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/C₀ (%)30 min?

A first-order reaction has a half-life of 20 min. What percentage f of the reactant is still left after 30 min?

t½ = 20 mint = 30 min
f = %
2.Easy
t (min)C (mol/L)15 minC = ?

A zero-order reaction A → products has a rate constant of 0.01 mol/(L·min). The initial concentration of A is 1.5 mol/L. Find the concentration CA after 15 min.

k = 0.01 mol/(L·min)CA0 = 1.5 mol/Lt = 15 min
CA = mol/L
3.Medium
t (min)X (%)t = ?75%

A first-order reaction in a batch reactor has k = 0.05 min⁻¹. How long does it take to reach 75% conversion? Find t.

k = 0.05 min⁻¹X = 75 %
t = min
4.Medium
t (min)C (mol/L)5 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.5 L/(mol·min) and starts at 0.5 mol/L. Find the concentration CA after 5 min.

k = 0.5 L/(mol·min)CA0 = 0.5 mol/Lt = 5 min
CA = mol/L
5.Hard
Tk40 °C0.0255 °C0.0481

The rate constant of a reaction is 0.02 min⁻¹ at 40 °C and 0.0481 min⁻¹ at 55 °C. Find the activation energy Ea.

k1 = 0.02 min⁻¹T1 = 40 °Ck2 = 0.0481 min⁻¹T2 = 55 °CR = 8.314 J/(mol·K)
Ea = kJ/mol
6.Hard
t (min)X (%)20 minX = ?

A first-order reaction has k = 0.02 min⁻¹ at 30 °C and an activation energy of 70 kJ/mol. The batch reactor is now run at 40 °C for 20 min. Find the conversion X reached.

k1 = 0.02 min⁻¹T1 = 30 °CEa = 70 kJ/molT2 = 40 °Ct = 20 minR = 8.314 J/(mol·K)
X = %

Answer key

  1. 1. f = 35.36 %
  2. 2. CA = 1.35 mol/L
  3. 3. t = 27.73 min
  4. 4. CA = 0.2222 mol/L
  5. 5. Ea = 49.98 kJ/mol
  6. 6. X = 62.13 %

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