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

The reaction A + B → C follows the rate law r = k·C_B², with k = 0.005 L/(mol·s). Find the reaction rate r when C_A = 2 mol/L and C_B = 1 mol/L.

r = k·C_B²k = 0.005 L/(mol·s)C_A = 2 mol/LC_B = 1 mol/L

r = mol/(L·s)

2.Easy

A first-order reaction A → products has a rate constant of 0.02 min⁻¹. The initial concentration of A is 1.2 mol/L. Find the concentration C_A after 40 min.

k = 0.02 min⁻¹C_A0 = 1.2 mol/Lt = 40 min

C_A = mol/L

3.Medium

A second-order reaction (−r_A = k·C_A²) in a batch reactor has k = 0.5 L/(mol·min) and starts at 0.5 mol/L. How long does it take to reach 90% conversion? Find t.

k = 0.5 L/(mol·min)C_A0 = 0.5 mol/LX = 90 %

t = min

4.Medium

A second-order reaction (−r_A = k·C_A²) in a batch reactor has k = 0.05 L/(mol·min) and starts at 0.5 mol/L. How long does it take to reach 80% conversion? Find t.

k = 0.05 L/(mol·min)C_A0 = 0.5 mol/LX = 80 %

t = min

5.Hard

A reaction has a rate constant of 0.002 min⁻¹ at 40 °C and an activation energy of 70 kJ/mol. Find the rate constant k₂ at 60 °C.

k₁ = 0.002 min⁻¹T₁ = 40 °CT₂ = 60 °CE_a = 70 kJ/molR = 8.314 J/(mol·K)

k₂ = min⁻¹

6.Hard

The rate constant of a reaction is 0.1 min⁻¹ at 20 °C and 0.338 min⁻¹ at 30 °C. Find the activation energy E_a.

k₁ = 0.1 min⁻¹T₁ = 20 °Ck₂ = 0.338 min⁻¹T₂ = 30 °CR = 8.314 J/(mol·K)

E_a = kJ/mol

Answer key

1. r = 0.005 mol/(L·s)
2. C_A = 0.5392 mol/L
3. t = 36 min
4. t = 160 min
5. k₂ = 0.01005 min⁻¹
6. E_a = 89.98 kJ/mol

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