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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Chiram on February 07, 2009, 01:13:01 PM

Title: Mass balance equation, and problem doing first step.
Post by: Chiram on February 07, 2009, 01:13:01 PM
I got a Balance reaction problem here and I can't quite figure out the mass balance equation and the first step in calculation. My problem is this:

The equilibrium constant for formation of CuCl2- is given by:
Cu+ + 2Cl-  ::equil:: CuCl2- , ksp = 3,2E5

What is the solubility of CuCl in a solution having an analytical NaCl concentration of 1.0e-2M?

I started writing down all the balance equations and ksp's.

CuCl  ::equil:: Cu+ + Cl- , ksp = 1.9E-7
NaCl  ::equil:: Na+ + Cl- , ksp = 38.65
2H2O  ::equil:: H3O+ + OH- , ksp = 1.0E-14

Some equation missing ?

I'm not sure what the mass balance equation should be, I think it would be rather complex, can anybody help and knows what my first step should be, because often in these diffucult Balance reaction problems you just need to find the first step and then your on a roll :). Often aproximations are needed, but first i need the mass balance equation.








Title: Re: Mass balance equation, and problem doing first step.
Post by: Borek on February 07, 2009, 03:26:45 PM
Are you sure you need it? ICE table will be enough. Water and Na+ can be neglected.
Title: Re: Mass balance equation, and problem doing first step.
Post by: Chiram on February 07, 2009, 06:59:30 PM
Ice table, what are meaning by that...
Title: Re: Mass balance equation, and problem doing first step.
Post by: ARGOS++ on February 07, 2009, 07:06:23 PM

Dear Chiram;

Could this be of some help to you?:   http://en.wikipedia.org/wiki/ICE_table

Good Luck!
                    ARGOS++