1. Physical and Chemical Properties and Changes

2. Physical Properties Any characteristic of a material that you can observe easily without changing the substance that makes up the material You can sift out the different substances by physical properties Easily observed properties

3. Physical Properties Viscosity – resistance to flowViscosity –Low viscosity = thin liquids (runny) –High viscosity = thick liquids (slow) Conductivity – heat flow –Good conductor = heats easily (metals) –Bad conductor = heats poorly (wood) Malleability – easily shaped –Not brittle

4. Chemical Properties A characteristic of a substance that indicates if it can undergo a certain internal change These are usually internal occurrences Not easily observed properties

5. Physical vs. Chemical Properties Physical Properties –Color –Shape –Size –Density –Amount –Volume Chemical Properties –Flammability –Rusting –Burning –Corrosion –Reactivity

6. Matter can be changed two ways Physically Physical reaction Physical change Chemically Chemical reaction Chemical change

7. Physical Changes Most Physical changes can be reversed Affects one or more physical property of a substance with out changing it’s identity Changes of state are physical changes (solid  liquids   gas)

8. Physical Changes Do NOT CHANGE THE TYPE OF MATTER –Nothing new or different is formed Could be a change in: Mass Volume Density Change in state –Color –Shape Size

9. Examples of Physical Changes Boiling Freezing Dissolving Breaking Making a mixture 2 or more types of matter (substances) mixed together –Not in specific amounts – Can be separated physically

10. Chemical Changes A change that occurs when a substance changes composition by forming one or more new substances that have different chemical and physical properties Chemical changes are occurring everywhere, including inside our body Chemical changes cannot be reversed

11. Chemical Changes Evidence of a chemical reaction – Formation of gas – Formation of precipitate – Change in color – Change in energy Endothermic Absorbs heat energy (gets cold) Exothermic Releases heat energy (gets hot)

12. Evidence: (signs of) Physical vs. Chemical Changes Physical Changes –Change of shape –Change of color –Melting point –Boiling point –Dissolving Chemical Changes –Changes in the presence of light –Flammability –Reacting with water –Reacting with acids –Decomposing –Producing a gas –Absorbs or releases heat