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

The reaction A + B → C follows the rate law r = k·C_B, with k = 0.02 s⁻¹. Find the reaction rate r when C_A = 0.4 mol/L and C_B = 0.2 mol/L.

r = k·C_Bk = 0.02 s⁻¹C_A = 0.4 mol/LC_B = 0.2 mol/L

r = mol/(L·s)

2.Easy

A first-order reaction has a half-life of 10 min. Find its rate constant k.

t_½ = 10 min

k = min⁻¹

3.Medium

A reaction with rate law −r_A = k·C_A² has k = 1 L/(mol·min) and starts at 0.5 mol/L. Find the concentration C_A after 2 min.

k = 1 L/(mol·min)C_A0 = 0.5 mol/Lt = 2 min

C_A = mol/L

4.Medium

In a first-order reaction the concentration of A falls from 1.5 mol/L to 0.3 mol/L in 60 min. Find the rate constant k.

C_A0 = 1.5 mol/LC_A = 0.3 mol/Lt = 60 min

k = min⁻¹

5.Hard

Two experiments measure the initial rate of A → products. With C_A0 = 0.25 mol/L the rate is 0.02 mol/(L·s); with C_A0 = 0.75 mol/L it is 0.06 mol/(L·s). Find the reaction order n with respect to A.

C_A0,1 = 0.25 mol/Lr₁ = 0.02 mol/(L·s)C_A0,2 = 0.75 mol/Lr₂ = 0.06 mol/(L·s)

n =

6.Hard

A first-order reaction has k = 0.01 min⁻¹ at 25 °C and an activation energy of 70 kJ/mol. The batch reactor is now run at 35 °C for 10 min. Find the conversion X reached.

k₁ = 0.01 min⁻¹T₁ = 25 °CE_a = 70 kJ/molT₂ = 35 °Ct = 10 minR = 8.314 J/(mol·K)

X = %

Answer key

1. r = 0.004 mol/(L·s)
2. k = 0.06931 min⁻¹
3. C_A = 0.25 mol/L
4. k = 0.02682 min⁻¹
5. n = 1
6. X = 22.12 %

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