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
CA​ (mol/L)r0.5r = ?CB​ = 2 mol/L

The reaction A + B → C follows the rate law r = k·CA², with k = 0.02 L/(mol·s). Find the reaction rate r when CA = 0.5 mol/L and CB = 2 mol/L.

r = k·CA²k = 0.02 L/(mol·s)CA = 0.5 mol/LCB = 2 mol/L
r = mol/(L·s)
2.Easy
t (min)C (mol/L)5 minC = ?

A first-order reaction A → products has a rate constant of 0.25 min⁻¹. The initial concentration of A is 1.2 mol/L. Find the concentration CA after 5 min.

k = 0.25 min⁻¹CA0 = 1.2 mol/Lt = 5 min
CA = mol/L
3.Medium
t (min)C (mol/L)5 min0.72

In a first-order reaction the concentration of A falls from 1.2 mol/L to 0.72 mol/L in 5 min. Find the rate constant k.

CA0 = 1.2 mol/LCA = 0.72 mol/Lt = 5 min
k = min⁻¹
4.Medium
t (min)X (%)t = ?95%

A first-order reaction in a batch reactor has k = 0.05 min⁻¹. How long does it take to reach 95% conversion? Find t.

k = 0.05 min⁻¹X = 95 %
t = min
5.Hard
Tk30 °C0.00545 °C0.0223

The rate constant of a reaction is 0.005 min⁻¹ at 30 °C and 0.0223 min⁻¹ at 45 °C. Find the activation energy Ea.

k1 = 0.005 min⁻¹T1 = 30 °Ck2 = 0.0223 min⁻¹T2 = 45 °CR = 8.314 J/(mol·K)
Ea = kJ/mol
6.Hard
Tk30 °C0.0160 °C0.0597

The rate constant of a reaction is 0.01 min⁻¹ at 30 °C and 0.0597 min⁻¹ at 60 °C. Find the activation energy Ea.

k1 = 0.01 min⁻¹T1 = 30 °Ck2 = 0.0597 min⁻¹T2 = 60 °CR = 8.314 J/(mol·K)
Ea = kJ/mol

Answer key

  1. 1. r = 0.005 mol/(L·s)
  2. 2. CA = 0.3438 mol/L
  3. 3. k = 0.1022 min⁻¹
  4. 4. t = 59.91 min
  5. 5. Ea = 79.93 kJ/mol
  6. 6. Ea = 50.01 kJ/mol

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