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 has a half-life of 20 min. What percentage f of the reactant is still left after 80 min?

t_½ = 20 mint = 80 min

f = %

2.Easy

A zero-order reaction A → products has a rate constant of 0.01 mol/(L·min). The initial concentration of A is 1.5 mol/L. Find the concentration C_A after 30 min.

k = 0.01 mol/(L·min)C_A0 = 1.5 mol/Lt = 30 min

C_A = mol/L

3.Medium

A second-order reaction (−r_A = k·C_A²) has k = 0.2 L/(mol·min) and an initial concentration of 2 mol/L. Find its first half-life t_½.

k = 0.2 L/(mol·min)C_A0 = 2 mol/L

t_½ = min

4.Medium

A reaction with rate law −r_A = k·C_A² has k = 0.05 L/(mol·min) and starts at 1 mol/L. Find the concentration C_A after 15 min.

k = 0.05 L/(mol·min)C_A0 = 1 mol/Lt = 15 min

C_A = mol/L

5.Hard

Two experiments measure the initial rate of A → products. With C_A0 = 0.1 mol/L the rate is 0.012 mol/(L·s); with C_A0 = 0.2 mol/L it is 0.017 mol/(L·s). Find the reaction order n with respect to A.

C_A0,1 = 0.1 mol/Lr₁ = 0.012 mol/(L·s)C_A0,2 = 0.2 mol/Lr₂ = 0.017 mol/(L·s)

n =

6.Hard

A reaction has an activation energy of 55 kJ/mol. At 30 °C it is too slow. To what temperature T₂ (in °C) must it be heated to make it 3 times faster?

E_a = 55 kJ/molT₁ = 30 °Ck₂/k₁ = 3R = 8.314 J/(mol·K)

T₂ = °C

Answer key

1. f = 6.25 %
2. C_A = 1.2 mol/L
3. t_½ = 2.5 min
4. C_A = 0.5714 mol/L
5. n = 0.5025
6. T₂ = 46.07 °C

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