Unit 10- States of Matter - PowerPoint PPT Presentation

Loading...

PPT – Unit 10- States of Matter PowerPoint presentation | free to download - id: 769e39-YjgzY



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Unit 10- States of Matter

Description:

Unit 10- States of Matter III. Changes of State A. Phase Changes A. Phase Changes Evaporation molecules at the surface gain enough energy to overcome IMF Volatility ... – PowerPoint PPT presentation

Number of Views:25
Avg rating:3.0/5.0
Slides: 19
Provided by: Rober1390
Learn more at: http://msrobbinspnhs.weebly.com
Category:
Tags: change | matter | phase | states | unit

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Unit 10- States of Matter


1
III. Changes of State
  • Unit 10- States of Matter

2
A. Phase Changes
3
A. Phase Changes
  • Evaporation
  • molecules at the surface gain enough energy to
    overcome IMF
  • Volatility
  • measure of evaporation rate
  • depends on temp IMF

4
A. Phase Changes
Boltzmann Distribution
p. 477
5
A. Phase Changes
  • Dynamic Equilibrium
  • trapped molecules reach a balance between
    evaporation condensation

6
A. Phase Changes
p.478
  • Vapor Pressure
  • pressure of vapor above a liquid at equilibrium

v.p.
  • depends on temp IMF
  • directly related to volatility

temp
7
A. Phase Changes
  • Boiling Point
  • temp at which v.p. of liquid equals external
    pressure
  • depends on Patm IMF
  • Normal B.P. - b.p. at 1 atm

8
A. Phase Changes
  • Melting Point
  • equal to freezing point
  • Which has a higher m.p.?
  • polar or nonpolar?
  • covalent or ionic?

polar
ionic
9
A. Phase Changes
  • Sublimation
  • solid ? gas
  • v.p. of solid equals external pressure
  • EX dry ice, mothballs, solid air fresheners

10
B. Heating Curves sketch this in your notes
11
B. Heating Curves
  • Temperature Change
  • change in KE (molecular motion)
  • depends on heat capacity
  • Heat Capacity
  • energy required to raise the temp of 1 gram of a
    substance by 1C
  • Volcano clip -

water has a very high heat capacity
12
B. Heating Curves
  • Phase Change
  • change in PE (molecular arrangement)
  • temp remains constant
  • Heat of Fusion (?Hfus)
  • energy required to melt 1 gram of a substance at
    its m.p.

13
B. Heating Curves
  • Heat of Vaporization (?Hvap)
  • energy required to boil 1 gram of a substance at
    its b.p.
  • usually larger than ?Hfuswhy?
  • EX sweating, steam burns, the drinking bird

14
C. Phase Diagrams
  • Show the phases of a substance at different temps
    and pressures.

15
C. Phase Diagrams
  • The diagram on the last slide shows the phase
    diagram for water
  • Each region represents a pure phase
  • Line between regions is where the two phases
    exist in equilibrium
  • Triple point is where all 3 curves meet, the
    conditions where all 3 phases exist in
    equilibrium!

16
Phase changes by Name
Critical Point
Pressure (kPa)
Temperature (oC)
17
C. Phase Diagrams
  • With a phase diagram, the changes in mp and bp
    can be determined with changes in external
    pressure
  • What are the variables plotted on a phase diagram?

18
(No Transcript)
About PowerShow.com