CLASSIFICATION AND SEPARATION OF MATTER
Pre-lab Questions:
Define the following: (You will need to use your textbook and any other references, such
as a dictionary, in addition to the text of this experiment.)
(a) homogeneous mixture
(b) heterogeneous mixture
(c) solution
(d) physical change
(e) chemical change
(f) filtrate
(g) chromatography
Classify each of the following as element, compound or mixture:
(a) sodium
(f) blood plasma
(b) sand
(g) ethyl alcohol
(c) calcium carbonate
(h) air
(d) beer
(i) gasoline
(e) sulfur
(j) sucrose
List several types of chromatography. How do the types of chromatography you have listed
differ? How are they similar?
Laboratory tests established the following properties of sulfur (S), carbon (C) and iron (Fe).
S
C
Fe
Solubility in water
insoluble
insoluble
insoluble
Solubility in carbon disulfide soluble
insoluble
insoluble
Attraction to a magnet
unattracted unattracted attracted
Given a powdered mixture containing sulfur, carbon and iron, devise a stepwise procedure
which would separate all the components. (Note: Carefully describe the separation procedures
you use and how you would obtain the pure solid components. Carbon disulfide is extremely
flammable; do not use an open flame in your scheme. Carbon disulfide is also very
poisonous.)
EXPERIMENT 1: CLASSIFICATION AND SEPARATION OF MATTER
PART I: Separation of a Solid Mixture
If you have not already done so, please read the foreword to this manual before beginning the
experiment.
In this experiment some properties of three substances will be studied. Based upon the
observed properties a scheme must be developed to separate the components of a mixture.
Before beginning the experiment, several techniques which will be useful in completing the
separation of a mixture will be demonstrated by your instructor. Use the space below to
record important notes.
Obtain approximately 0.1 g each (do not weigh) of sand, NaCl (sodium chloride) and
CaCO3equivalent to 0.1 g - it is not necessary to weigh the solids on the balance at this point
in the (calcium carbonate) in 13 x 100 mm test tubes. Use the approximate volume that is
procedure. Describe the appearance of each of the solids.
Obs. #1 (sand)
Obs. #2 (NaCl)
Obs. #3 (CaCO3)
To each test tube containing one of the solids add 5 mL of deionized water. Stopper and
shake. Record your observations.
Obs. #4 (sand + H2O)
<H4
Obs. #5 (NaCl + H2O)
Obs. #6 (CaCO3 + H2O)
If a change occurs in Obs. #4 - 6, is it a physical or chemical change? ________________ If a
chemical changes occurs, write the chemical equation.
Eq. #1
Clean the three 13 x 100 mm test tubes and obtain another 0.1 g sample of each solid. To each
test tube containing one of the solids add 5 mL of dilute (6 M) HCl (hydrochloric acid).
Caution: Dilute hydrochloric acid is corrosive. Be very careful when adding this solution
to the solids. Do not stopper or shake these test tubes. Record your observations.
Obs. #7 (sand + HCl)
Obs. #8 (NaCl + HCl)
Obs. #9 (CaCO3 + HCl)
If a change occurs in Obs. #7 - 9, is it a physical or chemical change? ________________ If a
chemical changes occurs, write the chemical equation.
Eq. #2
Summarize your observations (#4 - 9) in a tabular form similar to that used in Problem 4 of
the Pre-lab.
If you had a mixture of sand and salt (NaCl), briefly describe how you would separate and
determine the composition of the mixture. (Note: Use the decanting and filtering techniques
demonstrated by your instructor.)
Expl. #1
If you had a mixture of sand and calcium carbonate (CaCO3), briefly describe how you would
separate and determine the amount of each the mixture. (Note: Use the decanting and filtering
techniques demonstrated. One of the components of the mixture may be converted into
another compound during this procedure.)
Expl. #2
Shown below is an incomplete flow chart for the separation of a mixture of the three solids
(sand, NaCl and CaCO3). Based on your observations, complete the flow chart by filling in
the blank spaces (A, B, and C) with the name of the solid obtained. Due to a chemical
reaction, one of these will be different than the original solids in the mixture.
B
Obtain an unknown mixture of sand, sodium chloride, and calcium carbonate from your
instructor. Record the unknown number.
Unknown Number _______________
Using the analytical balance, weigh your evaporating dish to the nearest 1 mg and record the
mass.
Mass of evaporating dish ...................... ______________ g
Add about 1 gram of the unknown to the evaporating dish and reweigh.
Mass of evaporating dish + unknown................................ ______________ g
Calculate the mass of the original unknown sample.
Mass of original sample........................ ______________ g
Add 5 mL of deionized water to the unknown sample in the evaporating dish. Stir the mixture
carefully to dissolve Component A. What is the identity of Component A?
Identity of Component A _______________
Weigh a piece of filter paper to use in the next step.
Mass of filter paper............................______________ g
When the evaporation is complete, cool the dish to room temperature. Weigh the evaporating
dish and the solid residue. Record the mass.
