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 first-order reaction A → products has a rate constant of 0.02 min⁻¹. The initial concentration of A is 1.5 mol/L. Find the concentration CA after 30 min.

k = 0.02 min⁻¹CA0 = 1.5 mol/Lt = 30 min
CA = mol/L
2.Easy
t (min)C (mol/L)5 minC = ?

A first-order reaction A → products has a rate constant of 0.2 min⁻¹. The initial concentration of A is 0.5 mol/L. Find the concentration CA after 5 min.

k = 0.2 min⁻¹CA0 = 0.5 mol/Lt = 5 min
CA = mol/L
3.Medium
t (min)C (mol/L)t½​ = ?C0​/2

A second-order reaction (−rA = k·CA²) has k = 0.1 L/(mol·min) and an initial concentration of 2 mol/L. Find its first half-life t½.

k = 0.1 L/(mol·min)CA0 = 2 mol/L
t½ = min
4.Medium
t (min)C (mol/L)2 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.5 L/(mol·min) and starts at 0.5 mol/L. Find the concentration CA after 2 min.

k = 0.5 L/(mol·min)CA0 = 0.5 mol/Lt = 2 min
CA = mol/L
5.Hard
1/Tln kT = 40 °Cln 0.01ln A = ?Ea​ = 70 kJ/mol

A first-order reaction has a rate constant of 0.01 s⁻¹ at 40 °C and an activation energy of 70 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.01 s⁻¹T = 40 °CEa = 70 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹
6.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.20.01run 20.60.03n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.2 mol/L the rate is 0.01 mol/(L·s); with CA0 = 0.6 mol/L it is 0.03 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.2 mol/Lr1 = 0.01 mol/(L·s)CA0,2 = 0.6 mol/Lr2 = 0.03 mol/(L·s)
n =

Answer key

  1. 1. CA = 0.8232 mol/L
  2. 2. CA = 0.1839 mol/L
  3. 3. t½ = 5 min
  4. 4. CA = 0.3333 mol/L
  5. 5. A = 4.75 × 10⁹ s⁻¹
  6. 6. n = 1

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