Chapter 16: Liquids and Solids - Vocabulary

Vocabulary flashcards covering key terms and definitions on intermolecular forces, liquid properties, phase diagrams, and thermodynamics from Chapter 16.

Intermolecular Forces of Attraction

Forces between molecules strong enough to control physical properties such as melting point, boiling point, vapor pressure, and viscosity.

Ion-Ion Interactions

Very strong electrostatic attractions between cations and anions in an ionic solid, typically ranging from $400\text{ to }4000\,\text{kJ/mol}$.

Dipole-Dipole Interactions

Attractive forces ($5\text{ to }25\,\text{kJ/mol}$) resulting from the alignment of polar molecules with permanent dipoles, where the positive end of one molecule is attracted to the negative end of another.

Instantaneous Dipole

A temporary dipole created when electrons happen to be more concentrated in one place than in another within an atom or molecule.

London Dispersion Force

A weak short-range attraction ($0.05\text{ to }40\,\text{kJ/mol}$) between an instantaneous dipole and an induced dipole, existing in all atoms and molecules.

Hydrogen Bonding

A particularly strong dipole-dipole interaction ($10\text{ to }40\,\text{kJ/mol}$) occurring between a hydrogen atom directly bonded to $\text{F}$, $\text{O}$, or $\text{N}$ and a lone pair on a nearby $\text{F}$, $\text{O}$, or $\text{N}$ atom.

Cohesive Forces

Intermolecular forces of attraction existing between like molecules within a substance.

Adhesive Forces

Intermolecular forces of attraction existing between unlike molecules, such as between a liquid and a solid surface.

Surface Tension

The energy required to increase the surface area of a liquid, driven by cohesive forces between liquid molecules acting to minimize surface area.

Viscosity

A liquid's resistance to flow caused by cohesive forces creating internal friction that reduces the rate of flow.

Capillary Action

The movement of a liquid up a narrow tube caused by stronger adhesive forces between the liquid and solid than cohesive forces within the liquid.

Vapor Pressure Curve

A plot of vapor pressure ($P$) versus temperature ($T$) for a given substance.

Clausius-Clapeyron Equation

An equation relating the vapor pressure $P_1$ at temperature $T_1$ to the vapor pressure $P_2$ at temperature $T_2$: $\ln\left(\frac{P_2}{P_1}\right) = \frac{\Delta H_{\text{vap}}}{R}\left(\frac{1}{T_1} - \frac{1}{T_2}\right)$.

Boiling Point

The temperature at which the vapor pressure of a liquid equals the surrounding atmospheric pressure.

Normal Boiling Point ($T_b$)

The temperature at which a liquid boils under a standard atmospheric pressure of $1\,\text{atm}$.

Phase Diagram

A pressure-temperature ($P\text{--}T$) diagram for a single substance showing lines of phase boundaries between solid, liquid, and gas phases.

Vaporization Curve

The line on a phase diagram along which the liquid and gas phases are in equilibrium; it is identical to the vapor pressure curve.

Sublimation Curve

The line on a phase diagram along which the solid and gas phases are in equilibrium.

Fusion Curve

The line on a phase diagram along which the solid and liquid phases are in equilibrium.

Triple Point

The specific pressure and temperature condition on a phase diagram where solid, liquid, and gas phases all coexist in equilibrium.

Critical Point

The point on a phase diagram at which the liquid and vapor phases become indistinguishable.

Critical Temperature ($T_c$)

The temperature at the critical point, above which a gas cannot be liquefied regardless of the amount of pressure applied.

Supercritical Fluid

A state of matter formed when a substance is maintained at a temperature and pressure above its critical point.

Heating Curve

A plot of temperature versus heat added at a constant rate for a given substance as it transitions through phases.