Chapter 8
Solutions
Solubility
Percent Concentration
Colloids and Suspensions
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Solubility
The maximum amount of solute that
can dissolve in a specific amount of
solvent usually 100 g.
g of solute
100 g water
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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
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Learning Check S1
At 40C, 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 40C
B. ___200 g KBr in 200 g of water at 40C
C. ___25 KBr in 50 g of water at 40C
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Solution S1
At 40C, 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 40C, which is greater than its solubility
C. 2 Same as 60 g KBr in 100 g of water,
which is less than its solubility
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Temperature and Solubility of
Solids
Temperature
0°
20°C
50°C
100°C
Solubility (g/100 g H2O)
KCl(s)
NaNO3(s)
27.6
74
34.0
88
42.6
114
57.6
182
The solubility of most solids (decreases or
increases ) with an increase in the
temperature. LecturePLUS Timberlake
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Temperature and Solubility of
Solids
Temperature
0°
20°C
50°C
100°C
Solubility (g/100 g H2O)
KCl(s)
NaNO3(s)
27.6
74
34.0
88
42.6
114
57.6
182
The solubility of most solids increases with
an increase in the temperature.
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Temperature and Solubility of
Gases
Temperature
0°C
20°C
50°C
Solubility (g/100 g H2O)
CO2(g)
O2(g)
0.34
0.17
0.076
0.0070
0.0043
0.0026
The solubility of gases (decreases or
increases) with an increase in
temperature.
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Temperature and Solubility of
Gases
Temperature
0°C
20°C
50°C
Solubility (g/100 g H2O)
CO2(g)
O2(g)
0.34
0.17
0.076
0.0070
0.0043
0.0026
The solubility of gases decreases with an
increase in temperature.
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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?
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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.
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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
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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
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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
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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
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Other Salts
4. Most salts containing CO32-, PO43-, S2and OH- are not soluble.
Examples:
soluble
not soluble
Na2CO3
CaCO3
K 2S
CuS
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Learning Check S3
Indicate if each salt is (1)soluble or (2)not
soluble:
A. ______ Na2SO4
B. ______ MgCO3
C. ______ PbCl2
D. ______ MgCl2
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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
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