Intermolecular Forces and Polarity

Polarity and Intermolecular Forces

Polar vs Nonpolar

• A polar molecule is sharing electrons unequally (two different poles, one positive and the other negative)

• A nonpolar is sharing electrons equally (tug of war with two trucks pulling with the exact same force)

INTRAmolecular VS INTERmolecular Forces

INTRAmolecular forces are the bonds that occur inside or within a single moelcule.

INTERmolecular forces (IMF) exist between two or more molecules

Multiple Choice

Intermolecular Forces are the forces that exist

• Between two or more molecules

• Within a single molecule

• Only in molecules containing carbon

• In all molecules

INTERmolecular Forces

Examples of intermolecular forces include london dispersion (LDF), dipole/dipole, and hydrogen bonding

Multiple Choice

Examples of an intermolecular force include

• london disperson

• hydrogen bonding

• dipole dipole

• all of the above

Multiple Choice

Which type of intermolecular force is the strongest?

• LDF

• dipole-dipole

• Hydrogen bonding

• Covalent bonding

London Dispersion Force (LDF)

The weakest force

Occurs between ALL MOLECULES

If a molecule is nonpolar then the only force present will be LDF

Dipole Dipole Forces

Occurs between all polar molecules

The attraction of the positive end of one molecule to the negative end of another

Hydrogen Bonding

Must have a hydrogen directly bonded to a F, N or O.

Strongest type of intermolecular force

Multiple Choice

For hydrogen bonding to occur, a molecule must have a hydrogen bonded to

• carbon

• another hydrogen

• Fluorine, Chlorine or Oxygen

• Fluorine, Nitrogen or Oxygen

Polar and Nonpolar

Nonpolar molecules will contain only london dispersion forces

Polar molecules will contain london dispersion and dipole dipole

Molecules with hydrogen bonding will contain all three types of forces

Multiple Choice

Which of the following is an example of a polar molecule

• water

• propane

• methane

• carbon dioxide

Multiple Choice

Is methane (CH₄) polar or nonpolar?

• polar

• nonpolar

Multiple Choice

What forces are present in methane (CH₄)?

• LDF

• dipol-dipole

• Hydrogen bonding

• All of the above

Multiple Choice

Does this molecule contain hydrogen bonding?

• yes

• no