Equilibrium Practice Test
1. The reaction below can be shifted towards the products by…
MgO(s) + H2 (g) ↔ Mg (s) + H2O (g)
ΔH = -14kJ
a. Increasing pressure
c. Removing hydrogen
b. Decreasing temp
d. Adding a catalyst
2. 2A (g) + B (g) ↔ 2C (g)
Initially, 0.60 mol of A and 0.75 mol of B are put in a 1.0 L container. At equilibrium, 0.3 mol of C
remains. What is the equilibrium constant for this reaction?
a. 0.60
b. 0.90
c. 1.7
d. 3.4
e. 6.0
3. N2 (g) + 3H2 (g) ↔ 2NH3 (g) ΔH = -92kJ
Which change would cause K to decrease?
a. Remove NH3
b. Increase temp
4. NiO (s) + H2 (g) ↔ Ni (s) + H2O (g)
The equilibrium expression is…
[𝑁𝑖][𝐻2𝑂]
a. K = [𝑁𝑖𝑂][𝐻2]
c. Add H2
d. Add a catalyst
[𝑁𝑖]
b. K = [𝑁𝑖𝑂][𝐻2]
1
c. K = [𝑁𝑖𝑂][𝐻2]
d. K =
e. K =
1
[𝐻2]
[𝐻2𝑂]
[𝐻2]
5. Which of the following is not true at equilibrium?
a. Concentrations remain steady
d. The reactions continue
b. [Products] = [Reactants]
occurring
c. Rateforward = Ratereverse
6. N2 (g) + 3H2 (g) ↔ 2NH3 (g) ΔH = -92kJ
Which conditions would most favor the production of ammonia?
a. High temp and pressure
d. Low temp, high pressure
b. High temp
e. Low temp, low pressure
c. High temp, low pressure
7. The mass of HgO in the container could be increased by
2HgO (s) ↔ 2Hg (l) + O2 (g) ΔH = 43.4 Kcal
a. Adding more Hg
d. Increasing temp
b. Removing some O2
e. Removing some Hg
c. Increasing pressure
8. Which of the following would change the equilibrium constant?
a. Add more reactants
b. Add more products
c. Increase pressure
d. Change temp
e. Add a catalyst
9. 4H2 (g) + CS2 (g) ↔ CH4 (g) + H2S (g)
Initially, 2.50 mol H2, 1.50 mol CS2, 1.50 mol CH4, and 2.00 mol H2S are placed in a 5.0 L
container and are allowed to reach equilibrium. At equilibrium, [CH4] = 0.25M.
a. How many moles of CS2 are there at equilibirium?
b. What is the concentration of H2 at equilibrium?
c. What is K?
10. A (g) ↔ B (g)
K<1
Initially, you have only B in your container. Fill in the graphs below showing the concentrations of A
and B over time, and the rates of the forward and reverse reactions over time. Label your lines.