Question

The rate constant for the first order decomposition of H₂O₂ is given by the following equation:

log k = 14.34 − 1.25 × 10⁴ K/T

Calculate E_a for this reaction and at what temperature will its half-period be 256 minutes?

Answer 1

Arrhenius equation is given by,

The given equation is

From equation (i) and (ii), we obtain

= 1.25 × 10⁴ K × 2.303 × 8.314 J K⁻¹ mol⁻¹

= 239339.3 J mol⁻1 (approximately)

= 239.34 kJ mol⁻¹

Also, when t_1/2 = 256 minutes,

= 2.707 × 10⁻³ min⁻¹

= 4.51 × 10⁻⁵ s⁻¹

It is also given that, log k = 14.34 − 1.25 × 10⁴ K/T

= 668.95 K

= 669 K (approximately)