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)5 minC = ?

A first-order reaction A → products has a rate constant of 0.25 min⁻¹. The initial concentration of A is 0.5 mol/L. Find the concentration CA after 5 min.

k = 0.25 min⁻¹CA0 = 0.5 mol/Lt = 5 min
CA = mol/L
2.Easy
t (min)C (mol/L)30 minC = ?

A first-order reaction A → products has a rate constant of 0.025 min⁻¹. The initial concentration of A is 1.2 mol/L. Find the concentration CA after 30 min.

k = 0.025 min⁻¹CA0 = 1.2 mol/Lt = 30 min
CA = mol/L
3.Medium
t (min)X (%)t = ?95%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 1 L/(mol·min) and starts at 1 mol/L. How long does it take to reach 95% conversion? Find t.

k = 1 L/(mol·min)CA0 = 1 mol/LX = 95 %
t = min
4.Medium
t (min)X (%)t = ?60%

A zero-order reaction has k = 0.025 mol/(L·min) and starts at 0.5 mol/L. How long does it take to reach 60% conversion? Find t.

k = 0.025 mol/(L·min)CA0 = 0.5 mol/LX = 60 %
t = min
5.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.50.002run 210.004n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.5 mol/L the rate is 0.002 mol/(L·s); with CA0 = 1 mol/L it is 0.004 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.5 mol/Lr1 = 0.002 mol/(L·s)CA0,2 = 1 mol/Lr2 = 0.004 mol/(L·s)
n =
6.Hard
Tk30 °Ck1​?2·k1​

A reaction has an activation energy of 60 kJ/mol. At 30 °C it is too slow. To what temperature T2 (in °C) must it be heated to make it 2 times faster?

Ea = 60 kJ/molT1 = 30 °Ck2/k1 = 2R = 8.314 J/(mol·K)
T2 = °C

Answer key

  1. 1. CA = 0.1433 mol/L
  2. 2. CA = 0.5668 mol/L
  3. 3. t = 19 min
  4. 4. t = 12 min
  5. 5. n = 1
  6. 6. T2 = 39.09 °C

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