1. States of Matter Chapter 10

2. Chapter 10 Study List Solids-characteristics Kinetic energy
Melting/freezing
Crystalline solid
Amorphous solid
Sublimation
Deposition
Phase diagram-interpret
Phase changes
Energy loss/gain with changes
Read Ch 10 –all
Practice 1-14, 17-19, 20-24, 29-30,
35,37, 39, 41, 42, 46-55
Kinetic energy
Kinetic theory
Gas pressure
Atmospheric pressure
High, low pressure
Converting from one pressure unit to another
Kelvin
Relationship bet. Kelvin & KE
Absolute zero
Liquids-characteristics
Boiling
Vaporization
Vapor pressure

3. Kinetic Energy Kinetic-motion Kinetic energy
energy of motion
Kinetic energy helps determine phase of substance

4. Kinetic Theory basic assumptions
gas composed of particles
hard spheres w/ large empty spaces between
No attractive or repulsive forces between atoms, molc.
particles in a gas move rapidly in constant random motion
Fill container
Move rapidly
Change direction when collide

5. all collisions are elastic
More KT
all collisions are elastic
energy transferred from 1 particle to another
total KE const.

6. force exerted per area by a gas
Gas Pressure
force exerted per area by a gas
P=Force/Area
Based on collisions
more collisions greater pressure
Measured in pascals (Pa)

7. Atmospheric pressure Measures collisions of air molc.
Decreases with increase in altitude
Measured by barometer
Units
101.3 kPa = 760 mm Hg
= 1 atmosphere
Standard pressure (of STP)

8. Weather and pressure high pressure - sinking air – clear, often cool
low pressure -rising air, clouds, precipitation

9. Solve this:
On a clear day in January, the air pressure is 1.01 atm. What is the air pressure in kPa, mm Hg?
1.01 atm x kPa =102.3 kPa
1 atm
1.01 atm x 760 mm Hg = mm Hg

10. Kelvin temperature When a substance is heated: Temperature
Some energy is stored as potential energy with no change in temp
Remaining energy increases motion of particles-KE
Temperature
measures average KE of particles (not all part. have same KE)
Higher temp=higher avg. KE

11. Kelvin Temperature scale
direct measure of avg. KE
@ 200K particles have 2x avg. KE of those particles at 100K
Absolute zero –theoretically where all molecular motion ceases
In lab from 0 K (1 x 10-10)
Water (freeze 273 K, boil 373 K)

12. Solids definite volume, shape ; do not flow
forces held together stronger than liquids
so more energy is needed to break apart

13. Solids Crystalline repeating 3-d arrangement of atoms
specific melting point
Regular shape
Same chem formula may give different crystal shapes- allotrope
Carbon - diamond, graphite

14. X-stal

15. solids Amorphous irregular arrangement of atoms
melts over a range of temps.
Ex. glass, plastics, rubber
particles vibrate with definite spatial limitations so some kinetic energy

16. Liquids Fluid that flows-particles slide by each other
Move more slowly than gases
particles held together by weak attractive forces
disruptive motion of particles
Interplay between attraction and disruption of particles
liquids more dense than gases-why?

17. Phase change Vaporization Evaporation
Liquid to gas (vapor)
Evaporation
Vaporization that is not at boiling point
Liquid evaporates more quickly when heated-why?
Increasing avg KE, more particles can overcome attractive force that keeps them together in liquid
Evaporation is a cooling process-why?
Those with highest KE leave the liquid, slower molc remain, avg KE decreases so temp decreases

18. Liquids - Vapor Pressure
Closed container/system
Evaporated particles create pressure on container
Reach equilibrium
Rate of evaporation=rate of condensation
Vapor pressure influences rate of evaporation
Humid day vs dry day-when is evaporation faster?
Why?

19. Boiling point
Temperature at which vapor pressure is equal to external pressure
Increase KE allows particles to overcome attractive force and escape
Lower pressure, lower boiling point

20. Inc. in air pressure, inc. b.p. pressure cooker 2 atm 120oC
Water
Sea Level: 100o C
Denver = 1 mi. ~ 95o C
Mt. Everest (28,028’) = 70o C
Inc. in air pressure, inc. b.p.
pressure cooker 2 atm 120oC

21. Melting and freezing points
Melting point
Temperature at which solid changes to liquid
Heat is added, speeds molc., breaks attraction between molc.
Freezing point
Heat is lost by substance
Molc slow to where attraction is greater than motion
Freezing and melting points are same temperature
Water-both 0 o C or 273 K

22. Phase changes Phase diagram
Shows the relationship between pressure, temperature and phase of substance
Triple point-temp and pressure conditions where substance can exist in all three phases

23. Phase changes
Substances change phase as energy is added to or lost from substance
Particles slow down (energy loss) or speed up (energy gain)
Energy gain-melting, vaporization/boiling, sublimation
Energy loss-freezing, condensation, deposition

24. And those words are..
Sublimation-solid to gas without passing through liquid phase
High vapor pressure
Examples- CO2, ice in freezer, iodine
Deposition-gas to solid without passing through liquid phase
Examples-Snow, frost

25. Phase changes with diagram