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_A², with k = 0.5 L/(mol·s). Find the reaction rate r when C_A = 0.4 mol/L and C_B = 0.2 mol/L.

r = k·C_A²k = 0.5 L/(mol·s)C_A = 0.4 mol/LC_B = 0.2 mol/L

r = mol/(L·s)

2.Easy

A first-order reaction A → products has a rate constant of 0.2 min⁻¹. The initial concentration of A is 0.5 mol/L. Find the concentration C_A after 5 min.

k = 0.2 min⁻¹C_A0 = 0.5 mol/Lt = 5 min

C_A = mol/L

3.Medium

A first-order reaction in a batch reactor has k = 0.01 min⁻¹. How long does it take to reach 60% conversion? Find t.

k = 0.01 min⁻¹X = 60 %

t = min

4.Medium

In a first-order reaction the concentration of A falls from 0.8 mol/L to 0.56 mol/L in 40 min. Find the rate constant k.

C_A0 = 0.8 mol/LC_A = 0.56 mol/Lt = 40 min

k = min⁻¹

5.Hard

The rate constant of a reaction is 0.05 min⁻¹ at 35 °C and 1.13 min⁻¹ at 65 °C. Find the activation energy E_a.

k₁ = 0.05 min⁻¹T₁ = 35 °Ck₂ = 1.13 min⁻¹T₂ = 65 °CR = 8.314 J/(mol·K)

E_a = kJ/mol

6.Hard

A first-order reaction has a rate constant of 0.01 s⁻¹ at 60 °C and an activation energy of 75 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.01 s⁻¹T = 60 °CE_a = 75 kJ/molR = 8.314 J/(mol·K)

A = s⁻¹

Answer key

1. r = 0.08 mol/(L·s)
2. C_A = 0.1839 mol/L
3. t = 91.63 min
4. k = 0.008917 min⁻¹
5. E_a = 90.04 kJ/mol
6. A = 5.75 × 10⁹ s⁻¹

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