posted by Trixie on .
1x10-2 mol of MgSO4 (Ksp = 9) is added to 1 L of water. Will 1x10-5 mol of CaSO4 (Ksp = 10-6) completely dissolve in the solution?
I think the answer is yes...because the Q will be less than Ksp of 10^-6??
Which of the following salts would you expect to result in the greatest freezing point depression if 1 mol were placed in 1 L of water?
A. NaCl Ksp = 36
B. AgCl Ksp = 10-10
C. AgNO3 Ksp = 0.5
D. They would all be the same
I think it would be C because there are more particles...but I am not totally sure..?
Which of the following stresses would NOT result in increased dissolving of Ca(OH)2 in a saturated solution (select all that apply)?
Addition of water
Addition of HCl
Addition of more Ca(OH)2
Addition of Ca(NO3)2
I know the addition of more Ca(OH)2 wouldn't since it's saturated..but I am not sure of the others?
Your response to the first one is correct. The response to the last one is partly correct. The middle one makes no sense to me. I can go through and parse it for you.
The first one is ok.
The second one:
First, what is it with Ksp for NaCl of 36 and Ksp for AgNO3 of 0.5? Hogwash!!! And Ksp for AgCl is correct; however, it is not soluble in 1 L of water (except to the extent of about 1 x 10^-5 M and that isn't much). The correct answer isn't there. NaCl and AgNO3 will have the most effect (both give two particles) while AgCl will have little to no effect since it isn't soluble(it has two particles, too). I suspect the answer is supposed to be D (since all of them have two particles) and the test maker forgot that AgCl isn't that soluble.
For the last one:
You know adding more water will increase the soubility.
YOu know adding HCl will neutralize the Ca(OH)2 and that will increase the solubility.
Adding solid Ca(OH)2 to a saturated solution will not increase the solubility as you have correctly answered.
The last one, I believe, will NOT increase the solubility. In fact, I think it will decrease the solubility. If we take the equilibrium of
Ca(OH)2(s) ==> Ca^+2 + 2OH^-
Adding Ca^+2 from Ca(NO3)2 will shift the equilibrium to the left, thus decreasing the solubility. Since decreasing the solubility is NOT increasing it, I think both C and D are correct.