More about
Mixtures
Suspensions,
Colloids, and
Solutions
Types of Mixtures
 Mixtures
can be classified into three groups,
based on particle sizes in the mixture.



Suspensions – large particles
Colloids – smaller particles
Solutions – smallest particles
Suspensions are…
 Mixtures
that contain large particles
that are heavy enough to settle out
over time.
 The


particles in a suspension…
Scatter light.
Can be removed by a filter.
 Examples:

Snow Globe, Italian Dressing, Glitter
Ball
Colloids are…
 Mixtures
that contain smaller
particles that do not settle out over
time.
 The


particles in a colloid…
Scatter light.
Cannot be removed by a filter (they
are too small).
 Examples:

Whipped Cream, Fog, Smoke, Milk,
Marshmallows, Jell-O
Solutions are…
 Mixtures
that contain very small
particles that dissolve in another
substance.
 The


particles in a solution…
Do not scatter light.
Cannot be removed by a filter.
 Examples:

Salt water, sugar water, air,
lemonade, soda pop
Alloys – Solid Solutions!
 Solutions
where solids are dissolved in
metals are called alloys.
 Examples:



Bronze – Tin (Sn) dissolved in copper
(Cu)
Brass – Zinc (Zn) dissolved in copper
(Cu).
Steel – Carbon (C), nickel (Ni) and
other metals dissolved in iron (Fe).
What is dissolving?
Watch this to see how water dissolves salt:
http://group.chem.iastate.edu/Greenbow
e/sections/projectfolder/flashfiles/thermoc
hem/solutionSalt.html
Not everything dissolves!
 Insoluble means a substance does not
dissolve.
 Soluble means that a substance
dissolves.
Examples:
 Sand is insoluble in water.
 Sugar is soluble in water.
Two Parts of a Solution
 Solute
The substance that is dissolved.
(Smaller amount)
 Solvent
The substance that dissolves the solute.
(Larger amount)
Example:
 In a solution of salt water,


The solute is salt.
The solvent is water.
Water as a Solvent
 Many
substances dissolve in water.
 Water
is used as a solvent so often,
it is known as the
Universal Solvent
Measuring Solutes
 Concentration
The measurement of how much solute is dissolved
in a solvent.
 Dilute
solutions contain a small amount of solute.
 Concentrated
of solute.
solutions contain a large amount
Saturated Solution
A “full” solution – it contains all the solute it can hold.
How much solute can dissolve?

If you keep adding sugar to
lemonade or tea, will it keep
dissolving?

Eventually the solution will become
saturated.

The sugar will begin to sink to the
bottom of the glass instead of
dissolving.

Solubility
The maximum amount of solute a
solvent can hold at a given
temperature.
How to Dissolve Solutes Faster

Stirring the Solution

Crushing the Solute
Ground sugar vs. sugar cubes

Changing the Temperature

To dissolve a solid in liquid –
INCREASE temperature.
Example: More sugar dissolves in hot
tea than iced tea.

To dissolve a gas in liquid –
DECREASE temperature.
Example: More gas bubbles dissolve in
cold soda than in warm soda.