SCH4U / AP Chem Exam: Unit 4a Chemical Equilibrium Practice Test (ICE Tables, Keq, Qc)

Chemical Equilibrium Practice Test - Unit 4a
Type 1: Calculating Keq from Equilibrium Concentrations

1. Question: A 5.00 L container at 230 °C reaches equilibrium with 0.0185 mol of PCl3, 0.0870 mol of Cl2,
and 0.0158 mol of PCl5. Calculate the value of Keq for the reaction:

PCl3(g) + Cl2(g) ⇌ PCl5(g)

2. Question: A 2.50 L container holds 0.240 mol of CO, 0.4775 mol of H2, and 0.0375 mol of methanol
(CH3OH) at 250 °C in an equilibrium mixture. Calculate Keq for:

CO(g) + 2H2(g) ⇌ CH3OH(g)

3. Question: In a 6.75 L container at 298 K, a system is at equilibrium with 4.725 mol of N2O3, 2.025 mol
of NO2, and 2.025 mol of NO. Calculate the value of Keq for:

N2O3(g) ⇌ NO2(g) + NO(g)




Type 2: Calculating Keq and Equilibrium Concentrations (ICE)

1. Question: Initially, 1.000 mol of water vapor is placed into a 3.00 L container at a specific temperature.
When equilibrium is reached, 0.900 mol of H2O remains. Calculate the equilibrium concentrations of all
substances and the Keq value:

2H2O(g) ⇌ 2H2(g) + O2(g)




2. Question: A student places 3.000 mol of N2 and 2.500 mol of H2 into a 1.00 L closed system. At
equilibrium, the concentration of ammonia (NH3) is 0.850 mol/L. Use an ICE table to find the remaining
equilibrium concentrations and Keq:

N2(g) + 3H2(g) ⇌ 2NH3(g)




3. Question: A sample of 0.873 mol of nitric oxide (NO) and 0.0437 mol of bromine (Br2) is placed in a
3.50 L container. At equilibrium, the mixture contains 0.0518 mol of nitrosyl bromide (NOBr). Calculate
the Keq for the reaction:

2NO(g) + Br2(g) ⇌ 2NOBr(g)