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/C₀t½​ = 15 min0.5

A first-order reaction has a half-life of 15 min. Find its rate constant k.

t½ = 15 min
k = min⁻¹
2.Easy
t (min)C (mol/L)10 minC = ?

A first-order reaction A → products has a rate constant of 0.1 min⁻¹. The initial concentration of A is 2 mol/L. Find the concentration CA after 10 min.

k = 0.1 min⁻¹CA0 = 2 mol/Lt = 10 min
CA = mol/L
3.Medium
t (min)X (%)t = ?20%

A zero-order reaction has k = 0.02 mol/(L·min) and starts at 0.8 mol/L. How long does it take to reach 20% conversion? Find t.

k = 0.02 mol/(L·min)CA0 = 0.8 mol/LX = 20 %
t = min
4.Medium
t (min)X (%)t = ?80%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 0.2 L/(mol·min) and starts at 1.5 mol/L. How long does it take to reach 80% conversion? Find t.

k = 0.2 L/(mol·min)CA0 = 1.5 mol/LX = 80 %
t = min
5.Hard
Tk50 °Ck1​?5·k1​

A reaction has an activation energy of 50 kJ/mol. At 50 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 5 times faster?

Ea = 50 kJ/molT1 = 50 °Ck2/k1 = 5R = 8.314 J/(mol·K)
T2 = °C
6.Hard
Tk40 °C0.0150 °C?

A reaction has a rate constant of 0.01 min⁻¹ at 40 °C and an activation energy of 55 kJ/mol. Find the rate constant k2 at 50 °C.

k1 = 0.01 min⁻¹T1 = 40 °CT2 = 50 °CEa = 55 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹

Answer key

  1. 1. k = 0.04621 min⁻¹
  2. 2. CA = 0.7358 mol/L
  3. 3. t = 8 min
  4. 4. t = 13.33 min
  5. 5. T2 = 80.59 °C
  6. 6. k2 = 0.01923 min⁻¹

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