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)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.1 min⁻¹. Find its half-life t½.

k = 0.1 min⁻¹
t½ = min
2.Easy
t (min)C (mol/L)20 minC = ?

A zero-order reaction A → products has a rate constant of 0.02 mol/(L·min). The initial concentration of A is 1.2 mol/L. Find the concentration CA after 20 min.

k = 0.02 mol/(L·min)CA0 = 1.2 mol/Lt = 20 min
CA = mol/L
3.Medium
t (min)X (%)t = ?50%

A zero-order reaction has k = 0.005 mol/(L·min) and starts at 1 mol/L. How long does it take to reach 50% conversion? Find t.

k = 0.005 mol/(L·min)CA0 = 1 mol/LX = 50 %
t = min
4.Medium
t (min)X (%)t = ?99%

A first-order reaction in a batch reactor has k = 0.02 min⁻¹. How long does it take to reach 99% conversion? Find t.

k = 0.02 min⁻¹X = 99 %
t = min
5.Hard
Tk30 °C0.0270 °C?

A reaction has a rate constant of 0.02 min⁻¹ at 30 °C and an activation energy of 55 kJ/mol. Find the rate constant k2 at 70 °C.

k1 = 0.02 min⁻¹T1 = 30 °CT2 = 70 °CEa = 55 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹
6.Hard
1/Tln kT = 60 °Cln 0.05ln A = ?Ea​ = 40 kJ/mol

A first-order reaction has a rate constant of 0.05 s⁻¹ at 60 °C and an activation energy of 40 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.05 s⁻¹T = 60 °CEa = 40 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹

Answer key

  1. 1. t½ = 6.931 min
  2. 2. CA = 0.8 mol/L
  3. 3. t = 100 min
  4. 4. t = 230.3 min
  5. 5. k2 = 0.2545 min⁻¹
  6. 6. A = 93498 s⁻¹

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