Chemical Change and Physical Change

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					 Chemical Changes
   and Physical
     Changes

  Objective: The student will identify
evidence of chemical changes through
 color, gas formation, solid formation,
        and temperature change.
       Testing a Tablet
• Suppose you read about a mysterious
  material beneath the Antarctic icecap
  that has been discovered by
  scientists.  How would you learn
  about such a material? A chemist
  would study it to learn about its
  chemical and physical properties.
  You can do the same thing.
                         Materials
•   Goggles
•   Mystery tablet
•   Test tube
•   Water
•   Sheet of black
    construction paper
•   Hand lens
•   Small plastic jar
•   Match
•   Science notebook
            Procedures
• Observe the tablet carefully. Record in
  your Science Notebook any properties
  you can observe just by looking at the
  tablet and handling it. Then break the
  tablet into four pieces of about the
  same size.
• Add one piece of the tablet to a test
  tube half full of water. Observe what
  happens and record your observations
  in your Science Notebook.
          Procedures cont.
• Hold the bottom of the test tube in
  one hand. Cover the opening of the
  test tube with your thumb. Describe
  what you feel.
• Place a piece of the tablet on a sheet
  of black paper and crush it. Examine
  the small pieces carefully with a
  hand lens. Describe what you see.
         Procedures cont.
• Place another piece of the tablet in a
  small jar and add a small amount of
  water.
• Have your teacher light a match for
  you. While the tablet is still reacting,
  dip the flame into the beaker, keeping
  it above the surface of the liquid.
  Observe what happens and record
  your observations.
         Analyze and Conclude
• Describe what happened when the tablet was
  added to water.
• Describe how the tablet changed during a physical
  change?
• Describe how the tablet changed during a chemical
  change?
• In step 3, how did the bottom of the test tube feel?
  What did you feel with your thumb?
• What can you infer about the gas that was
  produced during the reaction? Give evidence to
  support your inference.
• Make a list of the physical and chemical properties
  of the tablet. What do you think the tablet might
  be?
   Changes

Question: If I mix substance A with
 substance C and/or substance B with
 substance C, will there be a chemical
 change?

Hypothesis: If I mix substance A with
 substance C and/or substance B with
 substance C, then I think there will be a
 chemical change because …
                Materials
• 1 canister with
  substance A
• 1 canister with
  substance B
• 1 medicine cup with
  substance C
• 1 Zip-lock bag
• Paper towels
• Safety goggles
• Science Notebook
                Procedures
• Place substance A into one corner and
  substance B into the other corner of a zip-lock
  bag.
• Carefully place the cup in the bag.
• Keep it upright! Zip the bag closed.
• Tilt the cup over so that substance C spills into
  the bag.
• Observe.
• Feel the outside of the bag.
• What type of change do you think occurred?
  Why?
• Write down any evidence of a chemical change.
    Conclusion



• When I mixed substance A with substance
  C and substance B with substance C, a
  ______________ did occur.      The bag
  expanded and a gas was produced. There
  was also a temperature change and a color
  change.
                 Vocabulary
• Physical property – a characteristic that can be
  measured or detected by the senses.
• Chemical property – the ability or tendency of a
  material to change its chemical makeup.
• Physical change – a change in the size, shape,
  or state of matter with no new matter being
  formed.
• Chemical change – a change in matter that
  results in new substances being formed.