The solution for this problem is: Get into moles first. .0560 grams over 540.8 grams per mole = 1.04 x l0^-4 moles Sr3(As04)2 = 3 Sr++(aq) plus 2 As04^-3(aq) Ksp = (Sr++)^3(As04^-3)^2 (Sr++) = 3 X 1.04 x l0^-4= 3.11 x l0^-4 (As04^-3) = 2 x 1.04 x l0^-4= 2.07 x l0^-4 Ksp = (1.04 x l0^-4)^3 (2.07 x l0^-4)^2 which equals 4.82 x 10^-20
