the solubility product constant for MX2 is 7.9*10-8 how many grams of MX2 (101.13 g/mol) will dissolve in 146 ml of water at 25 degrees

Answer 1

MX₂(s) <==> M²⁺⁽aq) + 2X^-(aq)

Ksp = 7.9x10^-8 = [M²⁺][X^-]²

Let s = [M²⁺], then 2s = [X^-]

7.9x10^-8 = (s)(2s)² = 4s³

s = 2.70x10^-3 M = [M²⁺]

2.7x10^-3 mol / L x 0.146 L = 3.94x10^-4 moles

3.94x10^-4 mols x 101.13 g/mol = 0.0399 g will dissolve in 146 ml H₂O