1. Observing Chemical Change
How can changes in matter be described?
How can you tell when a chemical reaction has occurred? √
Only three NEW vocabulary words! √ √ √ √ √ √ √

2. Vocabulary Review Reactants and products
Matter-anything that has mass and takes up space
Chemistry-the study of matter and how matter changes
Physical properties and Chemical properties
Physical and Chemical change (salt in water versus burning wood)
Reactants and products

3. Bonding and Chemical Change
Chemical changes occur when bonds break and new bonds form.

4. Evidence for Chemical Reactions
Change in properties and change in energy (only sure evidence)
Change in physical properties…new substances
color
Precipitate (solid formed during a chemical reaction)
A gas from solid or liquid reactants
Physical properties such as texture and harness may also change
Moist dough becomes a dry, porous solid after baking

5. More on Chemical Reactions
Changes in chemical properties
Na and Cl are reactive elements but their product (NaCl) is stable
One or more new substances are produced in a chemical reaction
When an electric current is passed through water (electrolysis) H2 (gas) and O2 (gas) are produced.

6. Review Endothermic Reaction
Chemical reactions occur when bonds break and new bonds form. They usually absorb heat or liberate heat(release it).
Endothermic reactions absorb energy when the bonds break
Energy is absorbed from nearby matter
Often temperature changes
Baking soda combined with vinegar absorbs heat, making it feel colder
When heat is added constantly, (egg frying)

8. Review: Exothermic Reaction
The making or breaking of chemical bonds results in a net release of energy
Energy typically releases as heat
Fuel and oxygen in the plane’s engine release heat causing the gases in the engine to expand. This moves the gases out of the plane which exerts a force that moves the plane forward.

9. Bonding and Chemical Change