1. Physical & Chemical Changes
Physical Changes
Substance stays the same
Change in shape or form
Breaking of glass
Molding a shape out of clay

2. Different substances are formed Change in molecules Cement hardening
Chemical Changes
Different substances are formed
Change in molecules
Cement hardening
Rust
Baking a cake
Dynamite exploding

3. Glucose and oxygen react to form carbon dioxide and water.
6.2 Chemical Reactions
Glucose and oxygen react to form carbon dioxide and water.

4. This reaction is exothermic and released heat energy.
Energy of Reactions
The activation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.
This reaction is exothermic and released heat energy.
This reaction is endothermic and absorbed heat energy.

5. Energy and Chemical Reactions
Problem- Reactions occur too slowly
Must speed up reactions with Enzymes
Enzymes are protein molecules that act as catalysts to speed up reactions
A catalyst speeds up chemical reactions

6. Enzyme Action – Joining
Enzyme attaches to molecules
Holds molecules near each other so they can connect together with bonds
Bonds form between molecules creating a larger molecule or compound

7. EX. H2O2 H2O + ½ O2 LIVER CATALASE
Hydrogen peroxide is broken apart into water and oxygen. The reverse reaction also occurs