Reaction kinetics worksheet with answers

Free printable Reaction kinetics 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
t (min)C (mol/L)5 minC = ?

A first-order reaction A → products has a rate constant of 0.1 min⁻¹. The initial concentration of A is 1.5 mol/L. Find the concentration CA after 5 min.

k = 0.1 min⁻¹CA0 = 1.5 mol/Lt = 5 min
CA = mol/L
2.Easy
t (min)C (mol/L)45 minC = ?

A first-order reaction A → products has a rate constant of 0.025 min⁻¹. The initial concentration of A is 0.8 mol/L. Find the concentration CA after 45 min.

k = 0.025 min⁻¹CA0 = 0.8 mol/Lt = 45 min
CA = mol/L
3.Medium
t (min)C (mol/L)10 minC = ?

A reaction with rate law −rA = k·CA² has k = 1 L/(mol·min) and starts at 1.5 mol/L. Find the concentration CA after 10 min.

k = 1 L/(mol·min)CA0 = 1.5 mol/Lt = 10 min
CA = mol/L
4.Medium
t (min)X (%)t = ?50%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 0.25 L/(mol·min) and starts at 0.5 mol/L. How long does it take to reach 50% conversion? Find t.

k = 0.25 L/(mol·min)CA0 = 0.5 mol/LX = 50 %
t = min
5.Hard
1/Tln kT = 40 °Cln 0.02ln A = ?Ea​ = 40 kJ/mol

A first-order reaction has a rate constant of 0.02 s⁻¹ at 40 °C and an activation energy of 40 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.02 s⁻¹T = 40 °CEa = 40 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹
6.Hard
Tk30 °C0.140 °C0.355

The rate constant of a reaction is 0.1 min⁻¹ at 30 °C and 0.355 min⁻¹ at 40 °C. Find the activation energy Ea.

k1 = 0.1 min⁻¹T1 = 30 °Ck2 = 0.355 min⁻¹T2 = 40 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. CA = 0.9098 mol/L
  2. 2. CA = 0.2597 mol/L
  3. 3. CA = 0.09375 mol/L
  4. 4. t = 8 min
  5. 5. A = 94065 s⁻¹
  6. 6. Ea = 100 kJ/mol

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