Chemical Forums

Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: owsik on May 01, 2014, 01:51:37 PM

Title: Collision theory, Activation energy and pre-exp factor.
Post by: owsik on May 01, 2014, 01:51:37 PM

Hello, it's me again.
I know you do not solve homeworks etc.
But all I'm asking for is just to show me correct formula, since I'm dumb and I cannot come up with anything relatively useful.

So questions is:
The rate constant for the biomolecular gas-phase reaction:

CO + O₂ :rarrow:CO₂ + O

is 1.22 x10⁵ dm³mol^-1s^-1 at 2500K, and is equal 3.66 x10⁵ dm³mol^-1s^-1 at 2800K. Calculate the value of the activation energy and pre-exponential factor for the reaction.

So, I'm aware of formula that consist Steric factor and activation energy, however I do not know how am I supposed to relate them both rates and temperatures??

Any hints, most welcome,

Regards

Owsik

Title: Re: Collision theory, Activation energy and pre-exp factor.
Post by: Corribus on May 01, 2014, 02:53:41 PM

You have two temperatures and two rate constants, and two unknowns. Is there an equation you know of that relates A to Ea as a function of T and the rate constant, for which you can set up a system of two equations of two unkonwns?

Title: Re: Collision theory, Activation energy and pre-exp factor.
Post by: owsik on May 01, 2014, 03:01:05 PM

That's the problem, I don't know this kind of equation.
I do know Equation that relates ONE pre-exp factor, and ONE temperature.
https://www.dropbox.com/s/x8gbuxodk55epeg/WP_20140501_005.jpg

Title: Re: Collision theory, Activation energy and pre-exp factor.
Post by: Corribus on May 01, 2014, 03:17:12 PM

Right, basically Arrhenius equation: http://en.wikipedia.org/wiki/Arrhenius_equation

Do you know how to solve two equations for two unknowns?

Title: Re: Collision theory, Activation energy and pre-exp factor.
Post by: owsik on May 08, 2014, 06:21:26 AM

cheers I've done this one