if the activation energy for a given compound is found to be 10 kJ/mol, with a frequency factor of 4.0x10^13 s-1, what is the rate constant for this reaction at 398K?

Answer 1

k = Ae^(-Ea/RT)
You can read more about it here.
http://en.wikipedia.org/wiki/Arrhenius_equation

Answer 2

I should have written E^a as E_a. Ea is the activation energy.