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Homework Help: Process Engineering - Mole Ratio and mole fractions

  1. Oct 28, 2012 #1
    1. The problem statement, all variables and given/known data

    A mineral slurry contains 3 components, solids, liquids and toluene.

    The slurry has 20 wt% solids and 80 wt% liquid. In the liquid portion of the slurry the mole ratio of toluene to water is 1:5.67

    Determine the composition of the slurry (solids, toluene and water) in wt%.


    Determined the composition of the liquid (toluene and water) in wt%.

    2. Relevant equations

    3. The attempt at a solution

    Wasn't sure how to do this question without the molecular mass of Toluene (Which I googled, I don't think we were suppose to know what chemical compound of toluene to solve this question).

    However, is there an alternative method of solving this problem WITHOUT knowing the molar mass or chemical compound of Toluene (we were allowed to use a Periodic Table).

    Thanks a bunch
    Last edited: Oct 28, 2012
  2. jcsd
  3. Oct 28, 2012 #2


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    Staff: Mentor

    You can easily calculate molar mass of toluene knowing its formula - and toluene is one of rather basic substances, often used in commercial processes.
  4. Oct 28, 2012 #3
    Alright, because this was a practice exam question (not homework), just thought that it'd give you all the information you'd need to know (and that the 'formula' for toluene wasn't given to you).

    So there is no way you can do it without the molecular mass of Toluene? (or calculate it with the only given numbers?)
  5. Oct 28, 2012 #4


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    Staff: Mentor

    No, there is no way to convert between molar ratio and weight percent without knowing molar masses. Where do you get them from is a separate problem - buy you need them.
  6. Dec 3, 2012 #5
    You need to find the molecular mass of toluene and water.
    Last edited: Dec 3, 2012
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