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Find the molecular and empiral formula

  1. Sep 3, 2009 #1
    1. The problem statement, all variables and given/known data
    Digiton is a substance that technologists use to determine cholesterol levels. It contains only (C,H, and O) and its percent composition is 54.71% C, 7.54% H, and 37.74% O by mass. The experimentally determined molecular mass is 1229g/mol. What is the empirical amd molecular 1 formular for digiton?



    3. The attempt at a solution
    ok so C=12g, H=1g and O=16g

    First,
    54.71/12= 4.56 mol
    7.54/1= 7.54 mol
    37.74/16= 2.36 mol

    Secondly, I gotta divide by the smallest number which in this case is 2.36
    4.56/2.36= 1.9~2
    7.54/2.36= 3.2
    2.36/2.36=1
    since 3.2 is to far away i multplied it by 5 to get a number that i can round. My end solution for the empirical formula was C10H15O5.

    Now to get the molecular i found the grams in the empirical which was 215g. Now 1229/215=5.7 which i THINK i have to get a whole number and it took me x3 to get 17.1 which can be rounded to 17. So im stuck on to what to do in finding the molecular formula if everything above this is right which im fairly confident it is.. please help
     
  2. jcsd
  3. Sep 3, 2009 #2
    You may want to attempt solving for the molecular formula first--you're given all the information necessary to calculate moles of each element per mole of compound.

    Then divide by the greatest common factor to get the empirical formula.
     
  4. Sep 4, 2009 #3

    Borek

    User Avatar

    Staff: Mentor

    Empirical formula should contain lowest possible numbers. 5, 10 and 15 are all multiplies of the same smaller number.

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