What is the molar solubility of calcium phosphate, given that K_sp = 2.0 × 10^–33?

Assuming that the density of the saturated solution is 1.00 g/cm³, what is the solubility in grams of Ca₃(PO₄)₂ per 100 grams of solvent?

Strategy This problem asks us to find the equilibrium concentration of ions in a saturated solution. So it is actually similar to problems we solved earlier in this chapter. Hence we will use the same general approach. To find molar solubility, begin by creating an equilibrium table for a solution with unknown equilibrium concentrations and solve the resulting equilibrium expression for the unknown. Convert the concentration units to grams of solute per 100 grams of solvent, using the molar mass of the solute and the density of the solution. (Because the solution will be very dilute, we will assume that there is no significant difference between 100 g of solution and 100 g of solvent.)