1. Ch. 2 Notes Day 3

2. Objectives Review states of matter Review phase changes
SWBAT identify different forms of physical change and chemical change
SWBAT differentiate between physical and chemical change

3. Physical Change
When you change the properties of a substance, but not the composition.
Physical changes can ALWAYS be reversed!!
Examples:
Phase changes (changing the state of matter)
Changing the shape or size of a substance
Mixing or separating two substances together mechanically
Homogeneous and heterogeneous mixtures

4. Filtration
Separating particles based on their size (typically heterogeneous mixtures)
Uses a material that has holes where small particles can pass through and larger ones cannot
Examples:
Coffee pot
Soup ladle with holes
Sieve for sand

5. Distillation
Separates substances based on their boiling points (typically homogeneous mixtures)
For example, the boiling point of water is much lower than salt. The fresh water turns to a gas, while the salt is left behind
Examples
Purifying salt water
Distillation of whiskey

6. Chemical Property
Any ability of a substance to change the composition of matter
Chemical properties are observed when substances change
Flammability – a substance’s ability to burn when oxygen is present
Ex. Gasoline, very flammable. Milk, not flammable
Reactivity – how easily a substance reacts with others
Ex. Oxygen, highly reactive. Lead, not very reactive

7. Chemical Change
When a substance reacts with others, and forms one or more NEW substances
CANNOT BE REVERSED!!
Evidence of chemical change
Change in color
Change in odor
Production of gas

8. More evidence of chemical change
Formation of a precipitate.
Precipitate – a solid that forms when two solutions are mixed together
Production of light.
Light – the chemical reaction produces energy