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)r1.5r = ?CB​ = 0.2 mol/L

The reaction A + B → C follows the rate law r = k·CB, with k = 0.1 s⁻¹. Find the reaction rate r when CA = 1.5 mol/L and CB = 0.2 mol/L.

r = k·CBk = 0.1 s⁻¹CA = 1.5 mol/LCB = 0.2 mol/L
r = mol/(L·s)
2.Easy
t (min)C (mol/L)10 minC = ?

A first-order reaction A → products has a rate constant of 0.2 min⁻¹. The initial concentration of A is 1.2 mol/L. Find the concentration CA after 10 min.

k = 0.2 min⁻¹CA0 = 1.2 mol/Lt = 10 min
CA = mol/L
3.Medium
t (min)C (mol/L)30 minC = ?

A reaction with rate law −rA = k·CA² has k = 1 L/(mol·min) and starts at 1.5 mol/L. Find the concentration CA after 30 min.

k = 1 L/(mol·min)CA0 = 1.5 mol/Lt = 30 min
CA = mol/L
4.Medium
t (min)X (%)t = ?95%

A first-order reaction in a batch reactor has k = 0.02 min⁻¹. How long does it take to reach 95% conversion? Find t.

k = 0.02 min⁻¹X = 95 %
t = min
5.Hard
Tk35 °C0.00260 °C0.0279

The rate constant of a reaction is 0.002 min⁻¹ at 35 °C and 0.0279 min⁻¹ at 60 °C. Find the activation energy Ea.

k1 = 0.002 min⁻¹T1 = 35 °Ck2 = 0.0279 min⁻¹T2 = 60 °CR = 8.314 J/(mol·K)
Ea = kJ/mol
6.Hard
Tk25 °Ck1​?10·k1​

A reaction has an activation energy of 55 kJ/mol. At 25 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 10 times faster?

Ea = 55 kJ/molT1 = 25 °Ck2/k1 = 10R = 8.314 J/(mol·K)
T2 = °C

Answer key

  1. 1. r = 0.02 mol/(L·s)
  2. 2. CA = 0.1624 mol/L
  3. 3. CA = 0.03261 mol/L
  4. 4. t = 149.8 min
  5. 5. Ea = 89.98 kJ/mol
  6. 6. T2 = 59.52 °C

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