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Homework Help: Combustion analysis problem? - General Chemistry

  1. Sep 27, 2009 #1
    1. The problem statement, all variables and given/known data
    When a sample that is .91 grams is burned in oxygen, it produces 2.073 grams of carbon dioxide, .304 grams of water, and .0944 grams of nitrogen. What is the empirical formula of the compound?

    3. The attempt at a solution
    I converted all of the products to moles:
    CO2: .0471 moles
    H2O: .0169 moles
    N2: .00337 moles.

    This gave me C.0471H.0338N.00674.

    Simplifying the ratios, I got C7H5N.

    My problem is that I don't have any idea of what to do with the oxygen. I don't even know if/how much of it it is present in the sample, because the sample is burned.

    Thanks in advance for any help.
  2. jcsd
  3. Sep 27, 2009 #2


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    Science Advisor
    2017 Award

    From the amounts of carbon dioxide, water, and nitrogen produced, you should be able to figure out the mass of carbon, hydrogen and nitrogen in the original sample. The remaining mass is presumably due to oxygen.
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