BCH 119S Lecture Notes - Lecture 2: Gecko, Rubber Band, Intermolecular Force
30 Jan 2016
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A: delta h>0, delta s >0; heat is going in. Q: gecko toe pads stick equally well to leaves (which have a hydrophobic surface) when dry/wet. They can also stick well to glass (polar) when dry. A: van der waals (need lots of surface area) *need bond length and van der waal radii. Covalent bond/halogen bond (similar to h-bond but geometry differs) Acceptors: lone e- pair (has to be a full-time e- pair)=6. Ph is the negative log base 10 of h+ H+ can be net transferred over large distances rapidly without any one proton moving very far. We use bronsted-lowry definition of acids and bases because in water. Ph is important b/c it affects different functional groups. Lower pka->group favors deprotonation (remains a- until more h+ are present at a lower ph) Buffering capacity is greatest at the pka and most effective within +/- Different ionizable groups are effective as buffers at different ph"s.
