What is concentration of iron ions and barium ions?

Question

1.) What is concentration of barium ions in a saturated solution of barium sulfate?

Ksp(BaSO4) = (2.291x10^-8)

2.) What is the concentration of iron(II) ions in a saturated solution of iron(II) sulfide?

Ksp(FeS) = (3.792x10^-19)

Answer 1

1).

BaSO₄(s) <==> Ba²⁺(aq) + SO₄^2-(aq) ... Ksp = 2.291x10^-8

Ksp = [Ba²⁺][SO₄^2-]

2.291x10^-8 = (x)(x) = x²

x = 1.514x10^-4 M = [Ba²⁺]

2).

FeS(s) <==> Fe²⁺(aq) + S^2-(aq) ... Ksp = 3.792x10^-19

Ksp = [Fe²⁺][S^2-] = (x)(x) = x²

x = 6.158x10^-10 = [Fe²⁺]