Drill:

Drill:•Determine the KQ/HQ ratio to make a buffer solution with a pH of 4.70

•Ka for HQ = 3.0 x 10-5

Drill: Calculate [H2Q], [HQ-], [Q-2], [H+], & pH of 0.20 M KHQ.

Ka1 = 2.0 x 10-4

Ka2 = 8.0 x 10-9

Solubility

Solubility•The amount of one substance that will dissolve in another

Saturated Solution•When the maximum

amount of one substance is dissolved

in another

Precipitation•When more than the maximum amount of solute is added to a solution, a ppt will

form

Precipitation• When dissolved

particles join together forming a new phase and exit the solution

Precipitate (ppt)•The new phase that

forms and leaves the solution

Ppt Examples•Water vapor combining to

form rain

•Dissolved ions combining to form a solid

Write the equilibrium expression for

AgCl(s) Ag+ + Cl-

Solubility Product

MX(s)

M+(aq) + X-

(aq)

Ksp =[M+][X-]

Solubility Product

MX2(s)

M+2(aq) + 2 X-

(aq)

Ksp =[M+2][X-]2

Write the equation & equilibrium expression for:

Al2(SO4)3

Solubility Calculations

•Calculate the solubility of

BaSO4(s)

•Ksp = 1.2 x 10-10

Solubility Product

BaSO4(s)

Ba+2(aq) + SO4

-2(aq)

Ksp =[Ba+2][SO4-2]

•Calculate the solubility of

SrCr2O7(s)

•Ksp = 2.5 x 10-13

•Calculate the solubility of

PbI2(s)

•Ksp = 8.0 x 10-9

•Calculate the solubility of

Mn2S3(s)

•Ksp = 1 x 10-98

Drill:Write the reaction &

equilibrium expression when solid Fe2(SO4)3 is

added to water.

Drill: Calculate the solubility of M3X4

Ksp for M3X4

= 6.9 x 10-207

Solubility Concepts

AgI(s) Ag+ + I-

Ksp = [Ag+][I-] at Eq.

Qsp = [Ag+][I-] init.

Solubility Concepts•If Qsp > Ksp a

precipitate will form

•If Qsp < Ksp no precipitate will form

150 mL 0.0010 M KI is added to 100 mL 0.050

M Pb(NO3)2. Ksp for PbI2 = 8.0 x 10-9

•Will a ppt form?

Calculate the solubility of

AgI(s)

•Ksp = 1.5 x 10-16

Common Ion Solubility

Calculations

Common Ion Effect

•Solubility of a solid is reduced when one of its ions is already

in solution

•Calculate the solubility of AgI(s)

in 0.10 M NaI

•Ksp = 1.5 x 10-16

•Calculate the solubility of MZ2(s)

in

0.20 M M(NO3)2

Ksp = 2.0 x 10-15

Drill: 10.0 mL 0.050 M KCl is added to 15 mL 0.075 M Pb(NO3)2. Ksp PbCl2 = 1.7 x 10-5

•Will a ppt form?

•Calculate the solubility of M2Z3(s)

in

0.20 M M(NO3)3

Ksp = 2.0 x 10-16

Drill: Calculate the solubility of CaCO3 in water. Ksp = 4.9 x 10-15

•Calculate the solubility of PbI2(s)

in 0.010 M NaI

•Ksp = 3.2 x 10-8

The Really Bad Solubility

Problems

Aqueous NaI is added (dropwise) to a solution of 0.10 M AgNO3(s) &

0.10 M CuNO3

AgI Ksp = 1.0 x 10-16

CuI Ksp = 5.1 x 10-12

•Aqueous KCl is added (dropwise) to a solution

of 0.10 M AgNO3 & 0.10 M Cu(NO3)2

•AgCl Ksp = 1.8 x 10-10

•CuCl2 Ksp = 5.1 x 10-12

Drill: Calculate the solubility of

PbS(s)

Ksp = 1.0 x 10-28

Review

•Calculate the solubility of

PbCl2(s)

•Ksp = 1.6 x 10-5

•Calculate the solubility of Sc(OH)3(s)

•Ksp = 2.7 x 10-31

•Calculate the solubility of

Ca(OH)2.

•Ksp = 4.0 x 10-6

Calculate the pH of Li2CO3

Ksp = 8.2 x 10-4

Ka1 = 4.4 x 10-7

Ka2 = 4.7 x 10-11

•Calculate the solubility of AgI(s)

in 0.20 M NaI

•Ksp = 1.5 x 10-16

The solubility of MX2(s) is

2.0 x 10-5 M.

Calculate its Ksp

•Aqueous MgCl2 is added (dropwise) to a

solution of 0.20 M KOH & 0.10 M K2SO4

•Mg(OH)2 Ksp = 5.0 x 10-6

•MgSO4 Ksp = 5.6 x 10-5

10.0 mL 0.050 M KCl is added to 15 mL 0.060 M Pb(NO3)2.

Ksp PbCl2 = 1.7 x 10-5

•Will a ppt form?

Drill:•The solubility of YF3 is 2.0 x 10-8. Calculate the value of Ksp.