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.

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1.Easy
N2​O4​0.2mol/L⇌2NO2​0.1mol/LKc​ = ?

For the reaction N2O4 ⇌ 2NO2, the equilibrium concentrations are [N2O4] = 0.2 mol/L, [NO2] = 0.1 mol/L. Find the equilibrium constant Kc.

[N2O4] = 0.2[NO2] = 0.1
Kc =
2.Easy
N2​0.1mol/L+3H2​0.05mol/L⇌2NH3​0.4mol/LKc​ = ?

For the reaction N2 + 3H2 ⇌ 2NH3, the equilibrium concentrations are [N2] = 0.1 mol/L, [H2] = 0.05 mol/L, [NH3] = 0.4 mol/L. Find the equilibrium constant Kc.

[N2] = 0.1[H2] = 0.05[NH3] = 0.4
Kc =
3.Medium
H2​I2​HII0.20.20C−x−x+2xE0.2 − x0.2 − x2x

0.2 mol/L of H₂ and 0.2 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 = 0.2 mol/LKc = 16
[H2] = mol/L
4.Medium
H2​I2​HII0.40.40C−x−x+2xE0.4 − x0.4 − x2x

0.4 mol/L of H₂ and 0.4 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 = 0.4 mol/LKc = 4
[H2] = mol/L
5.Hard
PCl5​PCl3​Cl2​I0.200C−x+x+xE0.2 − xxx

PCl₅ decomposes: PCl₅ ⇌ PCl₃ + Cl₂, with Kc = 0.1 at the reaction temperature. A container starts with 0.2 mol/L of PCl₅ only. Find the equilibrium concentration [Cl2].

[PCl₅]₀ = 0.2 mol/LKc = 0.1
[Cl2] = mol/L
6.Hard
PCl5​PCl3​Cl2​I0.100C−x+x+xE0.1 − xxx

PCl₅ decomposes: PCl₅ ⇌ PCl₃ + Cl₂, with Kc = 0.02 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 = 0.02
[Cl2] = mol/L

Answer key

  1. 1. Kc = 0.05
  2. 2. Kc = 12800
  3. 3. [H2] = 0.06667 mol/L
  4. 4. [H2] = 0.2 mol/L
  5. 5. [Cl2] = 0.1 mol/L
  6. 6. [Cl2] = 0.03583 mol/L

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