E 60.B 61.A 62.E 63.B 64.A catalyst affects both the forward and reverse rate of the reaction. Therefore, the equilibrium constant is not affected. 65.The reaction will shift toward the products. 66.[NH3] will increase. 67.[H2] will increase. 68.The amount of NH3 produced will increase. 69.Addition of a catalyst will have no effect on the position of the equilibrium. 70. Kc = 17.3 71. Kc = 3.1 72. Kc = 14.0 73. 4.75 M 74. 1.5 M 75. 0.12 76.20 M 77.6.8 M 78.270 79. 0.033 M 80. 0.264 M 81.High pressure, low temperature, use of a catalyst. Pressure is kept high because high pressure concentrates the reactants to a greater extent than it does the products. Temperature is kept low because the reaction is exothermic, and use of a catalyst facilitates the reaction progress. 82.Kc here will be [Ag+(aq)][Cl-(aq)]. If Keq is very small, then the concentrations of the dissolved ions must also be small, implying that AgCl is not very soluble. 83.It will increase. 84.The temperature will decrease. 85.The mass of carbon will decrease. 86.toward the reactants

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87. 4 88. 1.67 moles each of acid and ethanol 89. 3.33 moles each of ester and water 90. Kc = [H2][I2]/[HI]2 91. increase 92. decrease 93. decrease 94. increase 95.1.6 mol 96.0.62 mol 97.1.1 mol 98.1.4 mol 99.0.020 100.FALSE 101.FALSE 102.TRUE 103.TRUE 104.TRUE

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15967_Chapter 14 Questions