Activation energy and pre exponential factor

[Diamond101]

Homework Statement

Calculate activation energy and pre exponential factor, i need help with the pre exponential factor

Homework Equations

Temperature °C
-20 = 253 k
-10= 263
0=273
10=283
20=293
Rate const. s-1
1.15
3.85
11.3
28.7
74.0

The Attempt at a Solution

i already plotted the graph on excel . i got ea= -(r * gradient)= -8.314*0.7703*10^4) =64 kj/mol
Pre exponential factor= E^(LN k + ea/RT) ^=E^(4.3+ 64/ 8.314*293 K) =?

 

[Borek]

What's the problem with keying these numbers into the calculator?