LecturePLUS 1

Chapter 8Solutions

Solubility

Percent Concentration

Colloids and Suspensions

LecturePLUS 2

Solubility

The maximum amount of solute that can dissolve in a specific amount of solvent usually 100 g.

g of solute

100 g water

LecturePLUS 3

Saturated and Unsaturated

A saturated solution contains the maximum

amount of solute that can dissolve.

Undissolved solute remains.

An unsaturated solution does not contain all

the solute that could dissolve

LecturePLUS 4

Learning Check S1

At 40C, the solubility of KBr is 80 g/100 g

H2O. Indicate if the following solutions are

(1) saturated or (2) unsaturated

A. ___60 g KBr in 100 g of water at 40C

B. ___200 g KBr in 200 g of water at 40C

C. ___25 KBr in 50 g of water at 40C

LecturePLUS 5

Solution S1

At 40C, the solubility of KBr is 80 g/100 g H2O.

Indicate if the following solutions are

(1) saturated or (2) unsaturated

A. 2 Less than 80 g/100 g H2O

B. 1 Same as 100 g KBr in 100 g of water

at 40C, which is greater than its solubility

C. 2 Same as 60 g KBr in 100 g of water,

which is less than its solubility

LecturePLUS 6

Temperature and Solubility of Solids

Temperature Solubility (g/100 g H2O)

KCl(s) NaNO3(s)

0° 27.6 74

20°C 34.0 88

50°C 42.6 114

100°C 57.6 182

The solubility of most solids (decreases or increases ) with an increase in the temperature.

LecturePLUS 7

Temperature and Solubility of Solids

Temperature Solubility (g/100 g H2O)

KCl(s) NaNO3(s)

0° 27.6 74

20°C 34.0 88

50°C 42.6 114

100°C 57.6 182

The solubility of most solids increases with an increase in the temperature.

LecturePLUS 8

Temperature and Solubility of Gases

Temperature Solubility (g/100 g H2O)

CO2(g) O2(g)

0°C 0.34 0.0070

20°C 0.17 0.0043

50°C 0.076 0.0026

The solubility of gases (decreases or increases) with an increase in temperature.

LecturePLUS 9

Temperature and Solubility of Gases

Temperature Solubility (g/100 g H2O)

CO2(g) O2(g)

0°C 0.34 0.0070

20°C 0.17 0.0043

50°C 0.076 0.0026

The solubility of gases decreases with an increase in temperature.

LecturePLUS 10

Learning Check S2

A. Why would a bottle of carbonated drink

possibly burst (explode) when it is left out

in the hot sun ?

B. Why would fish die in water that gets too warm?

LecturePLUS 11

Solution S2

A. Gas in the bottle builds up as the gas becomes less soluble in water at high temperatures, which may cause the bottle to explode.

B. Because O2 gas is less soluble in warm

water, the fish may not obtain the needed

amount of O2 for their survival.

LecturePLUS 12

Soluble and Insoluble Salts

A soluble salt is an ionic compound that dissolves in water.

An insoluble salt is an ionic compound that does not dissolve in water

LecturePLUS 13

Solubility Rules

1. A salt is soluble in water if it contains any one of the following ions:

NH4+ Li+ Na+ K+ or NO3

-

Examples:

soluble salts

LiCl Na2SO4 KBr Ca(NO3)2

LecturePLUS 14

Cl- Salts

2. Salts with Cl- are soluble, but not if the

positive ion is Ag+, Pb2+, or Hg22+.

Examples:

soluble not soluble(will not dissolve)

MgCl2 AgCl

PbCl2

LecturePLUS 15

SO42- Salts

3. Salts with SO42- are soluble, but not if

the positive ion is Ba2+, Pb2+, Hg2+ or Ca2+.

Examples:

soluble not soluble

MgSO4 BaSO4

PbSO4

LecturePLUS 16

Other Salts

4. Most salts containing CO32-, PO4

3-, S2-

and OH- are not soluble.

Examples:

soluble not soluble

Na2CO3 CaCO3

K2S CuS

LecturePLUS 17

Learning Check S3

Indicate if each salt is (1)soluble or (2)not soluble:

A. ______ Na2SO4

B. ______ MgCO3

C. ______ PbCl2

D. ______ MgCl2

LecturePLUS 18

Solution S3

Indicate if each salt is (1) soluble or

(2) not soluble:

A. _1_ Na2SO4

B. _2_ MgCO3

C. _2_ PbCl2

D. _1_ MgCl2