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 0.25 min⁻¹. Find its half-life t½.

k = 0.25 min⁻¹
t½ = min
2.Easy
t (min)C/C₀t½​ = 40 min0.5

A first-order reaction has a half-life of 40 min. Find its rate constant k.

t½ = 40 min
k = min⁻¹
3.Medium
t (min)C (mol/L)15 minC = ?

A reaction with rate law −rA = k·CA² has k = 0.8 L/(mol·min) and starts at 2 mol/L. Find the concentration CA after 15 min.

k = 0.8 L/(mol·min)CA0 = 2 mol/Lt = 15 min
CA = mol/L
4.Medium
t (min)C (mol/L)t½​ = ?C0​/2

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

k = 0.5 L/(mol·min)CA0 = 0.5 mol/L
t½ = min
5.Hard
t (min)X (%)20 minX = ?

A first-order reaction has k = 0.005 min⁻¹ at 30 °C and an activation energy of 90 kJ/mol. The batch reactor is now run at 60 °C for 20 min. Find the conversion X reached.

k1 = 0.005 min⁻¹T1 = 30 °CEa = 90 kJ/molT2 = 60 °Ct = 20 minR = 8.314 J/(mol·K)
X = %
6.Hard
Tk30 °C0.0545 °C?

A reaction has a rate constant of 0.05 min⁻¹ at 30 °C and an activation energy of 40 kJ/mol. Find the rate constant k2 at 45 °C.

k1 = 0.05 min⁻¹T1 = 30 °CT2 = 45 °CEa = 40 kJ/molR = 8.314 J/(mol·K)
k2 = min⁻¹

Answer key

  1. 1. t½ = 2.773 min
  2. 2. k = 0.01733 min⁻¹
  3. 3. CA = 0.08 mol/L
  4. 4. t½ = 4 min
  5. 5. X = 91.72 %
  6. 6. k2 = 0.1057 min⁻¹

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