1. GAS DENSITY AND AVAGODRO’S LAW ONE MOLE OF ANY GAS OCCUPIES A VOLUME OF 22.4 LITERS AT STP. 1.GAS PRESSURE IS A COLLIGATIVE PROPERTY AT STP. 2.COLLIGATIVE: THE PRESSURE IS DEPENDANT ON THE NUMBER OF MOLES OF GAS, INDEPENDENT OF THE SPECIES OF GAS AT STP. 3.IF YOU KNOW THE STP DENSITY OF A GAS, YOU CAN RATIO TO MASS/22.4L TO GET MOLAR MASS. 1.EXAMPLE THE DENSITY OF A GAS IS 2g/1L, WHAT IS THE MOLAR MASS AT STP. 2 GRAMS = MOLAR MASS, MOLAR MASS =22.4 X 2 = 44.8 G/MOL 1L 22.4L VOLUME = MOLES X 22.4L AT STP

2. GAS LAWS – U DO IT NOW DECEMBER 15 2006 LESSON What would be the volume of 4 moles of H 2 OR A SAMPLE 4 moles of N 2 AT STP  VOLUME = MOLES X 22.4L AT STP VOLUME = 4 X 22.4L AT STP VOLUME = 89.6 L AT STP BOTH GASES ARE 89.6L, VOLUME IS A COLLIGATIVE PROPERTY. HOW MANY MOLES ARE IN 44.8L OF O 2 ?  VOLUME = MOLES X 22.4L AT STP 44.8 = MOLES X 22.4L AT STP MOLES = 44.8/22.4 AT STP MOLES = 2

3. CALCULATE THE MOLAR MASS OF A GAS WITH A DENSITY OF 0.1g/mL, what is the molar mass AT STP.   GAS LAWS – U DO IT NOW DECEMBER 15 2006 LESSON MASS = MOLAR MASS VOLUME(L) 22.4L 0.1 g = MOLAR MASS 0.001L 22.4L MOLAR MASS 2240g/ MOL TO CONVERT FROM Ml to L DIVIDE #mL/1000. HERE, IT IS: 1 mL = 0.001 L 1000L VOLUME IN THE DENSITY MUST BE IN LITERS BECAUSE THE VOLUME IN AVAGODRO’S LAW IS 22.4 L