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Homework Help: Molecular formula question

  1. Oct 9, 2006 #1
    i have a question. the problem is

    a compound contains only nitrogen and hydrogen and is 87.4% nitrogen by mass. a gaseous sample of the compound has a density of .977g/L at 710. torr and 100. degree celsius. what is the molecular compound.

    i have tried it a little by making the mass of nitrogen 87.4 g. and found out the mass of hydrogen by subtracting 87.4 by 100. then i used the mass of each to find out the volume of each. then i used the ideal gas law for both nitrogen and hydrogen. this is all i did so far. i am not even sure if what i did is right. can you guys help me
     
  2. jcsd
  3. Oct 10, 2006 #2

    GCT

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    Homework Helper

    Hello kevinf and welcome to PF. first use the ideal gas formula

    PV=nRT

    (n/V)=P/RT

    n=total moles of the Nitrogen and Hydrogen gas

    Found out how to convert the "total concentration to average density."
     
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