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​ = 8 min0.5

A first-order reaction has a half-life of 8 min. Find its rate constant k.

t½ = 8 min
k = min⁻¹
2.Easy
t (min)C/C₀ (%)60 min?

A first-order reaction has a half-life of 20 min. What percentage f of the reactant is still left after 60 min?

t½ = 20 mint = 60 min
f = %
3.Medium
t (min)X (%)t = ?50%

A first-order reaction in a batch reactor has k = 0.01 min⁻¹. How long does it take to reach 50% conversion? Find t.

k = 0.01 min⁻¹X = 50 %
t = min
4.Medium
t (min)X (%)t = ?75%

A first-order reaction in a batch reactor has k = 0.08 min⁻¹. How long does it take to reach 75% conversion? Find t.

k = 0.08 min⁻¹X = 75 %
t = min
5.Hard
Tk30 °Ck1​?3·k1​

A reaction has an activation energy of 55 kJ/mol. At 30 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 3 times faster?

Ea = 55 kJ/molT1 = 30 °Ck2/k1 = 3R = 8.314 J/(mol·K)
T2 = °C
6.Hard
Tk40 °Ck1​?2·k1​

A reaction has an activation energy of 100 kJ/mol. At 40 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 2 times faster?

Ea = 100 kJ/molT1 = 40 °Ck2/k1 = 2R = 8.314 J/(mol·K)
T2 = °C

Answer key

  1. 1. k = 0.08664 min⁻¹
  2. 2. f = 12.5 %
  3. 3. t = 69.31 min
  4. 4. t = 17.33 min
  5. 5. T2 = 46.07 °C
  6. 6. T2 = 45.76 °C

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