1. PHASE CHANGES
Matter has the ability to move from one state to another.

2. States of Matter Review
SOLID LIQUID GAS
Arranged: tightly Arranged: loosely Arranged: very
packed packed loosely packed
Move: vibrate in Move: slide past Move: rapid,
place each other random motions
Attraction: strong Attraction: medium Attraction: weak
Energy: low Energy: medium Energy: high

3. H2O
Solid: Ice Liquid: Water Gas: Water Vapor

4. PHASE CHANGES What are phase changes?
Phase changes are REVERSIBLE physical changes that occurs when a substance changes from one STATE of matter to another.

5. HEAT ENERGY HEAT ENERGY needs to be added or removed.
How do phase changes occur?
HEAT ENERGY needs to be added or removed.

6. MELTING When a substance changes from a solid to liquid.
Example: an ice cube turning into water when taken out of the freezer.
Heat needs to be ADDED for this phase change to occur.
Particles start Particles end
solid liquid

7. FREEZING When a substance changes from a liquid to solid.
Example: water turning into an ice cube when placed in the freezer.
Heat energy needs to be REMOVED for this phase change to occur.
Particles start Particles end
liquid solid

8. VAPORIZATION When a substance changes from a liquid to gas.
Example: water boiling on the stove turning into water vapor.
Heat energy needs to be ADDED for this phase change to occur.
2 types: Boiling happens throughout a liquid while evaporation occurs at the surface.
Particles start Particles end
liquid gas

9. CONDENSATION When a substance changes from a gas to liquid.
Example: water droplets forming on the side of a cold soda can.
Heat energy needs to be REMOVED for this phase change to occur.
Particles start Particles end
gas liquid

10. SUBLIMATION
When a substance changes from a solid to gas (without becoming a liquid first).
Example: solid CO2 becoming CO2 gas as in dry ice.
Heat energy needs to be ADDED for this phase change to occur.
Particles start Particles end
solid gas

11. DEPOSITION
When a substance changes from a gas to solid (without becoming a liquid first).
Example: when frost forms on a car window (water vapor comes in contact with cold window).
Heat needs to be REMOVED for this phase change to occur.
Particles start Particles end
gas solid

12. Gas
Liquid
Solid

13. Heat Energy ADDED Melting Vaporization Sublimation REMOVED Freezing
Condensation
Deposition