Ch. 11 Molecular Composition of Gases
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Transcript of Ch. 11 Molecular Composition of Gases
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.
V = knVolume = 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
`
The molar mass of a gas = 1 mol. of a gas = 22.4 L of a gas at STP.Sample Problem 11-1Sample Problem 11-2Ideal Gas Constant R = PV/nTIdeal gas law – relation between temp., pressure, volume, and # of moles of a gas.Sample Problems 11-3 to 11-5Mass / molar mass = # of molesPV = mRT/M
PV = nRT or PV = mRT/M
Sample Problem 11-6
Density = mass / volume
P = mRT/VM
D = MP / RT
Stoichiometry of Gases1. Volume to Volume Volume A Volume B
Volume A x mol. B / mol. A = VOLUME B
Sample Problem 11-7
2. Volume to MassVolume A Mol. A Mol. B mass
BUSE 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
3. Mass to VolumeMass 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