Chemistry is not one of my strong subjects, so please bear with me. Here's one of the questions we were given as homework, of which I'm having some trouble with. I'm sure it's pretty elementary, but the problem is that I'm unable to express the answer clearly enough. Question: The reaction of ethanoic acid with ethanol to form ethyl ethanoate and water is an example of dynamic equilibrium. It is catalysed by the presence of [tex]H^+[/tex] ions. [tex]CH_3CO_2H(l) + C_2H_5OH(l) \rightleftharpoons CH_3CO_2C_2H_5(l) + H_2O(l)[/tex] State why, in determining the value of [tex]K_c[/tex] for this reaction, it is only necessary to know the number of moles rather than the concentrations of each substance. My answer (We are given only two lines of answering space): EDIT: Deleted answer; it's severely wrong. I'll try and come up with a new one.