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)30 minC = ?

A zero-order reaction A → products has a rate constant of 0.025 mol/(L·min). The initial concentration of A is 1.5 mol/L. Find the concentration CA after 30 min.

k = 0.025 mol/(L·min)CA0 = 1.5 mol/Lt = 30 min
CA = mol/L
2.Easy
t (min)C (mol/L)20 minC = ?

A first-order reaction A → products has a rate constant of 0.08 min⁻¹. The initial concentration of A is 2 mol/L. Find the concentration CA after 20 min.

k = 0.08 min⁻¹CA0 = 2 mol/Lt = 20 min
CA = mol/L
3.Medium
t (min)C (mol/L)30 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.8 L/(mol·min) and starts at 0.5 mol/L. Find the concentration CA after 30 min.

k = 0.8 L/(mol·min)CA0 = 0.5 mol/Lt = 30 min
CA = mol/L
4.Medium
t (min)X (%)t = ?50%

A first-order reaction in a batch reactor has k = 0.3 min⁻¹. How long does it take to reach 50% conversion? Find t.

k = 0.3 min⁻¹X = 50 %
t = min
5.Hard
Tk25 °C0.00550 °C?

A reaction has a rate constant of 0.005 min⁻¹ at 25 °C and an activation energy of 70 kJ/mol. Find the rate constant k2 at 50 °C.

k1 = 0.005 min⁻¹T1 = 25 °CT2 = 50 °CEa = 70 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹
6.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.250.002run 20.50.008n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.25 mol/L the rate is 0.002 mol/(L·s); with CA0 = 0.5 mol/L it is 0.008 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.25 mol/Lr1 = 0.002 mol/(L·s)CA0,2 = 0.5 mol/Lr2 = 0.008 mol/(L·s)
n =

Answer key

  1. 1. CA = 0.75 mol/L
  2. 2. CA = 0.4038 mol/L
  3. 3. CA = 0.03846 mol/L
  4. 4. t = 2.31 min
  5. 5. k2 = 0.04444 min⁻¹
  6. 6. n = 2

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