50. For the reaction TlCl(s) Tl+(aq) + Cl−(aq), Kc =
1.8 10−4
at 25C. Which of the
following concerning a 125 mL solution containing
1.342 10−2
M Tl+,
4.472 10−3
M Cl−
and a large excess of TlCl(s) is/are correct?
1.
The mixture is at equilibrium.
2.
Additional TlCl(s) must dissolve to attain equilibrium.
3.
The reaction quotient (Q) is less than one.
A)
1 only
B)
2 only
C)
3 only
D)
2 and 3
E)
1 and 3
51. What is the reaction quotient (Q) for the equilibrium
CuSCN(s) Cu+(aq) + SCN−(aq)
when 0.3317 L of
2.000 10−7
M Cu+ is combined with 0.1018 L of
4.000 10−7
M SCN−
in the presence of an excess of CuSCN(s)?
A)
B)
C)
D)
E)
52. The reaction quotient for a system is
3.4 103
. If the equilibrium constant for the system is
1.5 10−4
, what will happen as the reaction mixture approaches equilibrium?
A)
The equilibrium constant will increase until it equals the reaction quotient.
B)
There will be a net gain in both product(s) and reactant(s).
C)
There will be a net gain in product(s).
D)
There will be a net gain in reactant(s).
E)
The equilibrium constant will decrease until it equals the reaction quotient.
53. CS2(g) + 3Cl2(g) CCl4(g) + S2Cl2(g)
At a given temperature, the reaction above is at equilibrium when [CS2] = 0.050 M, [Cl2] =
0.25 M, [CCl4] = 0.15 M, and [S2Cl2] = 0.35 M. What will be the direction of the reaction
when the reactants and products have the following concentrations: CS2 = 0.15 M, Cl2 =
0.21 M, CCl4 = 0.29 M, and S2Cl2 = 0.34 M?
A)
to the left
B)
to the right
C)
no change
D)
cannot predict unless we know the temperature
E)
cannot predict unless we know whether the reaction is endothermic or exothermic
54. For the reaction 2HI(g) H2(g) + I2(g), Kc = 0.290 at 400 K. If the initial concentrations
of HI, H2, and I2 are all 1.50 10–3 M at 400 K, which one of the following statements is
correct?
A)
The concentrations of HI and I2 will increase as the system is approaching
equilibrium.
B)
The concentrations of H2 and I2 will increase as the system is approaching
equilibrium.
C)
The system is at equilibrium.
D)
The concentrations of H2 and HI will decrease as the system is approaching
equilibrium.
E)
The concentration of HI will increase as the system is approaching equilibrium.
55. Hydrogen iodide undergoes decomposition according to the equation
2HI(g) H2(g) + I2(g)
The equilibrium constant Kc at 425°C for this system is 0.018. If 1.0 mol each of H2, I2, and
HI were placed together in a 1-L container at 425°C, then
A)
because of reaction, the total number of molecules would increase.
B)
the concentration of HI would decrease.
C)
because of reaction, the total number of molecules would decrease.
D)
the value of K would increase to 1.0.
E)
the concentration of H2 would decrease.
Test Bank General Chemistry, 10th edition 21
56. For the equilibrium PCl5(g) PCl3(g) + Cl2(g), Kc = 4.0 at 228°C. If pure PCl5 is placed
in a 1.00-L container and allowed to come to equilibrium, and the equilibrium concentration
of PCl5(g) is 0.26 M, what is the equilibrium concentration of PCl3?
A)
0.13 M
B)
0.37 M
C)
0.26 M
D)
1.0 M
E)
0.017 M
57. For the equilibrium N2O4(g) 2NO2(g), at 298 K, Kp = 0.15. For this reaction system,
it is found that the partial pressure of N2O4 is 3.2 10–2 atm at equilibrium. What is the
partial pressure of NO2 at equilibrium? (R = 0.0821 L · atm/(K · mol))
A)
4.6 atm
B)
21 atm
C)
0.0022 atm
D)
0.0048 atm
E)
0.069 atm
58. For the equilibrium PCl5(g) PCl3(g) + Cl2(g), Kc = 2.0 101 at 240°C. If pure PCl5 is
placed in a 1.00-L container and allowed to come to equilibrium, and the equilibrium
concentration of PCl3(g) is 0.47 M, what is the equilibrium concentration of PCl5(g)?
