1. Chemical and Physical Changes

2. Change Every piece of matter has physical and chemical properties.
But what happens when these properties get changed.

3. Physical Change
Physical Changes occur when we change some of the physical properties, but the material stays the same.

4. Physical Change
If two substances can be separated after being mixed then it was a physical change.
EX: Sugar water. When sugar dissolves in water it does not change it just spreads out. If we let the water evaporate sugar will be left behind.

5. Physical Change
Changes in state (solid, liquid, gas) are physical changes.

6. Changes in State
To change from one state to another energy is either absorbed or released.
If energy is absorbed the atoms move faster .
Melting: Going from solid to liquid.
Evaporation: Going from liquid to gas
Sublimation: Going from solid to gas
If energy is released the atoms move slower.
Condensation: Going from gas to a liquid
Freezing: Going from liquid to solid.

7. Chemical Changes
A chemical change occurs when a reaction takes place and a new substance is produced.

8. Chemical Change
How do you know when a substance is undergoing a reaction?
There are four types of evidence for chemical reactions.

9. Evidence of Chemical Change
Change in Color some times means a chemical change.

10. Evidence of Chemical Change
Production of a Gas

11. Evidence of Chemical Change
Formation of a precipitate.
A precipitate is hard chunks that form in a solid. .

12. Evidence of Chemical Change
Releasing heat or light.

13. Summing it up Physical change = keep same substance.
Chemical change = Create new substance.