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Saterial
Jan26-11, 08:56 PM
1. The problem statement, all variables and given/known data
At 35C, the rate constant for the reaction: C12H22O11 + H20 --> C6H12O6 + C6H12O6 is k=6.2 x 10^-5 s-1. The activation energy for the reaction is 108 kJ/mol. What is the rate constant for the reaction at 45C? Determine the impact on the rate.


2. Relevant equations
r=Ae^-Ae/RT
r=k[C12H22O11][H2O]

3. The attempt at a solution

I don't know if I am even using the right equation, (Arrhenius equation) however I tried seperating the reaction into 35C and 45C stages and analyzed from there. At 35C, Ae is given so I plugged the Ae into the Arrhenius eq at 45C and cancel out the A base as it is the same at both 35C and 45C.

Ended up with :
r=e^(-108000/8.314*10). (change in temp of 10C)

Does this make any sense or even work? If so, what does the second part of impact on the rate mean?

Thanks a bunch.

Borek
Jan27-11, 10:04 AM
What you found is ratio of rates, not rate. Use data for 35 deg C to find A, then just plug and chug for 45 deg C.

MikeyA
Jan27-11, 06:20 PM
Also, given that the constant is given by J/Mol K, I would have thought you were supposed to use Kelvins instead of degrees Celsius.

Borek
Jan28-11, 02:11 AM
When it comes to delta T it doesn't matter. A lot depends on how Saterial got to the expression shown.

MikeyA
Jan28-11, 09:33 AM
When it comes to delta T it doesn't matter. A lot depends on how Saterial got to the expression shown.

Ah. Missed we were using delta.