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)60 minC = ?

A first-order reaction A → products has a rate constant of 0.01 min⁻¹. The initial concentration of A is 2 mol/L. Find the concentration CA after 60 min.

k = 0.01 min⁻¹CA0 = 2 mol/Lt = 60 min
CA = mol/L
2.Easy
t (min)C (mol/L)40 minC = ?

A zero-order reaction A → products has a rate constant of 0.025 mol/(L·min). The initial concentration of A is 1.2 mol/L. Find the concentration CA after 40 min.

k = 0.025 mol/(L·min)CA0 = 1.2 mol/Lt = 40 min
CA = mol/L
3.Medium
t (min)X (%)t = ?75%

A zero-order reaction has k = 0.04 mol/(L·min) and starts at 2 mol/L. How long does it take to reach 75% conversion? Find t.

k = 0.04 mol/(L·min)CA0 = 2 mol/LX = 75 %
t = min
4.Medium
t (min)C (mol/L)15 min0.7

In a first-order reaction the concentration of A falls from 1 mol/L to 0.7 mol/L in 15 min. Find the rate constant k.

CA0 = 1 mol/LCA = 0.7 mol/Lt = 15 min
k = min⁻¹
5.Hard
Tk35 °C0.150 °C?

A reaction has a rate constant of 0.1 min⁻¹ at 35 °C and an activation energy of 120 kJ/mol. Find the rate constant k2 at 50 °C.

k1 = 0.1 min⁻¹T1 = 35 °CT2 = 50 °CEa = 120 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹
6.Hard
Tk25 °C0.0140 °C0.0387

The rate constant of a reaction is 0.01 min⁻¹ at 25 °C and 0.0387 min⁻¹ at 40 °C. Find the activation energy Ea.

k1 = 0.01 min⁻¹T1 = 25 °Ck2 = 0.0387 min⁻¹T2 = 40 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. CA = 1.098 mol/L
  2. 2. CA = 0.2 mol/L
  3. 3. t = 37.5 min
  4. 4. k = 0.02378 min⁻¹
  5. 5. k2 = 0.8795 min⁻¹
  6. 6. Ea = 70.03 kJ/mol

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