No, not the T. It could be EXCEPT Ksp is given at the T in the problem so that is ok. The problem here, I think, is that you failed to write the equation and because of that you slipped up on a tiny bit of the problem. Here is the dope.
.......Ca(OH)2 --> Ca^2+ + 2OH^-
I......solid........0........0
C......solid........s........2s
E......solid........s........2s
So you are exactly right and your work is great and s is your answer of 0.0105 M to the digit. BUT (OH^-) is 2s so if you will take the -log(2s) you will get the right answer for OH^- and convert that to pH.
Thanks for showing your work. It really helps us figure what's wrong.
The Ksp of calcium hydroxide, Ca(OH)2, is 4.68 x 10-6 at 289.15K. Calculate the pH of a saturated solution.
Here's my work:
4.68 x 10-6= 4s^3
s= 0.0105
-log(0.0105)= 1.98
14-1.98=12.02
The answer is supposed to be 12.324, but I'm not sure what I'm doing wrong. Is it because it is not at 25C? Please help!
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