Name: _________________________
Lab Partner: ____________________
Analysis of a Mixture
Introduction:
Chemists frequently work with mixtures. Usually, only one component of the
mixture is desired, which makes the other components impurities. Chemists have
developed techniques to remove the desired component from the impurities or to
isolate each individual substance in the mixture. A great amount of a chemist’s time
goes into separations.
Objectives:


To demonstrate the process of separating a sand/salt mixture.
To determine the percent by mass of each substance in the mixture.
Procedure:
Day One
1.
Measure the mass of a 150 mL beaker and record the mass below.
Mass of 150 mL beaker: ______________
2. Obtain a scoop of a sand salt mixture from your teacher.
Record the mass of the mixture.
Mass of beaker and sand salt mixture: _______________
Question: How can you determine the mass of the sand/salt mixture?
Mass of the sand/salt mixture: ________________
Question: Which part of the mixture is soluble (dissolvable) in water?
_____________________
3. Using a graduated cylinder measure about 40 ml of water and pour it into the
beaker. Stir the mixture using a stirring rod thoroughly for about a minute.
4. Initial (ex: AZ) (use a pencil) and weigh a piece of filter paper. Record the
mass below.
Mass of filter paper: __________________
5. Fold the paper into a cone (see diagram).
6. Assemble the following set-up (see diagram):
 Ring stand with a ring clamp attached.
 Clay triangle placed on ring clamp
 Place the funnel (with folded filter paper) in
the triangle.
 Carefully weigh a dry 250 mL beaker, record
the mass on the data chart. Place this clean
and dry 250 mL beaker beneath the funnel.
Too avoid splattering, make sure the end of
the funnel is inserted into the 250 mL
beaker.
Mass of 250 mL beaker : ______________
7. Swirl the mixture of sand, salt and water and immediately pour the mixture into the
funnel, getting as much sand onto the filter paper as possible. Rinse the remaining
sand out of the beaker using a wash bottle. Warning: Don’t use a lot of water.
This will increase the time needed to evaporate the water.
8. Remove the marked filter paper containing the sand from the funnel hand it over to
your teacher. Allow the filter paper to dry overnight.
The next day, record the mass of dried filter paper and sand.
Mass of dried filter paper and sand: ______________
Remove and label with your initials the 250 mL beaker containing the salt-water
mixture. Hand your beaker to your teacher.
Clean up your lab. station.
Day Two
Discuss with your partner how to obtain the salt from your mixture.
Describe your method:
What measurements do you need? Record your information.
Summarize your information from this laboratory activity using the data table below.
Data Table:
Mass of sand salt mixture
Mass of dry sand
Mass of dry salt
Calculations:
Find the percent sand and the percent salt in the original mixture using the following
units. Show all work using significant figures and show all units.
Percent by mass of sand in the mixture
% sand = mass of sand
mass of mixture
Answer:________
x 100
Percent by mass of salt in the mixture
% salt = mass of salt
x 100
mass of mixture
Answer:_________
Summary Questions:
1. Calculate your percent error for your sand and salt values. Show the work of both
calculations.
% Error for sand
% Error for salt
Measured Value: ____________
Accepted Value: ____________
Measured Value: ____________
Accepted Value: ____________
Percent Error: _________
Percent Error: _________
2. Another way of separating a mixture is through distillation. Look up this technique
and describe how you would separate a mixture containing the following: water,
gasoline, and alcohol.
________________________________________________________
________________________________________________________
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