Chemistry Matter Notes 3-7-11

Types of Matter

 * There is a lot of "free" space in a gas.
 * Gases can be expanded infinitely.
 * Gases diffuse and mix rapidly.

Gas Diffusion and Effusion
Pressure - Force applied per unit area is measured with a Barometer.
 * Diffusion is the gradual mixing of molecules of different gases.
 * Effusion is the movement of molecules through a small hole into an empty container.

Toricelli's barometer used a glass column suspended in a bowl of mercury. The pressure of the air molecules pushed the mercury up into the glass tube.

For gas laws we will use Pascal's, at m or mm Hg

P at m = PHg

Volume Changes
Compression - Larger volume applied to smaller volume.

Expansion - Smaller volume applied to larger volume.

For gas laws we will always use Liters for units.


 * Temperature - A measure of the average kinetic energy of a sample.


 * Units - For gas laws we always use Kelvin (K).


 * Kinetic Energy - 1/2 m x v^2

Higher temperature is to lower temperature

as

fast moving particles is to slow moving particles.

Absolute zero to the bottom of the temperature scale.

What would happen to absolute 0 to 0K? If you could get there -> Molecules would stop moving.

The conditions of 0^degreesC and 1 atm are called Standard Temperature and Pressure (STP)

Experiments show that at STP 1 mole of [aniseal?] gas occupies 22.414 L.

Guy Lussac's Law Higher temperature means faster movement is to higher pressure
 * How are pressure and temperature related?
 * As one goes up so does the other.

as

the faster the bullet is going is to the harder it hits you.

Boyle's Law

A bicycle pump is a good example of Boyle's Law.

As the volume of air trapped in the pump is reduced, its pressure goes up and air is forced into the tire.

Kinetic Molecular Theory of Gases
1. Gases are mostly empty space; the volume of particles is negligble.

2. Gas particles are in constant random motion.

3. Gas particles neither attract nor repel each other.

4. Pressure is due to collisions of gas particles with container walls.

5. The average Kinetic energy of a gas sample is proportional to the Kelvin temperature.