1. Molar Volume Avogadro’s Law: Equal volumes of gas at the same temperature and pressure contain equal numbers of particles. But the mass is different!!!

2. [http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_11/FG11_26-03h.JPG]

3. Molar Volume 1 mole of any gas occupies 22.4 L at Standard Temperature & Pressure (STP) [http://wps.prenhall.com/wps/media/objects/602/616516/Media_Assets/Chapter09/Text_Images/FG09_09-04UNT04.JPG]

4. Molar Volume What is STP? Scientists designate this so that measurements can be made anywhere under controlled conditions. T = 273 K P = 1 atm

5. Molar Volume Example: What is the volume of 20.0 g of Argon gas at STP? 20.0 g Ar1 mol Ar 40.0 g Ar 22.4 L Ar 1 mol Ar = 11.2 L Ar

6. Molar Volume Example: A helium balloon is filled to a volume of 4.00 L, how many helium atoms is this at STP? 4.00 L He1 mol He 22.4 L He 6.02 x 10 23 atoms 1 mol He = 1.08 x 10 23 atoms He