A chemical reaction has an energy of activation Ea = 1∙104 J mol-1 at T = 300 K. The first-order rate constant for this reaction was found to be 15.0 s-1. In the presence of a catalyst, the activation energy is reduced to 1∙103 J mol-1. Calculate the pre-exponential factor in the Arrhenius equation

Respuesta :

Answer : The pre-exponential factor in the Arrhenius equation is, 14.99  s⁻¹

Explanation :

Using Arrhenius equation,

[tex]K=A\times e^{\frac{-Ea}{RT}}[/tex]

Taking ln on both the sides, we get:

[tex]\ln K=\frac{-Ea}{RT}+\ln A[/tex]

where,

K = rate constant = [tex]15.0s^{-1}[/tex]

Ea = activation energy = 1.104 J/mol

T = temperature = 300 K

R = gas constant = 8.314 J/mole.K

A = Arrhenius constant

Now put all the given values in the above formula, we get the value of \ln a.

[tex]\ln (15.0s^{-1})=\frac{1.104J/mol}{(8.314J/mole.K)\times (300K)}+\ln A[/tex]

[tex]\ln A=2.708s^{-1}[/tex]

[tex]A=14.99s^{-1}[/tex]

Therefore, the pre-exponential factor in the Arrhenius equation is, 14.99  s⁻¹