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 CH 3 Li

Methanol

Dipole Moment (  ) is sum of the Bond Moments

Nonpolar Compounds Bond Moments Cancel Out

NCl 3 and BCl 3

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  bond  bond to adjacent atom  bond to adjacent bond position

Resonance Stabilization of Ions Pos. charge is “delocalized”

Two Nonequivalent Resonance Structures in Formaldehyde

Resonance in Acetate Anion

Resonance in [CH 2 NH 2 ] +

Definitions of Acids/Bases

Dissociation in H 2 O Arrhenius Acid forms H 3 O + Bronsted-Lowry Acid donates a H +

Resonance Stabilization

Measuring Acid Strength Ka

Acid Strength defined by pK a

Stronger Acid Controls Equilibrium

Reaction Described with Arrows

Equilibrium Reactions

Acids Can React with Water

The Effect of Resonance on pKa

Identify the Acid and Base

Equilibrium Favors Reactants

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

Draw the Acid-Base Complexes