Chapter 13:
Solutions and
Their Properties
or
Chemical Matchmaking
I.
Introduction
A. What is a Solution?
B. Quantitative Description of Solutions
C. Formation of Solutions
II.
Solubilities of Gases
III.
Colligative Properties
A. Vapor Pressures of Solutions
B. Osmotic Pressure
C. Freezing Point Depression
and Boiling Point Elevation
D. Solutions of Electrolytes
IV.
Colloidal Mixtures
(read/study on your own)
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I. Introduction
A. What is a Solution
Solution – Homogeneous mixture of two or more
substances (solvent and solute(s))
Solvent –
Chemical in the largest amount that
dissolves other components
Solute(s) – Chemical(s) being dissolved in solvent
Concentrated - Large amount of solute(s) in solution
Dilute -
Small amount of solute(s) in solution
Examples of Solutions
Example
Air (N2, O2,
etc)
Iced Latte
(H2O,
caffeine, etc.)
Brass (Cu, Zn,
etc.)
Pepsi (H2O,
CO2, etc.)
State of
Solution
State of
Solute
State of
Solvent
Gas
Gas
Gas
Liquid
Liquid
Liquid
Solid
Solid
Solid
Liquid
Gas
Liquid
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B. Quantitative Descriptions of Solutions
1.
% by mass 
mass solute
x100%
mass soln
volume solute
% by volume 
x100%
volume soln
2.
Parts Per Million=
mass of solute (g)
total mass of solution (g)
×1x106 ppm
mass of solute (g)
Parts Per Billion=
×1x109 ppb
total mass of solution (g)
moles solute
kg solvent
3.
molality 
4.
mole fraction (  ) 
5.
Normality (N) 
6.
Molarity (M) 
i
moles (i)
total moles
eq solute
L soln
moles solute
L soln.
3
Example Problem
An aqueous solution contains 45% by mass HF, what is
the molality of the solution?
4
C. Formation of Solutions (solid or liquid + liquid)
Why and How do Solutions Form?
H2O(l)
C5H12O(l)  Will an aqueous solution form?
H2O(l)
C14H9Cl5(l)  Will an aqueous solution form?
A Consideration
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http://cdn.greenmedinfo.com/sites/default/files/ckeditor/lrossi/images/Xerox4112653.jpg
Solution Formation and Energetics
1.
2.
3.
6
Intermolecular Forces and Solution Formation
1. Ideal Solution
-
2. Non-Ideal Solution
intermolecular forces
of attraction between
solute and solvent are similar to that
of the pure solvent and pure solute
a.) intermolecular forces of attraction
between solute and solvent are
stronger than that between the
individual compounds
b.) intermolecular forces of attraction
between solute and solvent are
slightly weaker than that between
the individual compounds
3. No Solution -
intermolecular forces of attraction between
solute and solvent are much weaker than
the individual compounds
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Intermolecular Forces and Solution Formation Cont’d
- polar and ionic solutes are more likely to be
soluble in polar solvents
- non-polar solutes are more likely to be soluble in
non-polar solvents
Vocabulary
Solid-Liquid Solutions
Saturated –
Solubility –
Unsaturated –
Supersaturated –
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https://web.nmsu.edu/~snsm/classes/chem116/notes/saturated.gif
Liquid-Liquid Solutions
Miscible –
Immiscible –
Example Problems
1. Which is more soluble in water, MTBE or DDT?
2. Would you expect butanol to be more soluble in water
or hexane?
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Effect of Temperature on Solution Formation
solids 
Lab
-
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Solubilities of Gases
1. Effect of Temperature on the Solubility of Gases
Gases 
Environmental Impact -
CO2 Concentration in Ocean Water
II.
High
Low
http://earthobservatory.nasa.gov/Features/OceanCarbon/, https://www3.epa.gov/climatechange/images/basics/factorysmoke.jpg
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2. Effect of Pressure on the Solubility of Gases
Liquids and Solids 
Gases 
Henry’s Law
- quantitative relationship between partial pressure
and solubility
12
Example Problem
The aqueous solubility of CO2 at 20.°C and 1.00 atm of
pressure is equivalent to 87.8 mL of CO2(g), measured at
STP, per 100. mL of water. What is the molarity of CO2 in
water that is at 20.°C and saturated with air at 1.00 atm?
The mole fraction of CO2 in air is 3.60x10-4. Assume that
the volume of water does not change when it becomes
saturated with air.
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III.
Colligative Properties
Colligative Types of Colligative Properties
A. Vapor Pressure of Solutions
B. Osmotic Pressure
C. Freezing Point Depression and Boiling Point
Elevation
A. Vapor Pressures of Solutions
Raoult’s Law
CH3OH
(methanol)
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H2 O
CH3OH in H2O
Example Problem
The vapor pressure of pure water at 60.C is 149 torr.
What is the vapor pressure of water in a solution
containing equal numbers of moles of water and ethylene
glycol?
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Raoult’s Law and Types of Solutions
1. Ideal Solution
- low solute concentration, solute and solvent have
similar sizes, types and numbers of IMF
2. Non-Ideal Solution
a. Positive Deviations
- solute-solvent interactions are weaker than
solvent-solvent and solute-solute interactions
b. Negative Deviations
- solute-solvent interactions are strong, i.e. when Hbonds are formed
16
Example Problem
It has been proposed that fuel cells will soon be used
to power cell phones and laptops. One possible fuel
for these fuel cells consists of a methanol/water
mixture. Using the data below and Raoult’s Law,
determine the composition of the liquid and vapor
phases (which are in equilibrium with each other) of
a methanol/water fuel mixture at 72.0°C and a total
pressure of 101.325 kPa.
T (°C)
PH2O (kPa)
PCH3OH (kPa)
67.6
28.233
113.68
69.3
30.328
121.06
71.2
32.964
129.41
73.1
35.772
139.55
75.3
75.3
151.28
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Fractional Distillation of an Ideal Solution
Fractional Distillation of a Non-Ideal Solution
Azeotrope -
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B. Osmotic Pressure
Osmosis – net movement of solvent through a
semipermeable membrane from a dilute
solution to a more concentrated solution
h
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Calculating Osmotic Pressure
When pressure of liquid column is great enough, rate at which
solvent travels between the solutions is equal and the net flow
of solvent stops. This pressure is the osmotic pressure ().
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Biological Applications of Osmosis
Crenation
Isotonic Solution Hemolysis
Isotonic Soln –
Crenation –
Hemolysis –
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C. Boiling Point Elevation and Freezing Point
Depression of Non-Electrolyte Solutions
C12H22O11
(sugar)
H2O
1.
C12H22O11 in H2O
Boiling Point Elevation
Mathematical Relationship
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2.
Freezing Point Depression
At any temperature at which the solid and the liquid state
coexist, there will be equilibrium, with molecules moving
bewtween the states. If a solute is added it disrupts the
ability of the liquid to reform the solid by slowing that rate
down. In order to reestablish the equilibrium, the solution
must cool so that the rate of solid transferring to the
solution matches the rate of that with the added solute.
Mathematical Relationship
24
D. Solutions of Electrolytes
Van’t Hoff – first Nobel
Prize in chemistry
0.0100 m CH4N2O
∆Tf = -0.0186 ºC
0.0100 m NaCl
∆Tf = -0.0361 ºC
Van’t Hoff Factor
25
Problems With van’t Hoff Factors
Stoichiometric Concentration -
Activity -
26
Calculating Activities (pg 30-35 GCN)
27
Activities Continued
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IV.
Colloidal Mixtures
(read/study on your own)
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