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)5 minC = ?

A first-order reaction A → products has a rate constant of 0.2 min⁻¹. The initial concentration of A is 0.5 mol/L. Find the concentration CA after 5 min.

k = 0.2 min⁻¹CA0 = 0.5 mol/Lt = 5 min
CA = mol/L
2.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
3.Medium
t (min)X (%)t = ?75%

A zero-order reaction has k = 0.05 mol/(L·min) and starts at 0.8 mol/L. How long does it take to reach 75% conversion? Find t.

k = 0.05 mol/(L·min)CA0 = 0.8 mol/LX = 75 %
t = min
4.Medium
t (min)C (mol/L)15 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.2 L/(mol·min) and starts at 1.5 mol/L. Find the concentration CA after 15 min.

k = 0.2 L/(mol·min)CA0 = 1.5 mol/Lt = 15 min
CA = mol/L
5.Hard
Tk20 °C0.130 °C0.387

The rate constant of a reaction is 0.1 min⁻¹ at 20 °C and 0.387 min⁻¹ at 30 °C. Find the activation energy Ea.

k1 = 0.1 min⁻¹T1 = 20 °Ck2 = 0.387 min⁻¹T2 = 30 °CR = 8.314 J/(mol·K)
Ea = kJ/mol
6.Hard
t (min)X (%)30 minX = ?

A first-order reaction has k = 0.01 min⁻¹ at 25 °C and an activation energy of 70 kJ/mol. The batch reactor is now run at 50 °C for 30 min. Find the conversion X reached.

k1 = 0.01 min⁻¹T1 = 25 °CEa = 70 kJ/molT2 = 50 °Ct = 30 minR = 8.314 J/(mol·K)
X = %

Answer key

  1. 1. CA = 0.1839 mol/L
  2. 2. k = 0.08664 min⁻¹
  3. 3. t = 12 min
  4. 4. CA = 0.2727 mol/L
  5. 5. Ea = 99.99 kJ/mol
  6. 6. X = 93.05 %

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