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PartB Distribution of coefficent in immiscible solvents

  1. Feb 16, 2009 #1
    1. The problem statement, all variables and given/known data
    Hey guys, I have lab result here for Distribution of coefficient for the solid between water and metylene chloride


    Benzoic Acid: 5mg (Weight of solute in methylene chloride)
    45mg (Weight of the solute in water )

    Succinic Acid: 1mg (Weight of solute in methylene chloride)
    49mg (Weight of the solute in water)

    Sodium Benzoate: none ( Weight of solute in methylene )
    50mg (Weight of the solute in water)



    2. Relevant equations
    Becaue the volume of methylene chloride and water (2mL each) are the same in my lab,
    K (distribution of coefficient)
    = (the weight of the solute in methylene chloride)/ (the weight of solute in water)



    3. The attempt at a solution

    Benzoic Acid: K=5/45=0.11
    Succinic Acid: K=1/49=0.02
    Sodium Benzoate: K=0/50=0

    Well, I just did what the equation say that but I'm not so sure why the values of K are so small number campare to caffeine K is 4.6 between methylene chloride and water. Thank you so much in advance.

    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Feb 17, 2009 #2

    Borek

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    Staff: Mentor

    Is methylene chloride polar enough to dissolve ionic substance?
     
  4. Feb 17, 2009 #3
    if you are referring to sodium benzoate, it dissoloves in water completely becaue of the inonic bond, I think.
     
  5. Feb 17, 2009 #4

    Borek

    User Avatar

    Staff: Mentor

    Will it dissolve in methylene chloride?

    What about acids?
     
  6. Feb 17, 2009 #5
    I don't think sodium benzoate dissolves in methylene chloride becaue methylene chloride is organic compound and non polar. Other acids such as benzoic acid and succinic acid dissolves mostly in Water because they are di-polar but still dissolves tiny amount in methyle chloride.
     
  7. Feb 17, 2009 #6

    Borek

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    Staff: Mentor

    Not bad. Perhaps you don't have a full picture yet, but you are definitely on the right track.

    Benzoic acid is weak, or strong? What happens when it dissociates? What about solubility of charged and uncharged forms in both solvents?

    What about caffeine?
     
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