Types of Matter There is a lot of “free” space in a gas.There is a lot of “free” space in a gas. Gases can be expanded infinitely.Gases can be expanded infinitely. Gases fill containers uniformly and completely.Gases fill containers uniformly and completely. Gases diffuse and mix rapidly.Gases diffuse and mix rapidly.

Kinetic Molecular Theory (KMT) 1) Gases are mostly empty space; the volume of particles is negligible. 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.

GAS DIFFUSION AND EFFUSION diffusion is the gradual mixing of molecules of different gases.diffusion is the gradual mixing of molecules of different gases. effusion is the movement of molecules through a small hole into an empty container.effusion is the movement of molecules through a small hole into an empty container.

Torricelli’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. The weight of the mercury in the tube was equal to the weight of the air pressing down on the mercury in the dish. Pressure - Force applied per unit area is measured with a Barometer For gas laws we will use Pacals, atm or mm Hg as units

Volume Changes Compression - larger volume to smaller volume Expansion - smaller volume to larger volume. For gas laws we will always use Liters (L) for units

Temperature- A measure of the average kinetic energy of a sample Kinetic Energy - 1/2 m x v 2 What does this mean? If you have the same gas at two different temperatures, the gas at the higher temperature is going faster. Units- for gas laws we always use Kelvin (K) as units

Absolute Zero the bottom of the temperature scale

The conditions 0 0 C and 1 atm are called standard temperature and pressure (STP). PV = nRT R = PV nT = (1 atm)(22.414L) (1 mol)( K) R = L atm / (mol K) 5.4 Experiments show that at STP, 1 mole of an ideal gas occupies L.

Gay-Lussac’s Law How are Pressure and Temperature Related? As one goes up so does the other.

Boyle ’ s Law A bicycle pump is a good example of Boyle’s law. As the volume of the air trapped in the pump is reduced, its pressure goes up, and air is forced into the tire.

If we place a balloon in liquid nitrogen it shrinks: Charles’ Law = Temperature and Volume Change together So, gases shrink if cooled. Conversely, if we heat a gas it expands (as in a hot air balloon).