1. States of matter Solids and Liquids
L. Scheffler
Lincoln High School

2. Gases, Solids, and Liquids
Particle Properties
Phase
Spacing
Energy
Motion
Volume
Shape
Solid
close
low
vibrational
definite
definite
Liquid
close
moderate
rotational
definite
indefinite
Gas
far apart
high
translational
indefinite
indefinite

3. Other States of Matter Amorphous Solids Plasmas
Most solids with particles in repeating geometric patterns are crystals. Those with particles arranged randomly are amorphous.
Plasmas
a. Hot, ionized gas particles.
b. Electrically charged.
c. Most common state in universe.

4. Chumbler - Properties of Matter
Examples of Plasmas
Plasma can be found in stars, fluorescent light bulbs, Cathode Ray Tubes, neon signs, and lightening.
Chumbler - Properties of Matter

5. Plasmas
Microscopic Explanation for Properties of Plasmas
Plasmas have an indefinite shape and an indefinite volume because the particles can move past one another.
Plasmas are easily compressible because there is a great deal of free space between particles.
Plasmas are good conductors of electricity and are affected by magnetic fields because they are composed of ions (negatively charged electrons and positively charged nuclei).

6. Description of Phase Change
PHASE CHANGES
Description of Phase Change
Term for Phase Change
Heat Movement During
Phase Change
Solid to liquid
Melting
Heat goes into the solid as it melts.
Liquid to solid
Freezing
Heat leaves the liquid as it freezes.

7. Description of Phase Change
PHASE CHANGES
Description of Phase Change
Term for Phase Change
Heat Movement During
Phase Change
Liquid to gas
Vaporization, which includes boiling and evaporation
Heat goes into the liquid as it vaporizes.
Gas to liquid
Condensation
Heat leaves the gas as it condenses.
Solid to gas
Sublimation
Heat goes into the solid as it sublimates.

8. Heating Curves
The temperature of most pure substances is constant during a phase change.

9. Cooling Curves
The temperature of most pure substances is constant during a phase change.

10. Heat of Fusion
The heat required to convert a substance from the solid to the liquid phase is known as the heat of fusion
The heat of fusion is a property of the substance.
For water the heat of fusion is 335 Joules per gram

11. Heat of Vaporization
The heat required to convert a substance from the liquid to the gas phase is known as the heat of vaporization
The heat of vaporization for a substance depends on the temperature
For water the heat of vaporization is about 2240 Joules per gram
The heat required to vaporize a substance is generally much higher than the heat it takes to melt it.

12. Evaporation
The molecular velocities of the particles in the liquid phase vary according to a Maxwell-Boltzman distribution
The faster moving particles at the surface may escape the confines of the liquid entirely.
Some particles in the vapor phase may be recaptured by the liquid.
Since the higher energy particles are more likely to escape the average energy of the liquid particles is reduced.
Evaporation is a cooling effect, while condensation is a warming effect

13. Vapor Pressure Explaining Vapor Pressure on the Molecular Level
Dynamic Equilibrium: the point when as many molecules escape the surface as strike the surface.
Vapor pressure is the pressure exerted when the liquid and vapor are in dynamic equilibrium.

14. Vapor Pressure and the Boiling Point
Liquids boil when the external pressure equals the vapor pressure.
The vapor pressure of a liquid increases with temperature
The temperature of boiling point increases as pressure increases.
There are two ways to get a liquid to boil: increase temperature or decrease pressure.
Pressure cookers operate at high pressure. At high pressure the boiling point of water is higher than at 1 atm. Therefore, there is a higher temperature at which the food is cooked, reducing the cooking time required.
Normal boiling point is the boiling point at 760 torr (1 atm).

15. Gas-Liquid Equilibration

16. Vapor Pressure
Volatility, Vapor Pressure, and Temperature

17. Phase Diagrams
A Phase Diagram is a graph of pressure vs. Temperature summarizing all equilibria between phases.
Given a temperature and pressure, phase diagrams tell us which phase(s) will exist.
Key Features of a phase diagram:
Vapor-pressure curve: generally as pressure increases, temperature increases.
Melting point curve: as pressure increases, the solid phase is favored if the solid is more dense than the liquid Triple point: temperature and pressure at which all three phases are in equilibrium.
Normal boiling and melting points (I.e. at 1 atm)
Critical point: critical temperature and pressure for the gas.

18. Phase Diagrams
Any temperature and pressure combination not on a curve represents a single phase.

19. Phase Diagram
A phase diagram shows the relationship between the three phases of matter
The boiling point of a substance depends on the pressure.
The melting point is not significantly affected by the pressure

20. Phase Diagram
The boiling point of a liquid is the temperature at which the vapor pressure of the liquid is equal to atmospheric pressure
At the triple point all three phases are in equilibrium

21. Phase Diagrams of H2O and CO2
Water:
The melting point curve slopes to the left because ice is less dense than water.
Triple point occurs at C and 4.58 mmHg.
Normal melting (freezing) point is 0C.
Normal boiling point is 100C.
Critical point is 374C and 218 atm.
Carbon Dioxide:
Triple point occurs at -56.4C and 5.11 atm.
Normal sublimation point is -78.5C. (At 1 atm CO2 sublimes it does not melt.)
Critical point occurs at 31.1C and 73 atm.

22. Phase Diagrams of H2O & CO2

23. Critical Pressure and Temperature
Gases liquefied by increasing pressure at some temperature.
Critical temperature: the minimum temperature for liquefaction of a gas using pressure.
Critical pressure: pressure required for liquefaction.

24. Critical Temperature