Polarity and Intermolecular Forces

Question 1

Molecules are polar if:

Answer 1

• The central atom has lone pairs
• The central atoms is attached to more than one type of atom

Question 2

Which molecules have higher melting and boiling points?

Answer 2

Polar molecules have higher melting and boiling points compared to non-polar molecules of similar size and mass

Question 3

Intramolecular Forces

Answer 3

Forces that bond atoms to each other within a molecule

Question 4

Intermolecular Forces

Answer 4

• Forces that attract molecules to each other
• Physical properties like melting points, boiling points and solubility are determined by the strength of intermolecular forces

Question 5

London dispersion forces

Answer 5

• Relatively weak forces that exist between all molecules resulting from the temporary displacements of the electrons around the atoms
• The strength of dispersion forces tend to increase with increasing molecular mass since there are more electrons

Question 6

Dipole-Dipole forces

Answer 6

• Relatively strong forces of attraction between oppositely charged ends of polar molecules

Question 7

Hydrogen Bonding

Answer 7

• In water, there is a special dipole-dipole force called hydrogen bonding, it is much stronger than ordinary dipole-dipole forces
• Hydrogen bonded to an N,O or F atom