I need to find out Molar solubility of CuS. How many grams of CuS are present in 15.0 L of a saturated CuS solution,

Answer 1

...............CuS ==> Cu^2+ +S^2-
equilibrium..............x.....x

Ksp = (Cu^2+)(S^2-)
Ksp = (x)(x)
Solve for x which gives you the molar solubility (that's moles/L)
grams/L = moles x molar mass
Then you want grams/15 L so multiply by 15.