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### Topic: Conservation of Mass problems (Equation Derivations)  (Read 8251 times)

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#### iclaudia

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##### Conservation of Mass problems (Equation Derivations)
« on: October 19, 2004, 03:50:11 AM »
Hello  I am taking an intermediate level analytical chemistry course...

right now we are doing acid-base equilibria..

my professor seems to be emphasizing equation derivations with various equilibrium constants...and alpha fractions..

what is the best way....or rather..is there a really great method out there to do these derivations with success?

It seems that my algebra skills still get me stuck through certain points of the derivations...like I'm not sure which variable needs to be substituted with another rearranged equation from somewhere else...

so please..if anyone can point me in the right direction?  Perhaps refer a good textbook source ?  or some study guide?

I need to nail this stuff before the 16th of November!

Thanks much--
Stephanie

#### Mitch

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##### Re:Conservation of Mass problems (Equation Derivations)
« Reply #1 on: October 19, 2004, 08:59:09 PM »
Give an example and we'll work through it with you.
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#### iclaudia

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##### Re:Conservation of Mass problems (Equation Derivations)
« Reply #2 on: October 20, 2004, 01:54:17 AM »
Here is a good problem (hopefully):

What is the pH of a 1.0 (greek xi symbol) 10^-5 M solution of a tetraprotic acid with pK1 = 1.00, pK2 = 1.50, pK3 = 5.00, and pK4 = 10.00?  Try to use early assumptions in the derivation of your equation to simplify the algebra, but remember to test every assumption you make.

This is a practice problem that my professor handed out.  I really have no idea where to start...