Intermolecular Forces

Question 1

Intermolecular forces are very weak

Answer 1

They are the forces between molecules and they are much weaker than covalent ionic on metallic bonds

They are three types:

1) London forces
2) permanent dipole permanent dipole bonds
3) hydrogen bonding

Question 2

Stronger London forces mean higher melting and boiling points

Answer 2

Larger molecules have larger electron clouds meaning stronger London forces

When you boil a liquid you need to overcome the intermolecular forces therefore more energy is needed to overcome stronger intermolecular forces therefore they will have higher boiling points

Question 3

Intermolecular forces in organic molecules depend on the shape

Answer 3

The shape of an organic compound molecule affects the strength of intermolecular forces

For example alkanes

They have covalent bonds inside the molecules between the molecules that are London forces which hold them together

The longer the carbon chain the stronger the London forces because they’re more molecular surface contact and more electrons to interact

So as a molecule gets longer it gets harder to separate them because it takes more energy to overcome the London forces