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/C₀t½​ = 10 min0.5

A first-order reaction has a half-life of 10 min. Find its rate constant k.

t½ = 10 min
k = min⁻¹
2.Easy
t (min)C (mol/L)15 minC = ?

A first-order reaction A → products has a rate constant of 0.05 min⁻¹. The initial concentration of A is 1 mol/L. Find the concentration CA after 15 min.

k = 0.05 min⁻¹CA0 = 1 mol/Lt = 15 min
CA = mol/L
3.Medium
t (min)C (mol/L)t½​ = ?C0​/2

A second-order reaction (−rA = k·CA²) has k = 0.8 L/(mol·min) and an initial concentration of 0.5 mol/L. Find its first half-life t½.

k = 0.8 L/(mol·min)CA0 = 0.5 mol/L
t½ = min
4.Medium
t (min)C (mol/L)t½​ = ?C0​/2

A second-order reaction (−rA = k·CA²) has k = 0.2 L/(mol·min) and an initial concentration of 0.5 mol/L. Find its first half-life t½.

k = 0.2 L/(mol·min)CA0 = 0.5 mol/L
t½ = min
5.Hard
Tk20 °C0.0145 °C0.0501

The rate constant of a reaction is 0.01 min⁻¹ at 20 °C and 0.0501 min⁻¹ at 45 °C. Find the activation energy Ea.

k1 = 0.01 min⁻¹T1 = 20 °Ck2 = 0.0501 min⁻¹T2 = 45 °CR = 8.314 J/(mol·K)
Ea = kJ/mol
6.Hard
Tk20 °C0.0145 °C?

A reaction has a rate constant of 0.01 min⁻¹ at 20 °C and an activation energy of 90 kJ/mol. Find the rate constant k2 at 45 °C.

k1 = 0.01 min⁻¹T1 = 20 °CT2 = 45 °CEa = 90 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹

Answer key

  1. 1. k = 0.06931 min⁻¹
  2. 2. CA = 0.4724 mol/L
  3. 3. t½ = 2.5 min
  4. 4. t½ = 10 min
  5. 5. Ea = 49.98 kJ/mol
  6. 6. k2 = 0.182 min⁻¹

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