1. Phases of Matter

2. Why do liquids & solids exist?
What holds them together?
Intermolecular forces
-forces of attraction between molecules

3. Kinetic Energy Atoms & molecules are in constant motion
Temperature = measure of average KE of particles in sample of matter

4. If temperature ↑,
the average KE↑
If temperature ,
then average KE 

5. Temperature vs. Phase
gas & solid at same temp have same average KE
but … the particles in the 2 phases
move very differently

6. Gases: Movement: particles are far apart
move rapidly from place to place
Movement:
can move from place to place
they can tumble
they can shake

7. Solids: Movement: can only vibrate in back and forth motion
particles tightly packed in orderly pattern
particles can’t move very much
Movement:
can only vibrate in
back and forth motion

8. Liquids: Movement: • can vibrate • very hindered movement moving
• particles can move a little bit but bump into
their neighbors
Movement:
• can vibrate
• very hindered
movement moving
place to place
or tumbling

9. What is a phase change? It is a transition between phases There are 6
What are they?

10. Solidification l → s
(freezing)
2. melting s → l
3. evaporation l → g
4. condensation g → l
5. sublimation s → g
6. deposition g → s

11. Melting solid →liquid

12. source
Boiling liquid →gas

13. Deposition gas→solid

14. Condensation gas→liquid

15. Sublimation gas→solid
Freezing liquid→solid
source

16. Phase Changes
When a substance goes from the gas to a condensed phase (s or l), what happens?
particles get closer together and their motion slows down

17. Phase Changes
When a substance goes from solid to liquid or gas, what happens?
particles move farther apart and their motion increases