Consider the reaction

CaSO4(s)rightleftharpoons Ca^2+(aq)+ SO_4^2-(aq)
At 25 C the equilibrium constant is Kc = 2.4 \times 10^-5 for this reaction.

If excess CaSO4(s) is mixed with water at 25C to produce a saturated solution of CaSO4, what are the equilibrium concentration of Ca^2+?

2 answers

......CaSO4(s) ==>Ca^2+(aq) + SO4^2-(aq)
I.....solid........0............0
C.....solid........x............x
E.....solid........x............x

Substitute the E line of the ICE chart into Ksp expression and solve for x = (Ca^2+) = (SO4^2-).
I got 4.9*10^-3 M. Thanks and

If the resulting solution has a volume of 1.9L , what is the minimum mass of CaSO4 (s) needed to achieve equilibrium?