Chapter 15 Lessons 1 & 2 Worksheet
Multiple Choice – Pick the best answer to the question
1. At equilibrium, __________.
a. all chemical reactions have ceased
b. the rates of the forward and reverse reactions are equal
c. the rate constants of the forward and reverse reactions are equal
d. the value of the equilibrium constant is 1
e. the limiting reagent has been consumed
2. Which one of the following will change the value of an equilibrium constant?
a. changing temperature
b. adding other substances that do not react with any of the species involved in the equilibrium
c. varying the initial concentrations of reactants
d. varying the initial concentrations of products
e. changing the volume of the reaction vessel
3. Which of the following expressions is the correct equilibrium-constant expression for the equilibrium
between dinitrogen tetroxide and nitrogen dioxide?
N2O4 (g)  2NO2 (g)
a. K =
b. K =
 NO2 
 N 2O4 
2
 NO2 
 N 2O4 
c. K =
 NO2 
2
 N 2O4 
d. K = [NO2][N2O4]
e. K = [NO2]2[N2O4]
4. Which of the following expressions is the correct equilibrium-constant expression for the following
reaction?
CO2 (g) + 2H2 (g)  CH3OH (g)
a. K =
b. K =
c. K =
CH3OH 
CO2 
CH3OH 
CO2  H 2 
2
CO2  H 2 
CH3OH 
d. K =
e. K =
CO2  H 2 
CH3OH 
CH3OH
2
CO2  H 2 
5. The equilibrium-constant expression depends on the __________ of the reaction.
a. stoichiometry
d. the quantities of reactants and
b. mechanism
products initially present
c. stoichiometry and mechanism
e. temperature
6. The equilibrium constant for reaction 1 is K. The equilibrium constant for reaction 2 is __________.
(1) SO2 (g) + (1/2) O2 (g)  SO3 (g)
(2) 2SO3 (g)  2SO2 (g) + O2 (g)
a. K2
b. 2K
c. 1/2K
d. 1/K2
e. -K2
7. The value of Keq for the following reaction is 0.25: SO2 (g) + NO2 (g)  SO3 (g) + NO (g)
The value of Keq at the same temperature for the reaction is __________.
2SO2 (g) + 2NO2 (g)  2SO3 (g) + 2NO (g)
a. 0.50
b. 0.063
c. 0.12
d. 0.25
e. 16
8. The equilibrium expression for Kp for the reaction is __________. 2O3 (g)  3O2 (g)
3PO 2
2PO3
2PO3
b. K =
3PO 2
3PO3
c. K =
2PO 2
a. K =
d. K =
PO32
PO 2 2
e. K =
PO 23
PO32
9. The equilibrium expression for Kp for the reaction is ____. N2 (g) + O2 (g)  2NO (g)
a. Kp =
 2PO2  2PN 2 
2 PNO
 PO2  PN 2 
b. Kp =
2 PNO
 PO2  PN 2 
c. Kp =
PNO
d. Kp =
 2 PNO 
 2 PN 2  2 PO2 
e. none of the above
10. The Keq for the reaction is 7.52 × 10-2 at 480.0°C. 2Cl2 (g) + 2H2O (g)  4HCl (g) + O2 (g)
What is the value of Keq at this temperature for the following reaction?
4HCl (g) + O2 (g)  2Cl2 (g) + 2H2O (g)
a. 0.0752
b. -0.0752
c. 13.3
d. 5.66 × 10-3
e. 0.150
11. The Keq for the equilibrium is 5.4 × 1013 at 480.0°C. 2NO (g) + O2 (g)  2NO2 (g) What is the
value of Keq at this temperature for the following reaction?
4NO (g) + 2O2 (g)  4NO2 (g)
a. 5.4 × 1013
b. 5.4 × 10-13
c. 1.9 × 1012
d. 1.9 × 10-12
e. 2.9 × 1027
12. The Keq for the equilibrium is 7.52 × 10-2 at 480.0°C. 2Cl2 (g) + 2H2O (g)  4HCl (g) + O2 (g)
What is the value of Keq at this temperature for the following reaction?
2HCl (g) +
1
O2 (g)  Cl2 (g) + H2O (g)
2
a. 13.3
b. 3.65
c. -0.0376
d. 5.66 × 10-3
e. 0.274
13. Which of the following expressions is the correct equilibrium-constant expression for the reaction?
2SO2 (g) + O2 (g)  2SO3 (g)
a. [SO3] / [SO2][O2]
b. [SO2] / [SO3]
c. [SO3]2 / [SO2]2[O2]
d. [SO3]2 / [SO2]2[O2]2
e. [SO3] / [SO2][O2]2
14. Which of the following expressions is the correct equilibrium-constant expression for the reaction?
(NH4)2Se (s)  2NH3 (g) + H2Se (g)
a. [NH3][H2Se] / [(NH4)2Se]
b. [(NH4)2Se] / [NH3]2[H2Se]
c. 1 / [(NH4)2Se]
d. [NH3]2[H2Se]
e. [NH3]2[H2Se] / [(NH4)2Se]
15. The expression for Kp for the reaction is __. 4CuO (s) + CH4 (g)  CO2 (g) + 4Cu (s) + 2H2O (g)
a. Kp =
PCH 4
PCO2 PH 2 2
b. Kp =
Cu  PCO2 PH2O2
4
CuO PCH 4
c. Kp =
PCO2 PH 2O2
PCH 4
PCO2 PH 2O2
d. Kp =
PCuO
PCH 4
e. Kp =
PH 2O2 PCO2
16. The equilibrium constant for the gas phase reaction:
N2 (g) + 3H2 (g)  2NH3 (g)
is Keq = 4.34 × 10-3 at 300°C. At equilibrium, __________.
a. products predominate
b. reactants predominate
c. roughly equal amounts of products and reactants are present
d. only products are present
e. only reactants are present
17. The equilibrium constant for the gas phase reaction: 2SO2 (g) + O2 (g)  2SO3 (g)
is Keq = 2.80 × 102 at 999 K. At equilibrium, __________.
a.
b.
c.
d.
e.
products predominate
reactants predominate
roughly equal amounts of products and reactants are present
only products are present
only reactants are present
Short answer:
18. The diagram represents an equilibrium mixture produced for a reaction:
A + X  AX. If the volume is 1L, is K greater or smaller than 1? Justify your
answer.
19. Let the diagram represent a reaction shown going to
completion.
a. Write a balanced reaction for the reaction.
b. Write the equilibrium constant expression for the reaction.
20. The reaction A2 + B2 AB has an equilibrium constant
Kc = 1.5.
a. Which reaction mixture is at equilibrium?
b. For those mixtures not at equilibrium, how will the
reaction proceed to reach equilibrium?
21. The reaction A2 + B  AB has an equilibrium constant of Kp =
2. How many B atoms should be added to the diagram to illustrate
an equilibrium mixture?