AP CHEM Unit 3: Intermolecular Forces + Properties

15 terms that you should know to ACE your test!

True or False: Ion-dipole interactions are stronger than hydrogen bonds and are crucial in the solvation of ionic compounds.

True: Ion-dipole forces are stronger due to the full charge on the ion interacting with a dipole.

True or False: London dispersion forces are insignificant in large nonpolar molecules.

False: dispersion forces increase with molecular size and polarizability.

True or False: Boiling point trends across a group of molecules can be explained by differences in intermolecular forces, molecular mass, and surface area.

True

True or False: Network covalent solids exhibit localized electron bonding, which limits their electrical conductivity despite strong intramolecular forces.

True: In network covalent solids like diamonds, electrons are localized in fixed bonds, preventing free movement and hence electrical conductivity, despite very strong bonding.

True or False: The shape of a molecule can affect its boiling point even if it contains the same types of intermolecular forces.

True: Molecular geometry impacts surface area and the effectiveness of dispersion forces.

Fill in the blank: When a liquid evaporates, the molecules with the greatest ________ energy escape first, leaving behind molecules with lower ______ energy.

Kinetic

Fill in the blank: The unusually high boiling point of water can be attributed to extensive ________ between its molecules.

hydrogen bonding

________ solids are held together by electrostatic attractions and tend to have high melting points and low vapor pressures.

Ionic

Intermolecular forces are generally weaker than ________ forces, which involve actual sharing or transfer of electrons.

Intramolecular

The ________ of a liquid is defined as the pressure exerted by a vapor in equilibrium with its liquid phase at a given temperature.

Vapor pressure

Ion-Dipole Interaction

An intermolecular force between an ion and the partial charge on a polar molecule; critical in dissolving salts in polar solvents.

Hydrogen bonding

A strong type of dipole-dipole interaction occurring when hydrogen is bonded to highly electronegative atoms (F, O, or N), leading to significant effects on boiling point, solubility, and structure.

Ideal gas law

The equation PV = nRT that relates pressure (P), volume (V), amount (n), ideal gas constant (R), and temperature (T) for an ideal gas.

Absorbance (A)

A measure of how much light is absorbed by a solution at a particular wavelength, defined by A = εbc in the Beer-Lambert law.

Retention Factor (Rf)

The ratio of the distance traveled by a compound to the distance traveled by the solvent front in chromatography, used to identify substances based on their movement.