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)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.02 min⁻¹. Find its half-life t½.

k = 0.02 min⁻¹
t½ = min
2.Easy
t (min)C/C₀t½​ = 3 min0.5

A first-order reaction has a half-life of 3 min. Find its rate constant k.

t½ = 3 min
k = min⁻¹
3.Medium
t (min)C (mol/L)20 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.8 L/(mol·min) and starts at 1 mol/L. Find the concentration CA after 20 min.

k = 0.8 L/(mol·min)CA0 = 1 mol/Lt = 20 min
CA = mol/L
4.Medium
t (min)C (mol/L)20 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.2 L/(mol·min) and starts at 1.5 mol/L. Find the concentration CA after 20 min.

k = 0.2 L/(mol·min)CA0 = 1.5 mol/Lt = 20 min
CA = mol/L
5.Hard
Tk30 °Ck1​?5·k1​

A reaction has an activation energy of 100 kJ/mol. At 30 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 5 times faster?

Ea = 100 kJ/molT1 = 30 °Ck2/k1 = 5R = 8.314 J/(mol·K)
T2 = °C
6.Hard
Tk40 °C0.00550 °C?

A reaction has a rate constant of 0.005 min⁻¹ at 40 °C and an activation energy of 120 kJ/mol. Find the rate constant k2 at 50 °C.

k1 = 0.005 min⁻¹T1 = 40 °CT2 = 50 °CEa = 120 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹

Answer key

  1. 1. t½ = 34.66 min
  2. 2. k = 0.231 min⁻¹
  3. 3. CA = 0.05882 mol/L
  4. 4. CA = 0.2143 mol/L
  5. 5. T2 = 42.82 °C
  6. 6. k2 = 0.02082 min⁻¹

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