Chemical equilibrium worksheet with answers

Free printable Chemical equilibrium worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
CO0.25mol/L+H2​O0.15mol/L⇌CO2​0.25mol/L+H2​0.12mol/LKc​ = ?

For the reaction CO + H2O ⇌ CO2 + H2, the equilibrium concentrations are [CO] = 0.25 mol/L, [H2O] = 0.15 mol/L, [CO2] = 0.25 mol/L, [H2] = 0.12 mol/L. Find the equilibrium constant Kc.

[CO] = 0.25[H2O] = 0.15[CO2] = 0.25[H2] = 0.12
Kc =
2.Easy
PCl5​0.25mol/L⇌PCl3​0.2mol/L+Cl2​0.5mol/LKc​ = ?

For the reaction PCl5 ⇌ PCl3 + Cl2, the equilibrium concentrations are [PCl5] = 0.25 mol/L, [PCl3] = 0.2 mol/L, [Cl2] = 0.5 mol/L. Find the equilibrium constant Kc.

[PCl5] = 0.25[PCl3] = 0.2[Cl2] = 0.5
Kc =
3.Medium
H2​I2​HII0.10.10C−x−x+2xE0.1 − x0.1 − x2x

0.1 mol/L of H₂ and 0.1 mol/L of I₂ are put in a container and react: H₂ + I₂ ⇌ 2HI, with Kc = 64. Find the equilibrium concentration [H2].

[H₂]₀ = [I₂]₀ = 0.1 mol/LKc = 64
[H2] = mol/L
4.Medium
H2​I2​HII110C−x−x+2xE1 − x1 − x2x

1 mol/L of H₂ and 1 mol/L of I₂ are put in a container and react: H₂ + I₂ ⇌ 2HI, with Kc = 16. Find the equilibrium concentration [H2].

[H₂]₀ = [I₂]₀ = 1 mol/LKc = 16
[H2] = mol/L
5.Hard
PCl5​PCl3​Cl2​I1.500C−x+x+xE1.5 − xxx

PCl₅ decomposes: PCl₅ ⇌ PCl₃ + Cl₂, with Kc = 0.05 at the reaction temperature. A container starts with 1.5 mol/L of PCl₅ only. Find the equilibrium concentration [PCl5].

[PCl₅]₀ = 1.5 mol/LKc = 0.05
[PCl5] = mol/L
6.Hard
PCl5​PCl3​Cl2​I0.400C−x+x+xE0.4 − xxx

PCl₅ decomposes: PCl₅ ⇌ PCl₃ + Cl₂, with Kc = 0.1 at the reaction temperature. A container starts with 0.4 mol/L of PCl₅ only. Find the equilibrium concentration [Cl2].

[PCl₅]₀ = 0.4 mol/LKc = 0.1
[Cl2] = mol/L

Answer key

  1. 1. Kc = 0.8
  2. 2. Kc = 0.4
  3. 3. [H2] = 0.02 mol/L
  4. 4. [H2] = 0.3333 mol/L
  5. 5. [PCl5] = 1.25 mol/L
  6. 6. [Cl2] = 0.1562 mol/L

Full step-by-step solutions: practise this topic on examproblems.com.