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The Physical Separation of
Substances
Distillation Filtration •
By: Allan Y, Pauline W, Alex W, and Justus S
•
•
• Evaporation
Recrystallization
Paper Chromatography
Hand Separation
Solvent Extraction
Gravity Separation
Allows for the separation of liquids from
solids
Usually involves a liquid (filtrate) that is
passed through a filter; the material that
remains on the filter is called the residue
Filtration
Filtration
Filtration cannot be used to separate
dissolved solids from a liquid (filtration
only works when the solid particles are big
enough to be seen)
Distillation
As a liquid with the lowest boiling temperature
in the solution boils first, the vapor produced
ascends to the top of the distillation flask, passes
a thermometer, and enters the side-arm of the
flask which leads to the condenser. As the vapor
enters the cold inner surface of the condenser, the
gas cools and condenses back into a liquid,
which drips out the end of the condenser as the
distillate
Hand Separation
Separation of
MECHANICAL
MIXTURES
Can often be separated
by HAND or by use of
SIEVE or MAGNET
Evaporation
Separation of SOLID-IN-LIQUID
SOLUTIONS
Can often be separated by allowing liquid to
EVAPORATE or to be BOILED AWAY,
leaving solid
SOLVENT EXTRACTION
There are two ways in which this
technique can be used …
# 1…
Extraction of a solid from a mechanical
mixture
This method requires a liquid that
dissolves one or more solids present so
the desired product is left behind or
dissolved and separated by evaporation
#2 …
Extraction of a dissolved liquid or solid
from a liquid solution
To carry out this technique, a solution
with one or more solid and/or liquid
substances dissolved in a liquid solution,
a solvent must contain two properties:
The added solvent is immiscible with the
solvent present
The added solvent dissolves one or more
desired substances from the substances and
leaves behind the unwanted
After the solvent is added, the mixture is mixed
in a separatory funnel and the added solvent is
drained from the original solvent
RECRYSTYALLIZATION
Recrystallization is a variation of
evaporation in which a solid in a solid-in-liquid solution is separated in a pure crystalline state
A saturated solution must be prepared in order for recrystallization to occur
A solid is added to a solvent until no more solid can dissolve and adding just enough hot solvent to dissolve the solid, the mixture is allowed to cool and evaporate, forming crystals
Once the crystals have formed, they are
removed by either hand separation or
filtration
Gravity Separation
Separation of two components of a homogeneous mixture
Clarification and thickening are two different products from the same method
Method: in a mix of a solid and liquid, the solid will gradually gather at the bottom of the container while the liquid remains on top
Gravity Separation
Clarification wishes the purified liquid at the end
Thickening wishes the purified solid at the end
When feasible, centrifugal force may also be used in place of gravity (faster separation due to higher pressure upon contents)
Paper Chromatography
Separates small amounts of Solid-in-Liquid
solutions containing two or more dissolved
solids
It requires a drop of the mixture placed near
the end of a sheet of absorbent paper
That end is dipped in the “developing”
mixture
Paper Chromatography
As the solvent gradually travels up the sheet
it will carry along the dissolved solids
The edge of the solvent’s travels is known
as the “solvent front”
Depending on how readily the solids are
dissolved by the solvent, various streaks of
color will appear behind the solvent front
The END!!!!!!!!
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