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 first-order reaction A → products has a rate constant of 0.25 min⁻¹. The initial concentration of A is 1.5 mol/L. Find the concentration CA after 5 min.

k = 0.25 min⁻¹CA0 = 1.5 mol/Lt = 5 min
CA = mol/L
2.Easy
t (min)C (mol/L)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.2 min⁻¹. Find its half-life t½.

k = 0.2 min⁻¹
t½ = min
3.Medium
t (min)X (%)t = ?75%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 0.25 L/(mol·min) and starts at 0.5 mol/L. How long does it take to reach 75% conversion? Find t.

k = 0.25 L/(mol·min)CA0 = 0.5 mol/LX = 75 %
t = min
4.Medium
t (min)X (%)t = ?90%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 0.8 L/(mol·min) and starts at 1.5 mol/L. How long does it take to reach 90% conversion? Find t.

k = 0.8 L/(mol·min)CA0 = 1.5 mol/LX = 90 %
t = min
5.Hard
Tk40 °C0.00560 °C?

A reaction has a rate constant of 0.005 min⁻¹ at 40 °C and an activation energy of 50 kJ/mol. Find the rate constant k2 at 60 °C.

k1 = 0.005 min⁻¹T1 = 40 °CT2 = 60 °CEa = 50 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹
6.Hard
Tk35 °C0.00560 °C0.0698

The rate constant of a reaction is 0.005 min⁻¹ at 35 °C and 0.0698 min⁻¹ at 60 °C. Find the activation energy Ea.

k1 = 0.005 min⁻¹T1 = 35 °Ck2 = 0.0698 min⁻¹T2 = 60 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. CA = 0.4298 mol/L
  2. 2. t½ = 3.466 min
  3. 3. t = 24 min
  4. 4. t = 7.5 min
  5. 5. k2 = 0.01584 min⁻¹
  6. 6. Ea = 90 kJ/mol

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