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)60 minC = ?

A first-order reaction A → products has a rate constant of 0.01 min⁻¹. The initial concentration of A is 0.5 mol/L. Find the concentration CA after 60 min.

k = 0.01 min⁻¹CA0 = 0.5 mol/Lt = 60 min
CA = mol/L
2.Easy
t (min)C (mol/L)40 minC = ?

A first-order reaction A → products has a rate constant of 0.02 min⁻¹. The initial concentration of A is 0.8 mol/L. Find the concentration CA after 40 min.

k = 0.02 min⁻¹CA0 = 0.8 mol/Lt = 40 min
CA = mol/L
3.Medium
t (min)C (mol/L)t½​ = ?C0​/2

A second-order reaction (−rA = k·CA²) has k = 0.05 L/(mol·min) and an initial concentration of 0.5 mol/L. Find its first half-life t½.

k = 0.05 L/(mol·min)CA0 = 0.5 mol/L
t½ = min
4.Medium
t (min)X (%)t = ?60%

A first-order reaction in a batch reactor has k = 0.08 min⁻¹. How long does it take to reach 60% conversion? Find t.

k = 0.08 min⁻¹X = 60 %
t = min
5.Hard
Tk35 °C0.0545 °C0.104

The rate constant of a reaction is 0.05 min⁻¹ at 35 °C and 0.104 min⁻¹ at 45 °C. Find the activation energy Ea.

k1 = 0.05 min⁻¹T1 = 35 °Ck2 = 0.104 min⁻¹T2 = 45 °CR = 8.314 J/(mol·K)
Ea = kJ/mol
6.Hard
Tk20 °C0.00535 °C?

A reaction has a rate constant of 0.005 min⁻¹ at 20 °C and an activation energy of 40 kJ/mol. Find the rate constant k2 at 35 °C.

k1 = 0.005 min⁻¹T1 = 20 °CT2 = 35 °CEa = 40 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹

Answer key

  1. 1. CA = 0.2744 mol/L
  2. 2. CA = 0.3595 mol/L
  3. 3. t½ = 40 min
  4. 4. t = 11.45 min
  5. 5. Ea = 59.69 kJ/mol
  6. 6. k2 = 0.01112 min⁻¹

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