Chemical and Physical Changes

1
Chemical and Physical Changes
2
Physical Changes

• Only changes physical properties, does not become
  a new substance (usually reversible).
• Phase changes
• Dissolving
• Breaking

3
Chemical Changes

• When 1 or more substances form a new substance.
• Evidence
• Production of a gas (not phase change)
• Formation of a precipitate
• Change in color
• Change in temperature (without
• heat being added or taken
• away)
• Emission of light or odor

4
Is it a chemical or physical change?

• Sugar dissolving in tea

• Chemical Change

• Physical Change

5
OOPS!

• Did it change size, color, shape (Physical
  Change)?
• or
• Did it become different matter (Chemical Change)?

6
Correct!
7
Is it a chemical or physical change?

• Logs burning

• Chemical Change

• Physical Change

8
OOPS!

• Did it change size, color, shape (Physical
  Change)?
• or
• Did it become different matter (Chemical Change)?

9
Correct!
10
Is it a chemical or physical change?

• Cutting paper

• Chemical Change

• Physical Change

11
OOPS!

• Did it change size, color, shape (Physical
  Change)?
• or
• Did it become different matter (Chemical Change)?

12
Correct!
13
Is it a chemical or physical change?

• Crushing an aspirin

• Chemical Change

• Physical Change

14
OOPS!

• Did it change size, color, shape (Physical
  Change)?
• or
• Did it become different matter (Chemical Change)?

15
Correct!
16
Is it a chemical or physical change?

• Metal rusting

• Chemical Change

• Physical Change

17
OOPS!

• Did it change size, color, shape (Physical
  Change)?
• or
• Did it become different matter (Chemical Change)?

18
Correct!
19
Is it a chemical or physical change?

• Lighter fluid burning

• Chemical Change

• Physical Change

20
OOPS!

• Did it change size, color, shape (Physical
  Change)?
• or
• Did it become different matter (Chemical Change)?

21
Correct!
22
Is it a chemical or physical change?

• An egg rotting

• Chemical Change

• Physical Change

23
OOPS!

• Did it change size, color, shape (Physical
  Change)?
• or
• Did it become different matter (Chemical Change)?

24
Correct!
25
Is it a chemical or physical change?

• An egg breaking

• Chemical Change

• Physical Change

26
OOPS!

• Did it change size, color, shape (Physical
  Change)?
• or
• Did it become different matter (Chemical Change)?

27
Correct!
28
Law of Conservation of Mass

• No matter what change occurs
• mass before mass after
• of atoms before of atoms after

29
Images Cited

• http//www.learner.org/channel/courses/essential/p
  hysicalsci/session4/closer1.html
• http//www.hcbe.net/itc/powerpoints/science/files/
  CF61DBA93ED44B4B8A5C75E1A1AEB2CC.ppt