How Do You Calculate Keq from a 66.6% Yield in Esterification?

[ChemDoodle]

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 I've 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.?

 

[Borek]

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.

--

 

[ChemDoodle]

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 because its equimolar & stoich is 1:1.

 

[Borek]

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

--