CHEM 40A - chapter 2

conjugation

-two pi bonds are connected by one single (sigma) bond

-continuous (like ring or chain)

resonance

-involve movement of pi-electrons or lone-pair electrons conjugated to pi-bonds

aromaticity

-must be cyclic

-each atom must be sp2 hybridized some execeptions

-# of pi electrons = 4n+2 (n = positive integer including 0)

-ring must be planar

H bond donors

must be H attached to O or N

H bond acceptors

atom (O,N, or F)

increases solubility

if more polar or ionic bonds than nonpolar

higher molecular weight

higher boiling point and melting point

stronger IMF

higher boiling point and melting point

saturated fats

-shape of alkane

-tighter packing —> higher melting point

unsaturated fats

-alkene —> disrupts “packing” & vdw forces

-lower melting point —> liquid @ ambient temp