1. Ch. 11 Molecular Composition of Gases
If the volume of a gas in the product and reactant of a chemical equation is left at a constant temp. and pressure, then it can be shown as a ration.
Avogadro’s principle – says that equal volumes of gases at the same temp. and pressure contain equal numbers of molecules.

2. V = kn
Volume = constant x number of moles
The volume of a gas is directly proportional to the number of moles of a gas. (At a constant temp. and pressure)
Each gas will occupy the same volume at the same temp. and pressure  Avogadro’s principle.
Standard molar volume of a gas is the volume occupied by 1 mole of a gas at STP 22.4 L

3. The molar mass of a gas = 1 mol. of a gas = 22.4 L of a gas at STP.
Sample Problem 11-1
Sample Problem 11-2
Ideal Gas Constant  R = PV/nT
Ideal gas law – relation between temp., pressure, volume, and # of moles of a gas.
Sample Problems 11-3 to 11-5
Mass / molar mass = # of moles
PV = mRT/M

4. PV = nRT or PV = mRT/M
Sample Problem 11-6
Density = mass / volume
P = mRT/VM
D = MP / RT

5. Stoichiometry of Gases
1. Volume to Volume
Volume A  Volume B
Volume A x mol. B / mol. A = VOLUME B
Sample Problem 11-7

6. 2. Volume to Mass
Volume A  Mol. A  Mol. B  mass B
USE n = PV / RT to convert volume to mass
Mol. A x mol. B / mol. A = mol. B x molar mass B = MASS B
Sample Problem 11-8

7. 3. Mass to Volume
Mass A  Mol. A  Mol. B  Volume B
Mass A / Molar mass A x mol. B / mol. A = mol. of B
Use V = nRT/P to covert mol. of B into volume of B
Sample Problem 11-9