Question

For a given reaction, the rate constant doubles when the temperature is increased from 27 o C to 49 o C. What is the activation energy?

Answer 1

We like for you not to use multiple screen names.
Use the Arrhenius equation.
Use k1 = k1 or choose any convenient number (like 1).
Then k2 = 2k1 or twice the number you choose (use 2 if you used k1 = 1)
Remember to use K for temperature.

Answer 2

T1= 27+273.15=300.15K
T2=90+273.15=363.15 K

In(1/300.15)-(2/363.15)= 5.709???? Did I get it?

Answer 3

No. I suggest you look up the Arrhenius equation and use it. Where is Ea? Where is R? Which R will you use? You have T1 and T2 right but no where in the Arrhenius equation do you take ln (1/T1 - 1/T2)