Download 2012-09-20_PhasesChanges

Cornell Notes: Please take out
your notebook and properly set
up your paper.
Topic: Phase Changes
Date: 9/20/2012
Physical vs. Chemical Changes

Phase changes are all classified as physical changes
because in chemical changes an entirely new
substance is produced.
 In
chemical changes, the compounds rearrange to form
new compounds.
 In physical changes the compounds don’t change at the
molecular level.
Energy
(usually in the form of heat)


Energy is added or taken away to create phase
changes.
When energy is added, particles move further
apart.
 Solid

 Liquid  Gas
When energy is taken away, particles move closer
together.
 Gas
 Liquid  Solid
Phase Changes






Melting = solid  liquid
Freezing = liquid  solid
Boiling / Vaporization / Evaporation
= liquid  gas
Condensation = gas  liquid
Sublimation = solid  gas (ex: dry ice)
Deposition = gas  solid (very rare)
Temperature and Pressure Points of
change




Melting Point = T & P when solid  liquid
Freezing Point = T & P when liquid  solid
Boiling Point = T & P when liquid  gas
Condensation Point = T & P when gas  liquid
Phase Change Diagram
LIQUID
deposition
SOLID
sublimation
GAS