A)
0.94 M
B)
0.24 M
C)
0.024 M
D)
0.011 M
E)
6.5 M
59. The equilibrium constant for the reaction H2(g) + I2(g) 2HI(g) is 62.5 at 800 K. What
is the equilibrium concentration of I2 if at equilibrium [HI] = 0.18 M and [H2] = 0.11 M?
A)
4.7 10–3 M
B)
0.25 M
C)
5.2 10–2 M
D)
0.18 M
E)
2.6 10–2 M
Test Bank General Chemistry, 10th edition 22
60. Consider the following equilibrium:
4NH3(g) + 3O2(g) 2N2(g) + 6H2O(g)
Suppose 0.30 mol of NH3 and 0.40 mol of oxygen are added to a 5.0-L container. If x mol of
water is present at equilibrium, how many moles of ammonia will remain at equilibrium?
A)
0.30 – x
B)
0.30 – x
C)
0.30 – x
D)
0.40 – x
E)
x
61. Consider the following equilibrium.
4NH3(g) + 3O2(g) 2N2(g) + 6H2O(g)
Suppose 0.30 mol of NH3 and 0.40 mol of oxygen are added to a 5.0-L container. If x mol of
water is present at equilibrium, what is the equilibrium concentration of oxygen?
A)
0.40 – 0.50x
B)
0.30 – 0.50x
C)
0.08 – 0.10x
D)
0.06 – 0.13x
E)
0.40 – x
62. Consider the following equilibrium:
2NO(g) + 3F2(g) 2NOF3(g)
Suppose 0.20 mol of NO and 0.30 mol of F2 are added to a 5.0-L container. If x mol of
NOF3 is present at equilibrium, how many moles of fluorine are present at equilibrium?
A)
0.30 – x
B)
0.30 – 2x
C)
0.06 – 0.20x
D)
0.30 – x
E)
0.20 – x
Test Bank General Chemistry, 10th edition 23
63. Consider the following equilibrium:
2NO(g) + 3F2(g) 2NOF3(g)
Suppose 0.20 mol of NO and 0.30 mol of F2 are added to a 5.0-L container. If x mol of
NOF3 is present at equilibrium, what is the equilibrium concentration of NO?
A)
0.20x
B)
0.05 – 0.50x
C)
0.20 – 2x
D)
0.04 – 0.20x
E)
0.20 – x
64. In an experiment, 0.42 mol H2 and 0.42 mol I2 are mixed in a 1.00-L container, and the
reaction forms HI. If Kc = 49. for this reaction, what is the equilibrium concentration of HI?
I2(g) + H2(g) 2HI(g)
A)
0.81 M
B)
0.74 M
C)
0.65 M
D)
0.105 M
E)
0.056 M
65. Hydrogen iodide undergoes decomposition according to the equation
2HI(g) H2(g) + I2(g)
The equilibrium constant Kp at 500 K for this equilibrium is 0.060. Suppose 0.520 mol of HI
is placed in a 1.00-L container at 500 K. What is the equilibrium concentration of H2(g)?
