SCH3AG Physical and Chemical Changes Lab
Introduction:
Substances undergo changes when their conditions are changed. A change in condition could be
an increase in temperature, a mechanical deformation, exposure to another substance, or any
number of other alterations. If the substance remains the same after the change, a physical
change has taken place.
If a new substance has appeared, a chemical change has occurred. In this experiment you will
observe the changes that a variety of substances undergo and identify them as either physical or
chemical changes.
Purpose:
Record an appropriate purpose in your formal lab report.
Apparatus:
9 large test tubes, crucible tongs, wooden splint, test tube rack, Bunsen burner, watch glass, a test
tube holder, gas starter, 250 mL beaker, magnet, iron ring mortar and pestle, crucible lid or cover,
retort stand, glass stir rod, petr idish, clay triangle
Materials:
sodium hydroxide solution, copper (II) sulfate, sucrose, sulfuric acid, iodine, water, iron (II)
sulfate solution
Procedure:
1. Place a check mark in the space provided as you read or complete each step of the procedure.
2. Read over the entire lab and write out an appropriate purpose for this lab on your looseleaf
paper. Under the materials section and the procedure section, simply refer to this handout as a
reference.
3. Summarize all of your observations systematically in a data table as outlined under the
observations section. Include detailed descriptions of the observations before, during, and after
the procedure performed.
4. The first experiment will be a teacher demo performed in the fume hood. Your teacher will
add a few crystals of iodine to a beaker. It will then be heated on a hot plate. Record your
before, during and after observations in your data table
5. The second experiment will be a teacher demo performed in the fume hood. Your teacher will
add 15-20 mL of concentrated sulfuric acid to 45 g of sucrose in a 250 mL beaker. Record your
before, during and after observations in your data table.
6. The rest of the experiment is to be completed by you and your lab partner. Add 3 mL of iron
(II) sulfate solution to a test tube. Add 3 mL of sodium hydroxide to a second test tube. Describe
each. Mix the two solutions together, observe immediately and after letting it stand for five
minutes.
7. Place 1.0 g of copper (II) sulfate (you measure this by comparison with a 1 g sample displayed
at the front) into a test tube. At your lab station, pour the copper (II) sulfate into a mortar. Use
the pestle to grind and crush the copper (II) sulfate to a fine powder. Half fill a 250 mL beaker
with water. Add the copper (II) sulfate to the water and stir using a glass stirring rod. Observe.
Observations:
This is a only a partial observations table to show you how to set one up properly. In your formal
lab report under the observations section, you will need to recopy your rough observations table
in good. To receive full marks it must be aneatly presented, detailed table with the following
headings.
Discussion:
1. a) Indicate whether each part of the experiment illustrates a physical or a chemical change.
b) What evidence can you use to help support your decision in each case? Give as many reasons
as possible for each choice.
2. Classify the following as either physical or chemical changes:
a) a banana rotting
b) stretching an elastic band
c) frying an egg
d) pouring mild onto your cereal
e) Lake Ontario freezing over in winter
f) a forest fire burning in Northern Ontario
Conclusions:
Explain, using your own words, what the main difference is between a physical change and a
chemical change. Give two examples of each type of change that you might observe occurring in
your everyday life. Make sure your examples are unique to your lab report!
Source of error:
List two areas where errors could have been made in the experiment. Why are these considered
errors? Explain how they will affect your experimental results.