1. University of Kentucky
Clicker Questions
Chapter 14
Chemical Equilibrium
Allison Soult
University of Kentucky

2. Which of the following best describes a reaction at equilibrium?
Reactants are being consumed and products are being formed.
The rate of the reaction is zero.
The rate of the forward and reverse reactions are equal.
Only products are present.
The rate of the forward reaction is greater than the rate of the reverse reaction.
Answer: c

3. Which of the following best describes a reaction at equilibrium?
Reactants are being consumed and products are being formed.
The rate of the reaction is zero.
The rate of the forward and reverse reactions are equal.
Only products are present.
The rate of the forward reaction is greater than the rate of the reverse reaction.
Answer: c

4. What is the equilibrium expression for the given reaction?
2A(aq) + 3B(aq) ⇌ C(aq) + 2D(aq)
Answer: b

5. What is the equilibrium expression for the given reaction?
2A(aq) + 3B(aq) ⇌ C(aq) + 2D(aq)
Answer: b

6. Reaction I Reaction III Reaction II A B
The following boxes represent reactions of the type A B at equilibrium. In which of the following is Keq = 2?
Reaction I
Reaction III
Reaction II A B
Reaction I
Reaction II
Reaction III
All have Keq = 2
None have Keq = 2
Answer: b

7. Reaction I Reaction III Reaction II A B
The following boxes represent reactions of the type A B at equilibrium. In which of the following is Keq = 2?
Reaction I
Reaction III
Reaction II A B
Reaction I
Reaction II
Reaction III
All have Keq = 2
None have Keq = 2
Answer: b

8. Which of the following is a true statement?
If a chemical equation is reversed, K is inverted.
If the coefficients in a chemical equation are multiplied by a factor, K is raised to the same factor.
If two equations are added, the corresponding K values are multiplied to obtain the overall equilibrium constant.
Statements 1–3 are ALL true.
None of the above statements are true.
Answer: d

9. Which of the following is a true statement?
If a chemical equation is reversed, K is inverted.
If the coefficients in a chemical equation are multiplied by a factor, K is raised to the same factor.
If two equations are added, the corresponding K values are multiplied to obtain the overall equilibrium constant.
Statements 1–3 are ALL true.
None of the above statements are true.
Answer: d

10. A (g) + 2 B (g) ⇌ AB2 (g) Kc = 59 AB2 (g) + B (g) ⇌ AB3 (g) Kc = ?
The equilibrium constant is given for two of the reactions below. Determine the value of the missing equilibrium constant.
  A (g) + 2 B (g) ⇌ AB2 (g) Kc = 59
AB2 (g) + B (g) ⇌ AB3 (g) Kc = ?
A (g) + 3 B (g) ⇌ AB3 (g) Kc = 478
3.5 × 10‒5
2.8 × 104
8.1
0.12 89
Answer: c

11. A (g) + 2 B (g) ⇌ AB2 (g) Kc = 59 AB2 (g) + B (g) ⇌ AB3 (g) Kc = ?
The equilibrium constant is given for two of the reactions below. Determine the value of the missing equilibrium constant.
  A (g) + 2 B (g) ⇌ AB2 (g) Kc = 59
AB2 (g) + B (g) ⇌ AB3 (g) Kc = ?
A (g) + 3 B (g) ⇌ AB3 (g) Kc = 478
3.5 × 10‒5
2.8 × 104
8.1
0.12 89
Answer: c

12. Methane reacts with water to form CO and H2 as follows: CH4 (g) + H2O (g) ⇌ CO (g) + 3 H2 (g) The value of Kp at 298 K for the reaction is 7.7 × 1024, calculate Kc.
4.60 × 1027
6.22 × 1021
3.15 × 1023
1.83 × 1024
1.29 × 1022
Answer: e

13. Methane reacts with water to form CO and H2 as follows: CH4 (g) + H2O (g) ⇌ CO (g) + 3 H2 (g) The value of Kp at 298 K for the reaction is 7.7 × 1024, calculate Kc.
4.60 × 1027
6.22 × 1021
3.15 × 1023
1.83 × 1024
1.29 × 1022
Answer: e

14. The reaction below has a Kc value of 61
The reaction below has a Kc value of 61. What is the Kp for this reaction at 500. K?
N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)
1.9 × 10–2
3.6 × 10–2 28 61 15
Answer: b

15. The reaction below has a Kc value of 61
The reaction below has a Kc value of 61. What is the Kp for this reaction at 500. K?
N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)
1.9 × 10–2
3.6 × 10–2 28 61 15
Answer: b

16. What is the equilibrium constant for the following reaction?
2 KClO3 (s) ⇌ 2 KCl (s) + 3 O2 (g) ΔH < 0
Keq =
[KCl]2[O2]3
[KClO3]2
Keq =
[KCl][O2]
[KClO3] a) b)
Answer: d
Keq =
[2 KCl][3 O2]
[2 KClO3] c) d)
Keq = [O2]3

17. What is the equilibrium constant for the following reaction?
2 KClO3 (s) ⇌ 2 KCl (s) + 3 O2 (g) ΔH < 0
Keq =
[KCl]2[O2]3
[KClO3]2
Keq =
[KCl][O2]
[KClO3] a) b)
Answer: d
Keq =
[2 KCl][3 O2]
[2 KClO3] c) d)
Keq = [O2]3