(R = 0.0821 L · atm/(K · mol))
A)
0.14 M
B)
0.085 M
C)
4.2 M
D)
0.025 M
E)
0.10 M
Test Bank General Chemistry, 10th edition 24
66. At 700 K, Kp for the following equilibrium is 5.6 10-3.
2HgO(s) 2Hg(l) + O2(g)
Suppose 51.2 g of mercury(II) oxide is placed in a sealed 3.00-L vessel at 700 K. What is
the partial pressure of oxygen gas at equilibrium? (R = 0.0821 L · atm/(K · mol))
A)
0.075 atm
B)
0.0056 atm
C)
4.5 atm
D)
19 atm
E)
2.3 atm
67. At 800 K, Kc for the following equilibrium is 4.2 10-3.
2HgO(s) 2Hg(l) + O2(g)
Suppose 10.9 g of mercury (II) oxide is placed in a sealed 3.50-L vessel at 800 K. What is
the partial pressure of oxygen gas at equilibrium? (R = 0.0821 L · atm/(K · mol))
A)
0.83 atm
B)
0.41 atm
C)
0.28 atm
D)
0.0042 atm
E)
16 atm
68. At 550 K, Kp = 7.7 102 for the following equilibrium.
SO2(g) + NO2(g) SO3(g) + NO(g)
If 0.496 mol each of SO3 and NO are placed in a 5.00-L container at 550 K, what is the
concentration of SO3 at equilibrium? (R = 0.0821 L · atm/(K · mol))
A)
4.3 M
B)
0.096 M
C)
0.099 M
D)
17 M
E)
0.025 M
69. Exactly 1.0 mol N2O4 is placed in an empty 1.0-L container and allowed to reach
equilibrium described by the equation N2O4(g) 2NO2(g).
If at equilibrium the N2O4 is 28.0% dissociated, what is the value of the equilibrium
constant, Kc, for the reaction under these conditions?
A)
0.44
B)
2.3
C)
0.31
D)
0.78
E)
0.11
70. Consider the following equilibrium:
CO2(g) + H2(g) CO(g) + H2O(g); Kc = 1.6 at 1260 K
Suppose 0.038 mol CO2 and 0.022 mol H2 are placed in a 1.50-L vessel at 1260 K. What is
the equilibrium partial pressure of CO(g)? (R = 0.0821 L · atm/(K · mol))
A)
9.9 atm
B)
1.1 atm
C)
4.1 atm
D)
2.6 atm
E)
1.5 atm
71. Which of the following, when added to an equilibrium mixture represented by the
equlibrium below, will not alter the composition of the original equilibrium mixture?
Mg(OH)2(s) Mg2+(aq) + 2OH−(aq)
A)
Addition of Mg(NO3)2(s) to the equilibrium mixture.
B)
Addition of Fe(NO3)3(aq) from the equilibrium mixture.
C)
Addition of Mg(OH)2(s) to the equilibrium mixture.
D)
Addition of HCl(aq) to the equilibrium mixture.
E)
Addition of NaOH(s) to the equilibrium mixture.
72. Consider the following equilibrium:
PCl3(g) + Cl2(g) PCl5(g); H = -92 kJ
The concentration of PCl3 at equilibrium may be increased by
A)
decreasing the temperature.
B)
adding Cl2 to the system.
C)
adding PCl5 to the system.
D)
increasing the pressure.
E)
adding a catalyst.
73. When cobalt chloride is added to pure water, the Co2+ ions hydrate. The hydrated form then
reacts with the Cl– ions to set up the equilibrium shown here:
Co(H2O)62+ + 4Cl– CoCl42– + 6H2O
(pink)
(blue)
Which statement accurately describes the change that the system will undergo if water is
added?
A)
The color will become more blue.
B)
The equilibrium will shift to the right.
C)
More water will be produced.
D)
More chloride ions will be produced.
E)
There will be less of the hydrated cobalt ion at the new equilibrium position.
74. Carbon monoxide is toxic because it can successfully compete with oxygen for hemoglobin
(Hb) sites according to the following equilibrium:
Hb(O2)4(aq) + 4CO(g) Hb(CO)4(aq) + 4O2(g)
From Le Châtelier’s principle, CO poisoning is reversed by
A)
increasing the O2 pressure.
B)
decreasing the amount of Hb.
C)
increasing the CO2 pressure.
D)
increasing the CO pressure.
E)
increasing the amount of Hb.
