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 0.08 min⁻¹. The initial concentration of A is 0.8 mol/L. Find the concentration C_A after 20 min.

k = 0.08 min⁻¹C_A0 = 0.8 mol/Lt = 20 min

C_A = mol/L

2.Easy

A first-order reaction A → products has a rate constant of 0.15 min⁻¹. The initial concentration of A is 0.5 mol/L. Find the concentration C_A after 5 min.

k = 0.15 min⁻¹C_A0 = 0.5 mol/Lt = 5 min

C_A = mol/L

3.Medium

A second-order reaction (−r_A = k·C_A²) in a batch reactor has k = 0.2 L/(mol·min) and starts at 2 mol/L. How long does it take to reach 75% conversion? Find t.

k = 0.2 L/(mol·min)C_A0 = 2 mol/LX = 75 %

t = min

4.Medium

In a first-order reaction the concentration of A falls from 1.5 mol/L to 1.2 mol/L in 5 min. Find the rate constant k.

C_A0 = 1.5 mol/LC_A = 1.2 mol/Lt = 5 min

k = min⁻¹

5.Hard

The rate constant of a reaction is 0.02 min⁻¹ at 20 °C and 0.0894 min⁻¹ at 35 °C. Find the activation energy E_a.

k₁ = 0.02 min⁻¹T₁ = 20 °Ck₂ = 0.0894 min⁻¹T₂ = 35 °CR = 8.314 J/(mol·K)

E_a = kJ/mol

6.Hard

A reaction has a rate constant of 0.005 min⁻¹ at 25 °C and an activation energy of 100 kJ/mol. Find the rate constant k₂ at 50 °C.

k₁ = 0.005 min⁻¹T₁ = 25 °CT₂ = 50 °CE_a = 100 kJ/molR = 8.314 J/(mol·K)

k₂ = min⁻¹

Answer key

1. C_A = 0.1615 mol/L
2. C_A = 0.2362 mol/L
3. t = 7.5 min
4. k = 0.04463 min⁻¹
5. E_a = 74.97 kJ/mol
6. k₂ = 0.1133 min⁻¹

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