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)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.02 min⁻¹. Find its half-life t½.

k = 0.02 min⁻¹
t½ = min
3.Medium
t (min)C (mol/L)2 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.5 L/(mol·min) and starts at 1.5 mol/L. Find the concentration CA after 2 min.

k = 0.5 L/(mol·min)CA0 = 1.5 mol/Lt = 2 min
CA = mol/L
4.Medium
t (min)X (%)t = ?60%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 0.05 L/(mol·min) and starts at 1.5 mol/L. How long does it take to reach 60% conversion? Find t.

k = 0.05 L/(mol·min)CA0 = 1.5 mol/LX = 60 %
t = min
5.Hard
1/Tln kT = 100 °Cln 0.05ln A = ?Ea​ = 80 kJ/mol

A first-order reaction has a rate constant of 0.05 s⁻¹ at 100 °C and an activation energy of 80 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.05 s⁻¹T = 100 °CEa = 80 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹
6.Hard
Tk35 °C0.160 °C0.323

The rate constant of a reaction is 0.1 min⁻¹ at 35 °C and 0.323 min⁻¹ at 60 °C. Find the activation energy Ea.

k1 = 0.1 min⁻¹T1 = 35 °Ck2 = 0.323 min⁻¹T2 = 60 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. t½ = 13.86 min
  2. 2. t½ = 34.66 min
  3. 3. CA = 0.6 mol/L
  4. 4. t = 20 min
  5. 5. A = 7.907 × 10⁹ s⁻¹
  6. 6. Ea = 40.03 kJ/mol

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