Asked by santoki

The rate constant of a first-order reaction is 4.25 x 10^-4 s^-1 at 350 Celsius. If the activation energy is 103 kJ/mol, calculate the temperature at which its rate constant is 8.75 x 10^-4 s^-1.
Answered by DrBob222
Use the Arrhenius equation.
Answered by santoki
I got 17 Kelvin in the end. Does that mean my final answer will be 290 C (converted C to K)?
Answered by DrBob222
I don't think so.
273 + C = K
273 + C = 17
C = ? not 290??
Second think I notice is that your calculated temperature decreased. k2 is about double k1 so wouldn't you think T would be higher. Did you convert kJ/mol to J/mol? That's a common error.
Answered by DrBob222
In fact, a rule of thumb in the kinetics business is that reaction rate can be doubled for every 10 degrees T. Since this ratio k2/k1 = about 2.05 I would guess T2 would be close to 365 or something like that.
Answered by santoki
ah you are right DrBob222. I converted kJ to J.
Answered by DrBob222
Just to be sure we're on the same page my post could be misinterpreted. You are SUPPOSED to convert kJ/mol to J/mol. Using kJ/mol won't work.
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