Find the concentration of Ca2+, in equilibrium with CaSO4(s) and 0.035 M SO4-2.

Answer 1

I am using Ksp from the web of 4.93E-5. Be sure to use the value for Ksp of CaSO4 in your text or in your notes.
...................CaSO4 ===> Ca^2+ + SO4^2-
I.....................solid...............0...........0
change...........solid..............x.............x
E......................solid..............x............x
Ksp = 4.93E-5 = (Ca^2+)(SO4^2-)
You know Ksp. The problem tells you [SO4]^2- is 0.035 M
Plug in those values and solve for (Ca^2+) and you're done. That wasn't bad was it.

Answer 2

Thank you so much for your help.