1. State Changes AKA= Phase Changes

2. Review: 3 States of Matter Solid Liquid Gas

3. What is a State Change? It is a change from one state of matter (solid, liquid, gas) to another. Phase changes are physical changes because: - It only affects physical appearance, not chemical make-up. - Reversible

4. What happens during a state change? During a state change, thermal (heat) energy is either absorbed or released. Heat energy is released as molecules slow down and move closer together. Heat energy is absorbed as molecules speed up and expand.

5. Types of Phase Changes

6. Melting Phase change from a solid to a liquid Molecules speed up, move farther apart, and absorb heat energy

7. Freezing Phase change from a liquid to a solid Molecule slow down, move closer together and release heat energy.

8. Vaporization (Boiling) Phase change from a liquid to gas. It occurs at the boiling point of matter. Molecules speed up, move farther apart, and absorb heat energy.

9. Evaporation Phase change from a liquid to a gas on the surface of a liquid (occurs at all temperatures). Molecules speed up, move farther apart, and absorb heat energy, enough to escape liquid.

10. Condensation Phase change from a gas to a liquid. Molecule slow down, move closer together and release heat energy.

11. Sublimation Phase change from a solid to a gas. Molecules speed up, move farther apart, and absorb heat energy.

12. Deposition Phase change from a gas to a solid. Molecules slow down, move closer together and release heat energy.

13. Graphing a Phase Change

15. Summary