1. Lesson 4: What are Chemical Changes in Matter
By: Mr. Leslie’s Class

2. The CHANGE
A chemical change is a change in matter that produces new kinds of matter with different properties.
Energy is always involved in a chemical change
The explosion of fireworks is an example of chemical change.

3. Chemical Change
Molecules break apart and form new combinations with other atoms and molecules.
What you start with is not what you end up with.
Would you eat this???

4. Old Matter becomes New Matter
Product
Reactant

5. Common Chemical Changes
Every time you ride in a car you depend on chemical changes.
The Car battery
Car engine burns gasoline
The exhaust includes the products of burning gasoline

6. Clues to seeing the CHANGE
Terminals - electrical
If you see:
Bubbles
change in color
change in state
Temperature
Odor
Light
Electricity
Sound
Motion
Thermal Energy is the most common form of energy involved in chemical changes.

7. How does this happen? How does a chemical change occur?
Atoms in molecules are held together by forces of attraction called chemical bonds.
Old bonds are broke and new ones are formed.

8. Compare Physical and Chemical Changes
Physical Changes
Chemical Changes