Polar Covalent Bonds; Acids and Bases Bond Moments and Dipole Moments Formal Charge Resonance Bronsted-Lowry Acid/Base Lewis Acid/Base

Pauling Electronegativity Scale

Electronegativity Trends Ability to Attract the Electrons in a Covalent Bond

Electrostatic Potential Map Cholormethane

Opposite polarity in CH3Li

Methanol

Dipole Moment (m) is sum of the Bond Moments

Nonpolar Compounds Bond Moments Cancel Out

NCl3 and BCl3

Nitromethane

Nitromethane has 2 Formal Charges

Bonding Pattens for C, N, and O

Common Cationic, Neutral and Anionic Forms

Both Resonance Structures Contribute to the Actual Structure

Dipole Moment reflects Both Resonance Structures

Curved Arrow Formalism Shows flow of electrons

Resonance Rules Cannot break single (sigma) bonds Only electrons move, not atoms 3 possibilities: Lone pair of e- to adjacent bond position Forms p bond - p bond to adjacent atom - p bond to adjacent bond position

Resonance Stabilization of Ions Pos. charge is “delocalized”

Two Nonequivalent Resonance Structures in Formaldehyde

Resonance in [CH2NH2]+

Definitions of Acids/Bases

Dissociation in H2O Arrhenius Acid forms H3O+ Bronsted-Lowry Acid donates a H+

Equilibrium Reactions

Measuring Acid Strength Ka

Acid Strength defined by pKa

Stronger Acid Controls Equilibrium

Reaction Described with Arrows

Identify the Acid and Base

Equilibrium Favors Reactants

Resonance in Acetate Anion

Resonance Stabilization

The Effect of Resonance on pKa

Draw the Conjugate Acid and Base

Propanol is a Base

Draw the Conjugate Acid and Base

Propanol is an Acid

Some Acid-Base Reactions

Carboxylic Acids can be Separated from non-acidic Compounds

Lewis Acids and Bases

Lewis Acid and Base Reactions

Lewis Base = Nucleophile Lewis Acid = Electrophile