2. Properties of Matter

3. Extensive and Intensive Properties

4. Physical and Chemical Properties Physical change: a change in the physical properties of a substance. Chemical change: the transformation of one or more substances into others. Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley

5. Phases of Matter Solid (s) ------  Liquid (l) ---------  Gas (g) Phases: ‘physical state’ Solids Definite volume and shape Liquids Definite volume, but form determined by container it is in Gases No definite volume or shape

6. Solids Strong attraction between molecules- fixed position (vibrate) Heat breaks fixed arrangement Liquids Molecules ‘flow’ Gases Heat causes attractions between individual molecules to be broken Move in random manner Bump into the container – ‘pressure’ Submicroscopic Level

7. Diffusion Gas molecules continue to move and bump into each other Move from higher concentration areas to lower areas of concentration Occurs in: Gases, liquids Diffusion Animation

8. Phase Changes Animation

9. Process of Evaporation Molecules are heated below the surface, gain kinetic energy and bump into molecules at the surface Surface molecules are released (attraction to other molecules broken) Why is this a cooling process? The slower moving molecules left behind (lower temperature) cools the air or body (perspiration)

10. Condensation This is a warming process Why? Gas particles cool and reach the surface. Kinetic energy absorbed by surface molecules. Molecules form attractions This increases temperature