Intermolecular Forces (Test 2)

Question 1

What are intermolecular forces?

Answer 1

• Forces that occur between molecules
• Only in covalent molecular
• 3 types of intermolecular forces (Hydrogen Bond, Dispersion & Dipole Dipole Forces)

Question 2

What are dispersion forces?

Answer 2

Dispersion forces are WEAK FORCES that exist between molecules of ALL covalent molecular substances & non-polar substances. As the weakest kind of imf’s the shape of the molecule affects the strength, the greater the surface contract, the greater the dispersion. Even if they have other forces, they still have dispersion forces.

• The larger the molecule -> stronger the dispersion forces (because the valence electrons are further away from nuclei and start to bunch up/move and form temporary dipoles)

Question 3

What are dipole-dipole forces

Answer 3

Dipole-dipole forces are weak forces due to charges involved are small and occur between 2 polar molecules.
These attractive forces occur because that part of the molecule which is slightly negatively charged can be attracted to a slightly positive part of another molecule.
The more polar the molecule is –> stronger the dipole-dipole forces will be.

Question 4

What are hydrogen bonds?

Answer 4

• Bonds that contain FON! (Fluoride or Oxygen or Nitrogen)
• This is due to the dipole-dipole force between molecules containing FON bonded to a HYDROGEN ATOM.
• This bond means it’s very polar due to HIGH electronegativity difference), thus a highly polar molecule.