CHEMISTRY 11 – PHYSICAL SEPARATION OF SUBSTANCES WORKSHEET
1) (a) If you wished to completely remove and save the liquid from a solid-in-liquid solution, which
separation method(s) could be used?
Distillation
(b) If you wished to completely remove and not save the liquid from a solid-in-liquid solution,
which separation method(s) could be used?
Evaporation or recrystallization
2) Which separation method(s) would be the most efficient to separate the following?
(a) Two miscible liquids
i. Distillation
ii. Solvent extraction
(b) Two immiscible liquids
i. Separatory funnel (gravity separation)
(c) A flour-like solid floating around in water
i. Filtration
ii. Gravity separation
(d) A mixture of three water-soluble dyes
i. Chromatography
(e) A mixture of sand, salt and water
i. Filtration
THEN USE
ii. Distillation
3) A red-brown solution of bromine in water (density = 1.01 g/mL) is poured into a separatory funnel.
Trichloroethane (density = 1.34 g/mL) is added and the mixture shaken thoroughly. Afterwards, two
liquid layers are seen in the funnel: a clear layer of water and reddish-orange layer of bromine in
trichloroethane. Which layer will be on top?
The layer having the lower density will be on top; that is, the water.
4) A mixture has been separated and the following chromatogram was produced. The two chemicals in
the mixture are in the list of chemicals below. Use the chromatogram to calculate the Rf values for
the two chemicals (show all of your work) and then identify the chemicals.
¥2
#
*
*2
1
Rftgfts
Rf
=
dan
=
=
1
4539¥
=
{gc#=
0.56
0.71
X
=
=
V
5) A pharmaceutical chemist runs a chromatography test on a substance and identifies two of its
components by comparing their Rf values against certain standards. If the two components have Rf
values of 1.0 and 0.41, and the solvent front has travelled 12.0 cm from the sample’s origin, what is
the separation distance on the chromatogram?
a
1.0
Rf=dd=
*2
0.41
Rfjdz
di=
¥0
=
-
12.0cm
sepdaisftainocne
d ,=4qacm
,£t
-12.0-4.92
7.08
=
cm
6) How can you separate all the components in a mixture containing sand, iron filings, water, gasoline,
red water-soluble dye and blue water-soluble dye? In pure form the dyes are powders.
sand
gas
,
ironfilings
,
red & blue
filter
Haq gas
,
dye
f\
Sand
red
,
filings
iron
dye
blue
&
,
HAO
,
funnel
Sand
iron
filings
leseparatoryjlmagnetls
gas
water
& blue
,
red
dye
ddistillationhs
-
red'& blue
water
reddye
chromatography
dye
-
blue
dye
7) A single solvent extraction removes 90% of a desired chemical from a solution. What percentage of
the chemical is left in the solution after two successive extractions?
amount
left
ii
0.10=10%11
after
"
one
two
extraction
extractions
=
=
0.10×0.10=0.010--1
%
8) How can you separate a mixture of the three solids: potassium sulphate (melting point = 1069°C,
soluble in water, insoluble in alcohol), calcium carbonate (melting point = greater than 1000°C,
insoluble in water, insoluble in alcohol) and naphthalene (melting point = 81°C, insoluble in water,
soluble in alcohol)?
potassium sulphate calcium
carbonate
naphthalene
,
,
FILTRATE
fswotyentaheoxntoraffifnnl
k
naphthalene
filter
calcium carbonate
potassium sulphate
,
alcohol
distil
L
alcohol
naphthalene
)
water
FILTRATE
THEN
filter
potassium
sulphate
,
fexsftoueetinotnwith
or
evaporate
resioue
,
,
Hao
fedviasptiotafe
water
potassium
Sulphate
9) Which process requires more energy: chromatography or distillation? Explain.
Distillation would require more energy because of the heating and cooling involved.
RESIDUE
calcium
carbonate