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Chemical Kinetics

Question

The rate constant for the first order decomposition of H₂O₂ is given by the following equation:
log k = 14.34 – 1.25 x 10⁴ k/T
Calculate E_afor this reaction and at what temperature will its half period be 256 minutes.

Solution

Using arrhenius equation

\log K = \log A - \frac{E_{a}}{2.303 R} - \frac{1}{T}

Comparing this equation with

\log K = 14.34 - \frac{1.25 \times 10^{4} K}{T} gives \frac{E_{a}}{2.303 R} = 1.25 \times 10^{4} K E_{a} = 1.25 \times 10^{4} K \times 2.303 \times 8.314 J {mol}^{- 1} K^{- 1} or E_{a} = 239.339 J {mol}^{- 1} = 239.339 kJ {mol}^{- 1} .