Question

A) The K_sp of BaCO₃ is 5.0 x 10^-9. What is the soliubility of barium carbonate in a solution that contains 1.56 M of Na₂CO₃?

B) At a ceratin temperature ths solubility of Ca₃(PO₄)₂ is 1.43 x 10^-6M. What is the K_sp at this temperature?

Express your answer in scientific notation.

Answer 1

A )

[CO3-2] = 1.56 M

BaCO3 ----------------------> Ba+2 + CO3-2

S S ------------> in absence common ion

S S + 1.56------------> in absence common ion

S 1.56   

Ksp = [Ba+2][CO3-2]

5.0 x 10^-9 = (S) x 1.56

S = 3.20 x 10^-9 M

solubility = 3.20 x 10^-9 M

B)

Solubility = S = 1.43 x 10^-6

Ca3(PO4)2 --------------------> 3 Ca+2 + 2 PO4-3

3S 2S

Ksp = [Ca+2]^3 [PO4-3]^2

Ksp = (3S)^2 (2S)^3

Ksp = 108 S^5

Ksp = 108 x (1.43 x 10^-6)^5

Ksp = 6.46 x 10^-28