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Homework Help: Empirical Formula from Stoichiometry?

  1. Oct 18, 2012 #1


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    Gold Member

    Empirical Formula from Stoichiometry!?

    1. The problem statement, all variables and given/known data
    More than 1 billion pounds of adipic acid (MW 146.1 g/mol) is manufactured in the US each year. Most of it is used to make synthetic fabrics. Adipic acid contains only C, H, and O. Combustion of a 1.6380g sample of adipic acid gives 2.960g of CO2 and 1.010 g of H2O. What is the simplest formula for adipic acid? What is its molecular formula?

    2. Relevant equations
    (Adipic Acid) + O2 -> CO2 + H2O

    3. The attempt at a solution
    Convert to .0561 mol H2O
    Convert to .0673 mol Co2
    Convert to .0112 mol adipic acid using stoichiometry (I understand this part).
  2. jcsd
  3. Oct 19, 2012 #2
    Re: Empirical Formula from Stoichiometry!?

    Divide each of the moles by the least amount (adipic acid), then you'll get (roughly) even numbers, which is the empirical formula.
  4. Oct 19, 2012 #3


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    Staff: Mentor

    Re: Empirical Formula from Stoichiometry!?

    Use given masses of water and carbon dioxide to calculate masses of hydrogen and carbon in the sample of adipic acid - you will see the sample weighted more. Missing mass is the oxygen. Then calculate moles of H, C and O (not H2, C and O2) and find their ratio as iRaid suggested.
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