Chapter 15 = Solutions
 Solutions = homogeneous mixtures
containing two or more substances

Solute = substance that gets dissolved;
smallest part of solution

Solvent = substance that does the
dissolving; largest part of solution
 Solutions
are not always made of 2 liquids

Carbon + Iron

Nitrogen + Oxygen
 Soluble
= substance that can be dissolved
in solvent
 Sugar and water
 Insoluble
= substance that can not be
dissolved in solvent
 Oil and water
 Miscible
= two liquids are soluble in each
other
 alcohol and water
 Immiscible
= two liquids are not soluble
in each other
 Oil and water
 Solvation-
the process of solvent particles
breaking apart solute crystals into particles
the size of ions

http://www.glencoe.com/sites/common_assets
/science/cmc/cim/animations/ch14_1.swf
 Tyndall

Effect
Solutions allow light to pass through without
being scattered
• Think about air

Non-solutions cause the light to be scattered
• Think about fog
We’ll cover this more in
depth in section 15.4
 Electrolyte-
solutions that can conduct
electricity due to ions in the solution
 Covalently
bonded molecules do not break
apart to form ions in solutions but they still
do dissolve

http://www.glencoe.com/sites/common_assets
/science/cmc/cim/animations/ch14_1.swf
Factors that Affect the Rate of Solvation

To increase solvation we need to increase the
number of times the solute and solvent touch
1.
Shake (agitate) the mixture
2.
Break to increase surface area
3.
Bake—increase temperature
 Solubility-maximum
amount of solute that
will dissolve in a given amount of solvent
at a specified temperature and pressure

Eventually, solute particles will begin to collide
with each other and form crystals.
 Unsaturated

Contains less than maximum amount of
dissolved solute
 Saturated

Contains maximum amount of dissolved
solute
 Supersaturated

Contains more than maximum amount of
dissolved solute
If you add extra solute to…
 Unsaturated

Solute will dissolve
 Saturated

Solute will dissolve
 Supersaturated

Solute will crystallize
Solubility Curves
 Each
substance has its own unique solubility
which can be displayed on a graph
 Supersaturated
solution- solution holding
more solute than a saturated solution at
the same temperature and pressure

Mentos and Diet Coke
• CO2 is greater than normal levels
• When Mentos are placed into the CO2 jumps out of
solution
 Temperature


and Solubility
SOLID- As temperature increases solubility of
a solid solute will increase (few exceptions)
GAS- as temperature increases solubility of a
gas will decrease
 Pressure

and solubility
Henry’s Law – solubility of any gas increases
as the external pressure is increased
• This is why cokes go flat. When you open the can
the external pressure has been reduced and this
decreases the solubility of the carbonation (CO2)

If 0.55 g of a gas dissolves in 1.0 L of water at 2
atm of pressure, how much will dissolve at 4.5 atm
of pressure?
0.55
x

2
4.5
2x = 2.475
X= 1.2375 g/L

A gas has solubility of 0.66 g/L at 10 atm of
pressure. What is the pressure on a 1 L sample
that contains 1.5 g of gas?
0.66 1.5

10
x
0.66 x = 150
X= 22.73 atm
3. A gas has a solubility of 1.46 g/L at 8 atm
of pressure. What is the pressure of a
1.0L sample that contains 2.7 g/L?
answer = 14.8 atm
4. If 0.68 g of a gas at 5 atm of pressure
dissolves in 1.0 L of water at 25°C, how
much will dissolve in 1.0L of water at 8
atm of pressure and the same
temperature?
answer = 1.09 g/L