GAS LAWS

Gas

•Particles have LOTS of energy; moving all around

•Gases take on the shape and volume of their container.

•Gases will spread out evenly = diffusion •Ruled by Gas Laws (Charles Law, Boyle’s

Law) •Examples: oxygen, carbon dioxide, “air”

Pressure

Pressure: amount of force on a unit of area. Can be measured in mm Hg, atm, Pascals

Formula for pressure: Pressure = Force/Area

Boyle’s Law

•Says: If you decrease the volume of a container of gas, the pressure will increase (temperature and # of particles must stay constant!)

•Deals with: volume and pressure. (NOT temperature!) Volume and pressure are INVERSELY related (one goes up, the other goes down)

•Thought examples: If I squeeze a balloon, the volume goes down, but the pressure goes up!

•Formula: P1V1 = P2V2

Practice #1

66 Liter of a gas is at a pressure of 8 atm. What is the volume of the gas at 2 atm?

P1V1 = P2V2

8 x 66 = 2 x V2

528/2 = V2

264 liters

Practice # 2

4.00 L of a gas are under a pressure of 6.00 atm. What is the volume of the gas at 2.00 atm?

P1V1 = P2V2

6 x 4 = 2 x V2

24/2 = V2

12 liters

Charles Law

•Says: the volume of a gas increases as the temperature increases (pressure must stay constant)

•Deals with: volume and temperature (not pressure!)

•Thought example: If I heat up a balloon, it will get larger. If I put a balloon in the freezer, it will get smaller.

Examples - Charles Law

600.00 mL of air is at 20.0oC. What is the volume at 60oC?

V1/T1 = V2/T2 600 /20 = V2/60 30 x 60 = (V2/60) 60 1800 mL = V2

Lussac’s Law

•Says: the pressure of a gas is directly proportional to the temperature

•Deals with: Pressure and Temperature (volume is kept constant)

•Thought example: If I heat up a sealed container of gas, the pressure will increase inside the container