Chemistry Lecture: Intermolecular Forces, Phase Changes, and Vapor Pressure Vocabulary

Vocabulary flashcards covering key terms from the video lecture on intermolecular forces, phase changes, phase diagrams, and vapor pressure.

Ion-dipole forces

Electrostatic interactions between an ion and the dipole of a polar molecule.

Ion-induced dipole forces

An ion induces a temporary dipole in a nonpolar molecule, leading to a transient interaction.

Permanent dipole

A molecule with a fixed dipole moment due to uneven charge distribution.

Nonpolar molecule

A molecule with zero net dipole moment due to symmetric charge distribution.

Polar molecule

A molecule with a net dipole moment from unequal sharing of electrons.

Hydration shell

Arrangement of water molecules around a dissolved ion, stabilizing it in solution.

Dipole moment

A measure of molecular polarity resulting from charge separation within the molecule.

Phase diagram

Graph showing the conditions under which distinct phases occur and transition boundaries between solid, liquid, and gas.

Normal boiling point

Boiling point at external pressure of 1 atm.

Triple point

Conditions where solid, liquid, and gas phases are all in equilibrium.

Critical point

Temperature and pressure above which a liquid and its vapor become indistinguishable; supercritical fluid exists.

Sublimation

Phase transition from solid to gas without passing through liquid; typically endothermic.

Deposition

Phase transition from gas to solid; typically exothermic.

Melting (fusion)

Phase transition from solid to liquid; endothermic.

Vaporization (evaporation)

Phase transition from liquid to gas; endothermic.

Endothermic

Process that absorbs heat energy.

Exothermic

Process that releases heat energy.

Dalton's law

Total pressure of a gas mixture equals the sum of the partial pressures of its components.

Vapor pressure

Pressure exerted by a vapor in equilibrium with its liquid or solid at a given temperature.

Boiling point

Temperature at which a liquid's vapor pressure equals the external pressure.

Volatile

A substance that vaporizes readily, having a relatively high vapor pressure at room temperature.

Clausius-Clapeyron relation

Vapor pressure equation: ln(P1/P2) = (ΔHvap/R)(1/T2 − 1/T1), linking temperature, pressure, and enthalpy of vaporization.

Molar heat of vaporization

ΔHvap; energy required to vaporize one mole of a substance at its boiling point (units: kJ/mol).

R (gas constant)

8.314 J/(mol·K); constant used in gas law equations.

Equilibrium (dynamic)

State in which opposing processes occur at equal rates, such as vaporization and condensation.