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 zero-order reaction A → products has a rate constant of 0.005 mol/(L·min). The initial concentration of A is 1.2 mol/L. Find the concentration CA after 5 min.

k = 0.005 mol/(L·min)CA0 = 1.2 mol/Lt = 5 min
CA = mol/L
2.Easy
t (min)C/C₀ (%)7.5 min?

A first-order reaction has a half-life of 15 min. What percentage f of the reactant is still left after 7.5 min?

t½ = 15 mint = 7.5 min
f = %
3.Medium
t (min)C (mol/L)20 min0.6

In a first-order reaction the concentration of A falls from 1.2 mol/L to 0.6 mol/L in 20 min. Find the rate constant k.

CA0 = 1.2 mol/LCA = 0.6 mol/Lt = 20 min
k = min⁻¹
4.Medium
t (min)X (%)t = ?30%

A zero-order reaction has k = 0.02 mol/(L·min) and starts at 1.5 mol/L. How long does it take to reach 30% conversion? Find t.

k = 0.02 mol/(L·min)CA0 = 1.5 mol/LX = 30 %
t = min
5.Hard
Tk40 °C0.00265 °C0.0258

The rate constant of a reaction is 0.002 min⁻¹ at 40 °C and 0.0258 min⁻¹ at 65 °C. Find the activation energy Ea.

k1 = 0.002 min⁻¹T1 = 40 °Ck2 = 0.0258 min⁻¹T2 = 65 °CR = 8.314 J/(mol·K)
Ea = kJ/mol
6.Hard
t (min)X (%)15 minX = ?

A first-order reaction has k = 0.01 min⁻¹ at 30 °C and an activation energy of 75 kJ/mol. The batch reactor is now run at 40 °C for 15 min. Find the conversion X reached.

k1 = 0.01 min⁻¹T1 = 30 °CEa = 75 kJ/molT2 = 40 °Ct = 15 minR = 8.314 J/(mol·K)
X = %

Answer key

  1. 1. CA = 1.175 mol/L
  2. 2. f = 70.71 %
  3. 3. k = 0.03466 min⁻¹
  4. 4. t = 22.5 min
  5. 5. Ea = 90.05 kJ/mol
  6. 6. X = 32.16 %

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