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 12 min. What percentage f of the reactant is still left after 30 min?

t½ = 12 mint = 30 min
f = %
2.Easy
t (min)C (mol/L)30 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 30 min.

k = 0.02 min⁻¹CA0 = 1.5 mol/Lt = 30 min
CA = mol/L
3.Medium
t (min)C (mol/L)2 minC = ?

A reaction with rate law −rA = k·CA² has k = 1 L/(mol·min) and starts at 1 mol/L. Find the concentration CA after 2 min.

k = 1 L/(mol·min)CA0 = 1 mol/Lt = 2 min
CA = mol/L
4.Medium
t (min)C (mol/L)5 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.2 L/(mol·min) and starts at 0.5 mol/L. Find the concentration CA after 5 min.

k = 0.2 L/(mol·min)CA0 = 0.5 mol/Lt = 5 min
CA = mol/L
5.Hard
Tk30 °Ck1​?3·k1​

A reaction has an activation energy of 70 kJ/mol. At 30 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 3 times faster?

Ea = 70 kJ/molT1 = 30 °Ck2/k1 = 3R = 8.314 J/(mol·K)
T2 = °C
6.Hard
t (min)X (%)15 minX = ?

A first-order reaction has k = 0.02 min⁻¹ at 25 °C and an activation energy of 50 kJ/mol. The batch reactor is now run at 40 °C for 15 min. Find the conversion X reached.

k1 = 0.02 min⁻¹T1 = 25 °CEa = 50 kJ/molT2 = 40 °Ct = 15 minR = 8.314 J/(mol·K)
X = %

Answer key

  1. 1. f = 17.68 %
  2. 2. CA = 0.8232 mol/L
  3. 3. CA = 0.3333 mol/L
  4. 4. CA = 0.3333 mol/L
  5. 5. T2 = 42.49 °C
  6. 6. X = 54.54 %

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