H2 Chemistry Chemical Equilibria Question!

• Cre8ion

  1 Jul 13, 21:16

  Hi, would appreciate if someone could answer the following question :)

  When we calculate Kc of reactions that place in aqueous medium, do we take into account the concentration of water, if it is a reactant or product?

  ie. CH3CO2H (l) + C2H5OH (l) <=> CH3CO2C2H5 (l) + H20 (l) 

  Is the Kc = [CH3CO2C2H5][H20] / [C2H5OH][CH3CO2H] ?

   

  Thanks ! :)

• UltimaOnline

  1 Jul 13, 22:16

  Originally posted by Cre8ion:

  Hi, would appreciate if someone could answer the following question :)

  When we calculate Kc of reactions that place in aqueous medium, do we take into account the concentration of water, if it is a reactant or product?

  ie. CH3CO2H (l) + C2H5OH (l) <=> CH3CO2C2H5 (l) + H20 (l) 

  Is the Kc = [CH3CO2C2H5][H20] / [C2H5OH][CH3CO2H] ?

  Thanks ! :)

  
  It depends on whether water was already initial present as a solvent (ie. in large excess), or if it functions solely as either a reactant or product.

  Notice that in your particular question, it is implied that no water was initially present. Hence water here is a product, and must therefore be included in your Kc expression and formula.