1. The Ideal Gas Law

2. Real Gas Behaviour There are several assumptions in the kinetic molecular theory that describe an ideal gas Gas molecules have zero volume Forces of attraction/repulsion are zero Molecules move in straight lines Collisions are completely elastic However, at high pressure and low temperature there are problems with these assumptions In very small volumes there will be many more interactions and collisions The volumes of the gas molecules is now a significant fraction of the container

3. Real GasIdeal Gas In some cases (polar molecules), mild attractions exist between particles (volume is mildly decreased) No attractions exist between particles (no IMF) Gas particles occupy spaceGas particles have no volume Some gases do condense at low temperature and high pressure Ideal gases will NOT condense into liquid “Mostly” obey the gas lawsObey gas laws perfectly Constant RANDOM motion Motion of particles is always in straight lines

4. The Ideal Gas Law Boyle’s Law: PV = kor V = k P Charles’ Law: V = k or V = aT T Avogadro’s Law: V = b or V = bn n V = kab X nT P V = RnTor PV = nRT P

5. PV= nRT P = pressure (kPa) V = volume (L) n = amount (mol) T = temperature (K) R = ?? Unit Analysis! PV = nRT R = PV nT R = (kPa)(L) (mol)(T) R = 8.314 kPa·L/mol·K

6. Try These… # 1- 1.09 g of H 2 is contained in a 2.00 L container at 20.0 °C. What is the pressure in this container in mm Hg? #2- What volume will 20.0 g of Argon occupy at STP?

7. #3- At what temperature will 0.654 moles of neon gas occupy 12.30 liters at 1.95 atmospheres? #4- At STP 3.00 liters of an unknown gas has a mass of 9.50 grams. Calculate its molar mass.

8. #5- Determine the number of grams of carbon dioxide in a 450.6 mL tank at 1.80 atm and minus 50.5 °C. Determine the number of grams of oxygen that the same container will contain under the same temperature and pressure.

9. #6- If 9.006 grams of a gas are enclosed in a 50.00 liter vessel at 273.15 K and 2.000 atmospheres of pressure, what is the molar mass of the gas? What gas is this?