pH Curves in 60 seconds

pH curves are inherently hard things to get your head around but once you do getting it is very worthwhile, so here is my 1 minute guide to what working them out...

1. Shape - Think of each curve as made up of 2 half curves and there are 4 possible half curves (weak acid, strong acid, strong base, weak base), the shapes will either be almost L shaped (Strong) or almost fallen over S shaped (weak) and either high (base) or low (acid). So, when drawing (or describing) a curve just think, what is in the conical flask before I started titrating and draw the half curve for that first, then think what am I adding to it from the burette and draw that sort of half curve next.
2. Intial pH - is the pH in the conical flask before you added anything
3. Estimate of final pH - this will be very close to the pH of whatever was in the burette but reduced a bit (if its a base) or increased (if its an acid)
4. Equivalence volume - Volume it gets v steep
5. Equivalence pH - Middle of v steep section
6. Getting Ka from graph - At 1/2 equivalence volume the Ka = H+ (or pKa = pH)
7. Where is there a buffering effect? - If you have a weak acid or a weak base, in the middle of the half curve for this solution the curve flattens for a bit, this is the buffering effect, this happens because there is a mixture of a weak acid and its conjugate base (or a weak base and its conjugate acid)

59, 60. Done