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Topic: activation energy with catalyst  (Read 2153 times)

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Offline Judau

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activation energy with catalyst
« on: February 11, 2012, 11:59:19 PM »
I don't know how to find the difference in activation energy between no catalyst and catalyst added, and the steps to calculate it from Arrhenius equation.
 k = Ae^-E_a/RT rearranged to  ln k = -Ea/RT+ lnA (like y = mx + b)

I need to find Ea-Eac
                      (NH2)2CO2(aq) + H2O(l):rarrow: CO2(g) + 2NH3(g)
No catalyst:   4.15 * 10-5 (s-1) @ 373K ,first order
With catalyst: 3.4 * 104  (s-1) @ 294K , first order

Assume the collision factor is the same for both.

I started by converted it to table of ln k vs 1/T
1/T        ln k
.00268  -10.1   (No catalyst)
.00340   10.4   (with catalyst)

so i tried to plug in individually to find the Ea for the slope, referring to y=mx+b, m = -Ea/R :rarrow: Ea= -m (R)
Ea = -(-10.1/.00268) (.008314 kJ/mol*K)  =  2.25 *10^-4 kJ/ mol
Eac = -(10.4/.00340) (.008314 kJ/mol*K)  = ..

and then I m bananaz , answer is 64.0 kJ...
how do I calculate it?
 


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