Question

A second-order reaction has a rate constant of 7.0 x 10^-4 /(M ⋅ s) at 30.°C. At 40.°C, the rate constant is 2.2 x 10^-3 /(M ⋅ s). What are the activation energy and frequency factor for this reaction? Predict the value of the rate constant at 45°C.

Activation energy = ----------- kJ/mol

Frequency factor = -------------- /(M ⋅ s)

Rate constant =-------------- /(M ⋅ s)

Answer 1

Arrhenius equation is

Here rate constant at

And rate constant at

ideal gas constant

is energy of activation.

Substitute values in Arrhenius equation

Hence, the activation energy is 90.3 kJ/mol.

Arrhenius equation is

Rearrange above equation

Substitute values for 30. deg C

Hence, frequency factor

At 45 deg C or

Arrhenius equation is

Hence, the rate constant at 45 deg C is