1. Evidence of Chemical Change
Physical and Chemical Changes

2. Objectives:
Learn that a chemical changes involves the formation of a new substance
Differentiate between chemical and physical changes

3. How can changes in matter be described?
Matter is described by characteristic properties, either chemical or physical, unique to a particular substance

4. Physical properties Can be observed using your five senses Smell Color
Texture
Density
Conductivity
Physical state

5. Chemical properties
The characteristic of a substance that describes its ability to change into other substances
Chemical changes happen during chemical reactions

6. Physical Changes
Any change that alters the appearance of a substance but does not change it into another substance
Bending
Crushing
Cutting
Melting
Freezing
boiling

7. Chemical Change
Atoms are rearranged to form new substances with different properties
Chemical reactions involve changes in properties and changes in energy that you can often observe

8. Evidences of chemical change
Color change
Gas bubbles form
Light given off
Temperature change
Precipitate forms
Odor change

9. Precipitate A solid that forms from liquids during a chemical reaction
Solution – is a liquid where the solute is dissolved in the liquid

10. Changes in energy
Endothermic reaction – more energy is required to break the bonds than reform – feels cold
Exothermic reaction – less energy is required to break the bonds than reform them – feels hot