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Homework Help: Hydrocarbon molecular weight grade 11

  1. Apr 29, 2010 #1
    1. The problem statement, all variables and given/known data

    A gaseous hydrocarbon weighing 0.185g occupies a volume of 110.cm^3 at 26 celsius and 743mmHg. what is the molecular weight of this compound?

    2. Relevant equations


    3. The attempt at a solution

    i have no idea where to start ;(
  2. jcsd
  3. Apr 29, 2010 #2
    The molecular weight is in g/mol; you have the mass of the sample, so now you need to find the moles so you can divide them. Rewriting the equation to get n, or the moles, by itself gives you n = PV/RT. Convert everything to the correct units, then plug them into the equation.
  4. Apr 30, 2010 #3
    ohh, i see it now.. many thanks =]
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