I am completely stuck on a couple of questions and would like a bit of help on these.(adsbygoogle = window.adsbygoogle || []).push({});

First one. This I have no idea where to even start and I can't find anything on it in my text either. So maybe a formula or point me in the right direction would help.

Calculate the fraction of atoms in a sample of argon gas at 400 K that have an energy of 12.5 kJ or greater.

This one is a bit easier. I am not 100% sure on how to do it, but I did guess this one right.:rofl:

The question is:

The activation energy of a certain reaction is 76.7 kJ/mol. How many times faster will the reaction occur at 50°C than at 0°C, assuming equal initial concentrations of reactants?

I used this equation:

[tex]ln k = ln A -\frac {E_a}{RT} [/tex]

I did that for both temps then divided them. I got a close answer to the correct one. The thing I am confused on is the A. My book says that is for the frequency factor when using the Arrhenius equation. I read in Wikipedia that is just the sqrt of the temp. So I did that and it came out close, but I am not sure if that is right. So I really just need to know how you find A.

Thanks for the help.:tongue:

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# Homework Help: A Couple of Kinetics Questions

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