Experiment
1.3
Identifying Chemical and Physical Changes (4)
Report = 83
Introduction: (5)
Matter can undergo many different changes. When
a physical change occurs, only the form of the
substance changes. For example, if water is boiled
and changed into vapor, the change is physical.
The material we end up with is still water, even if it
is in a different form. Other examples of physical
changes include dissolving a substance in water,
grinding matter into small pieces, or raising the
temperature of a substance. Chemical changes,
however, result in the formation of new materials.
Matter is reorganized, and the new substances
have properties that differ from the original
substances. Examples of chemical changes include
the burning of paper, the rotting of an apple, or the
rusting of iron. Some signs of chemical change
include a change of color, the formation of a
precipitate (a solid settling out of a solution), the
formation of a gas, and the release of heat.
As you observe chemical and physical changes in
matter, it is important to distinguish between pure
and impure substances. Pure substances are
those made up of only one type of matter.
Examples of pure substances include all elements
and all compounds. Impure substances are called
mixtures. Mixtures are combinations of two or
more pure substances. A solution of salt water is a
mixture of sodium chloride (common table salt) and
water, both of which are compounds.
In this experiment, you will be working with some
common substances as you observe both chemical
and physical changes. Learning to recognize
differences between chemical and physical
changes is important in explaining the behavior of
matter.
Objectives: (2)
1. Observe and define properties of some common
substances.
2. Recognize physical and chemical changes in
some common substances.
Materials: (5)
Apparatus:
Six 13 X 100 mm test tubes
safety goggles
microspoon
laboratory apron
test tube rack
rubber stopper
stirring rod
Tirrell burner
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Test tube holder
Crucible tongs
Reagents:
sodium hydrogen carbonate
sodium chloride
sucrose
Iron nail
0.1 M Copper(II) nitrate
Steel wool
iodine
deionized water
copper(II) nitrate. Wait about 10 minutes to
make any observations.
Procedure:
1. Put on your safety glasses and laboratory
apron.
2. Carefully observe each experiment and note
your observations. Label each experiment as
physical or chemical change with explanation.
Note: you do not have to do them in order
except you must start with #1.
3. Expt. #1. Obtain a iron nail and clean it with
steel wool. Place about 4 mL of 1.0 M
copper(II) nitrate into 13x100 test tube. Notice
the color of solution. Add the iron nail to the
Experiment 1-3
1M acetic acid
Paper towel
Barium hydroxide octahydrate
Ammonium chloride
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4. Expt. #2. Add about a microspoon of sodium
chloride into 13x100 test tube. Add 4 mL of DI
water into test tube. Using stirring rod, stir for
about 2-3 minutes. Make observations
5. Expt #3. Repeat step 4 with sucrose.
6. Expt #4. Add about a microspoon of sodium
hydrogen carbonate into 13x100 test tube.
Add 2 mL of acetic acid into test tube over a
sink. Make observations
7. Expt #5. Add about a microspoon of iodine to
a 13x100 test tube. Stopper the test tube with
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a stopper that has no holes. Set-up your Tirrell
burner. Gently heat the test tube. Hold the test
tube about 6 inches above the flame for about
1-3 minutes. Allow to cool and place back into
test tube rack. Make observations throughout
the whole experiment.
8. Expt #6. Set up Tirrell burner. Using crucible
tongs take about a 5 cm by 5 cm paper towel
and set it on fire. Make observations.
9. Expt. #7. Mass 4 grams of barium hydroxide
and add it to a clean, dry 50 mL beaker. Mass
2.75 grams of ammonium chloride and add it
the same 50 mL beaker. Using a stirring rod,
gently but vigorously stir the solids together for
3-5 minutes. Make observations.
10. Get stamp and clean up all material and
wash hands.
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Data and Observations: (38)
(28) Data
Experiment
Observation (14)
Physical or Chemical.
Explain! (14)
(10) Stamp............…..........
Analysis and Conclusions: (19)
(10) 1. Summarize the chemical changes you have
observed in this experiment.
(2) 3. What is the major gas produced when burning
paper?
(5) 2. Summarize the physical changes you observed in
this experiment.
(2) 4. What would the major use for experiment #7?
Synthesis: (17)
(2) 1. What metal was formed on the iron nail?
(2) 2. How could you recover sucrose or sodium chloride
once it has dissolved in water?
of a slow reaction and one example of a fast
reaction, other than the chemical reactions you
observed in this experiment.
(9) 3. What are the chemical formulas for each of the
substances you used in this experiment:
iron
sucrose
acetic acid
sodium hydrogen carbonate
sodium chloride
iodine
barium hydroxide
ammonium chloride
water
(4) 4. Think about some fast and slow reactions you have
observed in the last 24 hours. Give one example
Experiment 1-3
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