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Homework Help: Molecular formula of organic compound

  1. Jul 6, 2016 #1


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    1. The problem statement, all variables and given/known data
    Screen Shot 2016-07-06 at 2.52.22 PM.png
    2. Relevant equations

    3. The attempt at a solution
    Firstly I tried to find the empirical formula:

    C : H : O
    65.2 : 8.75 : 26.05 (mass)
    5.43 : 8.75 : 1.628 (mol)
    3.34 : 5.37 : 1
    10 : 16 : 3

    This gives a molecular mass of 184.

    Now with the structure: It has to contain a carboxylic group. I used trial and error and got the structure 1-hydroxyl dec-2-eneoic acid. Not sure if my naming is correct but the general idea is that there is a alcohol on one end, carboxylic acid on the other end, and a double bond in between. This means the mol of NaOH used = mol of compound Q. NaOH = 0.000237 mol. Molar mass = 0.0437 gram/0.000237 mol = 184.38 g/mol.

    Does this seems correct?

  2. jcsd
  3. Jul 6, 2016 #2


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    Science Advisor
    2017 Award

    What is the degree of unsaturation of the molecule? How many degrees of unsaturation does your proposed compound have? (Note that the problem does not require you to give a structural formula as many different structural formulas would be consistent with the observations given).
  4. Jul 8, 2016 #3


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    According to the alkane molecular formula there are 3 degrees of unsaturation since there needs to be 22 hydrogens for a 10 carbon compound to be saturated. However, for the molecule I proposed, I only had 2 degrees of unsaturation so I need to add another double bond. I miscounted before :( Thanks!
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