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Homework Help: Need help with chem problem

  1. Sep 18, 2007 #1
    1. The problem statement, all variables and given/known data

    A solution is made by disolving 0.40 mol isopropanol (C3H7OH) in 0.70 mol water.
    (a) What is the mole fraction of isopropanol?

    (b) What is the mass percent of isopropanol?
    (c) What is the molality of isopropanol?

    2. Relevant equations

    3. The attempt at a solution

    Not sure what steps to take here?
  2. jcsd
  3. Sep 18, 2007 #2
    Whoa man why are you posting so many times, if they don't answer they don't answer. I've been waiting for an answer, if someone knows then they'll hopefully help you if not? posting 20 times won't help.
  4. Sep 18, 2007 #3


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    Homework Helper

    Do you know the definitions of each of those quantities? Can you show the equations for them? Check your book. Tell us what is giving you trouble. You need to show more effort, we can't do all the work for you!
  5. Sep 18, 2007 #4
    mole fraction= amount (mol) of solute / amount (mol) of solute + amount (mol) of solven

    mass percent= mass of solute/ mass of solute + mass of solvent x 100

    molality = amount mol of solute/ mass kg of solvent

    i know the equations do i just plug the quantities in or is there more to it than that
  6. Sep 18, 2007 #5
    show more work in your post(s) and we'll be glad to help :)

    it won't help you very much if we just direct you straight to the answerrr
  7. Sep 19, 2007 #6


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    Homework Helper

    Just try to do the calculations. Look at what the equation is asking for. Was it given to you in the question? Do you have to do some calculations to get those quantities in the equation? The best way to get help is to show your work. That way we can see what you're not understanding.
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