Use the
side to list
main points
Organize
ideas
Ask
questions
such as
might be on
a test or
that you
wonder
about
Use
thinking
skills to
question,
bring ideas
together,
and extend
them
CORNELL NOTES
In the body of the notes:
Take notes in class in the format that is most
comfortable to you:
Outline, text, shorthand, sketches, diagrams,
examples
Do NOT copy notes word for word
think as you write
rephrase
abbreviate
organize
At the bottom, summarize main ideas at appropriate intervals
SOLUTIONS
A solution is a homogeneous mixture; particles are evenly
distributed throughout the mixture.
Proportions may vary
• Uniform ratio throughout the mixture
•
A liquid solution is clear. The particles are not visible, do not settle,
and can not be filtered.
A solution differs from a suspension in that the particles of a
suspension are visible, can be filtered, and settle.
A solution differs from a colloid in that the particles of a colloid
exhibit Tyndall effect., yet do not settle.
(TYNDALL effect: the scattering of light by particles such as
headlights in fog, flashlight through Jello or dilute milk)
A solution will not exhibit the Tyndall effect.
SOLUTIONS Solns
homogeneous mixture
evenly distributed particles
•
•
variable proportions
uniform ratio
Liq soln clear. particles are not visible, do not settle, and
can not be filtered.
 Not suspensions: particles of a susp are visible, can be
filtered, and settle.
 Not colloids: particles of a colld show Tyndall effect., yet
do not settle.
 (TYNDALL effect: the scattering of light by particles
such as headlights in fog, flashlight dilute milk)
 A soln will not exhibit the Tyndall effect.
SOLUTIONS Solns
Define
soln
homogeneous mixture
evenly distributed particles
Describe
soln
•
Are all
solns
liquid?
liquid soln clear. particles are not visible, do not settle, and
can not be filtered.
 Not suspensions: particles of a susp are visible, can be
filtered, and settle.
 Not colloids: particles of a colld exhibit Tyndall effect.,
yet do not settle.
 (TYNDALL effect: the scattering of light by particles
such as headlights in fog, flashlight dilute milk)
 A solution will not exhibit the Tyndall effect.
Contrast
liquid
soln with
susp and
colloids
•
variable proportions
uniform ratio
SOLUTIONS Solns
Define
solution
Describe
solution
Are all
solns
liquid?
Contrast
liquid
solution
with
suspensi
ons and
colloids
homogeneous mixture
evenly distributed particles
•
•
variable proportions
uniform ratio
liquid soln clear. particles are not visible, do not settle, and
can not be filtered.




Not suspensions: particles of a suspension are visible, can
be filtered, and settle.
Not colloids: particles of a colloid exhibit Tyndall effect.,
yet do not settle.
(TYNDALL effect: the scattering of light by particles
such as headlights in fog, flashlight dilute milk)
A solution will not exhibit the Tyndall effect.
Solutions are homogenous mixtures with variable proportions and
uniform ratios. Separate components are not visible/discernible.
Cherry Kool-aid
Red powder: flavor and color
 White crystals: sugar
 Clear liquid: water


One substance dissolved in another
◦ Solute: the substance being dissolved
◦ Solvent: the substance that dissolves the
solute
 Sugar is the SOLUTE (smaller quantity)
 Water is the SOLVENT (larger quantity)
Types of Solutions

Gas (solvent is gas)
◦ Gas into Gas: air
◦ Liquid into Gas: humidity
◦ Solid into Gas: air pollution

Liquid (solvent is liquid)
◦ Gas into Liquid: pop
◦ Liquid into Liquid: vinegar
◦ Solid into Liquid: sweet tea

Solid (solvent is solid)
◦ Gas into Solid: absorbent charcoal
◦ Liquid into Solid: dental fillings
◦ Solid into Solid: alloys of metal
The Dissolving Process

Two factors affect the dissolving process:
dissolution
◦ The constant motion of the particles (There’s
that good old kinetic molecular theory again!)
◦ The polarity of the solute and solvent (Recall
that polarity is when a compound has partial
charges because of uneven distribution of
charges)
Steps of the Dissolving Process
Moving solvent particles cluster around
solute molecules or particles at the
surface of the solid.
2. Solvent molecules pull solute off of the
solid surface and into solution.
3. Moving solvent particles continue to
spread solute evenly throughout the
solution,
The process repeats itself as fresh layers of
the solute are exposed.
1.
1. Solvent particles cluster around solute particles at the
surface.
2. Solvent particles pull solute particles away from
surface, into solution.
3. Moving solute particles continue to spread solute
evenly through solution.
MOLECULAR
1. Solvent particles cluster around solute particles at the
surface.
2. Solvent particles pull solute particles away from
surface, into solution.
3. Moving solute particles continue to spread solute
evenly through solution.
IONIC
IONIC COMPOUNDS
When an ionic substance dissolves in water, the
forces of the solvent pulling on the ions is
stronger than the forces holding the ions
together.
 The ions separate. This is called
DISSOCIATION
 Because charged ions are present in an ionic
solution, ionic solutions conduct electricity and
are called ELECTROLYTES.
 EXAMPLE: NaCl

MOLECULAR COMPOUNDS
Certain polar substances form ions when
they dissolve in water.This process is
called IONIZATION.
 Because ions are formed, the solution
conducts electricity.
 These substance are also
ELECTROLYTES.
 EXAMPLE: HCl, HC2H3O2

MOLECULAR COMPOUNDS
Other polar substances do not ionize in
water.
 Because ions are not formed, the solution
does not conduct electricity.
 These substances that do not ionize in
water and do not conduct electricity are
called NON-ELECTROLYTES.
 EXAMPLE: sugar

