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)30 minC = ?

A zero-order reaction A → products has a rate constant of 0.04 mol/(L·min). The initial concentration of A is 1.5 mol/L. Find the concentration CA after 30 min.

k = 0.04 mol/(L·min)CA0 = 1.5 mol/Lt = 30 min
CA = mol/L
2.Easy
t (min)C (mol/L)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.08 min⁻¹. Find its half-life t½.

k = 0.08 min⁻¹
t½ = min
3.Medium
t (min)X (%)t = ?99%

A first-order reaction in a batch reactor has k = 0.2 min⁻¹. How long does it take to reach 99% conversion? Find t.

k = 0.2 min⁻¹X = 99 %
t = min
4.Medium
t (min)C (mol/L)t½​ = ?C0​/2

A second-order reaction (−rA = k·CA²) has k = 0.2 L/(mol·min) and an initial concentration of 0.5 mol/L. Find its first half-life t½.

k = 0.2 L/(mol·min)CA0 = 0.5 mol/L
t½ = min
5.Hard
Tk20 °Ck1​?3·k1​

A reaction has an activation energy of 90 kJ/mol. At 20 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 3 times faster?

Ea = 90 kJ/molT1 = 20 °Ck2/k1 = 3R = 8.314 J/(mol·K)
T2 = °C
6.Hard
Tk40 °C0.150 °C0.181

The rate constant of a reaction is 0.1 min⁻¹ at 40 °C and 0.181 min⁻¹ at 50 °C. Find the activation energy Ea.

k1 = 0.1 min⁻¹T1 = 40 °Ck2 = 0.181 min⁻¹T2 = 50 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. CA = 0.3 mol/L
  2. 2. t½ = 8.664 min
  3. 3. t = 23.03 min
  4. 4. t½ = 10 min
  5. 5. T2 = 28.99 °C
  6. 6. Ea = 49.92 kJ/mol

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