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/C₀t½​ = 120 min0.5

A first-order reaction has a half-life of 120 min. Find its rate constant k.

t½ = 120 min
k = min⁻¹
2.Easy
t (min)C (mol/L)60 minC = ?

A first-order reaction A → products has a rate constant of 0.025 min⁻¹. The initial concentration of A is 2 mol/L. Find the concentration CA after 60 min.

k = 0.025 min⁻¹CA0 = 2 mol/Lt = 60 min
CA = mol/L
3.Medium
t (min)X (%)t = ?50%

A second-order reaction (−rA = k·CA²) in a batch reactor has k = 1 L/(mol·min) and starts at 1.5 mol/L. How long does it take to reach 50% conversion? Find t.

k = 1 L/(mol·min)CA0 = 1.5 mol/LX = 50 %
t = min
4.Medium
t (min)X (%)t = ?60%

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 60% conversion? Find t.

k = 0.25 L/(mol·min)CA0 = 1.5 mol/LX = 60 %
t = min
5.Hard
CA0​ (mol/L)r (mol/(L·s))run 10.250.008run 210.512n = ?

Two experiments measure the initial rate of A → products. With CA0 = 0.25 mol/L the rate is 0.008 mol/(L·s); with CA0 = 1 mol/L it is 0.512 mol/(L·s). Find the reaction order n with respect to A.

CA0,1 = 0.25 mol/Lr1 = 0.008 mol/(L·s)CA0,2 = 1 mol/Lr2 = 0.512 mol/(L·s)
n =
6.Hard
1/Tln kT = 100 °Cln 0.002ln A = ?Ea​ = 40 kJ/mol

A first-order reaction has a rate constant of 0.002 s⁻¹ at 100 °C and an activation energy of 40 kJ/mol. Find the pre-exponential factor A in the Arrhenius equation.

k = 0.002 s⁻¹T = 100 °CEa = 40 kJ/molR = 8.314 J/(mol·K)
A = s⁻¹

Answer key

  1. 1. k = 0.005776 min⁻¹
  2. 2. CA = 0.4463 mol/L
  3. 3. t = 0.6667 min
  4. 4. t = 4 min
  5. 5. n = 3
  6. 6. A = 795.3 s⁻¹

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