Question

13. A. The molar solubility of calcium carbonate in a water solution is _____M.

B. The equilibrium concentration of cyanide ion in a saturated zinc cyanidesolution is _____M.

C. The equilibrium concentration of copper(II) ion in a saturated copper(II) hydroxide solution is _____M.

Answer 1

13)

A)

Ksp of CaCO3 = 3.8 x 10^-9

CaCO3 (s)   ----------> Ca2+   +    CO32-

                                         S            S

Ksp = [Ca2+][CO32-]

3.8 x 10^-9 = S^2

S = 6.16 x 10^-5 M

molar solubility = 6.16 x 10^-5 M

B)

Ksp of Zn(CN)2 = 8.0 x 10^-12

Zn(CN)2   --------------> Zn2+   + 2 CN-

                                       S             2 S

Ksp = S x (2S)^2

8.0 x 10^-12 = 4 S^3

S = 1.26 x 10^-4 M

concentration of CN- = 2.52 x 10^-4 M

C)

Ksp of Cu(OH)2 = 1.6 x 10^-19

S = 3.42 x 10^-7 M

concentration of Cu2+ = 3.42 x 10^-7 M