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
2SO2​0.4mol/L+O2​0.2mol/L⇌2SO3​0.1mol/LKc​ = ?

For the reaction 2SO2 + O2 ⇌ 2SO3, the equilibrium concentrations are [SO2] = 0.4 mol/L, [O2] = 0.2 mol/L, [SO3] = 0.1 mol/L. Find the equilibrium constant Kc.

[SO2] = 0.4[O2] = 0.2[SO3] = 0.1
Kc =
2.Easy
N2​0.3mol/L+3H2​0.5mol/L⇌2NH3​0.2mol/LKc​ = ?

For the reaction N2 + 3H2 ⇌ 2NH3, the equilibrium concentrations are [N2] = 0.3 mol/L, [H2] = 0.5 mol/L, [NH3] = 0.2 mol/L. Find the equilibrium constant Kc.

[N2] = 0.3[H2] = 0.5[NH3] = 0.2
Kc =
3.Medium
H2​I2​HII0.250.250C−x−x+2xE0.25 − x0.25 − x2x

0.25 mol/L of H₂ and 0.25 mol/L of I₂ are put in a container and react: H₂ + I₂ ⇌ 2HI, with Kc = 25. Find the equilibrium concentration [HI].

[H₂]₀ = [I₂]₀ = 0.25 mol/LKc = 25
[HI] = mol/L
4.Medium
H2​I2​HII0.80.80C−x−x+2xE0.8 − x0.8 − x2x

0.8 mol/L of H₂ and 0.8 mol/L of I₂ are put in a container and react: H₂ + I₂ ⇌ 2HI, with Kc = 36. Find the equilibrium concentration [HI].

[H₂]₀ = [I₂]₀ = 0.8 mol/LKc = 36
[HI] = mol/L
5.Hard
PCl5​PCl3​Cl2​I0.800C−x+x+xE0.8 − xxx

PCl₅ decomposes: PCl₅ ⇌ PCl₃ + Cl₂, with Kc = 0.2 at the reaction temperature. A container starts with 0.8 mol/L of PCl₅ only. Find the equilibrium concentration [Cl2].

[PCl₅]₀ = 0.8 mol/LKc = 0.2
[Cl2] = mol/L
6.Hard
PCl5​PCl3​Cl2​I1.500C−x+x+xE1.5 − xxx

PCl₅ decomposes: PCl₅ ⇌ PCl₃ + Cl₂, with Kc = 0.2 at the reaction temperature. A container starts with 1.5 mol/L of PCl₅ only. Find the equilibrium concentration [Cl2].

[PCl₅]₀ = 1.5 mol/LKc = 0.2
[Cl2] = mol/L

Answer key

  1. 1. Kc = 0.3125
  2. 2. Kc = 1.067
  3. 3. [HI] = 0.3571 mol/L
  4. 4. [HI] = 1.2 mol/L
  5. 5. [Cl2] = 0.3123 mol/L
  6. 6. [Cl2] = 0.4568 mol/L

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