Topic 2: Mixing and Dissolving
Classification of Matter
Pure Substances
All pure substances contain only one type of
particle.
They can exist in three states of matter: solid, liquid
and gas.
Examples of Elements??
Examples of Compounds??
Mixtures
Mixtures contain two or more pure
substances
1. Homogeneous Mixtures: Look as
though they only have one substance.
E.g. Kool-aid, Hot chocolate
A homogeneous mixture where no settling
occurs is called a solution
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2. Heterogeneous Mixtures: Mixtures that
contain two or more parts that are still
visible.
Examples??
In-Between Mixtures
Suspension: A heterogeneous mixture in which the
particles settle slowly. E.g. _______________
Colloid: A heterogeneous mixture in which the
particles do not settle. E.g. ________________
Emulsion: A mixture in which droplets of fat are
prevented from joining together by an emulsifying
agent. E.g. _______________________
Dissolving
Dissolving: The complete intermingling of the
particles of two or more substances.
Solute: The substance that dissolves in the solvent
to form a solution. There is usually less solute than
solvent in a solution.
Solvent: The substance that dissolves a solute to
form a solution. There is usually more solvent than
solute.
You dissolve salt in water. Which is the solute??
Which is the solvent??
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Why substances dissolve
1. Some substances mix because
the particles of one move and
fill the spaces between the
particles of the other.
2. The particles of the solute are
more attracted to the particles
of the solvent then themselves .
Factors Affecting the Rate of
Dissolving
1.
2.
3.
4.
5.
Type of solute
Type of solvent
Temperature
Size of the pieces of solute –
small pieces will dissolve
faster.
Stirring – move the particles
around.
Water is the “Universal Solvent”.
Two-thirds of the earth is covered
with water.
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Solubility
The maximum amount of
solute you can add to a
fixed amount of solvent at
a given temperature.
Saturated and Unsaturated
Solutions
Unsaturated – a solution in
which more solute can dissolve
at a given temperature.
Saturated – a solution in
which no more solute can
dissolve at a given temperature.
Supersaturated mixture
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Solubility in g/100 mL of water at 0oC
Compound
table salt
baking soda
carbon dioxide
sugar
hydrogen
oxygen
ammonia
Solubility (g)
35.7
6.9
0.35
180
0.000 19
0.007
92
Insolubility
Not able to dissolve in a particular
solvent.
Particles are not attracted to the
particles of the solvent.
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