Calculate the molar solubility of CuS. How many grams of CuS are present in 15.0 L of a saturated CuS solution?
Solubility equilibrium expression for CuS (s)Cu +2 (aq) + S -2 (aq).
Solubility product constant expression :
Ksp = [Cu+2][S-2]
=1.27 * 10-36 .
Dissolution of 1 mol of CuS produces 1 mole of Cu+2 and 1 mol of S-2 at equilibrium
1 mol CuS = 1 mol Cu+2
1 mol CuS = 1 mol of S-2.
Molar solubility of Cu+2 at equilibrium ,[Cu+2 ]= S
Molar solubility of S -2. at equilibrium ,[S-2 ]= S.
Solubility product constant ,Ksp = [Cu+2][S-2]
Therefore ,S =
Hence molar solubility of CuS is 1.3*10-18 M.