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​ = 25 min0.5

A first-order reaction has a half-life of 25 min. Find its rate constant k.

t½ = 25 min
k = min⁻¹
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)t½​ = ?C0​/2

A second-order reaction (−rA = k·CA²) has k = 0.02 L/(mol·min) and an initial concentration of 0.8 mol/L. Find its first half-life t½.

k = 0.02 L/(mol·min)CA0 = 0.8 mol/L
t½ = min
4.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 2 mol/L. Find the concentration CA after 20 min.

k = 0.8 L/(mol·min)CA0 = 2 mol/Lt = 20 min
CA = mol/L
5.Hard
1/Tln kT = 60 °Cln 0.005ln A = ?Ea​ = 90 kJ/mol

A first-order reaction has a rate constant of 0.005 s⁻¹ at 60 °C and an activation energy of 90 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.005 s⁻¹T = 60 °CEa = 90 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹
6.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.20.002run 20.40.00566n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.2 mol/L the rate is 0.002 mol/(L·s); with CA0 = 0.4 mol/L it is 0.00566 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.2 mol/Lr1 = 0.002 mol/(L·s)CA0,2 = 0.4 mol/Lr2 = 0.00566 mol/(L·s)
n =

Answer key

  1. 1. k = 0.02773 min⁻¹
  2. 2. k = 0.231 min⁻¹
  3. 3. t½ = 62.5 min
  4. 4. CA = 0.06061 mol/L
  5. 5. A = 6.465 × 10¹¹ s⁻¹
  6. 6. n = 1.501

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