Question

A. Write the K_sp expression for the sparingly soluble compound silver phosphate, Ag₃PO₄. Ksp=?

B. Write the K_sp expression for the sparingly soluble compound barium phosphate, Ba₃(PO₄)₂. Ksp=?

C. The solubility of PbF₂ is measured and found to be 0.527 g/L. Use this information to calculate a K_sp value for lead fluoride. Ksp=?

D.The solubility of Ag₂CO₃ is measured and found to be 3.55E-2 g/L. Use this information to calculate a K_sp value for silver carbonate. ksp=?

Answer 1

A)

Ag3PO4(s)    <---------------> 3Ag⁺(aq) + PO4^3-(aq)

Ksp = [Ag⁺]^3[PO4^3-]

B)

Ba3(PO4)2    <--------------> 3Ba²⁺ + 2PO4^3-

Ksp = [Ba²⁺]^3[PO4^3-]^2

C)

PbF2 -----------------> Pb+2 + 2F-

                                     S        2S

solubility = 0.527 g/L

PbF2 molar mass = 245.2 g /mol

solubility = S = 0.527 / 245.2 mol / lit

                  = 0.002149 M

Ksp = [Pb+2][F-]^2

        = S x (2S)^2

       = 4S^3

       = 4 x 0.002149^3

       = 3.97 x 10^-8

K_sp value for lead fluoride. Ksp = 3.97 x 10^-8

D)

Ag2CO3 molar mass = 275.74 g / mol

Ag2CO3 solubilty = S = 3.55 x 10^-2 / 275.74

                                   = 0.0001287

Ag2CO3 --------------> 2 Ag+ + CO3^2-

                                       2S         S

Ksp = [Ag+]^2[CO3^2-]

        = (2S)^2 x S

      = 4S^3

      = 4 x 0.0001287^3

      = 8.53 x 10^-12

K_sp value for silver carbonate. ksp = 8.53 x 10^-12