Mixtures A combination of two or more substances that do not combine chemically but remain the same individual substances can be separated by physical means Two types Heterogeneous Homogeneous ID: 587399
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Slide1
Types of MixturesSlide2
Mixtures
A combination of two or more substances that do not combine chemically, but remain the same individual substances; can be separated by physical means
Two types:
Heterogeneous
Homogeneous
Based on the prefixes
“hetero” and “homo,”
what do you think are
characteristics of these
two types of mixtures
?Slide3
Heterogeneous Mixture
“Hetero” means different
Consists of visibly different substances or phases (solid, liquid, gas)
A
suspension
is a special type of
heterogeneous mixture of larger particles that eventually settle
Example:
Trail Mix
Notice the
visibly
different
substancesSlide4
Homogeneous Mixture
“Homo” means the same
Has the same uniform appearance and composition throughout; maintain one phase (solid, liquid, gas)
Commonly referred to as
solutionsExample:
Salt Water
Notice the
uniform
appearanceSlide5
Solution
A mixture of two or more substances that is identical throughout
Can be physically separated
Composed of
solutes
and
solvents
the substance in the smallest
amount and the one that dissolves in the solvent
the
substance in the larger
amount that dissolves the solute
Colloids (milk, fog, jello) are considered solutions
Iced Tea Mix
(solute)
Water
(solvent)
Iced Tea
(solution)
Salt water is considered a solution. How
can
it
be
physically separated?Slide6
Solutes Change Solvents
The amount of solute in a solution determines how much the physical properties of the solvent are changed
Examples:
Lowering the Freezing Point
The freezing point of a liquid solvent
decreases when a solute is dissolved in it.
Ex
. Pure water freezes at 32
0
F (0
0
C), but when salt is
dissolved in it, the freezing point is lowered.
This is why people use salt to melt ice.
Raising the Boiling Point
The boiling point of a solution is higher
than the boiling point of the solvent.
Therefore, a solution can remain a liquid at
a higher temperature than its pure solvent.
Ex
. The boiling point of pure water is 212
0
F (100
0
C),
but when salt is dissolved in it, the boiling
point is higher. This is why it takes salt water
longer to boil than fresh water. Slide7
Concentration
The amount of solute dissolved in a solvent at a given temperature
Described as
dilute
if it has
a low concentration of
solute
Described as
saturated
if it has a high concentration of solute
Described as
supersaturated
if
itcontains
more dissolved solute
than
normally possibleSlide8
Solubility
The amount of solute that dissolves in a certain amount of a solvent at a given temperature and pressure to produce a saturated solution
Influenced by:
Temperature
Pressure
Solids
increased temperature causes
them to be more soluble and vice versa
Gases increased temperature causes
them to be less soluble and vice versa
Ex. Iced Coffee
Solids
increased pressure has no
effect on solubility
Gases increased pressure causes them
to be more soluble and vice versa
Ex. Soda, “The Bends”
What do we call things that are not soluble?Slide9
Can you see two parts
in solutions or are they mixed together so well you only see one thing
?
you only see one thing
Are solutions mixtures or pure substances?MixturesWhat kind of states can a solution be?Solid, liquid, or gas
What are the two “s” words that every solution must have?
A solute and a solvent
Review SolutionsSlide10
In a salt water solution…
Is salt the solute or the solvent?
Solute
Is water the solute or the solvent?
SolventWhat does the solute do?Gets dissolvedWhat does the
solvent
do?
Does the dissolvingSlide11
Solute (salt)
Solvent (water)
A Salt Water Solution
AnimationSlide12
Types of SolutionsSlide13
Solutions
solute
solvent
solute
solute
solute
solute
solute
solute
solute
solvent
solvent
solvent
solvent
solvent
solvent
solvent
What is the Solute and what is the solvent? Label Each.
Cigarette Smoke and Air
Caffeine and Water (Cup of Coffee)
Water and Oxygen (Water in a Fish Tank)
Carbon Dioxide and Sugar Water (Sealed Can of Pop)
Oxygen and Nitrogen (Air)
Minerals and Water (Hard Water)
Water and Sugar (Maple Syrup)
Acetic Acid and Water (Vinegar)
Salt and Water (Ocean Water)
Make your own Slide14
Separating Mixtures & Solutions
Slide15Slide16
Mixtures
- can see two parts
Matter (Solid, Liquid, Gas)
Solutions
They’re mixed together so well you only see one thing – it looks pure but it isn’t
Pure Substances
You can only see one thing because there is only one kind of particle in it.
Mechanical Mixture
- can see two parts
A
solute
is the substance to be dissolved (sugar).
The
solvent
is the one doing the dissolving (water). Slide17
Suspensions
Suspensions
are mixtures with particles large enough to settle out unless the mixture is constantly stirred or agitated.Slide18
Colloids
Colloids
are mixtures with particles intermediate in size between solutions and suspensions.
You cannot see the individual particles.
The particles do not separate upon standing . http://commons.wikimedia.org/wiki/File:Hk-Symphony_of_Lights_3420.jpgSlide19
Examples of Colloids
Sol—Solids dispersed in liquids
Example: Paint
Gel—Solid network through a liquid
Example: GelatinLiquid Emulsion—Liquids dispersed in liquidsExample: Milk
Foam—Gases dispersed in liquids
Example: Shaving cream
Solid Aerosol—Solids dispersed in gasesExample: SmokeLiquid Aerosol—Liquids dispersed in gases
Example: FogSolid Emulsion—Liquids dispersed in solidsExample: Cheese