SEPARATION TECHNIQUES
for
HETEROGENEOUS MIXTURES
Heterogeneous mixtures are composed by substances that can be distinguished. Sometimes
there are practical reasons to for wanting to separate mixtures. To do this we can employ
separation techniques such as filtration and decantation.
Separation techniques are based on the different physical properties of the substances we
want to separate, such as boiling point, density, solubility or particle size.
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Watch glass
Funnel
Beaker
Magnet
Stirring rod
Crystallizer
Sieve
Scale
Ring stand
Clamps
Iron ring
LAB MATERIAL
Name correctly the following lab materials
PROCEDURE
1. Place your sample in a watch glass and determine its weight using the scale.
Sieve the sample to separate the chicken peas from the rest of the substances. Collect chickpeas
and the rest of the sample in different papers.
2. Determine the weight of the chickpeas using the scale
3. Use the magnets to separate the iron filings. Wrap up the magnet in a paper to make it easy.
4. Determine the weight of the iron filings using the scale
5. Pour the sand + salt sample into the beaker and add water to solve the salt. This is called solidliquid extraction.
6. Separate sand using filtration:
a. Prepare a filter paper
b. Place the filter into the funnel over the crystallizer
c. Pour the sand +salt mixture into de filter
d. Spread the sand in the filter and let it dry
e. Determine the weight of the sand using the scale
f. Recover salt using crystallization.
g. Determine the weight of the salt using the scale
Draw with detail the set-up for steps 4 to 6. Indicate in each case the components in the mixture
before and after the technique.
EXPERIMENTAL DATA
Substances
Weight (g)
Initial sample
Chickpeas
Iron filings
sand
salt
QUESTIONS
1.
Describe the initial aspect of the mixture
2.
Is it homogeneous or heterogeneous? Why?
3.
For each technique, indicates the substance it helped separating and the properties that made
the separation possible.
Substances
Properties
Sieving
Magnetic separation
Filtration
Crystallization
4.
Draw a conceptual map showing the steps followed to separate the mixture. (You can used the
back of the page). Indicate the name of the technique used in each case.