2. the Solubility of Barium Fluoride, Baf2, in 0.10 M Naf Is 1.7 X 10-4 M. Calculate The

1. A solution is 0.15 M in Pb+2 and 0.20 M in Ag+.

a) If solid Na2SO4 is very slowly added to this solution, which will precipitate first, PbSO4 or Ag2SO4? Neglect volume changes upon addition of the solid, but show all of your work clearly for full credit.

b) The addition of Na2SO4 is continued until the second cation just starts to precipitate as the sulfate. What is the concentration of the first cation at this point?

2. The solubility of barium fluoride, BaF2, in 0.10 M NaF is 1.7 x 10-4 M. Calculate the value of Ksp for BaF2.

3. What percentage of the Ba+2 in solution is precipitated as BaCO3 (s) if equal volumes of 0.0020 M Na2CO3 (aq) and 0.0010 M BaCl2 (aq) are mixed?

4. Consider a solution containing 0.020 M Cl¯ and 0.010 M CrO4-2 ions to which Ag+ ions are added slowly. Which precipitate forms first: AgCl or Ag2CrO4? No guessing, your answer must be theoretically sound.

Ksp(AgCl) = 1.8 x 10-10 and Ksp(Ag2CrO4) = 9.0 x 10-12.

5. A solution contains 0.070 M Ca+2 and 0.070 M Mg+2. Is it possible to precipitate 99.9% of the Ca+2 ions as CaCO3 without precipitating MgCO3? You must convince me of your answer.

6. A solution contains 0.045 M SO4-2. Calcium chloride is added to precipitate calcium sulfate.

a) At what concentration of Ca+2 does a precipitate first start to form?

b) Calculate [Ca+2] when 35% of the SO4-2 originally present in the solution remains.

7. Calculate the molar solubility of MgF2 in a 0.10 M NaF solution at 25 C.

8. What compound, if any, will precipitate when 80 ml of 1.0 x 10-5 M Ba(OH)2 is added to 20 ml of 1.0 x 10-5 M Fe2(SO4)3? OK, so something does precipitate. What will be the ion concentration of the one that does precipitate once equilibrium is reached?

9. A salt whose formula is of the form MX has a value of Ksp = 3.2 x 10-10. What value of Ksp must another salt, M’X3 have if the molar solubility of the two salts are to be identical?

10. The Ksp for zinc carbonate is 5.5 x 10-11. If I mix 100 ml of 0.1 M zinc nitrate and 100 ml of 0.2 M sodium carbonate, what are the equilibrium concentrations of all species at equilibrium?

11. In principle, the ions Ba2+ and Ca2+ can be separated by the difference in solubility of their fluorides, BaF2 and CaF2. If you have a solution that is 0.10 M in both Ba2+ and Ca2+, CaF2 will begin to precipitate first as the fluoride ion is added slowly to the solution. Show all work clearly for each part below for full credit.

A. What will be the concentration of the fluoride ion when it precipitates the maximum amount of Ca2+ ion without precipitating BaF2?

B. What concentration of Ca2+ remains in solution when BaF2 just begins to precipitate?