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.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
t (min)C (mol/L)t½​ = ?C0​/2

A first-order reaction has a rate constant of 0.2 min⁻¹. Find its half-life t½.

k = 0.2 min⁻¹
t½ = min
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)X (%)t = ?40%

A zero-order reaction has k = 0.05 mol/(L·min) and starts at 1.5 mol/L. How long does it take to reach 40% conversion? Find t.

k = 0.05 mol/(L·min)CA0 = 1.5 mol/LX = 40 %
t = min
4.Medium
t (min)C (mol/L)5 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.25 L/(mol·min) and starts at 2 mol/L. Find the concentration CA after 5 min.

k = 0.25 L/(mol·min)CA0 = 2 mol/Lt = 5 min
CA = mol/L
5.Hard
Tk20 °Ck1​?5·k1​

A reaction has an activation energy of 50 kJ/mol. At 20 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 5 times faster?

Ea = 50 kJ/molT1 = 20 °Ck2/k1 = 5R = 8.314 J/(mol·K)
T2 = °C
6.Hard
Tk25 °C0.155 °C?

A reaction has a rate constant of 0.1 min⁻¹ at 25 °C and an activation energy of 50 kJ/mol. Find the rate constant k2 at 55 °C.

k1 = 0.1 min⁻¹T1 = 25 °CT2 = 55 °CEa = 50 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹

Answer key

  1. 1. t½ = 3.466 min
  2. 2. t½ = 4.621 min
  3. 3. t = 12 min
  4. 4. CA = 0.5714 mol/L
  5. 5. T2 = 44.96 °C
  6. 6. k2 = 0.6322 min⁻¹

Full step-by-step solutions: practise this topic on examproblems.com.