ELECTROLYTES:
substances that conduct
electricity when dissolved in water

Ionic substances that separate into ions
(dissociate) or polar molecular substances
that form ions (ionization) when dissolved
conduct electricity and are called
ELECTROLYTES.
Review

A substance whose water solutions do
not conduct electricity is a nonelectrolyte.
◦ Many covalent compounds

A substance that separates into ions
(dissociates) or forms ions (ionizes) in a
water solution conducts electricity and is
called an electrolyte
◦ All ionic and some covalent compounds
COMPOUNDS THAT
DISSOLVE IN WATER
ELECTROLYTES
DO CONDUCT
ELECTRICITY
IONIC
COMPOUNDS
DISSOCIATE INTO
IONS
SOME POLAR
MOLECULAR
COMPOUNDS
IONIZE
NONELECTROLYTES
DO NOT
CONDUCT
ELECTRICITY
OTHER POLAR
MOLECULAR
COMPOUNDS
DISSOLVE WITH NO
FORMATION OF IONS
FACTORS THAT AFFECT THE RATE OF DISSOLUTION
Factors
TEMPERATURE
Solid in Liquid
Gas in Liquid
Temp >
Rate >
Temp >
Rate <
AGITATION
Agitation >
Rate >
Agitation >
Rate <
SIZE OF
PARTICLES
Size <
(surface area >)
Rate >
NA
PRESSURE
NA
Pressure >
Rate >
The solute
particles are less
energetic than
solvent
The solute
particles are
more energetic
than solvent
WHY?
Think BIG
Recall the Pop and Mentos experiment!
The pop “explodes” because the dissolved gas rapidly
leaves the solution because the candy gives it surfaces
to collect on (nucleation sites).
Particles in Solutions

Solvents with non-polar molecules
dissolve non-polar substances
◦ Oil, grease, dry cleaning fluid, paint, turpentine

Solvents with polar molecules dissolve
polar substances
◦ Water dissolves sugar, ionic compounds

LIKE DISSOLVES LIKE
Terms
Soluble: capable of being dissolved in a
particular solvent
 Insoluble: incapable of being dissolved in a
particular solvent

Miscible: liquids that dissolve freely in any
proportion
 Immiscible: liquids that are not soluble in
each other

Detergents and emulsifiers
Grease is non-polar
 Water is polar


DETERGENT has
◦ A non-polar end that dissolves the grease
◦ A polar end that dissolves in the water to
rinse it away
NONPOLAR
GREASE
DETERGENT
POLAR
WATER
CRAFTY CHEMISTRY
Artists use physical properties to create inspiring
beauty!
ART and SCIENCE
Solubility
There are limits to the amount of solute
that will dissolve in a given amount of
solvent at a given temperature
 There are some general terms:

◦ Unsaturated
◦ Saturated
◦ Super-saturated
Unsaturated

a solution that can dissolve more of a
given solute at a certain temperature
◦ A crystal of solute added to an unsaturated
solution will dissolve
 When you add a second spoon of sugar to your
cup of tea, it dissolves. The tea was an unsaturated
solution.
Saturated

a solution that has dissolved all of the solute
that it can at a certain temperature
◦ A crystal of solute added to a saturated solution will
drop to the bottom, un-dissolved.
 When you add three spoons of sugar to your tea, some sugar
drops to the bottom, undissolved. It is a saturated solution.

DYNAMIC EQUILIBRIUM exists:
◦ changing but balanced.
◦ Some solid dissolves, but as some dissolves, some recrystallizes
Super-saturated

an unstable solution that contains more solute
than a saturated solution at a certain
temperature
◦ A crystal of solute added to a super-saturated
solution will cause crystallization. So will any
disruption of the unstable solution.
◦ Make a saturated solution at an elevated temperature
and cool it slowly. At the lower temperature, the
solute will remain dissolved in an unstable situation. If
disrupted, the solute crystallizes.
 Hot-packs and rock candy
S
O
L
U
B
I
L
I
T
Y
C
U
R
V
E
Max g of solute that will
dissolve in 100 g of
solvent at a given
temperature
Solubility + Gas Laws = Safe SCUBA

Science of Diving
Concentration: the amount of solute in
a given amount of solvent or solution
Dilute: a relatively small amount of solute
in a relatively large amount of solvent
 Concentrated: a relatively large amount of
solute in a relatively small amount of
solvent


We can do better!
Percent by volume

mL of solute /100 mL of solution
Percent by mass

g of solute/100 mL of solution
PPM and PPB
x/1,000,000
 x/1,000,000,000


Serial dilutions are often used
◦ 1x, 10x, 100x, 1000x, etc.
Mass per volume

g solute/1000 mL solution
Molarity

M = mol solute/liter of solution

Chemists use this because it lets us work
concentration into stoichiometry
problems

SEE EXAMPLE PROBLEMS
Molality

m = mol solute/kg of solvent

Chemists sometimes use this because
volume of liquids changes with
temperature. Soon, we will be studying
the effect of concentration as
temperature changes.

SEE EXAMPLE PROBLEMS
Dilutions: a concentrated solution is diluted by adding
more solvent to get the desired concentration.
M1V1
=
Moles before dilution
=
◦ M = molarity = mol/L
◦ V = volume = L
M2V2
Moles after dilution
◦ M x V = mol/L x L = # mol of solute
Dilutions: a concentrated solution is diluted by adding
more solvent to get the desired concentration.

The # of moles before dilution is equal to the #
of moles after dilution. The same # of moles is
present in more solvent. The concentration (M,
molarity) changes, the volume (V) changes, but
not the # of moles of solute (M x V).
◦ Volume units may vary from L, but must be consistent within problem.

So,
M1V1 = M2V2

SEE EXAMPLE PROBLEMS