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 (%)20 min?

A first-order reaction has a half-life of 10 min. What percentage f of the reactant is still left after 20 min?

t½ = 10 mint = 20 min
f = %
2.Easy
t (min)C (mol/L)60 minC = ?

A first-order reaction A → products has a rate constant of 0.01 min⁻¹. The initial concentration of A is 0.8 mol/L. Find the concentration CA after 60 min.

k = 0.01 min⁻¹CA0 = 0.8 mol/Lt = 60 min
CA = mol/L
3.Medium
t (min)C (mol/L)60 min0.6

In a first-order reaction the concentration of A falls from 1.5 mol/L to 0.6 mol/L in 60 min. Find the rate constant k.

CA0 = 1.5 mol/LCA = 0.6 mol/Lt = 60 min
k = min⁻¹
4.Medium
t (min)X (%)t = ?99%

A first-order reaction in a batch reactor has k = 0.1 min⁻¹. How long does it take to reach 99% conversion? Find t.

k = 0.1 min⁻¹X = 99 %
t = min
5.Hard
Tk40 °C0.0555 °C?

A reaction has a rate constant of 0.05 min⁻¹ at 40 °C and an activation energy of 120 kJ/mol. Find the rate constant k2 at 55 °C.

k1 = 0.05 min⁻¹T1 = 40 °CT2 = 55 °CEa = 120 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹
6.Hard
Tk20 °C0.0535 °C?

A reaction has a rate constant of 0.05 min⁻¹ at 20 °C and an activation energy of 100 kJ/mol. Find the rate constant k2 at 35 °C.

k1 = 0.05 min⁻¹T1 = 20 °CT2 = 35 °CEa = 100 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹

Answer key

  1. 1. f = 25 %
  2. 2. CA = 0.439 mol/L
  3. 3. k = 0.01527 min⁻¹
  4. 4. t = 46.05 min
  5. 5. k2 = 0.4111 min⁻¹
  6. 6. k2 = 0.3684 min⁻¹

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