Exploring the Chemical World, PGCC, 2003
One characteristic that distinguishes a mixture from a pure substance is the ability to separate the mixture
into its components by simple physical means.
Whether a mixture is homogeneous or heterogeneous, its
components will have
properties that can be used to affect this separation
Some of the properties
that can aid in the isolation of components are:
particle size; color;
density; solubility in water;
ability to sublime; and magnetism
You will take advantage of these properties during the
You will be rotating from station to station in the laboratory to perform each of the separations that
For each mixture used you are to record the following information in the data section
before you begin that mixture
detailed physical description of the original mixture; include whether it is homogeneous
approach you might take to separate the mixture based on your visual inspection.
When you are finished the separation you must record
description of separated components
The stations are numbered 1 through 8.
It does not matter in what order you do the stations
but you should leave Stations 7 and 8 until you have completed Stations 1-6.
number (below) and the mixture number match the station number.
Obtain one small scoop of Mixture 1 (fine sand, SiO
, and table salt, NaCl) and place it in a
medium (25mm x 200mm) test tube. What does Mixture 1 look like?
After completing the
visual inspection, add approximately 5 mL of distilled water to the mixture.
Agitate the contents
to insure complete mixing.
What does this new mixture with the water mixture look like?
Has anything happened to the original mixture?
After allowing any material to settle, carefully pour off the water collecting it in a small
Keep the solid component in the test tube. What do you think is the identity
of the solid left in the test tube?