MP, BP, Dipoles + Bonds - Organic Chemistry

1st step in determining if dipole

determine molecular geometry (use central atom)

2nd step in determining if dipole

Identify polar bonds (bonds where atoms have different EN)

3rd step in determining if dipole

see if molecule symmetrical

If the molecule is symmetrical…

there is no polar dipole

If the molecule is not symmetrical and has polar bonds…

there is a molecular dipole

dipole points in the direction of…

the more electronegative atom

In order to be symmetric (in Trigonal Planar)

all 3 bonds must be the same

In order to be symmetric (in Tetrahedral)

all 4 bonds must be the same

boiling point and melting point trends are related to

how strongly molecules are attracted to each other

the stronger the non-covalent interactions the…

higher the boiling and melting points

Why do stronger bonds have higher BP and MP?

they require more energy to separate the bonds

Ion-Ion interactions are

ionic bonds, attractions of + and - charges

Order of bond strength (weak to strong)

dispersion, dipole-dipole, hydrogen bonds, ion-dipole, ion-ion

ion-ion bonds are (bond strength)

strongest

ion-ion bonds are (functional groups)

anions and cations

ion-dipole interactions are

anion or cations attracted to polar molecules

ion-dipole bonds are (bond strength)

second strongest

ion-dipole bonds are (functional groups)

anions or cations with molecules with dipoles

hydrogen bonds interactions are

acidic hydrogens with basic atoms (which has lone pair)

Hydrogen bonds are (bond strength)

middle

hydrogen bonds are (functional groups)

alcohols, carboxylic acid, amines with NHs, carboxylic amides with NH

alcohols have what bond

hydrogen bond

carboxylic acids have what bond

hydrogen bond

amines with NHs have what bond

hydrogen bond

carboxylic amides with NHs have what bond

hydrogen bond

dipole-dipole interactions are

between 2 molecules with dipoles

dipole-dipole bonds are (bond strength)

second weakest

dipole-dipole bonds are (functional groups)

ketones, aldehydes, esters, alkyl halides, nitriles

ketones have what bond

dipole-dipole

aldehydes have what bond

dipole-dipole

esters have what bond

dipole-dipole

alkyl halides have what bond

dipole-dipole

nitriles have what bond

dipole-dipole

dispersion bonds are also called

london forces

dispersion interactions are

property of all molecules

dispersion bonds are (bond strength)

weakest

dispersion bonds are (functional groups)

all functional groups

do linear or branched molecules have stronger bonds

linear (more surface area)

molecular dipoles are

related to how much molecules want to stick together