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)10 minC = ?

A first-order reaction A → products has a rate constant of 0.15 min⁻¹. The initial concentration of A is 1 mol/L. Find the concentration CA after 10 min.

k = 0.15 min⁻¹CA0 = 1 mol/Lt = 10 min
CA = mol/L
2.Easy
t (min)C (mol/L)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.08 min⁻¹. Find its half-life t½.

k = 0.08 min⁻¹
t½ = min
3.Medium
t (min)X (%)t = ?75%

A zero-order reaction has k = 0.05 mol/(L·min) and starts at 1.5 mol/L. How long does it take to reach 75% conversion? Find t.

k = 0.05 mol/(L·min)CA0 = 1.5 mol/LX = 75 %
t = min
4.Medium
t (min)C (mol/L)10 min0.32

In a first-order reaction the concentration of A falls from 0.8 mol/L to 0.32 mol/L in 10 min. Find the rate constant k.

CA0 = 0.8 mol/LCA = 0.32 mol/Lt = 10 min
k = min⁻¹
5.Hard
Tk35 °C0.00560 °C0.0216

The rate constant of a reaction is 0.005 min⁻¹ at 35 °C and 0.0216 min⁻¹ at 60 °C. Find the activation energy Ea.

k1 = 0.005 min⁻¹T1 = 35 °Ck2 = 0.0216 min⁻¹T2 = 60 °CR = 8.314 J/(mol·K)
Ea = kJ/mol
6.Hard
Tk20 °C0.0545 °C0.478

The rate constant of a reaction is 0.05 min⁻¹ at 20 °C and 0.478 min⁻¹ at 45 °C. Find the activation energy Ea.

k1 = 0.05 min⁻¹T1 = 20 °Ck2 = 0.478 min⁻¹T2 = 45 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. CA = 0.2231 mol/L
  2. 2. t½ = 8.664 min
  3. 3. t = 22.5 min
  4. 4. k = 0.09163 min⁻¹
  5. 5. Ea = 49.96 kJ/mol
  6. 6. Ea = 70.02 kJ/mol

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