Polarity in molecules

Question 1

What is polarity?

Answer 1

It is the unequal sharing of electrons between atoms in a covalent bond.

Question 2

How do you know when a molecule is polar and has a dipole moment?

Answer 2

When the bonds are polarized and the individual dipoles do not cancel out each other.

Question 3

What are the three types of intermolecular forces?

Answer 3

• Van der Waals’ forces
• Permanent dipoles-dipoles forces
• Hydrogen bonds

Question 4

For hydrogen bonding to occur, what do we need?

Answer 4

• one molecule must have F, O and N covalently bonded to a hydrogen atom
• another molecule must have F, O and N atom with lone pair of electrons

Question 5

What is the effect of intermolecular hydrogen bonding on physical properties of compounds?

Answer 5

• increases the melting poing and the boiling points of compounds
• increases the solubility of substances in water
• responsible for the unusual relative density of water and ice