The document discusses the different phases of matter - solids, liquids, and gases - and how phase changes occur. It defines the key properties of each phase and explains that the strength of attraction between particles determines the phase. Phase changes, such as melting, freezing, boiling, and condensing, involve either absorbing or releasing energy as the strength of attraction changes. A heating or cooling curve can represent temperature changes during phase changes graphically.

1. Phases of Matter, EnergyPhases of Matter, Energy
and Phase Changesand Phase Changes

2. Phase of MatterPhase of Matter
 Depends onDepends on
strength of forcesstrength of forces
of attractionof attraction
between particles.between particles.
..

3. SolidsSolids
 Definite shape and volume.Definite shape and volume.
 Most dense phase (Most dense phase (Exception is water!)Exception is water!)
 Difficult to compress.Difficult to compress.
 Particles vibrate in fixed positionsParticles vibrate in fixed positions
 Crystalline lattice structure.Crystalline lattice structure.
 Most attraction between particles.Most attraction between particles.
 Note:Note:
 AmorphousAmorphous solids include glass,solids include glass,
plastic, wax, and silly puttyplastic, wax, and silly putty

4. LiquidsLiquids
 Definite volumeDefinite volume
 No definite shapeNo definite shape
 Hard to compressHard to compress
 Particles slide past eachParticles slide past each
otherother
 Forces of attractionForces of attraction
between particles still highbetween particles still high

5. GasesGases
 No definite shape or volumeNo definite shape or volume
 Expands to fill containerExpands to fill container
 Lowest densityLowest density
 Little attraction betweenLittle attraction between
particlesparticles
 ““Vapor” = a gaseous state ofVapor” = a gaseous state of
something that is normally liquidsomething that is normally liquid
 (Ex: water vapor)(Ex: water vapor)

6. Changes in PhaseChanges in Phase
GasGas
CondensationCondensation VaporizationVaporization
(Boiling or Evaporating)(Boiling or Evaporating)
LiquidLiquid
SolidificationSolidification Melting (fusion)Melting (fusion)
SolidSolid

7. Phase ChangesPhase Changes
Short Summary video on phases: (1 min)
http://www.youtube.com/watch?v=s-KvoVzukHo&safe=active
Applet: (Excellent)
https://phet.colorado.edu/en/simulation/states-of-matter
http://www.harcourtschool.com/activity/states_of_matter/

8. Let’s Skip a PhaseLet’s Skip a Phase
 SublimationSublimation
 Directly from the solidDirectly from the solid
phase to the gas phase.phase to the gas phase.
 Happens with substancesHappens with substances
with weak intermolecularwith weak intermolecular
forces of attractionforces of attraction
 They separate easily!They separate easily!
http://www.youtube.com/watch?v=8tHOVVgGkpk

9. Energy During Phase ChangesEnergy During Phase Changes
 Solid Liquid or Liquid GasSolid Liquid or Liquid Gas
EndothermicEndothermic
Energy is absorbed and overcomes attractiveEnergy is absorbed and overcomes attractive
forces between particlesforces between particles
Add heat

10.  GasGas Liquid, LiquidLiquid, Liquid SolidSolid
ExothermicExothermic
As particles come closer together energy isAs particles come closer together energy is
releasedreleased
Remove heat

12. Heat EnergyHeat Energy
 Also called Thermal energy, it makes particlesAlso called Thermal energy, it makes particles
move more as it is addedmove more as it is added
http://www.youtube.com/watch?v=f1eAOygDP5s&safe=active

13. Heating & Cooling CurvesHeating & Cooling Curves
 Graphically represents temp. changes as heatGraphically represents temp. changes as heat
energy is added or taken away.energy is added or taken away.

14. Label This GraphLabel This Graph

15. Interpreting the GraphInterpreting the Graph
 The slanted portions =The slanted portions =
temp is changingtemp is changing
 Single phase is heatingSingle phase is heating
up or cooling downup or cooling down
 KE is changingKE is changing
 The flat portions =The flat portions =
temp not changingtemp not changing
 Substance undergoingSubstance undergoing
a phase changea phase change
 PE is changingPE is changing

16. Heating Curve for WaterHeating Curve for Water

17. What is Melting Pt? Boiling Pt?What is Melting Pt? Boiling Pt?