1. Chemical Changes

2. Indicators of a Chemical Reaction
1.Formation of a Precipitate 2. Gas bubbles are released 3. It changes energy (Heat is added or released) 4. It may change color 5. A change in odor

3. Formation of a Precipitate
There is a formation of a solid when combining two solutions

4. Bubbles
The formation of a gas (bubbles or fizzing) is a clue that a chemical reaction is taking place.
Example: Alka-Seltzer dropped in water

5. Change in Energy (Heat)
A chemical reaction involves the breaking of bonds in the reactants and the forming of bonds in the product.
Endothermic (Temperature drops)- Absorb more energy than they release.
Exothermic (Temperature Increases) - Release more energy than they absorb.

6. Change in Color
In a chemical reaction there is often a change in color from the original substance to the new one.
(Examples: Rusting, Fireworks, Leaves changing

7. Change in Odor
Chemical reactions may give off a smell or new odor. (Example: Food rotting, such as rotten eggs)