precipitationPrecipitation

A solution of Na2SO4 is added dropwise to a solution that is 0.0295M in Ba 2+ and 0.0295 M in Sr 2+. What concentration of SO4 2- is necessary to begin precipitation? (neglect volume. BaSO4: Ksp = 1.1 E-10 , SrSO4 : Ksp = 3.2 E-7

Calcium chloride, CaCl2, is added to 3.0 L of 0.050 M K2SO4 until a precipitate forms. How many grams of CaCl2 were added? Assume the volume of the solution is not changed significantly by the addition of the CaCl2. Ksp CaSO4 = 2.4 x 10-5