Mixtures and Solutions
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Mixtures and Solutions
• A mixture is a combination
of two or more components that
are NOT chemically combined,
and retain their identities.
Mixtures can be physically separated.
The identities of the substances DO NOT
change.
A homogeneous mixture is also called a
solution.
Mixtures
• When a mixture’s components are easily
recognizable, such as pizza, it is called a
heterogeneous mixture.
• In a homogeneous mixture such
as chocolate milk, the component
particles cannot be distinguished,
even though they still retain their
original properties.
Mixtures
• Common Techniques for Separating Mixtures
Distillation – separates a mixture based on boiling
points of the component.
Examples :
saltwater
crude oil into gasoline and kerosene
Magnet – separates iron from other objects.
Centrifuge – spins and separates according to densities.
Solutions
• A mixture that appears to be a single
substance but is composed of particles
of two or more substances that are
distributed evenly amongst each other.
A solution may be liquid, gaseous, or solid.
Examples of solutions
Liquid - seawater
Gas - air
Solid - alloys
Parts of a Solution
•SOLUTE – the part
of a solution that is
being dissolved
(usually the lesser
amount)
• SOLVENT – the
part of a solution
that dissolves the
solute (usually the
greater amount)
• Solute + Solvent =
Solution
Solute Solvent
Example
liquid
solid
Mercury in gold,
Hexane in wax
Steel, Brass’
Alloys,
Hydrogen into
metals
solid
solid
gas
solid
solid
liquid
Sugar, Salt, Tea,
Kool-Aide
liquid
liquid
Mixed drinks, Paint
thinners.
gas
liquid
Soft drinks****,
oxygen in water.
gas
Gas
Air
Solutions
• Dissolving – The process in which
particles of substances separate and
spread evenly amongst each other.
• Solute – substance that is dissolved. A solute is
soluble, or able to dissolve.
• A substance that is insoluble is unable to
dissolve, forms a mixture that is not
homogeneous, and therefore NOT a solution.
• Solvent – substance in which solute is dissolved.
Definitions
Solutions can be classified as
saturated or unsaturated or
super-saturated.
A saturated solution contains the
maximum quantity of solute
that dissolves at that
temperature.
An unsaturated solution contains
less than the maximum
amount of solute that can
dissolve at a particular
temperature
Definitions
SUPERSATURATED SOLUTIONS
contain more solute than is
possible to be dissolved
Supersaturated solutions are
unstable. The supersaturation is
only temporary, and usually
accomplished in one of two ways:
1. Warm the solvent so that it will
dissolve more, then cool the
solution
2. Evaporate some of the solvent
carefully so that the solute does
not solidify and come out of
solution.
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Solubility
• The solubility of a solute is the amount of solute needed
to make a saturated solution using a given amount of
solvent at a certain temperature.
• Solubility is usually expressed in grams of solute per 100
ml of solvent (g/100ml)
• Three (3) methods that affect solubility
– Mixing, stirring, or shaking
– Heating
– Crushing or grinding
Suspension
• A mixture in which particles of
a material are dispersed throughout a liquid or gas but are large
enough that they settle out.
– Particles are insoluble, so they DO NOT
dissolve in the liquid or gas.
– Particles can be separated using a filter.
• Examples:
• Salad dressing
• Medicines that say
“shake well before use”
Colloids
• A mixture in which the particles are
dispersed throughout but are not heavy
enough to settle out.
• Made up of solids, liquids and gases.
– Examples :
•
•
•
•
•
•
Mayonnaise
Stick deodorant
Milk
Jello
Whipped cream
Peanut butter
My Quickie Definitions
• Unsaturated – Can hold some more
• Saturated – Can’t hoolllddd nooo moorre
• Super-saturated – Found a way to make it
hold more
• Solubility – ability to be dissolved