States Of Matter

1. Solids – The particles (atoms) in a solid are packed tightly together and stay in fixed positions. A solid has a definite shape and a definite volume. Particles in a solid do move, but slowly! They vibrate back and forth.

States Of Matter

Types of Solids

2. Crystalline – Salt, sugar, snow and diamonds are all examples. The particles form a regular repeating pattern called a crystal. These solids melt at distinct temperatures called melting points.

3. Amorphous – Rubber, plastics, and glass would all be examples. The particles in these solids do not form a regular repeating pattern. These solids do not have distinct melting points.

States Of Matter

4. Liquids – Because the particles in a liquid have more movement, a liquid has no definite shape. However, liquids do have definite volumes.

5. Viscosity – The resistance of a liquid to flowing. Liquids with high viscosity flow slowly. Liquids with low viscosity flow quickly.

Honey vs. Water

States Of Matter

6. Gases – Gas particles spread apart filling all the space available to them. Thus a gas has neither a definite shape nor volume.

7. Measuring Gases – 3 parameters – Volume, Temperature, and Pressure –

8. Volume of a Gas – is equal to the volume of its container. Units – L, ml, cm3 or cc

States Of Matter9. Temperature – A measure of the average

energy of motion (kinetic) of the particles in a substance.

Faster Particles -> Greater Energy -> Higher Temperature

10. Pressure – The force of the outward push of the gas on the walls of its container divided by the area of the walls of the container.

Pressure = Force

Area Units = Pascals (Pa) or KiloPascals (kPa)

States Of Matter11. Relating Pressure and Volume –

Boyle’s Law -> As the pressure on a gas increases the volume of the gas decreases at a constant temperature.

Pressure Increases Volume Decreases

Pressure Decreases Volume Increases

States Of MatterBoyle’s Law Graph

States Of Matter

12. Relating Volume and Temperature –

Charles’ Law – As the temperature of a gas increases the volume of the gas increases at a constant pressure.

Temperature Increases Volume Increases

Temperature Decreases Volume Decreases

States Of MatterCharles’ Law Graph

States Of Matter

13. Relating Pressure and Temperature –

Temperature Increases Pressure Increases

Temperature Decreases Pressure Decreases

States Of Matter

14. Dalton’s Law – The Total Pressure (Tp) of a mixture of gases is equal to the sum of the Partial Pressures (Pp) of each of the gases in the mixture.

Tp = Pp1 + Pp2 + Pp3 + Pp4…….

States Of Matter

Practice Problem:

At sea level the partial pressures (Pp) of the gases in the air are 75 kPa for nitrogen, 15 kPa for oxygen and 10 kPa for all the other gases present. What is the total pressure (Tp) of the air at sea level?

Answer: Tp = 75 kPa + 15 kPa + 10 kPa

Tp = 100 kPa

States Of Matter

15. Thermal (Heat) Energy – The total energy of the particles of a substance. The more particle movement you have the greater the thermal energy. Thermal energy always moves from warm to cold. A thermal energy increase or decrease leads to a change of state.

States Of Matter

Changes in State (Physical Changes)

16. Melting -> Solid to Liquid for H2O -> 0o C

17. Freezing -> Liquid to Solid for H2O -> 0o C

States Of MatterChanges in State (Physical Changes)

18. Vaporization – Evaporation & Boiling

Liquid -> Gas

19. Evaporation (Drying) – happens only at the surface of the liquid. For example the drying of a puddle of H2O.

20. Boiling – takes place both above and beneath the surface of a liquid. You will see bubbles and vapor (gas) coming off the surface of the liquid. Water boils at 100o C.

States Of Matter Changes in State (Physical Changes)

21. Condensation – Gas -> Liquid Water condensates at 100o C.

22. Sublimation – Solid -> Gas Directly - there is no liquid phase.

Dry ice -> Frozen carbon dioxide (CO2) gas Moth balls are another example of a

substance that goes directly from a solid to a gas.