I know you're not supposed to consider water for equilibrium calculations (ICE tables and Kc) if it is liquid, but what if it is aqueous or gaseous? Thanks!
This is somewhat difficult to understand. In the gaseous state it is included. In reactions where it is a product it is included;e.g. alcohol + acid --> ester + H2O. In aqueous solution, it is not included for it is essentially a constant. In
NaOH(aq) + HCl(aq) ==> NaCl(aq) + H2O(aq)
In this acid/base neutralization the water is essentially 1000g/18 = about 55.5 M anywhere in the titration and the Keq numerica constant really is 55.5 times a K which ends up being another constant which we call Kc in aqueous solution. I encourage any other tutor to post his/her thoughts
Another way to look at this is that H2O is not included in aqueous solution for the same reason that we do not include solids; i.e., in solutions we consider the water s a pure substance. Thermodynamically, solids, by definition, have an activity of 1. Same for "pure" liquids.