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)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.05 min⁻¹. Find its half-life t½.

k = 0.05 min⁻¹
t½ = min
2.Easy
t (min)C (mol/L)10 minC = ?

A zero-order reaction A → products has a rate constant of 0.005 mol/(L·min). The initial concentration of A is 1 mol/L. Find the concentration CA after 10 min.

k = 0.005 mol/(L·min)CA0 = 1 mol/Lt = 10 min
CA = mol/L
3.Medium
t (min)C (mol/L)15 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.5 L/(mol·min) and starts at 0.5 mol/L. Find the concentration CA after 15 min.

k = 0.5 L/(mol·min)CA0 = 0.5 mol/Lt = 15 min
CA = mol/L
4.Medium
t (min)C (mol/L)10 min0.8

In a first-order reaction the concentration of A falls from 2 mol/L to 0.8 mol/L in 10 min. Find the rate constant k.

CA0 = 2 mol/LCA = 0.8 mol/Lt = 10 min
k = min⁻¹
5.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.40.008run 21.60.032n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.4 mol/L the rate is 0.008 mol/(L·s); with CA0 = 1.6 mol/L it is 0.032 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.4 mol/Lr1 = 0.008 mol/(L·s)CA0,2 = 1.6 mol/Lr2 = 0.032 mol/(L·s)
n =
6.Hard
Tk20 °C0.00540 °C0.116

The rate constant of a reaction is 0.005 min⁻¹ at 20 °C and 0.116 min⁻¹ at 40 °C. Find the activation energy Ea.

k1 = 0.005 min⁻¹T1 = 20 °Ck2 = 0.116 min⁻¹T2 = 40 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. t½ = 13.86 min
  2. 2. CA = 0.95 mol/L
  3. 3. CA = 0.1053 mol/L
  4. 4. k = 0.09163 min⁻¹
  5. 5. n = 1
  6. 6. Ea = 120 kJ/mol

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