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Question about Experimental Results

  1. Feb 6, 2005 #1
    Testing Solubility the following results were obtained:

    Tested in Water:
    Methanol: Soluble
    Ethanol: Soluble
    Diethyl Ether: non-soluble
    Cyclohexanol: soluble
    Acetone: soluble
    2-butanone: soluble
    Cyclohexanone: soluble

    Tested in Cyclohexane:
    Methanol: non-soluble
    Ethanol: non-soluble
    Diethyl Ether: Soluble
    Cyclohexanol: non-soluble
    Acetone: non-soluble
    2-butanone: non-soluble
    Cyclohexanone: non-soluble

    Are these results correct with what they should be?

    I believe that they are incorrect due to the fact that polar should be only soluble in polar and non-polar in non-polar but why would some polar be soluble in non-polar solvent and vice versa? What are some reasons if errors did occur in the solutions. Thank you. :bugeye:
     
  2. jcsd
  3. Feb 7, 2005 #2

    chem_tr

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    If you really did the experiment and saw these results, the reality is this one. You'll need to investigate why the result is like this.

    It would be better if you find a solvent miscibility table from the Internet. I think some errors are present in the results you have.
     
  4. Feb 7, 2005 #3
    As far as I can see, all water-miscible solvents in your experiment can contribute to hydrogen bonding, and all cyclohexane-miscible solvents cannot. It seems that in this test the possibility of hydrogen bonding is more important than just polarity. But, of course, it doesn't harm to doubt experimental results. But I guess that after doing thousands of experiments in different solvents, you will neither see a clear cut between polar and non-polar solvents nor even a clear cut between possible hydrogen bond formers and those that cannot. although the trends are there, largely.
    Also remember that miscibility might be a function of concentration.
     
  5. Feb 7, 2005 #4
    Does that mean that if a lower concentration of solutes was used in a greater concentration of solvent it would give the appearance that the solute dissolved when in fact it was an error due to concentration? Also, in all the experiments the same amount of solute and solvent was used to determine the solubility, i.e. 2 ml of water or cyclohexane and a 0.5 ml of the solute. I do not believe the concentration would be a factor in this experiment because some of the results were clear cut non-soluble when they should have been soluble. One reason could be due to contamination of the experimental materials but could any other factor be taken into consideration? Thank you for your continuing help. :bugeye:
     
  6. Feb 7, 2005 #5
    Therefore, if I understand correctly, the reasons for incorrect results would be that a) there was some contamination involved and b) not enough concentration of the solute was used. I finally understand oskall what you were trying to say about the concentrations. Thank you.
     
  7. Feb 7, 2005 #6

    GCT

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    You need to identify the different motifs in the molecule, a molecule may have a major polar as well as non-polar component.
     
  8. Feb 7, 2005 #7
    How do I identify the different motifs in the molecule? Can you please tell me if any on my list have a major polar and non-polar component? Thanks.
     
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