sp 3 hybridization tetrahedral geometry bond angle sp

sp 3 hybridization tetrahedral geometry bond angle =

sp 3 hybridization of carbon in methane tetrahedral geometry

sp 2 hybridization trigonal geometry

sp 2 hybridization of carbon in ethylene (a. k. a. ethene) trigonal geometry

sp hybridization of carbon in acetylene (a. k. a. ethyne)

Bronsted-Lowry Acid-Base Concept

Lewis Acid-Base Concept Electron pair donor Electron pair acceptor

General Acid-Base Reaction HA + H 2 O Ka = H 3 O + + A - [H 3 O+] [A-] [HA] p. Ka = - log Ka

Ka p. Ka

Electronegativity Effect on Acidity

Size Effect on Acidity (i. e. , Size of Conjugate Base)

Resonance Effect on Acidity

Buffer Effect Henderson-Hasselbalch Equation: p. H = p. Ka + log [A-] [HA] The Henderson-Hasselbalch equation describes how the p. H of a solution is governed by the p. Ka of the acid present and the logarithm of the ratio of the concentrations of the conjugate base and protonated form of the acid. If the p. H is greater than the p. Ka of the acid, it will predominantly exist in it’s conjugate base form. If the p. H is less than the p. Ka, the acid will exist predominantly in it’s protonated form. Buffer Effect: The ability of a solution to resist a change in p. H as H+ or HO- are added to it. Buffer Capacity: The amount of H+ or HO- that can be absorbed before the p. H begins to shift significantly. The buffer capacity of a solution is related to the total concentration of HA & A- in solution as well as the magnitude of the separation between the p. H & p. Ka. Of the many species capable of buffer action in biological systems, the most important biological buffers are H 2 PO 4 - (phosphate) and H 2 CO 3/HCO 3(carbonate) due to their higher relative concentrations (i. e. , greater buffer capacity). H 2 CO 3 HCO 3 - + H+ Carbonate: CO 2 + H 2 O H 2 PO 4 - + H+ HPO 42 - + H+ PO 43 - + H+ Phosphate: H 3 PO 4

Buffer Effect Acetate Titration Curve Phosphate Titration Curve PO 43 HPO 42 - PO 43 - + H+ CH CO - + H+ CH 3 CO 2 H 3 2 HPO 42 - H 2 PO 4 - HPO 42 - + H+ H 2 PO 4 - H 3 PO 4 H 2 PO 4 - + H+ H 3 PO 4

p. Ka’s of Some Amino Acids Titration Curve for the Amino Acid Histidine