posted by Anon .
Sodium sulfate is slowly added to a solution containing 0.0500 M Ca^2+ (aq) and 0.0390 M Ag^+ (aq). What will be the concentration of Ca^2+ (aq) when Ag2SO4(s) begins to precipitate?
What percentage of the Ca^2+ (aq) can be separated from the Ag^+ (aq) by selective precipitation?
You need to provide Ksp of each. I have those but all texts don't agree. I may use different ones than you have.
Just take the coeffficients to be the divisors of the denominator. Then take the reciprocal, divide by the lattice energy of the molar solubility, and you've got your solution!