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)10 minC = ?

A first-order reaction A → products has a rate constant of 0.15 min⁻¹. The initial concentration of A is 0.5 mol/L. Find the concentration CA after 10 min.

k = 0.15 min⁻¹CA0 = 0.5 mol/Lt = 10 min
CA = mol/L
2.Easy
t (min)C (mol/L)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.15 min⁻¹. Find its half-life t½.

k = 0.15 min⁻¹
t½ = min
3.Medium
t (min)C (mol/L)5 minC = ?

A reaction with rate law −rA = k·CA² has k = 1 L/(mol·min) and starts at 0.5 mol/L. Find the concentration CA after 5 min.

k = 1 L/(mol·min)CA0 = 0.5 mol/Lt = 5 min
CA = mol/L
4.Medium
t (min)C (mol/L)5 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.4 L/(mol·min) and starts at 2 mol/L. Find the concentration CA after 5 min.

k = 0.4 L/(mol·min)CA0 = 2 mol/Lt = 5 min
CA = mol/L
5.Hard
1/Tln kT = 40 °Cln 0.005ln A = ?Ea​ = 75 kJ/mol

A first-order reaction has a rate constant of 0.005 s⁻¹ at 40 °C and an activation energy of 75 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.005 s⁻¹T = 40 °CEa = 75 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹
6.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.40.002run 20.80.004n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.4 mol/L the rate is 0.002 mol/(L·s); with CA0 = 0.8 mol/L it is 0.004 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.4 mol/Lr1 = 0.002 mol/(L·s)CA0,2 = 0.8 mol/Lr2 = 0.004 mol/(L·s)
n =

Answer key

  1. 1. CA = 0.1116 mol/L
  2. 2. t½ = 4.621 min
  3. 3. CA = 0.1429 mol/L
  4. 4. CA = 0.4 mol/L
  5. 5. A = 1.621 × 10¹⁰ s⁻¹
  6. 6. n = 1

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