Chapter 11: Liquids, Solids, and Intermolecular Forces

Vocabulary practice flashcards covering intermolecular forces, phase changes, vapor pressure, and related concepts from Chapter 11 (Chemistry: Structure and Properties).

Intermolecular Forces (IMFs)

Attractive forces between neighboring molecules that are weaker than intramolecular bonds but strong enough to determine physical properties such as boiling point, melting point, vapor pressure, and viscosity.

Intramolecular Forces

Strong attractive forces within a molecule—such as covalent and ionic bonds—that hold atoms or ions together to form chemical compounds.

Evaporation

A slow phase transition from liquid to gas that occurs strictly at the surface of a liquid at any temperature below the boiling point, during which only high-energy molecules escape, causing cooling of the remaining liquid.

Boiling

A rapid phase transition from liquid to gas occurring throughout the entire volume of a liquid when its vapor pressure equals external pressure, producing vapor bubbles at a specific temperature.

Boiling Point

The specific temperature at which the vapor pressure of a liquid is equal to the external surrounding atmospheric pressure.

Dispersion Forces (London Forces)

Intermolecular attractions present in all atoms and molecules resulting from fluctuations in electron distribution that produce short-lived, temporary dipoles.

Temporary Dipole (Induced Dipole)

A separation of positive and negative electrical charge created within an atom or molecule due to a momentary, uneven distribution of its electron cloud.

Polarizability

The relative ease with which an electron cloud surrounding an atom, molecule, or ion can be distorted to induce an instantaneous dipole.

Constitutional Isomers

Molecules sharing identical chemical formulas but exhibiting different atom connectivities, affecting surface area and the resulting strength of dispersion forces.

Dipole–Dipole Interactions

Attractive electrostatic forces between polar molecules possessing permanent dipoles, where the positive end of one molecule aligns with the negative end of an adjacent molecule.

Hydrogen Bonding

A strong form of dipole–dipole attraction occurring between a hydrogen atom bonded directly to a highly electronegative atom ($\text{F}$, $\text{O}$, or $\text{N}$) and an electron-rich lone pair on an electronegative atom in a neighboring molecule.

Ion–Dipole Forces

Electrostatic interactions generated between a fully charged ion and the partial charges of a polar molecule, such as when ionic salts dissolve in water.

Sphere of Hydration

An organized cluster of water molecules surrounding a dissolved ion, oriented such that opposite partial charges face the ion to shield its electrostatic charge.

Vapor Pressure

The pressure exerted by a vapor in dynamic equilibrium with its liquid phase in a closed container at a given temperature.

Dynamic Equilibrium

A balanced state reached in a closed system where two opposing processes—such as the rate of vaporization and the rate of condensation—proceed at equal rates.

Volatile Liquid

A liquid with weak intermolecular attractions that vaporizes readily and consequently demonstrates a high vapor pressure.

Intensive Property (Vapor Pressure)

A characteristic property that depends entirely on the chemical identity of the liquid and its temperature, remaining independent of the liquid volume or exposed surface area.

Johannes Diderik van der Waals

The Dutch physicist ($1837\text{–}1923$) who formulated the theoretical basis for intermolecular forces, after whom van der Waals interactions are named.