18. Determine the Kc value for the following reaction if the equilibrium concentrations are: [HBr] = 0.20 M, [H2] = 0.10 M, [Br2] = 0.12 M
2 HBr (g) ⇌ H2 (g) + Br2 (g)
6.0 × 10–3
0.30
16.7
3.33
7.2 × 10–4
Answer: b

19. Determine the Kc value for the following reaction if the equilibrium concentrations are: [HBr] = 0.20 M, [H2] = 0.10 M, [Br2] = 0.12 M
2 HBr (g) ⇌ H2 (g) + Br2 (g)
6.0 × 10–3
0.30
16.7
3.33
7.2 × 10–4
Answer: b

20. PCl5 decomposes to PCl3 and Cl2
PCl5 decomposes to PCl3 and Cl2. If the initial concentration of PCl5 is M and the final concentration is M, what is the equilibrium constant for the reaction?
0.0533
0.0133
0.0720
0.0320
Answer: a

21. PCl5 decomposes to PCl3 and Cl2
PCl5 decomposes to PCl3 and Cl2. If the initial concentration of PCl5 is M and the final concentration is M, what is the equilibrium constant for the reaction?
0.0533
0.0133
0.0720
0.0320
Answer: a

22. The system is at equilibrium.
The equilibrium constant for the reaction 2A ⇌ 3B is 2.3. If [A] = 0.10 M and [B] = M, which of the following statements is true?
The system is at equilibrium.
The reaction will proceed to the left because Q < K.
The reaction will proceed to the right because Q < K.
The reaction will proceed to the left because Q > K.
The reaction will proceed to the right because Q > K.
Answer: c

23. The system is at equilibrium.
The equilibrium constant for the reaction 2A ⇌ 3B is 2.3. If [A] = 0.10 M and [B] = M, which of the following statements is true?
The system is at equilibrium.
The reaction will proceed to the left because Q < K.
The reaction will proceed to the right because Q < K.
The reaction will proceed to the left because Q > K.
The reaction will proceed to the right because Q > K.
Answer: c

24. At 425 °C, Kp = 4.18 × 10–9 for the following reaction: In a given experiment 0.50 atm of HBr is placed in a container. What is the equilibrium pressure for H2?
2 HBr (g) ⇌ H2 (g) + Br2 (g)
2.1 × 10–9 atm
4.6 × 10–5 atm
0.25 atm
0.50 atm
Answer: b

25. At 425 °C, Kp = 4.18 × 10–9 for the following reaction: In a given experiment 0.50 atm of HBr is placed in a container. What is the equilibrium pressure for H2?
2 HBr (g) ⇌ H2 (g) + Br2 (g)
2.1 × 10–9 atm
4.6 × 10–5 atm
0.25 atm
0.50 atm
Answer: b

26. At 425 °C, Keq = 4.18 × 10–9 for the following reaction:
In a given experiment 0.20 atm of HBr, atm of H2, and atm of Br2 are introduced into a container. What is the equilibrium concentration of HBr?
2 HBr (g) ⇌ H2 (g) + Br2 (g)
1.4 × 10–5 atm
0.010 atm
0.19 atm
0.22 atm
None of the above are correct
Answer: d

27. At 425 °C, Keq = 4.18 × 10–9 for the following reaction:
In a given experiment 0.20 atm of HBr, atm of H2, and atm of Br2 are introduced into a container. What is the equilibrium concentration of HBr?
2 HBr (g) ⇌ H2 (g) + Br2 (g)
1.4 × 10–5 atm
0.010 atm
0.19 atm
0.22 atm
None of the above are correct
Answer: d

28. Consider the following reaction at equilibrium:
What happens when the volume is increased?
H2 (g) + I2 (g) ⇌ 2 HI (g)
Reaction shifts right
Reaction shifts left
There is no effect
Can’t tell
Answer: c

29. Consider the following reaction at equilibrium:
What happens when the volume is increased?
H2 (g) + I2 (g) ⇌ 2 HI (g)
Reaction shifts right
Reaction shifts left
There is no effect
Can’t tell
Answer: c

30. Consider the following reaction at equilibrium:
What happens when the reaction mixture is heated?
2 KClO3 (s) ⇌ 2 KCl (s) + 3 O2 (g) ΔH < 0
Reaction shifts right
Reaction shifts left
There is no effect
Can’t tell
Answer: b

31. Consider the following reaction at equilibrium:
What happens when the reaction mixture is heated?
2 KClO3 (s) ⇌ 2 KCl (s) + 3 O2 (g) ΔH < 0
Reaction shifts right
Reaction shifts left
There is no effect
Can’t tell
Answer: b

32. N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g) ΔH = – 46.19 kJ
Given the following reaction, how could you increase the concentration of products?
N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g) ΔH = – kJ
Increase volume, add N2, or increase temperature
Increase volume, add N2, or decrease temperature
Decrease volume, add N2, or decrease temperature
Decrease volume, remove N2, or decrease temperature
Decrease volume, remove N2, or increase temperature
Answer: c

33. N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g) ΔH = – 46.19 kJ
Given the following reaction, how could you increase the concentration of products?
N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g) ΔH = – kJ
Increase volume, add N2, or increase temperature
Increase volume, add N2, or decrease temperature
Decrease volume, add N2, or decrease temperature
Decrease volume, remove N2, or decrease temperature
Decrease volume, remove N2, or increase temperature
Answer: c