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 0.01 min⁻¹. Find its half-life t½.

k = 0.01 min⁻¹
t½ = min
2.Easy
t (min)C (mol/L)5 minC = ?

A first-order reaction A → products has a rate constant of 0.25 min⁻¹. The initial concentration of A is 0.8 mol/L. Find the concentration CA after 5 min.

k = 0.25 min⁻¹CA0 = 0.8 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 = 0.2 L/(mol·min) and an initial concentration of 0.2 mol/L. Find its first half-life t½.

k = 0.2 L/(mol·min)CA0 = 0.2 mol/L
t½ = min
4.Medium
t (min)C (mol/L)t½​ = ?C0​/2

A second-order reaction (−rA = k·CA²) has k = 0.2 L/(mol·min) and an initial concentration of 0.5 mol/L. Find its first half-life t½.

k = 0.2 L/(mol·min)CA0 = 0.5 mol/L
t½ = min
5.Hard
Tk25 °Ck1​?3·k1​

A reaction has an activation energy of 40 kJ/mol. At 25 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 3 times faster?

Ea = 40 kJ/molT1 = 25 °Ck2/k1 = 3R = 8.314 J/(mol·K)
T2 = °C
6.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.20.012run 20.40.048n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.2 mol/L the rate is 0.012 mol/(L·s); with CA0 = 0.4 mol/L it is 0.048 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.2 mol/Lr1 = 0.012 mol/(L·s)CA0,2 = 0.4 mol/Lr2 = 0.048 mol/(L·s)
n =

Answer key

  1. 1. t½ = 69.31 min
  2. 2. CA = 0.2292 mol/L
  3. 3. t½ = 25 min
  4. 4. t½ = 10 min
  5. 5. T2 = 46.78 °C
  6. 6. n = 2

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