Chemical Forums
Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Thorr on August 08, 2007, 11:51:33 AM
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Hello,
I'm an post-grad medical student (this is not a homework problem) and I'm doing some research that lead to an interesting question in physical chemistry. Now I've had basic physical chemistry a few years back but this question is a bit over my head. I hope it is not to involved and I can at least get some pointers here on how to start writing down equations.
I've created a drawing that will better illustrate what the problem is, take a look.
The gist of the dillema is as follows:
- Say you have a container of size d filled with a water solution of a certain ionic species with the general form: AaBb. The compound has a dissociation constant of K = (A)a(B)b/(AB) at a certain temperature T and the total concentration (dissolved and undissolved together) of the compound is c
- You apply an outside electric field of strength E to the solution and the question is what the ion distributions will be.
Obviously the positively charged ions will flow and gather in the direction the electric field is pointing and vice versa for the negatively charged ions.
What I would need are two functions telling me how the concentration of A changes in relation to x (that goes form 0 to d) and the same for the concentration of B.
In the drawing I assumed that A is positive, B negative and E is pointing up - but this is just for the purposes of the picture it does not need to be so.
I know how to solve a much simpler problem that would involve just a single charged species dissolved at a certain concentration. But adding another ion and the dissociation constant complicates it too much and I can't work it out on my own.
Thank you so much for any and all help you can offer!
Cheers