1. Chapter 8
States of Matter

2. 8.1 Three States of Matter
States of Matter- These are physical forms in which a substance can exist. Let’s use water as an example.
Solid water is called ice.
Liquid water is called water.
Gaseous water is called water vapor.
Particles of Matter
Matter is made up of tiny particles called atoms and molecules. These particles can only be seen with a very powerful microscope. Atoms and molecules are always in motion bumping into each other.

3. Solids
Solid- particles are packed closely together and can only vibrate in place.
All solids have a definite shape and volume.

4. Two types of solids:
Crystalline- These solids have an orderly arrangement of particles in a repeating pattern.
Examples include iron, diamond, ice, crystal
Amorphous- These solids do not have a special arrangement.
Examples include glass, rubber, wax.

5. Liquids
Liquid- particles are close together, but they have enough room to slide past one another.
Liquids have a definite volume but they take the shape of the container they are in.

6. Liquids have several properties that make them unique.
Surface tension- A force that acts on the particles at the surface of the liquid.
This causes some particles to form spherical drops like beads.
Water has a high surface tension while rubbing alcohol has a low surface tension.
Viscosity- the resistance of a liquid to flow. The stronger the attractions between the molecules, the more viscous the liquid is.
Honey has a high viscosity.
Water has a low viscosity.

7. Gas Gas- particles are far apart and move independently.
Gases do not have a definite shape or a definite volume.
They fill the container.

8. 8.2 Changes in State
Change of state- The change of a substance from one physical state to another
ALL STATE CHANGES ARE PHYSICAL CHANGES.
Particles of a substance have different amounts of energy depending on the state of the substance.
Particles have different amounts of energy in different states.
Solids – low energy
Liquids – medium
Gases – high
YOU MUST ADD OR REMOVE ENERGY TO CHANGE STATES.

9. Changes in State Melting Freezing Vaporization (evaporation)
4. Condensation
5. Sublimation
6. Deposition
Vaporization
Condensation
Sublimation
Deposition
Freezing
Melting

10. Melting: Solid to Liquid
Melting- change in state from solid to liquid.
Adding energy to ice raises its temperature.
As the temperature increases, the particles energy increasaes
When a certain temperature is reached (0°C) the ice melts
Melting Point - The temperature at which a substance changes from a solid to a liquid.
Melting point is a physical property.
Different substances have different melting points.
Melting is endothermic- energy is gained by the substance

11. Freezing: Liquid to Solid
Freezing- change in state from a liquid to solid.
Freezing point- The temperature at which liquid changes into a solid. Freezing is the reverse of melting, so they occur at the same temperature.
Any solid is in the frozen state!
Freezing is exothermic- energy is removed from the substance

12. Vaporization: Liquid to Gas
Vaporization- change in state form a liquid to gas.
Vaporization can occur at the surface of a liquid that is below the boiling point.
Sweat will evaporate off your skin and spilled water will evaporate off a counter.
Boiling- Change of a liquid to a vapor, or gas, within the liquid. This occurs when the pressure inside the bubbles equals the outside pressure on the bubbles.
Boiling point- temperature at which a substance boils
Boiling requires energy so it is endothermic

13. Vaporization
Boiling
Evaporation

14. Effects of Pressure on Boiling Point
Water boils at 100ºC, but only at sea level because of atmospheric pressure.
Atmospheric pressure is caused by the gases that make up the atmosphere.
The higher you go above sea level, the fewer air particles there are above you so atmospheric pressure is less.
In Denver, the mile high city, water boils at 94o C.

15. Condensation: Gas to Liquid
Condensation- change of state from a gas to liquid.
Condensation point- temperature at which a substance goes from a gas to a liquid. Condensation is the reverse of vaporization, so they occur at the same temperature.
For a gas to become a liquid, large numbers of particles must clump together. Energy must be removed - exothermic

16. Sublimation: Solid to Gas
Dry ice (carbon dioxide) changes directly from a solid to a gas.
Sublimation- the change from a solid to a gas without being a liquid
The substance must gain a lot of energy for this to occur, therefore it is endothermic.

17. Deposition: Gas to Solid
Deposition: the change from a gas to a solid without being a liquid
Frost changes directly from gas to solid
Deposition is an exothermic change because a lot energy must be removed.

18. Change in temperature vs. Change in state
When substances gain or lose energy, the temperature will change or remain the same.
As the temperature rises, the particles gain energy.
Once the particles have enough energy, the state will change.
At this point the temperature will remain until the state change is complete.
Boiling water will remain at 100oC until it all evaporates.

19. Change in temperature vs. Change in state
Gas
vaporization
1000c
Condensation
Liquid
melting
00c
Solid
Freezing

20. Partner Share
Neatly and in your own words, Write at least 8 lines describing the difference between boiling and evaporation. Be sure to give an example of where there may be different boiling points for the same substance.

21. 8.3 Behavior of Gases Describing Gas Behavior
Gases behave differently from solids and liquids.
Gases have large amounts of empty space between molecules.

22. Temperature of Gases
Temperature is a measure of how fast the particles in an object are moving around.
On a hot day, particles move faster and hit the inside walls of a balloon more often. Thus, increasing energy and pushing on the walls.
On a cold day, particles have less energy They do not push very hard on the walls of the balloon.

23. Volume
Volume a measure of the size of a body or region in three dimensional space
Particles of a gas spread out so the volume of any gas depends on the container that the gas is in.

24. Pressure Pressure is the amount of force exerted per area on a surface
This is the amount of times the particles of a gas hit the inside of their container.
If you compare a basketball and a beach ball, you will notice the basketball is very firm.
It has a greater pressure.
The beach ball has a much lower pressure.

25. Gas Behavior Laws
Scientists found that temperature, pressure, and volume of a gas are related. Changing one of the factors will affect the others.
Boyles’s Law- Robert Boyle discovered if you have a fixed amount of gas at a constant temperature, the volume of the gas is indirectly related to the pressure. If you increase the pressure, then you will decrease the volume by the same amount.
Ex. Diver blowing an air bubble under the water, when the bubble reaches the surface, the bubbles volume has greatly increased.
Think: Boyle is the vice president (VP)(volume, pressure)

26. Gas Behavior Laws Ex. Taking a balloon outside into the cold
Charles’ Law- If you have a fixed amount of gas at a constant pressure, the volume of the gas will be directly related to the temperature. If the temperature increases, the volume will increase by the same amount.
Ex. Taking a balloon outside into the cold
Think: Charlie Brown is on TV (temperature, volume)

27. Gas Behavior Laws
Guy Lusaac’s Law -If you have a fixed amount of gas at a constant volume, the pressure of the gas will be directly related to the temperature. If the temperature increases, the pressure will increase by the same amount.
Think: G lives in a TP (temperature, pressure)

28. Gas Behavior Laws Boyle ↑ ↓ Charles Guy - Lussac Temperature Pressure
Volume
Boyle
_______________ ↑ ↓
Charles
Guy - Lussac
______________