Transcript SEPARATION TECHNIQUES - Dr. Vernon-

SEPARATION TECHNIQUES
•Filtration and Evaporation
•Distillation
•Paper Chromatography
Ms McGhee
Filtration and Evaporation
 Filtration is a method for
the separation of the
parts of a heterogeneous
mixture.
 When students mixed
two common substances,
a heterogeneous mixture
was formed.
 There was a new
precipitate formed in a
solution.
Filtration and Evaporation
 In preparation for the
filtration, the filter
paper must be folded
into a cone.
 The students may be
measuring the mass of
the filter paper so that
they can determine the
mass of the precipitate
after the experiment.
Filtration and Evaporation
 The cloudy,
heterogeneous mixture
is carefully poured into
a funnel that has been
set up with filter paper.
 Notice that the filtrate
is being collected in a
beaker.
Filtration and Evaporation
 The precipitate in the
original heterogeneous
mixture beaker must
be washed out using
the stirring rod and the
wash bottle.
 We have collected all
the precipitate in the
filter paper now.
Filtration and Evaporation
 Evaporation is a
method for separating
the components of a
homogeneous
mixture.
 After filtration, the
students evaporated
the filtrate solution to
separate it from any
dissolved solute.
Filtration and Evaporation
 The liquid (solvent)
from the filtrate
solution will evaporate
leaving behind any
dissolved solute.
Filtration and Evaporation
 Mean while, the
insoluble solid (original
precipitate!) that was
collected on the filter
paper was dried in an
oven.
 By taking the mass of the
filter paper before the
filtration and the mass of
the paper and solid after
it dries…
 …the mass of precipitate
can be calculated
Distillation
 Distillation is a
method for the
separation of the
components of a
homogeneous
mixture.
 The basis for
separation is the
different boiling
points of the
components in
the liquid.
Distillation
 The distillation
apparatus will be
used to separate
some of the
components of
imitation vanilla.
Distillation
 The component
with the lowest
boiling point will
boil off first.
 The vapor is
condensed and
this distillate is
collected in the
receiving flask.
Distillation
 When all of a
particular
component is
gone…
 …the temperature
will rise to the
next boiling point
 and that
substance will
form the next
distillate.
Imitation Vanilla Flavor
Ingredient
Chemical formula
Boiling point
(1 atm)
Water
H20
100C
propylene glycol
C3H8O 2
188C
vanillin
C8H8O 3
285C
caramel color
mixture of complex sugars
N/A
0.1% sodium benzoate
NaC6H5CO2
N/A
phosphoric acid
H3PO4
158C
ethyl vanillin
C9H10O3
285C
Paper Chromatography
 Paper chromatography
is an easy way to
separate the soluble
components of a
homogeneous mixture
 We will perform a
chromatographic
sparations of the
pigments in felt pens
Paper Chromatography
 Specific vocabulary
words include:
 Mobile phase
 Solvent
 Stationary phase
 Paper
 Separation is based on:
 Solubility of the sample
in the mobile phase
 Molecule size
 (and other factors)