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
H2​0.25mol/L+I2​0.5mol/L⇌2HI0.4mol/LKc​ = ?

For the reaction H2 + I2 ⇌ 2HI, the equilibrium concentrations are [H2] = 0.25 mol/L, [I2] = 0.5 mol/L, [HI] = 0.4 mol/L. Find the equilibrium constant Kc.

[H2] = 0.25[I2] = 0.5[HI] = 0.4
Kc =
2.Easy
N2​0.12mol/L+3H2​0.5mol/L⇌2NH3​0.5mol/LKc​ = ?

For the reaction N2 + 3H2 ⇌ 2NH3, the equilibrium concentrations are [N2] = 0.12 mol/L, [H2] = 0.5 mol/L, [NH3] = 0.5 mol/L. Find the equilibrium constant Kc.

[N2] = 0.12[H2] = 0.5[NH3] = 0.5
Kc =
3.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 = 36. Find the equilibrium concentration [H2].

[H₂]₀ = [I₂]₀ = 1 mol/LKc = 36
[H2] = mol/L
4.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 = 4. Find the equilibrium concentration [H2].

[H₂]₀ = [I₂]₀ = 0.1 mol/LKc = 4
[H2] = mol/L
5.Hard
PCl5​PCl3​Cl2​I0.500C−x+x+xE0.5 − xxx

PCl₅ decomposes: PCl₅ ⇌ PCl₃ + Cl₂, with Kc = 0.08 at the reaction temperature. A container starts with 0.5 mol/L of PCl₅ only. Find the equilibrium concentration [Cl2].

[PCl₅]₀ = 0.5 mol/LKc = 0.08
[Cl2] = mol/L
6.Hard
PCl5​PCl3​Cl2​I0.100C−x+x+xE0.1 − xxx

PCl₅ decomposes: PCl₅ ⇌ PCl₃ + Cl₂, with Kc = 0.05 at the reaction temperature. A container starts with 0.1 mol/L of PCl₅ only. Find the equilibrium concentration [Cl2].

[PCl₅]₀ = 0.1 mol/LKc = 0.05
[Cl2] = mol/L

Answer key

  1. 1. Kc = 1.28
  2. 2. Kc = 16.67
  3. 3. [H2] = 0.25 mol/L
  4. 4. [H2] = 0.05 mol/L
  5. 5. [Cl2] = 0.164 mol/L
  6. 6. [Cl2] = 0.05 mol/L

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