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

A first-order reaction A → products has a rate constant of 0.01 min⁻¹. The initial concentration of A is 1.2 mol/L. Find the concentration C_A after 20 min.

k = 0.01 min⁻¹C_A0 = 1.2 mol/Lt = 20 min

C_A = mol/L

2.Easy

A first-order reaction A → products has a rate constant of 0.1 min⁻¹. The initial concentration of A is 0.5 mol/L. Find the concentration C_A after 20 min.

k = 0.1 min⁻¹C_A0 = 0.5 mol/Lt = 20 min

C_A = mol/L

3.Medium

A reaction with rate law −r_A = k·C_A² has k = 0.2 L/(mol·min) and starts at 1.5 mol/L. Find the concentration C_A after 15 min.

k = 0.2 L/(mol·min)C_A0 = 1.5 mol/Lt = 15 min

C_A = mol/L

4.Medium

A reaction with rate law −r_A = k·C_A² has k = 0.1 L/(mol·min) and starts at 0.5 mol/L. Find the concentration C_A after 2 min.

k = 0.1 L/(mol·min)C_A0 = 0.5 mol/Lt = 2 min

C_A = mol/L

5.Hard

A reaction has a rate constant of 0.01 min⁻¹ at 20 °C and an activation energy of 50 kJ/mol. Find the rate constant k₂ at 35 °C.

k₁ = 0.01 min⁻¹T₁ = 20 °CT₂ = 35 °CE_a = 50 kJ/molR = 8.314 J/(mol·K)

k₂ = min⁻¹

6.Hard

A reaction has an activation energy of 100 kJ/mol. At 25 °C it is too slow. To what temperature T₂ (in °C) must it be heated to make it 10 times faster?

E_a = 100 kJ/molT₁ = 25 °Ck₂/k₁ = 10R = 8.314 J/(mol·K)

T₂ = °C

Answer key

1. C_A = 0.9825 mol/L
2. C_A = 0.06767 mol/L
3. C_A = 0.2727 mol/L
4. C_A = 0.4545 mol/L
5. k₂ = 0.02715 min⁻¹
6. T₂ = 43.05 °C

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