Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Help! How to get the mole fraction ?

  1. Nov 28, 2005 #1
    An aqueous antifreeze solution is 37.0% ethylene glycol (C2H6O2) by mass. The density of the solution is 1.047 g/cm3.

    Q: Calculate the mole fraction of ethylene glycol.

    I tried it many time, but still got the wrong answer.

    that is what i did:

    mole fraction:(X) = nA/(nA+nB)
    set the mass of the solution - m
    molar mass of C2H6O2: 62
    molar mass of H2O: 18 --- (I think the solvent should be H2O....but not quite sure)

    => [(0.37 * m)/62]/[(0.37 * m/62 + 0.63 * m/18)]
    = 13.8%------but that is wrong

    need help...please
     
  2. jcsd
  3. Nov 28, 2005 #2

    Borek

    User Avatar

    Staff: Mentor

    Check your math - equation is OK, just the result is wrong.
     
  4. Nov 28, 2005 #3
  5. Nov 28, 2005 #4
    oh....never mind...
    the system does not accept percentage....
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook