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)45 minC = ?

A first-order reaction A → products has a rate constant of 0.02 min⁻¹. The initial concentration of A is 0.5 mol/L. Find the concentration CA after 45 min.

k = 0.02 min⁻¹CA0 = 0.5 mol/Lt = 45 min
CA = mol/L
2.Easy
t (min)C (mol/L)10 minC = ?

A first-order reaction A → products has a rate constant of 0.1 min⁻¹. The initial concentration of A is 0.8 mol/L. Find the concentration CA after 10 min.

k = 0.1 min⁻¹CA0 = 0.8 mol/Lt = 10 min
CA = mol/L
3.Medium
t (min)C (mol/L)10 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.8 L/(mol·min) and starts at 1.5 mol/L. Find the concentration CA after 10 min.

k = 0.8 L/(mol·min)CA0 = 1.5 mol/Lt = 10 min
CA = mol/L
4.Medium
t (min)C (mol/L)t½​ = ?C0​/2

A second-order reaction (−rA = k·CA²) has k = 0.5 L/(mol·min) and an initial concentration of 0.5 mol/L. Find its first half-life t½.

k = 0.5 L/(mol·min)CA0 = 0.5 mol/L
t½ = min
5.Hard
1/Tln kT = 50 °Cln 0.01ln A = ?Ea​ = 100 kJ/mol

A first-order reaction has a rate constant of 0.01 s⁻¹ at 50 °C and an activation energy of 100 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.01 s⁻¹T = 50 °CEa = 100 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹
6.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.250.02run 20.750.54n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.25 mol/L the rate is 0.02 mol/(L·s); with CA0 = 0.75 mol/L it is 0.54 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.25 mol/Lr1 = 0.02 mol/(L·s)CA0,2 = 0.75 mol/Lr2 = 0.54 mol/(L·s)
n =

Answer key

  1. 1. CA = 0.2033 mol/L
  2. 2. CA = 0.2943 mol/L
  3. 3. CA = 0.1154 mol/L
  4. 4. t½ = 4 min
  5. 5. A = 1.461 × 10¹⁴ s⁻¹
  6. 6. n = 3

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