Test Bank General Chemistry, 10th edition 27
75. What effect will spraying liquid water into the equilibrium given below have if NH3 is far
more soluble in water than is N2 or H2?
N2(g) + 3H2(g) 2NH3(g)
A)
More NH3(g) will form.
B)
More H2(g) will form.
C)
Less NH3(g) will form.
D)
This will not affect the system.
E)
More N2(g) will form.
76. When cobalt chloride is added to pure water, the Co2+ ions hydrate. The hydrated form then
reacts with the Cl– ions to set up the equilibrium shown here:
Co(H2O)62+ + 4Cl– CoCl42– + 6H2O
(pink)
(blue)
Which statement describes the change that the system will undergo if potassium chloride is
added?
A)
It should become more pink.
B)
Nothing will change.
C)
The silver ion will react with the CoCl42–.
D)
Water will be produced.
E)
It should become more blue.
77. Consider the reaction represented by the equation N2(g) + 3H2(g) 2NH3(g). What
happens to the equilibrium position when an inert gas is added to this system (as represented
above) at equilibrium?
A)
If the container is rigid, the equilibrium position shifts. If the container is fitted
with a movable piston, nothing happens to the equilibrium position.
B)
If the container is rigid, nothing happens to the equilibrium position. If the
container is fitted with a movable piston, the equilibrium position shifts.
C)
Nothing happens to the equilibrium position no matter what the container is like.
D)
The equilibrium position shifts no matter what the container is like.
E)
The value of the equilibrium constant must be known to answer this question.
Test Bank General Chemistry, 10th edition 28
78. Which of the following equilibria would not be affected by pressure changes at constant
temperature?
A)
CO2(g) + H2(g) CO(g) + H2O(g)
B)
CO(g) + O2(g) CO2(g)
C)
2Hg(l) + O2(g) 2HgO(s)
D)
2H2(g) + O2(g) 2H2O(l)
E)
CaCO3(s) CaO(s) + CO2(g)
79. Which of the following equilibria would be affected by volume changes at constant
temperature?
A)
HCl(aq) + NaOH(aq) H2O(l) + NaCl(aq)
B)
C2H4(g) + H2(g) C2H6(g)
C)
2HCl(g) H2(g) + Cl2(g)
D)
SO3(g) + NO(g) NO2(g) + SO2(g)
E)
2HF(g) H2(g) + F2(g)
80. In which of the following reactions does a decrease in the volume of the reaction vessel at
constant temperature favor formation of the products?
A)
2H2(g) + O2(g) 2H2O(g)
B)
NO2(g) + CO(g) NO(g) + CO2(g)
C)
H2(g) + I2(g) 2HI(g)
D)
2O3(g) 3O2(g)
E)
MgCO3(s) MgO(s) + CO2(g)
81. Which of the following equilibria would be affected by volume changes at constant
temperature?
1.
2NO(g) + 3F2(g) 2F3NO(g)
2.
PCl3(g) + Cl2(g) PCl5(g)
3.
O3(g) + NO(g) NO2(g) + O2(g)
Test Bank General Chemistry, 10th edition 29
A)
1 only
B)
2 only
C)
3 only
D)
1 and 2
E)
1, 2, and 3
82. For which of the following systems at equilibrium and at constant temperature will
decreasing the volume cause the equilibrium to shift to the right?
A)
NH4Cl(s) NH3(g) + HCl(g)
B)
2NO2(g) 2NO(g) + O2(g)
C)
H2(g) + Cl2(g) 2HCl(g)
D)
N2(g) + 3H2(g) 2NH3(g)
E)
2H2O(g) 2H2(g) + O2(g)
83. For which of the following systems at equilibrium and at constant temperature will
increasing the volume have no effect on the equilibrium?
A)
C(s) + CO2(g) 2CO(g)
B)
SO2Cl2(g) SO2(g) + Cl2(g)
C)
COCl2(g) CO(g) + Cl2(g)
D)
I2(g) 2I(g)
E)
CO(g) + H2O(g) CO2(g) + H2(g)
84. In which of the following reactions does an instantaneous increase in the volume of the
reaction vessel favor formation of the products?
