Question

A certain first order reaction has a rate constant of 5.68 x 10–3 s–1 at 139°C and a rate constant of 8.99 x 10–1 s–1 at a temperature of 215°C.

Ea = 111 kJ mol–

q1) What is the value of the rate constant at 275°C?

q2) At what temperature does the rate constant have a value of 7.87 x 10–4 s–1?

I don't require the answer as i have it just the working out, i can't get to the answer for some reason.

Answer 1

Have you used the Arrhenius equation? Show your work; perhaps we can find the error.

Answer 2

lnK = -Ea/R (1/T) + lnA

lnK = -111000/8.314 (1/548.15) + lnA

so i've tried different things however given im provided with two rate constants and two temperatures im not sure which to use and also i don't have an A value. At first i tried to input one set of data and then find A corresponding and then find K but it doesnt work.

I tried to find A first and then find K but im not getting the right answer in the end
which is supposed to be 18.2s.