IMFproblems_answers

Intermolecular Forces

1. Intermolecular Forces for Specific Molecules

• CH3F:

  • Types of Forces: Dispersion, Dipole-dipole

  • Strongest Force: Dipole-dipole

• F2:

  • Types of Forces: Dispersion

  • Strongest Force: Dispersion

• CO2:

  • Types of Forces: Dispersion

  • Strongest Force: Dispersion

• OF2:

  • Types of Forces: Dispersion, Dipole-dipole

  • Strongest Force: Dipole-dipole

2. Intermolecular Forces Between NH3 and CH3OH

• Types of Forces: Dispersion, Dipole-dipole, Hydrogen bonding

• Strongest Force: Hydrogen bonding

3. Comparison of Boiling Points

• a. CH4 or CBr4:

  • Higher Boiling Point: CBr4

  • Reason: CBr4 has a larger molar mass, resulting in stronger dispersion forces compared to CH4.

• b. CH3CH2CH3 (propane) or CH3CH3 (ethane):

  • Higher Boiling Point: CH3CH2CH3

  • Reason: Propane has a greater molar mass than ethane, resulting in stronger dispersion forces.

• c. GeBr4 or GeF4:

  • Higher Boiling Point: GeBr4

  • Reason: GeBr4's larger molar mass compared to GeF4 leads to stronger dispersion forces.

4. Order of Decreasing Boiling Point

• Substances: C2H4(OH)2, Al2O3, O2

• Order: Al2O3 > C2H4(OH)2 > O2

• Explanation: Al2O3 has strong ionic bonds, C2H4(OH)2 has hydrogen bonding, and O2 has only dispersion forces, which are weaker.

Liquid Properties

5. Comparison of Liquid A and Liquid B

• If Liquid A has a higher surface tension and viscosity than Liquid B, then:

  • Correct Statement: a. The force needed to stir Liquid A is greater than the force needed to stir Liquid B.

6. Hydrogen Bond Formation

• a. CH4 and H2O:

  • No hydrogen bonds

• b. CH4 and NH3:

  • No hydrogen bonds

• c. HF and CH4:

  • No hydrogen bonds

• d. H2O and NH3:

  • Hydrogen bonds: Oxygen in H2O forms hydrogen bonds with the nitrogen in NH3.

• e. CH3OH and CH3NH2:

  • Hydrogen bonds: Oxygen in CH3OH forms hydrogen bonds with nitrogen in CH3NH2.