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 0.025 min⁻¹. The initial concentration of A is 1.2 mol/L. Find the concentration C_A after 30 min.

k = 0.025 min⁻¹C_A0 = 1.2 mol/Lt = 30 min

C_A = mol/L

2.Easy

A first-order reaction has a rate constant of 0.01 min⁻¹. Find its half-life t_½.

k = 0.01 min⁻¹

t_½ = min

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 2 mol/L. How long does it take to reach 60% conversion? Find t.

k = 0.5 L/(mol·min)C_A0 = 2 mol/LX = 60 %

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 90% conversion? Find t.

k = 0.05 L/(mol·min)C_A0 = 0.5 mol/LX = 90 %

t = min

5.Hard

A reaction has a rate constant of 0.02 min⁻¹ at 25 °C and an activation energy of 80 kJ/mol. Find the rate constant k₂ at 55 °C.

k₁ = 0.02 min⁻¹T₁ = 25 °CT₂ = 55 °CE_a = 80 kJ/molR = 8.314 J/(mol·K)

k₂ = min⁻¹

6.Hard

Two experiments measure the initial rate of A → products. With C_A0 = 0.4 mol/L the rate is 0.02 mol/(L·s); with C_A0 = 1.6 mol/L it is 0.32 mol/(L·s). Find the reaction order n with respect to A.

C_A0,1 = 0.4 mol/Lr₁ = 0.02 mol/(L·s)C_A0,2 = 1.6 mol/Lr₂ = 0.32 mol/(L·s)

n =

Answer key

1. C_A = 0.5668 mol/L
2. t_½ = 69.31 min
3. t = 1.5 min
4. t = 360 min
5. k₂ = 0.3823 min⁻¹
6. n = 2

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