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)90 minC = ?

A first-order reaction A → products has a rate constant of 0.02 min⁻¹. The initial concentration of A is 2 mol/L. Find the concentration CA after 90 min.

k = 0.02 min⁻¹CA0 = 2 mol/Lt = 90 min
CA = mol/L
2.Easy
t (min)C/C₀t½​ = 60 min0.5

A first-order reaction has a half-life of 60 min. Find its rate constant k.

t½ = 60 min
k = min⁻¹
3.Medium
t (min)X (%)t = ?90%

A zero-order reaction has k = 0.05 mol/(L·min) and starts at 1 mol/L. How long does it take to reach 90% conversion? Find t.

k = 0.05 mol/(L·min)CA0 = 1 mol/LX = 90 %
t = min
4.Medium
t (min)X (%)t = ?75%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 0.2 L/(mol·min) and starts at 0.5 mol/L. How long does it take to reach 75% conversion? Find t.

k = 0.2 L/(mol·min)CA0 = 0.5 mol/LX = 75 %
t = min
5.Hard
Tk30 °Ck1​?10·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 10 times faster?

Ea = 55 kJ/molT1 = 30 °Ck2/k1 = 10R = 8.314 J/(mol·K)
T2 = °C
6.Hard
Tk50 °Ck1​?10·k1​

A reaction has an activation energy of 90 kJ/mol. At 50 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 10 times faster?

Ea = 90 kJ/molT1 = 50 °Ck2/k1 = 10R = 8.314 J/(mol·K)
T2 = °C

Answer key

  1. 1. CA = 0.3306 mol/L
  2. 2. k = 0.01155 min⁻¹
  3. 3. t = 18 min
  4. 4. t = 30 min
  5. 5. T2 = 65.76 °C
  6. 6. T2 = 73.85 °C

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