An aqueous solution of sodium fluoride is slowly added to an aqueous solution containing 0.0380 M barium ions and 0.0570 M calcium ions. The K_sp of barium fluoride is 1.0 times 10^-8, the K_sp of calcium fluoride is 3.9 times 10^-11. After determining which ion (barium or calcium) begins to precipitate first, calculate how much of this ion is still dissolved in solution when the second ion begins to precipitate.
