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Homework Help: How to find empirical formula from combustion equation

  1. Sep 26, 2010 #1
    1. The problem statement, all variables and given/known data
    The organic solvent thiophene is a carbon-hydrogen-sulfur compound that makes C02, H20 AND S02 when burned in excess Oxygen. When subject to combustion analysis, a 1.3020g sample makes 2.7244 g CO2, .5575G H20 and .99151 SO2. Find the empirical formula of thiophene

    2. Relevant equations


    3. The attempt at a solution

    so first i wrote out the combustion

    Thiophene + O2 <> CO2+ H20+SO2 but i cant balance it yet

    I then found the amount of moles the compunts on teh right side

    CO2= 2.772g/44.009g/mol = .06186 moles / .00309 ~ 20 mol
    H20= .5575g/18.019g/mol= .00309mole / .00309 = 1 mol
    SO2=.9915g/64.045g/mol = .01548 mole / .00309 ~5 mol


    Thiophene + O2 <> 20(CO2)+ H20+5(SO2)


    But I have no idea where to go from here, any one have any hints?
  2. jcsd
  3. Sep 28, 2010 #2
    first try to find the percentage of carbon from co2 and hydrogen from h20 and sulphur from so2 then calculae percentage of oxygen from it.
    now find mole of each element from its percentage .then find its atomic ratio.this would give the value o empirical formula.
  4. Oct 3, 2010 #3
    thank you very much! I get it know :)
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