Chapter 14
Section 14.1
Types of Mixtures
Types of Mixtures
A mixture is a combination of two or more pure
substances that are not chemically combined
Types of Mixtures
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No Chemical Changes in a Mixture No chemical
changes happen when a mixture is made. So, each
substance has the same chemical makeup it had
before the mixture was formed. Making a mixture is a
physical change.
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TYPES OF MIXTURES
A- Heterogeneous mixture: mixture in which
individual substances remain distinct. The
different components can be seen as individual
substances. We can almost separate the
components with our eyes. The particles are
visible (bigger particles)
Heterogeneous mixtures

Heterogeneous mixtures are those where the
substances are not distributed evenly
There are two types of Heterogeneous mixtures:

1- SUSPENSIONS: is a mixture in which particles of a
material are dispersed throughout a liquid or a gas but
are large enough that they settle out if left
undisturbed . A suspension can be separated by
passing it through a filter. So suspension will separate
into 2 distinct layers if left undisturbed for awhile;
water on the top and solidlike on the bottom. When
stirred, the solidlike substance quickly begins flowing
like a liquid, substances behave like this is called
thixotropic
There are two types of Heterogeneous mixtures:
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2- COLLOIDS: is a mixture in which the
particles are spread throughout but are not large
enough to settle out. Particles diameter is
between 1 nm to 1000 nm. Milk is a colloid; Its
components can not be separated by settling or
filtration
The most abundant substance in the mixture is
the dispersion medium
Colloids are categorized according to the phases
of their dispersed particles and dispersing
mediums.
Types of colloids
Category
Example
Dispersed Particles
Dispersing Medium
Solid sol
colored gems
solid
solid
Sol
blood, gelatin
solid
liquid
Solid emulsion
butter, cheese
liquid
solid
Emulsion
milk, mayonnaise
liquid
liquid
Solid foam
marshmallow, soaps that float
gas
solid
Foam
whipped cream, beaten egg
white
gas
liquid
Solid aerosol
smoke, dust in air
solid
gas
Liquid aerosol
spray deodorant, fog, clouds
liquid
gas
Explain why?
Explain why The dispersed particles in a colloid
are prevented from settling out?
because The dispersing medium particles form
charged layers around the colloid particles.
These charged layers repel each other and keep
the particles from settling out.

How?
How can you settle colloid particles out of the
mixture?
1- If you interfere with the electrostatic layering,
colloid particles will settle out of the mixture. For
example, if you stir an electrolyte into a colloid,
the dispersed particles clump together,
destroying the colloid.
2- Heating also destroys a colloid because it gives
colliding particles enough kinetic energy to
overcome the electrostatic forces and settle out.

Brownian motion
Brownian motion is the erratic movement of colloid
particles.
 Explain how Brownian motion results?
It results from collisions of particles of the dispersion
medium with the dispersed particles. These collisions
help to prevent the colloid particles from settling out
of the mixture.
 Colloids exhibit the Tyndall effect. Which happened
when dispersed colloid particles scatter light

Tyndall effect
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TYPES OF MIXTURES
2- HOMOGENEOUS MIXTURES: Composed of two or
more substances and have variable composition BUT
The particles are distributed evenly throughout each
other SO
the composition is uniform
the solution appears to be one substance
When you look at a solution, it is not possible to
distinguish the solute from the solvent.
Solutions: are groups of molecules that are mixe
up in a completely even distribution
• A solution consists of a
1- solute: dissolved in a solvent.
2- Solvent: substance that dissolves another
• continuous phase -salt dissolved in water appears to
be a liquid
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Types of solutions:
A solution might exist as a gas, a liquid, or a solid,
depending on the state of its solvent
Forming solutions
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A substance that dissolves in a solvent is said to be
soluble in that solvent. For example, sugar is soluble
in water
Two liquids that are soluble in each other in any
proportion, such as those that form the antifreeze are
said to be miscible
A substance that does not dissolve in a solvent is said
to be insoluble in that solvent. Sand is insoluble in
water.
Two liquids that can be mixed together but separate
shortly after are said to be immiscible.
Questions
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Q: Distinguish between suspensions and colloids.
Suspension particles are larger than colloidal particles.
Suspension particles settle out of the mixture,
whereas colloidal particles do not.
Q: Identify the various types of solutions. Describe the
characteristics of each type of solution.
All solutions are homogeneous mixtures containing
two or more substances. Solutions might be liquid,
solid, or gas. Solution types are identified in Table
14.2.
Questions
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Q: Explain Use the Tyndall effect to explain why it is
more difficult to drive through fog using high beams
than using low beams.
High beams are aimed farther down the road than low
beams. Because the fog scatters light, there is less
light from the high beams to illuminate the road than
from the low beams. Also, because the high beams
are aimed more directly into the fog, more of their
light is reflected back toward the driver, making it
more difficult to see.
Questions
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Q: Explain Why do dispersed colloid particles stay
dispersed?
The particles do not settle out because they have
polar or charged layers surrounding them. These
layers repel each other and prevent the particles from
settling or separating.
Q: Summarize What causes Brownian motion?
Collisions of particles of the dispersion medium with
the dispersed particles results in Brownian motion.
Questions
Q: Make a comparison between solution, colloid and
suspension
End of section 14.1