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 (%)40 min?

A first-order reaction has a half-life of 8 min. What percentage f of the reactant is still left after 40 min?

t½ = 8 mint = 40 min
f = %
2.Easy
t (min)C (mol/L)5 minC = ?

A zero-order reaction A → products has a rate constant of 0.01 mol/(L·min). The initial concentration of A is 1.2 mol/L. Find the concentration CA after 5 min.

k = 0.01 mol/(L·min)CA0 = 1.2 mol/Lt = 5 min
CA = mol/L
3.Medium
t (min)X (%)t = ?99%

A first-order reaction in a batch reactor has k = 0.15 min⁻¹. How long does it take to reach 99% conversion? Find t.

k = 0.15 min⁻¹X = 99 %
t = min
4.Medium
t (min)X (%)t = ?80%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 0.5 L/(mol·min) and starts at 1 mol/L. How long does it take to reach 80% conversion? Find t.

k = 0.5 L/(mol·min)CA0 = 1 mol/LX = 80 %
t = min
5.Hard
Tk25 °C0.0265 °C?

A reaction has a rate constant of 0.02 min⁻¹ at 25 °C and an activation energy of 100 kJ/mol. Find the rate constant k2 at 65 °C.

k1 = 0.02 min⁻¹T1 = 25 °CT2 = 65 °CEa = 100 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹
6.Hard
1/Tln kT = 30 °Cln 0.02ln A = ?Ea​ = 75 kJ/mol

A first-order reaction has a rate constant of 0.02 s⁻¹ at 30 °C and an activation energy of 75 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.02 s⁻¹T = 30 °CEa = 75 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹

Answer key

  1. 1. f = 3.125 %
  2. 2. CA = 1.15 mol/L
  3. 3. t = 30.7 min
  4. 4. t = 8 min
  5. 5. k2 = 2.363 min⁻¹
  6. 6. A = 1.677 × 10¹¹ s⁻¹

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