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
t (min)C (mol/L)20 minC = ?

A first-order reaction A → products has a rate constant of 0.025 min⁻¹. The initial concentration of A is 0.8 mol/L. Find the concentration CA after 20 min.

k = 0.025 min⁻¹CA0 = 0.8 mol/Lt = 20 min
CA = mol/L
2.Easy
t (min)C (mol/L)15 minC = ?

A first-order reaction A → products has a rate constant of 0.1 min⁻¹. The initial concentration of A is 1.5 mol/L. Find the concentration CA after 15 min.

k = 0.1 min⁻¹CA0 = 1.5 mol/Lt = 15 min
CA = mol/L
3.Medium
t (min)C (mol/L)5 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.05 L/(mol·min) and starts at 2 mol/L. Find the concentration CA after 5 min.

k = 0.05 L/(mol·min)CA0 = 2 mol/Lt = 5 min
CA = mol/L
4.Medium
t (min)X (%)t = ?80%

A zero-order reaction has k = 0.02 mol/(L·min) and starts at 1 mol/L. How long does it take to reach 80% conversion? Find t.

k = 0.02 mol/(L·min)CA0 = 1 mol/LX = 80 %
t = min
5.Hard
Tk30 °Ck1​?2·k1​

A reaction has an activation energy of 90 kJ/mol. At 30 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 2 times faster?

Ea = 90 kJ/molT1 = 30 °Ck2/k1 = 2R = 8.314 J/(mol·K)
T2 = °C
6.Hard
Tk25 °C0.0245 °C?

A reaction has a rate constant of 0.02 min⁻¹ at 25 °C and an activation energy of 90 kJ/mol. Find the rate constant k2 at 45 °C.

k1 = 0.02 min⁻¹T1 = 25 °CT2 = 45 °CEa = 90 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹

Answer key

  1. 1. CA = 0.4852 mol/L
  2. 2. CA = 0.3347 mol/L
  3. 3. CA = 1.333 mol/L
  4. 4. t = 40 min
  5. 5. T2 = 36 °C
  6. 6. k2 = 0.196 min⁻¹

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