Chapter #11 Molecular Composition of Gases

Chapter 11.1 Gay-Lussac’s law of combining volumes of gases states that at constant temperature and pressure, the volumes of gaseous reactants and products can be expressed as ratios of small whole numbers.

Avogadro’s law states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.

Standard Molar Volume of a gas is the volume occupied by one mole of a gas at STP. 1 mole = 22.4 L

Chapter 11.2 The ideal gas law PV=nRT R is the gas constant 62.4 or you have to use the units of Pressure to pick which one… So… if pressure is in mmHg R=62.4 If pressure is in atm R= Temperature must be in Kelvin!!!

Molar mass or Density M= mRT M= DRT PV P D= MP RT M= Molar Mass m= mass in grams R= gas constant T= Kelvin Temperature P= Pressure V= Volume D= Density

Chapter 11.3 Stoichiometry of Gases Volume to volume calculations Liter to Liter same as Mole to Mole Given # of x what you want Liters what you have = Liters of what you want Mole to mole ratio from balanced equation

Chapter 11.4 Graham’s law of Effusion states that the rates of effusion of gases at the same temperature and pressure are inversely proportional to the square roots of their molar masses. A is the lighter gas, B is the heavier one.

Work Cited “Cartoon”. August 11, “Gay-Lussac’s Law”. February 13, s/chem/chap6/c asp s/chem/chap6/c asp “Avogadro’s Law”. February 13, GIF GIF “Grahams Law”. February 15, ations/EffusRatio.gif ations/EffusRatio.gif