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Warm-up

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Warm-up What does it mean to change something? Changes Physical vs. Chemical Physical Changes No NEW substances are made! It is a change that doesn t alter the ... – PowerPoint PPT presentation

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Title: Warm-up


1
Warm-up
  • What does it mean to change something?

2
Changes
  • Physical vs. Chemical

3
Physical Changes
  • No NEW substances are made!
  • It is a change that doesnt alter the substance,
    only one of its physical properties
  • Reminder a physical property is something you
    can observe without changing an object like
    volume, color, mass, density, etc.

4
Examples
  • Read page 88 and write down 3 examples of
    physical changes
  • Ice freezing
  • Wood sanded
  • Sugar dissolving
  • What else do you have?

5
Reversibility
  • You can reverse a physical change and return the
    substance back to its original state most of the
    time.

6
Chemical Change
  • NEW substance is made!
  • This is when one substance reacts with something
    else to turn into a new material with its own
    unique properties
  • Key words for identifying a Chemical Change
    (useful when the questions uses chemicals that
    you have never heard of!)
  • Reacts
  • Decomposes
  • Produces
  • Neutralizes

7
Examples
  • Look at the pictures on page 92 and write down 3
    examples of chemical changes
  • Soured milk
  • Effervescent tablets fizzing
  • Statue of Liberty turning green
  • Cake baked. Batter is a different substance than
    the finished baked cake!
  • What else do you have?

8
How can you tell a Chemical Change has occurred?
  • Color change
  • Odor change
  • Producing Gas
  • Fizzing and/or foaming
  • Sound is produced
  • Light is produced
  • Temperature changes
  • Precipitate forms (solid from the combination of
    2 liquids!)

9
How can you tell a Chemical Change has occurred?
(Examples)
  • Color change ? Bleach on jeans
  • Odor change ? Milk sours
  • Producing Gas ? Airborne medicine releasing gas
  • Fizzing and/or foaming
  • Sound is produced ? Snap rocks/ campfire
  • Light is produced ? Glow stick glowing
  • Temperature changes ? Campfire
  • Precipitate Forms ? Milk chunks from milk and
    vinegar mixing.

10
NO Reversibility
  • In a chemical change, the change usually CANNOT
    be reversed, it is permanent.
  • These changes can only be changed through more
    chemical means.

11
Chemical Changes continued!
  • Chemical Changes always involve physical changes,
    however they are only identified as a chemical
    change.
  • What does this mean?
  • When you bake a cake it will change state (liquid
    to solid) however it also releases gases.
  • Chemical Changes trump physical changes! ?
  • (Chemical always wins!)

12
Venn Diagram Assignment
  • Create a Venn Diagram to compare and contrast
    physical and chemical changes
  • You must include
  • 2 pictures of each type of change
  • 15 facts
  • At least 5 on each side and 3 in the middle,
    final 2 you get to choose
  • Due Thursday/Friday!
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