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Distribution coefficient problem for Organic Chem!

  1. Jul 15, 2009 #1
    1. The problem statement, all variables and given/known data
    When 100 mL of an aqueous solution containing 1.0 g of caffeine is extracted with 10 mL of chloroform at room temperature, 0.5 g of caffeine is transferred to the chloroform layer. Calculate the distribution coefficient of caffeine between chloroform and water at room temperature.


    2. Relevant equations

    The only thing I have is that Kd=concentration of A in S/ concentration of A in S'
    where A= the solute and S/S' are the immiscible solvents

    3. The attempt at a solution

    I have not a clue how to do this! If someone could walk me through it that would be great! thanks so much!
     
  2. jcsd
  3. Jul 16, 2009 #2
    What's the concentration of caffeine in the aqueous layer to start with? What about after adding the cloroform?
     
  4. Jul 16, 2009 #3

    Borek

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    Staff: Mentor

    Also: if there is 0.5g in chloroform, how much was left in water?
     
  5. Jul 16, 2009 #4
    I'm not sure. The book doesn't give any other numbers listed anywhere....thats a state school for ya! The only number that I have for caffeine listed is the 33.3 mg that is in the BC powder that the experiment is done with. I'm sorry! If there is no way to figure this out, its okay, but thanks for your replies!
     
  6. Jul 16, 2009 #5
    Well of course it's not given, you're supposed to calculate it! Concentration = amt of substance / volume
     
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