2.4.2 Effects on Physical Properties

• What are intermolecular forces?

  Forces between molecules
• Intermolecular forces are stronger than covalent bonds.

  False
• Arrange the intermolecular forces in order of increasing strength.

  1️⃣ London dispersion forces

  2️⃣ Dipole-dipole forces

  3️⃣ Hydrogen bonds
• Hydrogen bonds occur when a hydrogen atom bonded to a highly electronegative atom interacts with another electronegative atom
• The strength of London dispersion forces increases with molecular size.
• How do hydrogen bonds affect melting and boiling points?

  Increase them significantly
• Substances with hydrogen bonds have the highest melting and boiling points
• London dispersion forces result in the lowest melting and boiling points.
• Match the solvent type with the solute type that it can dissolve effectively:

  Polar solvent ↔️ Polar solute

  Nonpolar solvent ↔️ Nonpolar solute
• Substances with similar intermolecular forces are more likely to mix and dissolve
• What are intermolecular forces?

  Forces between molecules
• Hydrogen bonds occur when a hydrogen atom bonded to a highly electronegative atom interacts with another electronegative atom in a different molecule
• Hydrogen bonds are stronger than dipole-dipole forces.
• What creates dipole-dipole forces?

  Unequal electron distribution
• Match the intermolecular force with its characteristic:

  Hydrogen bonds ↔️ Strongest

  Dipole-dipole forces ↔️ Polar molecules

  London dispersion forces ↔️ Weakest, present in all molecules
• What causes London dispersion forces?

  Temporary fluctuations in electron distribution
• Hydrogen bonds occur between molecules containing hydrogen bonded to highly electronegative atoms like nitrogen, oxygen, or fluorine
• Dipole-dipole forces exist between all molecules.

  False
• How does molecular size affect London dispersion forces?

  Strength increases with size
• Hydrogen bonds are the strongest type of intermolecular force.
• Match the intermolecular force with its effect on molecular properties:

  Hydrogen bonds ↔️ Highest melting and boiling points

  Dipole-dipole forces ↔️ Moderate melting and boiling points

  London dispersion forces ↔️ Lowest melting and boiling points
• Arrange the intermolecular forces in order of increasing strength:

  1️⃣ London dispersion forces

  2️⃣ Dipole-dipole forces

  3️⃣ Hydrogen bonds
• Hydrogen bonds result in the highest melting and boiling points due to their strong attraction.
• London dispersion forces are the weakest type of intermolecular force, but their strength increases with molecular size.
• Which type of intermolecular force leads to the highest melting and boiling points?

  Hydrogen bonds
• "Like dissolves like" is a principle that explains the effect of intermolecular forces on solubility.
• Match the solvent type with the solute type it dissolves best:

  Polar solvent ↔️ Polar solute

  Nonpolar solvent ↔️ Nonpolar solute
• What is surface tension influenced by?

  Intermolecular forces
• Water has high surface tension due to strong hydrogen bonds.
• Viscosity measures a fluid's resistance to flow.
• Which intermolecular force results in the highest viscosity?

  Hydrogen bonds