1. Physical vs. Chemical Properties
Unit 2.5

2. Introductory Video

3. Physical Properties
Physical Property- characteristic of a substance that you can observe without changing the identity of the substance
Examples: color, density, melting point, and boiling point.
Physical Change-a change of matter from one form to another without changing what it’s made of
Examples: Water freezing (solid), then melting (liquid), then evaporating (gas)

4. Physical Properties
Distillation- separating a mixture physically through evaporating a liquid and re-condensing its vapor.
Ex. Wine Distillery

5. Chemical Properties
Chemical Property- characteristic of a substance that indicates whether it can undergo a certain chemical (permanent) change
Chemical Change- changes the types and amounts of elements in the substance
Indications that a chemical change MAY have occurred:
Change in Smell
Produces heat, light, or sound
Color change (does not always indicate a chemical change though…ex. Example: blue and yellow gatorade make green gatorade- just a mixture)
production of gas or precipitate (solid)
Dark bottles- blocks UV light- prevents change in identity of the liquid in the bottle (wine)

6. Physical vs.Chemical Changes
Physical or Chemical Change?
Baking a Cake
Boiling Water
Scrambling an Egg

7. Physical and Chemical Changes
Weathering: 2 Types
Physical change: An example is when rocks split as water freezes or as erosion occurs
Chemical change: An example is when oxygen in the air reacts with iron in the rock to make iron oxide (rust)
Ex. Physical Weathering Ex. Chemical Weathering

8. Law of Conservation of Mass
Mass cannot be created or destroyed, it can only change forms
Burning a log seems to make mass disappear
“missing” mass is actually present in the gases and the heat energy that are produced as the log burns