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

t½ = 10 mint = 30 min
f = %
2.Easy
t (min)C (mol/L)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.25 min⁻¹. Find its half-life t½.

k = 0.25 min⁻¹
t½ = min
3.Medium
t (min)C (mol/L)30 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.8 L/(mol·min) and starts at 0.5 mol/L. Find the concentration CA after 30 min.

k = 0.8 L/(mol·min)CA0 = 0.5 mol/Lt = 30 min
CA = mol/L
4.Medium
t (min)X (%)t = ?95%

A first-order reaction in a batch reactor has k = 0.02 min⁻¹. How long does it take to reach 95% conversion? Find t.

k = 0.02 min⁻¹X = 95 %
t = min
5.Hard
t (min)X (%)10 minX = ?

A first-order reaction has k = 0.01 min⁻¹ at 25 °C and an activation energy of 80 kJ/mol. The batch reactor is now run at 45 °C for 10 min. Find the conversion X reached.

k1 = 0.01 min⁻¹T1 = 25 °CEa = 80 kJ/molT2 = 45 °Ct = 10 minR = 8.314 J/(mol·K)
X = %
6.Hard
Tk30 °C0.00560 °C0.0729

The rate constant of a reaction is 0.005 min⁻¹ at 30 °C and 0.0729 min⁻¹ at 60 °C. Find the activation energy Ea.

k1 = 0.005 min⁻¹T1 = 30 °Ck2 = 0.0729 min⁻¹T2 = 60 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. f = 12.5 %
  2. 2. t½ = 2.773 min
  3. 3. CA = 0.03846 mol/L
  4. 4. t = 149.8 min
  5. 5. X = 53.26 %
  6. 6. Ea = 75 kJ/mol

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