1. Chemical Properties
CHAPTER 2 SECTION 3

2. Chemical Properties
The ability to produce a change in the composition of matter.
Chemical properties can only be observed when the substances in a sample of matter are changing into different substances.

3. A material’s ability to burn in the presence of oxygen For example:
Flammability
A material’s ability to burn in the presence of oxygen
For example:
Newspaper
Gasoline
Oil
Warehouse chemicals

4. Reactivity
A property that describes how readily a substance combines chemically with other substances.

5. Chemical And Physical Changes

6. Physical Change
The substance does not change in composition only in form.
Properties that may change are size, shape, and state of matter.
These are usually easily reversible
For example:
ironing a wrinkled shirt

7. Chemical Change
Occurs when a substance reacts and forms one or more new substances. The composition of the original substance changes. These are not easily reversible, they require another reaction to reverse the change.

8. Recognizing a Chemical Change
Three common types of evidence:
Change in color
Production of a gas
Formation of a precipitate

9. A Change in Color
Oxidation of metals

10. Baking soda + liquid = carbon dioxide
Production of a Gas
Baking a cake
Baking soda + liquid = carbon dioxide

11. Formation of a Precipitate
Mixing milk and lemon juice
Proteins in milk + acid = precipitate
Precipitate: a solid that forms and separates from a liquid mixture.

12. Watch a precipitate!