1. Chapter 13 Phase Changes
Notes #8b

2. 13.4 Phase Changes Phase changes that REQUIRE energy
Melting – ice is an example: heat is transferred to the ice, which breaks some of the hydrogen bonds.
Melting Point – the temperature at which the forces holding its crystal lattice together are broken and it becomes a liquid.
Vaporization – the process by which a liquid changes to a gas or vapor.
Evaporation – vaporization that occurs only at the surface of a liquid. This is how our bodies regulate temperature.

3. 13.4 Phase Changes Phase changes that REQUIRE energy
vapor pressure – pressure exerted by a vapor over a liquid
boiling point – the temperature at which the vapor pressure of a liquid equals the external or atmospheric pressure.
Sublimation process by which a solid changes directly to a gas without first becoming a liquid -(dry ice).
Triple Point Point at which all three states of matter can coexist at equilibrium.

4. 13.4 Phase Changes Phase changes that RELEASE energy
Condensation – process by which a gas or vapor becomes a liquid (reverse of vaporization.)
Deposition – process by which a substance changes from gas or vapor to a solid (reverse of sublimation.)
Freezing – reverse of melting
Freezing Point – temperature at which a liquid is converted into a crystalline solid.

5. 13.4 Phase Changes
Phase diagrams

6. Label the following on a phase diagram in your notes
Triple point
s,l,g
Normal Boiling/Normal Freezing point
Critical Point
Sublimation