Separation of Mixtures Lab
Suppose that you are the new owner of the Eagle Recycling Factory and
you are looking for business.
An official from the city of Fremont, Mr. Jones, tells you that they
have a dump truck full of recycled materials that must be physically
separated, and they will pay you $5,000 if you can do it. Unfortunately,
the job is made more difficult by the fact that someone has ground all
of the materials into a fine powder, making it impossible to separate
them by hand.
Fortunately, Mr. Smith knows what the materials in the truck are:
Aluminum cans, steel cans, soda bottles ( PET#1), milk jugs (HDPE #2)
There are several ways that chemists use to separate mixtures.
The different physical properties of the components of the mixtures
are used to separate and isolate each component.
Magnetic properties can be used to separate some metals.
Solubility can be used to separate soluble components from insoluble
components. Different boiling points or melting points can be used to
separate mixtures. Mass and charge are often used to separate
mixtures using a method called chromatography. You may have seen this
method on CSI. Density can be used to separate components that float
from components that sink. For example, some things will sink in fresh
water but float in salt water. Keep in mind, though, that once the
mixture gets wet the pieces stick together and may be more difficult
to separate.
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In your factory, you have the following materials at your disposal:
A long conveyor belt
Several powerful magnets hanging above the conveyor belt
A tank that can be filled with water
Strainers for filtering material
Sources of fresh or ocean(salt) water.
Your job: Find a way to separate the four recycled materials. You will
need to do this in several steps.
Your team will design a procedure to separate the material and then
test the procedure in the lab to determine if it works as planned. Your
team’s plan should include the step by step procedure that you think will
work. Prepare a table to record your measurements, observations and
results of each test.( Don’t forget to weigh the mixture sample before
you start)
When the components are separated, dry them and weigh each
component.
Calculate the percentage of each component in the total sample of
recycled material.
Your conclusion will include how effective your separation method works
and how the factory could be laid out to continue this type of
separation daily. If your separation method did not work, explain what
went wrong and how it might be corrected.
Discussion Questions:
1. What problems did you encounter while trying to separate this
mixture?
2. Is this mixture a good representation of what is in the recycle bins
at home?
3. How would separate paper if it had been part of the mixture?
4. Is there way to separate #3 and #4 plastics (one sinks and one
floats) if they were added to the mixture?
5. What can be done to encourage more people to separate
recyclables instead of throwing them in the garbage?