1. Physical Change & Chemical Change

2. Physical Change A change that affects 1 or more physical properties.
Examples – a melting popsicle, cutting wood, dissolving sugar, crushing a can
DOES NOT AFFECT THE IDENTITY of the matter.

3. Chemical Change
Occurs when 1 or more substances change into new substances that have new or different properties.
Examples – milk goes bad, Efferdent tablets reacting in water, fireworks going off, baking a cake.

4. Chemical Change
Signs of a chemical change – change in odor, change in color, release of energy (sound, heat, light), bubbling, precipitate forming
Precipitate – a solid formed when 2 substances dissolved in water form

5. Chemical Change
Chemical properties describe whether a chemical change will occur or will not occur
chemical change = chemical reaction

6. Chemical Change vs. Physical Change
Chemical change – Changes composition of a substance, or what its made of. Changes its identity
Physical change – Does not change the composition of a substance, only its appearance. Does not change its identity.

7. Reversing a change
Physical change – use physical properties. Usually pretty easy.
Chemical change – use chemical properties. Not as easy to do, or sometimes impossible.