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)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.025 min⁻¹. Find its half-life t½.

k = 0.025 min⁻¹
t½ = min
2.Easy
t (min)C/C₀ (%)5 min?

A first-order reaction has a half-life of 10 min. What percentage f of the reactant is still left after 5 min?

t½ = 10 mint = 5 min
f = %
3.Medium
t (min)C (mol/L)30 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.2 L/(mol·min) and starts at 0.5 mol/L. Find the concentration CA after 30 min.

k = 0.2 L/(mol·min)CA0 = 0.5 mol/Lt = 30 min
CA = mol/L
4.Medium
t (min)C (mol/L)15 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.1 L/(mol·min) and starts at 1.5 mol/L. Find the concentration CA after 15 min.

k = 0.1 L/(mol·min)CA0 = 1.5 mol/Lt = 15 min
CA = mol/L
5.Hard
Tk25 °Ck1​?2·k1​

A reaction has an activation energy of 100 kJ/mol. At 25 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 2 times faster?

Ea = 100 kJ/molT1 = 25 °Ck2/k1 = 2R = 8.314 J/(mol·K)
T2 = °C
6.Hard
1/Tln kT = 60 °Cln 0.001ln A = ?Ea​ = 50 kJ/mol

A first-order reaction has a rate constant of 0.001 s⁻¹ at 60 °C and an activation energy of 50 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.001 s⁻¹T = 60 °CEa = 50 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹

Answer key

  1. 1. t½ = 27.73 min
  2. 2. f = 70.71 %
  3. 3. CA = 0.125 mol/L
  4. 4. CA = 0.4615 mol/L
  5. 5. T2 = 30.21 °C
  6. 6. A = 69150 s⁻¹

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