intermolecular forces

Question 1

what is the weakest intermolecular force?

Answer 1

London forces (induced dipole-dipole)

Question 2

what does the strength of london forces depend on?

Answer 2

the Mr
the larger the Mr of the molecule, the stronger the intermolecular forces
- straight chain molecules have stronger london forces than branched as they can pack closely together + reduces distance over the forces acts = stronger

Question 3

what is a permanent dipole-dipole force?

Answer 3

δ+ and δ- charges on polar molecules cause weak electrostatic forces of attraction between molecules

Question 4

what is the strongest type of intermolecular force?

Answer 4

hydrogen bonding

Question 5

what is hydrogen bonding?

Answer 5

acts between hydrogen and nitrogen, oxygen and fluorine
- the lone pair of electrons on these electronegative atoms forms a bond with the δ+ hydrogen atom from another molecule

Question 6

why does water have an unusually high melting and boiling point for a simple molecular structure?

Answer 6

it has hydrogen bonds

Question 7

why does ice have a lower density than liquid water?

Answer 7

hydrogen bonds hold the molecules in a rigid structure with a lot of air gaps