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/C₀ (%)45 min?

A first-order reaction has a half-life of 30 min. What percentage f of the reactant is still left after 45 min?

t½ = 30 mint = 45 min
f = %
2.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 1.5 mol/L. Find the concentration CA after 10 min.

k = 0.15 min⁻¹CA0 = 1.5 mol/Lt = 10 min
CA = mol/L
3.Medium
t (min)X (%)t = ?80%

A first-order reaction in a batch reactor has k = 0.1 min⁻¹. How long does it take to reach 80% conversion? Find t.

k = 0.1 min⁻¹X = 80 %
t = min
4.Medium
t (min)C (mol/L)15 min0.5

In a first-order reaction the concentration of A falls from 1 mol/L to 0.5 mol/L in 15 min. Find the rate constant k.

CA0 = 1 mol/LCA = 0.5 mol/Lt = 15 min
k = min⁻¹
5.Hard
Tk20 °C0.0160 °C0.402

The rate constant of a reaction is 0.01 min⁻¹ at 20 °C and 0.402 min⁻¹ at 60 °C. Find the activation energy Ea.

k1 = 0.01 min⁻¹T1 = 20 °Ck2 = 0.402 min⁻¹T2 = 60 °CR = 8.314 J/(mol·K)
Ea = kJ/mol
6.Hard
Tk20 °C0.0250 °C0.288

The rate constant of a reaction is 0.02 min⁻¹ at 20 °C and 0.288 min⁻¹ at 50 °C. Find the activation energy Ea.

k1 = 0.02 min⁻¹T1 = 20 °Ck2 = 0.288 min⁻¹T2 = 50 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. f = 35.36 %
  2. 2. CA = 0.3347 mol/L
  3. 3. t = 16.09 min
  4. 4. k = 0.04621 min⁻¹
  5. 5. Ea = 74.98 kJ/mol
  6. 6. Ea = 70.02 kJ/mol

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