A)
PCl5(g) PCl3(g) + Cl2(g)
B)
N2(g) + 3H2(g) 2NH3(g)
C)
H2(g) + I2(g) 2HI(g)
D)
MgO(s) + CO2(g) MgCO3(s)
E)
N2(g) + O2(g) 2NO(g)
85. Consider the following equilibrium:
NH4Cl(s) NH3(g) + HCl(g)
Suppose a vessel containing NH4Cl(s), NH3(g) and HCl(g) is at equilibrium. If the volume
of the vessel is instantaneously doubled while keeping the temperature constant, when a new
equilibrium is reached, which of the following statements is incorrect?
A)
The value of Kp remains unchanged.
B)
The number of moles of NH4Cl decreases.
C)
The total pressure is halved.
D)
The partial pressures of NH3 and HCl in the vessel remain unchanged.
E)
The amount of NH3 and HCl doubles.
86. For a specific reaction, which of the following statements can be made about the
equilibrium constant?
A)
It can be changed by the addition of a catalyst.
B)
It increases when the concentration of one of the products is increased.
C)
It increases when the concentration of one of the reactants is increased.
D)
It always remains the same.
E)
It changes with changes in the temperature.
87. Ammonia is prepared industrially by the reaction
N2(g) + 3H2(g) 2NH3(g)
For the reaction, H° = –92.2 kJ and K (at 25°C) = 4.0 108. When the temperature of the
reaction is increased to 500°C, which of the following statements is true?
A)
At equilibrium, more NH3 is present at 500°C than at 25°C.
B)
The reaction of N2 with H2 to form ammonia is endothermic.
C)
K for the reaction will be larger at 500°C than at 25°C.
D)
Product formation (at equilibrium) is less favored as the temperature is raised.
E)
None of the above statements is true.
88. When the pressure of an equilibrium mixture of SO2, O2, and SO3 is halved at constant
temperature, what is the effect on Kp?
2SO2(g) + O2(g) 2SO3(g)
A)
Kp is doubled.
B)
Kp is halved.
C)
Kp is unchanged.
D)
Kp is tripled.
E)
Kp is decreased by a third.
89. Consider the following equilibrium at 25°C:
2ICl(g) I2(g) + Cl2(g); H = 27 kJ; Kp = 6.2 10–6
Which of the following would be true if the temperature were increased to 100°C?
1.
The value of Kp would increase.
2.
The concentration of ICl(g) would increase.
3.
The partial pressure of I2 would increase.
A)
1 only
B)
2 only
C)
3 only
D)
1 and 2
E)
1 and 3
90. The following equilibrium is established in a sealed, rigid container. How could the partial
pressure of SO2 at equilibrium be increased?
SO2Cl2(g) SO2(g) + Cl2(g); H = +67 kJ
A)
by adding an inert gas such as helium
B)
by increasing the temperature
C)
by removing SO2Cl2 as it is formed
D)
by adding Cl2 to the system
E)
by decreasing the volume of the reaction vessel
91. One method for the decomposition of carbon dioxide proceeds as follows:
2CO2(g) 2CO(g) + O2(g); H = 559 kJ
Which of the following changes will cause an increase in the equilibrium concentration of
CO?
A)
adding more O2 to the system
B)
adding a catalyst
C)
removing CO2 from the system
D)
increasing the pressure of the system at constant temperature
E)
increasing the temperature of the system
92. Consider the following equilibrium:
2NH3(g) N2(g) + 3H2(g); H = 92 kJ
What change should be made in order to increase the value of Kp for this reaction?
A)
Increase the pressure.
B)
Decrease the temperature.
C)
Increase the temperature.
D)
Decrease the pressure.
E)
Nothing; Kp cannot be changed.
93. For the following reaction system at equilibrium, which one of the changes below would
cause the equilibrium to shift to the right?