Mass of cool evaporating dish and solid residue (Component A) ............ ______________
Mass of Component A ........................ ______________
Pour 5 mL of 6 M HCl (hydrochloric acid) into the funnel containing components B and C.
Upon addition of the 6 M HCl stir the solid gently with a clean glass stirring rod, being
careful not to tear the filter paper. Add an additional 2 mL of dilute (6 M) HCl to be sure the
reaction is complete. How can you tell that the reaction is complete?
Expl. #3
If the water were evaporated from the solution above, what would be the identity of the solid
residue?
Identity of Solid Residue ______________
Dispose of the solution. Rinse the solid Component B with a small amount of deionized water
from the wash bottle. Carefully lift the filter paper and Component B into a beaker and leave
them to dry until the next laboratory. What is the identity of Component B?
Identity of Component B ______________
When the filter paper and Component B are dry, weigh them together. Determine the mass of
components B and C.
Mass of filter paper + Component B after drying ....................______________ g
Mass of Component B.........................______________ g
Mass of Component C.........................______________ g
Calculate the percentage of each component in the original sample. (Show your work in the
space provided. All work must be shown to receive credit.)
% of sand in original sample .................______________ %
% of NaCl in original sample.................______________ %
% of CaCO3 in original sample...............______________ %
PART II: CANDY CHROMATOGRAPHY
Introduction:
Paper chromatography is a widely used method of separation. This lab will demonstrate the
basic techniques of paper chromatography. The substance is separated in the stationary phase
by the mobile phase. In this lab, the separation of the dyes used in two different kinds of
candy is performed. By comparing the Rf values of the dyes in each of the candies, we can
hypothesize that the dyes with the same Rf values are the same compound. However, since
the separation of the dyes is dependent on many different factors, we can only guess that the
two red dyes or blue dyes are the same compound, unless the name of the dye is given on
each package and is the same on each. The candy dyes may also be compared to solutions of
FD&C food dyes.
Purpose:
The purpose of this experiment is to separate and compare dyes found in two different kinds
of candy.
Materials:
1-600 ml beaker
vinegar
capillary tubes
pencil
prepared sample of candy coating dye
ruler
chromatography paper (4 x 20 cm)
plastic wrap
Safety:

Always wear aprons and goggles in the lab.
Procedure:
1. Obtain a beaker, add enough vinegar to cover the bottom, and cover the beaker with
plastic wrap.
2. Draw a pencil line 1 cm from the bottom of the chromatography paper.
3. Place the point of the capillary tube into the sample; some solution will be drawn up.
Gently and quickly touch the top of the capillary tube to the line drawn to make a spot.
Allow the spot to dry.
4. Spot twice more, allowing the sample to dry in between applications. Label with pencil
at the bottom the location of each sample. See diagram.
5. Repeat steps 3 & 4 with the dye from the other candy. (optional – spot standard FD&C
dyes as well. Keep spots 1.5 cm apart on the paper.)
6. Place the spotted paper in the beaker, spotted side down, with only the very top of the
paper touching the side of the beaker. The spots should not be in the water. Cover the
beaker with the plastic wrap.
7. Allow the chromatogram to develop until the solvent (vinegar) nearly reaches the top of
the beaker. Remove the sample from the beaker and draw a line across the paper at the
furthest point of the solvent's progression.
8. Draw the chromatogram in the data section, measure the distances traveled by the solvent
and each dye, and calculate an Rf value for each observed color dye contained in the
sample.
Data Table:
Color ________
Color ________
Color ________
Color ________
Rf ________
Rf ________
Rf ________
Rf ________
Color ________
Color ________
Color ________
Color ________
Rf ________
Rf ________
Rf ________
Rf ________
Rf 
distance from the origin (starting line) to center of spot
distance from the origin to solvent front (line from step 7)
Conclusions:
You are given a test tube containing a mixture of compounds A, B, C, D along with the following experimental
information:
C is soluble in Y. A and D are insoluble in X. A is insoluble in Y C is soluble in X. A is magnetic. B is
insoluble in Y. B is soluble in X. B and C are not magnetic. D is insoluble in Y. D is not magnetic.
Prepare a table which better organizes the experimental observations. Describe a procedure you could use to
separate the mixture. Your description should include text, a flow chart , or both.
Briefly describe how you would separate each of the following mixtures using procedures performed in this
experiment. Explain why you chose each method.
(a) a dye. Several milliliters are available for testing.
(b) a handful of sand in a gallon of gasoline.
(c) a mixture of sand and water (Note: The sand is very fine, and some tiny pieces are floating in the water).
(d) one liter of a solution containing water and ethanol.
(e) one drop of mixed pigments used in the production of green paint.
How could you tell if M&Ms and Skittles use the same red dye?
Define "chromatography" in one sentence.
What is the purpose of doing chromatography?
Do you think the mobile phase affects the Rf? Why?