INTERMOLECULAR FORCES

Question 1

what are the 3 types of intermolecular forces

Answer 1

dipole-dipole forces
VDW forces
hydrogen bonding

Question 2

describe dipole dipole forces

Answer 2

when there is a dipole moment
- one side delta positive and the other delta negative
intermolecular : weak - delta plus on one molecule attracts to delta minus on another molecule
intramolecular: strong - covalent bonds join atoms within the molecule

Question 3

describe VDW forces

Answer 3

electrons in charge clouds are constantly moving
if electrons are more at one end of the molecule there is a temporary dipole
this induces a dipole in the next molecule
temporary delta positive attracts induced delta negative in the next molecule

Question 4

what affects VDW forces

Answer 4

1. more electrons = stronger VDW forces
2. bigger surface area = stronger VDW forces

Question 5

describe hydrogen bonding

Answer 5

oxygen is very electronegative
forms a dipole (o- / h+)
lone pair on o attractred to +h
the o-h-o section is linear

Question 6

when do hydrogen bonds occur

Answer 6

only form when f, o, n are attached to h
are represented by ———-
are longer than covalent bonds

Question 7

put the intermolecular forces in order of strength

Answer 7

weakest
VDW
dipole dipole
hydrogen bonds
strongest