1. Lesson 7
Just a Phase

2. Matter exists in three phases: Solid, Liquid, Gas
Concepts
Matter exists in three phases: Solid, Liquid, Gas
Phase changes require the gain or loss of heat energy
Substances have melting and boiling points

3. Obtain a knowledge of phase change
Objectives
Obtain a knowledge of phase change
Observe phase changes of ice as it is heated
Measure temperature changes in melting ice
Plot graphs of measurements taken
Interpret the graphs that you plot

4. The terms “phase” and “state” are used interchangeably
Notes
The terms “phase” and “state” are used interchangeably
The three phases of matter are
Solid - Has a definite volume and if force is not applied to it a definite shape. The particles in a solid are closely packed and vibrate in relation to one another.

5. Liquid – Has a definite volume but no definite shape
Liquid – Has a definite volume but no definite shape. When placed in a container it takes the shape of the container. The particles in a liquid have more kinetic energy than those in a solid and can change relative to one another.

6. Gas – Has no definite shape or volume
Gas – Has no definite shape or volume. Its particles have enough energy to move to all parts of the container

7. A fourth phase of matter exist at high temperatures
A fourth phase of matter exist at high temperatures. It is called plasma. Plasma can be found in stars.
Phase changes take place when molecules lose kinetic energy and come closer together ( gases to liquid to solid) or gain kinetic energy and move farther apart ( solid to liquid to gas)

8. Phase changes are dependant on temperature and pressure
For an object to rise in temperature it must absorb energy
The amount of energy needed to raise the temperature by a specific number of degrees depends on the amount of material and the type of material. This is call specific heat capacity

9. Specific Heat Capacity Chart
Substance
Specific Heat Capacity (J/g×°C)
Water, liquid
4.184
Water, solid (ice)
2.03
Water, gas (steam)
2.0
Iron (s)
0.45
Mercury (l)
0.14
Carbon(graphite) (s)
0.71
Silver (s)
0.24
Gold (s)
0.13
Copper (s)
0.387
Air (g)
1.00
Carbon Dioxide(g)
0.832
Ethyl alcohol (l)
2.45
Granite(s)
0.803
Lead(s)
0.128
Paraffin
2.9
Stainless Steel(s)
0.51
Carbon(diamond) (s)
0.502
Aluminum (s)
0.89

10. Latent Heat of Fusion – the heat absorbed when a solid turns to a liquid
Latent Heat of vaporization – Energy absorbed when a liquid turns to a gas
Phase changes in the opposite direction involve loss of heat to the environment

11. Melting – Changing from solid to liquid
Freezing – Changing from liquid to solid
Boiling – Changing from a liquid to a gas also called vaporization
Evaporation – Changing from a liquid to a gas

12. Condensing – Changing from a gas to a liquid
Misconceptions Corrected
Loss of mass does not occur with phase change

13. Melting and dissolving are not the same thing
Phase change is related to temperature change
Increasing the heat does not affect the boiling point of a substance

14. Water does not always boil at 100 degrees C
Water does not always boil at 100 degrees C. That is at one atmosphere with pure water
Substances that melt are not necessarily hot
Change of state is not a chemical reaction
Freezing and melting points are the same