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Fraction of solute in two layers

  1. May 11, 2009 #1
    Derive the following equation for the fraction of a solute in layer 1 of the 2 layers formed by two immiscible liquids;

    Fraction of solute in layer 1 = (KD*V1)/((KD*V1)+V2)

    where KD=Distribution coefficient for the solute between chemical in V1 and chemical in V2
    V1=Volume of liquid in layer 1
    V2=Volume of liquid in layer 2

    I understand that to find the fraction of A in the total A+B you simply divide A by A+B. But how does the distribution coefficient fit into this?
     
  2. jcsd
  3. May 12, 2009 #2

    Borek

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    Staff: Mentor

    Distribution coefficient is a ratio of concentrations.
     
  4. May 12, 2009 #3
    yes i have that information, im having trouble understanding how to incorporate it into the expression for the fraction of solute in each of the layers of liquid at equilibrium. Essentially i want to know where this equation comes from. Any ideas/ answers would be greatly appreciated :biggrin:
     
  5. May 12, 2009 #4

    Borek

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    Staff: Mentor

    Write equations describing your system. Definitions of fractions won't hurt either.
     
  6. May 22, 2009 #5
    Using the definition of KD being ratio of concentrations in the 2 layers, try writing KD in terms of solute present in the 2 layers, A & B and the volumes V1 & V2

    With the equation that you've made and A/(A+B) you should be able to slove this quite neatly
     
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