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_A·C_B, with k = 0.5 L/(mol·s). Find the reaction rate r when C_A = 0.25 mol/L and C_B = 0.6 mol/L.

r = k·C_A·C_Bk = 0.5 L/(mol·s)C_A = 0.25 mol/LC_B = 0.6 mol/L

r = mol/(L·s)

2.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 120 min.

k = 0.01 min⁻¹C_A0 = 1.2 mol/Lt = 120 min

C_A = mol/L

3.Medium

A reaction with rate law −r_A = k·C_A² has k = 0.4 L/(mol·min) and starts at 0.5 mol/L. Find the concentration C_A after 30 min.

k = 0.4 L/(mol·min)C_A0 = 0.5 mol/Lt = 30 min

C_A = mol/L

4.Medium

A zero-order reaction has k = 0.04 mol/(L·min) and starts at 1 mol/L. How long does it take to reach 50% conversion? Find t.

k = 0.04 mol/(L·min)C_A0 = 1 mol/LX = 50 %

t = min

5.Hard

A reaction has a rate constant of 0.02 min⁻¹ at 30 °C and an activation energy of 120 kJ/mol. Find the rate constant k₂ at 40 °C.

k₁ = 0.02 min⁻¹T₁ = 30 °CT₂ = 40 °CE_a = 120 kJ/molR = 8.314 J/(mol·K)

k₂ = min⁻¹

6.Hard

Two experiments measure the initial rate of A → products. With C_A0 = 0.2 mol/L the rate is 0.01 mol/(L·s); with C_A0 = 0.6 mol/L it is 0.27 mol/(L·s). Find the reaction order n with respect to A.

C_A0,1 = 0.2 mol/Lr₁ = 0.01 mol/(L·s)C_A0,2 = 0.6 mol/Lr₂ = 0.27 mol/(L·s)

n =

Answer key

1. r = 0.075 mol/(L·s)
2. C_A = 0.3614 mol/L
3. C_A = 0.07143 mol/L
4. t = 12.5 min
5. k₂ = 0.09148 min⁻¹
6. n = 3

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