Br2(g) + 2NO(g) 2NOBr(g); H° = –30 kJ
A)
Remove some NO.
B)
Remove some Br2.
C)
Add some NOBr.
D)
Increase the volume of the reaction vessel.
E)
Decrease the temperature.
Test Bank General Chemistry, 10th edition 33
94. Solid HgO, liquid Hg, and gaseous O2 are placed in a glass bulb and allowed to reach
equilibrium.
2HgO(s) 2Hg(l) + O2(g); H = 181.6 kJ
The amount of Hg(l) in the bulb could be increased
A)
by removing some HgO(s).
B)
by adding an inert gas.
C)
by adding some HgO(s).
D)
by increasing the pressure.
E)
by increasing the temperature.
95. Consider the following equilibrium:
CO2(g) + C(graphite) 2CO(g); H = 172.5 kJ
The equilibrium constant for this reaction will
A)
increase if the temperature is decreased.
B)
decrease with increasing temperature.
C)
increase at some pressures and decrease at other pressures.
D)
increase with increasing temperature.
E)
not change if the temperature is increased.
96. Consider the following equilibrium:
N2O4(g) 2NO2(g)
Suppose two different experiments were conducted on this equilibrium, at two different
temperatures.
Trial
Temperature
Initial Moles of N2O4
Equilibrium Moles of N2O4
1
25°C
1.00
0.815
2
55°C
1.00
0.500
What conclusion may be drawn from the above data?
A)
Kc > Kp at all temperatures.
B)
The reaction is exothermic.
C)
The forward reaction proceeds faster than the reverse reaction.
D)
Kp = 1 at 55°C.
E)
The equilibrium constant increases with increasing temperature.
Test Bank General Chemistry, 10th edition 34
97. The following equilibrium is exothermic. How could the yield of diiodine pentoxide be
increased?
I2(g) + 5CO2(g) 5CO(g) + I2O5(g)
A)
by decreasing the pressure
B)
by increasing the pressure
C)
by decreasing the volume of the reaction vessel
D)
by decreasing the temperature
E)
by increasing the temperature
98. Consider the reaction
S2Cl2(l) + CCl4(l) CS2(g) + 3Cl2(g); H° = 84.3 kJ
If the above reactants and products are contained in a closed vessel and the reaction system
is at equilibrium, the number of moles of CS2 can be increased by
A)
increasing the size of the reaction vessel.
B)
adding some Cl2 to the system.
C)
adding some S2Cl2 to the system.
D)
decreasing the temperature of the reaction system.
E)
adding some CCl4 to the system.
99. Consider the following system at equilibrium: N2(g) + 3H2(g) 2NH3(g);
H = −92.94 kJ Which of the following changes will shift the equilibrium to the right?
I.
increasing the temperature
II.
decreasing the temperature
III.
increasing the volume
IV.
decreasing the volume
V.
removing some NH3
VI.
adding some NH3
VII.
removing some N2
VIII.
adding some N2
A)
II, III, V, VIII
B)
I, III, V, VII
C)
I, VI, VIII
D)
I, IV, VI, VII
E)
II, IV, V, VIII
100. For the endothermic reaction 2CO2(g) + N2(g) 2NO(g) + 2CO(g), the conditions that
favor maximum conversion of the reactants to products are
A)
high temperature and low pressure.
B)
high temperature, pressure being unimportant.
C)
low temperature and low pressure.
D)
low temperature and high pressure.
E)
high temperature and high pressure.
101. Which of the following statements is incorrect concerning the addition of a catalyst to an
equilibrium reaction system?
A)
The catalyst speeds up the attainment of equilibrium.
B)
If the reactants are capable of forming many different products, a catalyst may
selectively speed up one reaction over another.
C)
The catalyst increases the rate of both the forward and the reverse reaction.
D)
The catalyst increases the yield of the products.
E)
The catalyst is not consumed in either the forward or the reverse reaction.