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Can someone explain this?

  1. Feb 1, 2012 #1
    How does one use ratios of gas densities to estimate the molecular mass and find the molecular
  2. jcsd
  3. Feb 1, 2012 #2
    Conceptually keep in mind Ideal Gas Law PV=nRT can allow one to show that at STP one mole of gas molecules exist in 22.4 liters of volume.
    since gas density is gms/ liter (mass/volume) one can calculate the gms of gas from the density to make 22.4 liters or one mole of gas.... gms per mole then gives a Gram Molecular Weight

    If the density is given at a different temperature and pressure recalculate it for STP
  4. Feb 2, 2012 #3


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    Staff: Mentor

    You are right, but mixing mass and "grams of gas" in one sentence is not a good idea. "Grams" are not a synonym of "mass".

    No need for that - you can calculate volume of 1 mole of gas for these conditions and use this volume to calculate mass of 1 mole.
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