Sciencemadness Discussion Board

I.C.E table help

CaptainOfSmug - 17-3-2014 at 18:55

Hello all! I'm currently refreshing on some general equilibrium problems and am trying to figure out these ice tables... or more I have them figured out but have a question that I can't seem to find in any of my text books or on google (could be poor searches on my part).

Anyways, my real question is when you set up the tables you of course have the
A+B-><-AB
I
C
E

Now, every problem I've worked my E equation is always some value-x for the reactant side of the reaction and value+x on the side of the products. Is this absolutely always true? I've looked online at other examples and it always seems to be the case but it seems rather odd to me.

My thoughts are that it could have something to do with calculating Q and comparing it to K or maybe having to do with the magnitude of K.

Am I over thinking this?

Anyways any help is appreciated!

Thanks in advanacec

DraconicAcid - 17-3-2014 at 19:08

The reaction is going to shift one way or the other- if it shifts to products, then all the reactants will decrease and the products will increase. if it shifts to reactants, then all the products will decrease and the reactants will increase. If you have an initial concentration of zero for one species, then you know it has to increase, along with everything else on that side of the equation.

CaptainOfSmug - 17-3-2014 at 19:33

Thank you very much! I knew I was over thinking that!