Chemistry: Liquids and Intermolecular Forces

Flashcards covering vocabulary terms related to liquids and intermolecular forces in chemistry.

Intermolecular Forces

Attractions between molecules; weaker than intramolecular attractions (covalent bonds).

Boiling Points, Melting Points, Viscosity, Surface Tension, and Capillary Action

Physical properties that reflect intermolecular forces.

Types of Intermolecular Forces

Weakest to strongest: Dispersion forces < Dipole-dipole forces < Hydrogen bonding.

Dispersion Forces

Temporary polarization of a nonpolar particle to create attraction.

Polarizability

The ease with which an electron cloud can be distorted.

Factors Affecting Dispersion Forces

More electrons, larger size, and shape (less compact = more dispersion force).

Dipole-Dipole Interactions

Molecules with a positive and a negative end that attract each other.

Hydrogen Bonding

Arises from the high electronegativity of nitrogen, oxygen, and fluorine when bonded to hydrogen.

Hydrogen Bond

Attraction between a hydrogen atom attached to a highly electronegative atom (N, O, F) and a nearby small electronegative atom in another molecule or chemical group.

Ion-Dipole Forces

Interaction found in solutions of ions; enables ionic substances to dissolve in polar solvents.

Viscosity

Resistance of a liquid to flow.

Surface Tension

Extra inward forces on the surface of a liquid.

Cohesive Forces

Forces that bind similar molecules to one another.

Adhesive Forces

Forces that bind a substance to a surface.

Capillary Action

The rise of liquids up narrow tubes due to adhesive and cohesive forces.

Phase Change

Conversion from one state of matter to another.

Heat of Fusion

Energy required to change a solid at its melting point to a liquid.

Heat of Vaporization

Energy required to change a liquid at its boiling point to a gas.

Critical Temperature

Temperature beyond which a gas cannot be compressed.

Critical Pressure

Pressure needed to compress a liquid at its critical temperature.

Supercritical Fluid

State beyond the critical temperature; exhibits properties of both liquids and gases.

Vapor Pressure

The pressure exerted by a vapor when it is in dynamic equilibrium with its liquid.

Boiling Point

Temperature at which the vapor pressure of a liquid equals atmospheric pressure.

Normal Boiling Point

Temperature at which the vapor pressure of a liquid is 760 torr (1 atm).

Phase Diagram

Graph showing states of matter under conditions of temperature and pressure.

Triple Point

Point on a phase diagram where all three phases (solid, liquid, gas) are present.

Liquid Crystals

Intermediate state between solid and liquid, exhibiting some properties of both.