posted by .

When 1 gram of sex hormone (contains C, H, and O) was burned in a combustion analysis, 1.5 grams of CO2 and 0.405 grams of H2O were obtained. The molar mass was found to be 352g/mol. What is the molecular formula for the sex hormone?

  • Chemistry -

    Convert 1.5 g CO2 to g C.
    Convert 0.405 g H2O to g H.
    Determine O by
    1.00 g sample- gC - gH = g O.

    Convert g each to moles.
    moles C = g/atomic mass C.
    moles H = g/atomic mass H.
    moles O = g/atomic mass O.

    Now find the ratio of the atoms to each other with the smallest number being 1.00. The easy way to do that is to divide the smallest number by itself; therefore, that number will be 1.00 and the other numbers will follow. Round to whole numbers (BUT don't round too much). If one of the numbers is further away than about 0.2 or so from a whole number, I would multiply the first set of numbers by 2, then 3, then 4, then 5, etc until all are reasonably close to whole numbers. That gives you the empirical formula.
    To find the molecular formula, divide 352/mass empirical formula and round that answer to a whole number. That will be n in the following:
    (CxHyOz)n where x,y,z are the subscripts in the empirical formula. Post your work if you need help through this. Be glad to help.

  • Chemistry -

    okay,this is what i have so far:
    so is the chemical formula:
    O2 + CxHyOz --> CO2 + H2O ?

    CO2: 0.41 g of C
    1.09 g of O2
    H2O: 0.045 g of H2
    0.36 g of O

    Empirical Formula: CH2O -> n = 0.033 mol

    C: 0.033 mol x 12g/mol = 0.396 g of C
    H2: 0.033 mol x 2g/mol = 0.066 g of H2
    O: 0.033 mol x 16g/mol = 0.528 g of O

    is this right?

  • Chemistry -

    .41 (I used 0.409 since I'm allowed three places) is correct.
    .045 g H is correct; not H2.
    Then 1 - 0.409 - 0.045 = 0.546 g Oxygen.

    Then 0.409/12 = ? moles C
    0.045/1 =? moles H
    0.546/16 = ? moles O.
    Then continue.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry

    Combustion analysis of 1.00g of the male sex hormone, testosterone, yields 2.90 g of CO2 and .875 g H2O. What are the mass percents of carbon, hydrogen, and oxygen in testosterone?
  2. Chemistry

    mass-mass conversions and mass-mole conversions: what is the difference and how do you do each?
  3. Chemistry

    1)The chemical formula for aspirin is C9H8O4. What is the mass of 0.40 mol of aspirin?
  4. chemistry

    Combustion analysis, Empirical and Molecular formulas, help!?
  5. chem

    the combustion of 1.83 grams of a compound which only contains C,H, and O yields 4.88 grams of CO2, and 1.83 grams of H2O. What is the empirical formula of this compound?
  6. Chemistry

    I don't really understand why unit analysis works. I found a simple example on a website (I can post the link in a comment if you want). It says, For example, convert 18 grams of water to moles. The molar mass of water is 18 g/mol; …
  7. Science

    The combustion of a compound which contains only C and H yields 2.58 g of CO2 and 0.53 g of H2O. What is the empirical formula of the compound?
  8. chemistry(ch1001)

    When 6.853 mg of sex hormone was burned in a combustion analysis,19.73 mg of CO2 and 6.391 mg of H2O were obtained. What is the empirical formula of the compound ?
  9. chem

    When 3.517 grams of a hydrocarbon, CxHy, were burned in a combustion analysis apparatus, 11.59 grams of CO2 and 3.164 grams of H2O were produced. In a separate experiment, the molar mass of the compound was found to be 40.06 g/mol. …
  10. chemistry

    A 8.408 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 12.53 grams of CO2 and 3.849 grams of H2O are produced. In a separate experiment, the molar mass is found to be 118.1 g/mol. Determine …

More Similar Questions