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 0.05 min⁻¹. Find its half-life t½.

k = 0.05 min⁻¹
t½ = min
2.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
3.Medium
t (min)C (mol/L)60 min0.4

In a first-order reaction the concentration of A falls from 0.8 mol/L to 0.4 mol/L in 60 min. Find the rate constant k.

CA0 = 0.8 mol/LCA = 0.4 mol/Lt = 60 min
k = min⁻¹
4.Medium
t (min)X (%)t = ?75%

A zero-order reaction has k = 0.05 mol/(L·min) and starts at 2 mol/L. How long does it take to reach 75% conversion? Find t.

k = 0.05 mol/(L·min)CA0 = 2 mol/LX = 75 %
t = min
5.Hard
t (min)X (%)45 minX = ?

A first-order reaction has k = 0.02 min⁻¹ at 30 °C and an activation energy of 60 kJ/mol. The batch reactor is now run at 50 °C for 45 min. Find the conversion X reached.

k1 = 0.02 min⁻¹T1 = 30 °CEa = 60 kJ/molT2 = 50 °Ct = 45 minR = 8.314 J/(mol·K)
X = %
6.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.40.02run 21.60.16n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.4 mol/L the rate is 0.02 mol/(L·s); with CA0 = 1.6 mol/L it is 0.16 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.4 mol/Lr1 = 0.02 mol/(L·s)CA0,2 = 1.6 mol/Lr2 = 0.16 mol/(L·s)
n =

Answer key

  1. 1. t½ = 13.86 min
  2. 2. t½ = 27.73 min
  3. 3. k = 0.01155 min⁻¹
  4. 4. t = 30 min
  5. 5. X = 98.03 %
  6. 6. n = 1.5

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