CHEM 2061: Intermolecular Forces of Solids and Liquids Flashcards

Vocabulary flashcards covering intermolecular forces, liquid/solid properties, phase changes, and phase diagrams based on Dr. Niki Shoup's CHEM 2061 lecture notes.

Phase

A homogeneous part of a system that is in contact with other parts of the system but has a well-defined boundary.

Intramolecular Forces

Attractive forces that exist between atoms within a molecule (chemical bonds).

Intermolecular Forces (IMAFs)

Attractive forces that exist between molecules, which hold solids and liquids together.

Dispersion Forces

The weakest intermolecular force, present in every compound, caused by fleeting dipoles in molecules.

Dipole Induced Dipole

Interactions between two molecules in which one molecule is polar (or an ion) and the other is polarizable.

Polarizable

The ability of an electron cloud to move around a molecule and create more electron density on one side versus the other.

Dipole-Dipole Interactions

Intermolecular forces between polar molecules that possess a permanent dipole moment.

Ion-Dipole Interactions

Intermolecular forces between polar molecules and ions.

Solvation

The process of salts going into solution, driven by ion-dipole interactions.

Hydrogen Bonding

The strongest IMAF; a special type of dipole-dipole interaction where a hydrogen atom bonded to a nitrogen, oxygen, or fluorine interacts with another nitrogen, oxygen, or fluorine atom.

Surface Tension

The amount of energy required to increase the surface area of a liquid by a unit area.

Capillary Action

A type of surface tension in which a liquid interacts directly with its container.

Cohesion

Intermolecular forces between molecules of the same substance.

Adhesion

Intermolecular forces between molecules of different substances.

Viscosity

A liquid's resistance to flow, which depends on IMAFs, temperature, and molecular entanglement.

Evaporation

The process by which a liquid is converted into a vapor.

Boiling Point

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

Molar Heat of Vaporization ($\Delta H_{\text{vap}}$)

The heat required to vaporize $1\,\text{mole}$ of liquid, measured in $\text{kJ/mol}$.

Critical Temperature

The highest temperature at which a substance can exist as a liquid.

Critical Pressure

The minimum pressure that must be applied to bring about liquefaction at the critical temperature.

Freezing

The phase change from a liquid to a solid.

Melting (Fusion)

The phase change from a solid to a liquid.

Molar Heat of Fusion

The energy required to melt $1\,\text{mole}$ of a solid.

Sublimation

The phase change directly from a solid to a gas.

Deposition

The phase change directly from a gas to a solid.

Heat of Sublimation

The sum of the molar heat of fusion and the molar heat of vaporization.

Phase Diagram

A map that shows which phase a compound will exist in at a given temperature and pressure.