The rate constant for the decomposition of hydrocarbons is 2.418 × 10–5s–1 at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor.


Given,


k = 2.418 × 10-5 s-1


T = 546 K


Ea = 179.9 kJ mol-1 = 179.9 × 103J mol-1


The Arrhenius equation is given by k = Ae-Ea/RT


Taking natural log on both sides,


Ln k = ln A-(Ea/RT)


Substituting the values,


ln(2.418 × 10-5 ) = ln A-179.9/(8.314 × 546)


ln A = 12.5917


A = 3.9 × 1012 s-1(approximately)


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