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 0.025 min⁻¹. Find its half-life t½.

k = 0.025 min⁻¹
t½ = min
2.Easy
t (min)C (mol/L)20 minC = ?

A first-order reaction A → products has a rate constant of 0.02 min⁻¹. The initial concentration of A is 1.5 mol/L. Find the concentration CA after 20 min.

k = 0.02 min⁻¹CA0 = 1.5 mol/Lt = 20 min
CA = mol/L
3.Medium
t (min)X (%)t = ?90%

A zero-order reaction has k = 0.05 mol/(L·min) and starts at 1.2 mol/L. How long does it take to reach 90% conversion? Find t.

k = 0.05 mol/(L·min)CA0 = 1.2 mol/LX = 90 %
t = min
4.Medium
t (min)X (%)t = ?90%

A first-order reaction in a batch reactor has k = 0.08 min⁻¹. How long does it take to reach 90% conversion? Find t.

k = 0.08 min⁻¹X = 90 %
t = min
5.Hard
Tk30 °Ck1​?5·k1​

A reaction has an activation energy of 80 kJ/mol. At 30 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 5 times faster?

Ea = 80 kJ/molT1 = 30 °Ck2/k1 = 5R = 8.314 J/(mol·K)
T2 = °C
6.Hard
Tk35 °C0.00560 °C0.0161

The rate constant of a reaction is 0.005 min⁻¹ at 35 °C and 0.0161 min⁻¹ at 60 °C. Find the activation energy Ea.

k1 = 0.005 min⁻¹T1 = 35 °Ck2 = 0.0161 min⁻¹T2 = 60 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. t½ = 27.73 min
  2. 2. CA = 1.005 mol/L
  3. 3. t = 21.6 min
  4. 4. t = 28.78 min
  5. 5. T2 = 46.19 °C
  6. 6. Ea = 39.92 kJ/mol

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