Additional aqueous equilibria....

Oops, looks like I missed a couple days. Sorry 'bout that.

So far this week, we have looked more closely at buffers. The key to most buffer problems is to try and wrestle the information you are given into the Henderson-Hasselbalch equation and solve for the bit of info that you're missing. The nitrite/nitrous acid buffer that we looked at in class also (sort of) demonstrated something called the common ion effect. We'll get more into common ion effects tomorrow.

Buffers let us control pH of a solution, but how do we determine concentration of an acid or base in solution? Titrations let us see how the pH of a solution changes as we add acid or base. We talked about titrations as stoichiometry problems in Gen Chem I, now we want to understand what's happening in a pH titration in a little more detail. This is easiest to do by looking at a pH titration curve. Using a titration curve, we can pick out regions where buffers are formed (that allows us to calculate the Ka of an acid), and equivalence points where the amount of acid and base added to the titration reflects the stoichiometry of a balanced reaction.

Don't forget about the Mastering Chemistry assignment, due tomorrow. For anyone who hasn't already heard, since labs were cancelled on Tuesday because of the lovely little snow storm, we have cancelled Chem 210L labs for the week. You will be doing the Titrations, Indicators and Buffers experiment the week after Spring Break.