Multiple
Choice
Identify the letter of the choice that best completes the statement or answers the
question.
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1.
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Write a balanced chemical
equation which corresponds to the following equilibrium constant
expression.
K = 
a. | HF(aq)  F-(aq) +
H3O+(aq) | b. | F-(aq) +
H3O+(aq) HF(aq) + H2O(l) | c. | HF(aq) + H2O(l) F-(aq) +
H3O+(aq) | d. | H+(aq) + OH-(aq)
H2O(l) | e. | F-(aq) + H3O+(aq)
HF(aq) | | |
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2.
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The oxidation of sulfur dioxide
produces sulfur trioxide.
2 SO2(g) + O2(g) 2
SO3(g)
Calculate the value of Kc, given that Kp = 2.8
× 102 at 999 K. (R = 0.08206
L·atm/mol·K) a. | 4.4 ×
10-5 | b. | 0.29 | c. | 3.4 | d. | 2.3 ×
104 | e. | 6.8 ×
103 | | |
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3.
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A 4.00 L flask is filled with
0.75 mol SO3, 2.50 mol SO2, and 1.30 mol O2, and allowed to reach
equilibrium. Predict the effect on the concentrations of SO3 as equilibrium is achieved by
using Q, the reaction quotient. Assume the temperature of the mixture is chosen so that
Kc = 12.
2 SO3(g) 2 SO2(g) +
O2(g)
a. | [SO3] will decrease because
Q > K. | b. | [SO3] will decrease because
Q < K. | c. | [SO3] will increase because
Q < K. | d. | [SO3] will increase because
Q > K. | e. | [SO3] will remain the same
because Q = K. | | |
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4.
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The reaction below is studied
at a high temperature.
PCl5(g) PCl3(g) +
Cl2(g)
At equilibrium, the partial pressures of the gases are as follows: PCl5 =
1.8 × 10-2 atm, PCl3 =
5.6 × 10-2 atm, and Cl2 =
3.8 × 10-4 atm. What is the value of
Kp for the reaction? a. | 3.8 ×
10-7 | b. | 1.2 ×
10-3 | c. | 3.1 | d. | 8.5 × 102 | e. | 2.6 × 106 | | |
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5.
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When 0.20 mole NH4Cl
is dissolved in water to a volume of 1.00 L, 0.0053% of the NH4+ dissociates to
form NH3. What is the equilibrium constant for the reaction?
NH4+(aq) +
H2O(l) NH3(aq) +
H3O+(aq)
a. | 2.2 ×
10-11 | b. | 1.1 ×
10-10 | c. | 5.6 ×
10-10 | d. | 1.4 ×
10-8 | e. | 5.6 ×
10-6 | | |
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6.
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The equilibrium constant at 25
°C for the dissolution of silver bromide is 5.4 × 10-13.
AgBr(s) Ag+(aq) +
Br-(aq)
If an excess quantity of AgBr(s) is added to water and allowed to equilibrate, what is
the equilibrium concentration of Ag+? a. | 2.9 ×
10-25 M | b. | 2.7 ×
10-13 M | c. | 5.4 ×
10-13 M | d. | 1.1 ×
10-12 M | e. | 7.3 ×
10-7 M | | |
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7.
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The equilibrium constant,
Kc, for the following reaction is 1.0 ×
10-5 at 1500 K.
N2(g) + O2(g) 2 NO(g)
If 0.750 M N2 and 0.750 M
O2 are allowed to equilibrate at 1500 K, what is the concentration of NO? a. | 6.7 × 10-4
M | b. | 1.2 ×
10-3 M | c. | 2.4 ×
10-3 M | d. | 2.7 ×
10-3 M | e. | 5.5 ×
10-3 M | | |
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8.
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Determine the equilibrium
constant for the following reaction
Ca2+(aq) + 2 H2O(l) Ca(OH)2(s) + 2 H+(aq)
given the chemical reactions
below.
Ca(OH)2(s) Ca2+(aq) + 2 OH-(aq) K =
6.5 ×
10-6
H2O(l) H+(aq) +
OH-(aq) K = 1.0 ×
10-14
a. | 1.5 ×
10-23 | b. | 6.5 ×
10-20 | c. | 1.3 ×
10-19 | d. | 1.5 ×
10-9 | e. | 1.5 ×
1019 | | |
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9.
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Assume that the following
chemical reaction is at equilibrium.
I2(g) + Cl2(g) 2 ICl(g) ΔH° = -26.9 kJ
At 25 °C,
Kp = 2.0 × 105. If the temperature is
decreased to 5 °C, which statement
applies? a. | Kp will decrease and the reaction will proceed in
the forward direction. | b. | Kp will decrease and the
reaction will proceed in the backward direction. | c. | Kp will remain unchanged and the reaction will proceed in the
forward direction. | d. | Kp will remain unchanged
and the reaction will proceed in the backward direction. | e. | Kp will increase and the reaction will proceed in the forward
direction. | | |
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10.
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The thermochemical equation for
the formation of ammonia from elemental nitrogen and hydrogen is as
follows.
N2(g) + 3 H2(g) 2 NH3(g) ΔH = -92.2 kJ
Which of the following will drive the equilibrium system to the
right? a. | adding NH3(g) | b. | removing N2(g) | c. | increasing the volume of the reaction
vessel | d. | increasing the temperature | e. | adding H2(g) | | |
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