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# hot to calculate pKw watch

1. I know how to calculate pKa for a weak acid,eg CH3COOH. it's the pH when [CH3COO]= [CH3COOH], half way to the straight part of the titration curve.(not half way in the straight part of the curve) but what about pKw, is it the pH for the [H] when Kw =[OH], or is it just the pH, that is the pH for the [H] when [H]= Kw/[OH]. which one is it? by analogy i think it is that when Kw =[OH]?
2. isnt it always 14
3. i thinks pkW = 14 - pOH??

not too sure tough
4. pKw is -log of Kw....? Kw is always 1x10^-14 at RTP
5. so it is 14 yea...pKw = pH + pOH
i thinks pkW = 14 - pOH??

not too sure tough
thats pH uve calculated there
7. (Original post by mackin boi)
so it is 14 yea...pKw = pH + pOH

Kw = [H+] * [OH-]

So to find pH (of a base of known conc)....

[H+] = Kw / [OH-]

Then pH = -log [H+]

You just assume that of all the OH- ions in solution, they all come from the base and none come from water dissociating
8. pKw = -log Kw
Kw = 10 ^-pKw

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