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/C₀ (%)45 min?

A first-order reaction has a half-life of 15 min. What percentage f of the reactant is still left after 45 min?

t½ = 15 mint = 45 min
f = %
2.Easy
t (min)C/C₀ (%)7.5 min?

A first-order reaction has a half-life of 15 min. What percentage f of the reactant is still left after 7.5 min?

t½ = 15 mint = 7.5 min
f = %
3.Medium
t (min)X (%)t = ?95%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 0.25 L/(mol·min) and starts at 1.5 mol/L. How long does it take to reach 95% conversion? Find t.

k = 0.25 L/(mol·min)CA0 = 1.5 mol/LX = 95 %
t = min
4.Medium
t (min)X (%)t = ?90%

A first-order reaction in a batch reactor has k = 0.3 min⁻¹. How long does it take to reach 90% conversion? Find t.

k = 0.3 min⁻¹X = 90 %
t = min
5.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.20.012run 20.80.192n = ?

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 = 0.8 mol/L it is 0.192 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 = 0.8 mol/Lr2 = 0.192 mol/(L·s)
n =
6.Hard
t (min)X (%)30 minX = ?

A first-order reaction has k = 0.01 min⁻¹ at 20 °C and an activation energy of 50 kJ/mol. The batch reactor is now run at 40 °C for 30 min. Find the conversion X reached.

k1 = 0.01 min⁻¹T1 = 20 °CEa = 50 kJ/molT2 = 40 °Ct = 30 minR = 8.314 J/(mol·K)
X = %

Answer key

  1. 1. f = 12.5 %
  2. 2. f = 70.71 %
  3. 3. t = 50.67 min
  4. 4. t = 7.675 min
  5. 5. n = 2
  6. 6. X = 67.11 %

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