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Homework Help: Preparation of esters & Keq

  1. Dec 20, 2009 #1
    In the preparation of isoamyl acetate, a student reported a % yield of 66.6%.Assuming that he used equimolar amounts of the starting materials,what is the equilibirium constant of the esterification process?

    I need conc of products & conc of reactants to get Keq but how do i get that? They only said that equimolar amounts were used & that means there is no limiting or excess reagent.

    All ive managed to get so far is that i need to use the reaction:
    CH3CO2H + HOCH2CH2CH(CH3)2 ---> CH3CO2CH2CH2CH(CH3)2 +H2O

    Keq= [CH3CO2CH2CH2CH(CH3)2] / [CH3CO2H] [HOCH2CH2CH(CH3)2]

    But how do i get these conc.?
     
  2. jcsd
  3. Dec 20, 2009 #2

    Borek

    User Avatar

    Staff: Mentor

    You have to assume that volume has not changed and use stoichiometry to calculate final amounts of unreacted rectants. That's in a way similar to using ICE table.

    And don't forget C=n/V.

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  4. Dec 20, 2009 #3
    33.4% of the reactants have not reacted. So if we assume V=100ml that means 33.4ml have not reacted and 66.6 ml is V for the product. Is this correct?
    Incase it is, how do i get n? I only need n for one species cuz its equimolar & stoich is 1:1.
     
  5. Dec 20, 2009 #4

    Borek

    User Avatar

    Staff: Mentor

    Start assuming initially n=1. Write expression for K. Check if volume doesn't cancel out.

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