Chapter 12

Intramolecular Forces

Forces that hold the molecule together, such as covalent bonds.

Intermolecular Forces

Attractive forces that hold molecules, atoms, or ions to each other in liquid and solid phases; weaker than intramolecular forces.

Van der Waals Forces

All attractive forces between neutral atoms and molecules.

Dispersion Forces

Result from Coulombic attractions between instantaneous dipoles of non-polar molecules; depend on electron mobility.

Dipole-Dipole Attractions

Attractive forces between polar molecules; the strength depends on the magnitude of the dipole.

Hydrogen Bonding

A special type of dipole-dipole interaction that occurs in molecules with H bonded to highly electronegative atoms like N, O, or F.

Surface Tension

The tendency of liquids to minimize their surface area, leading to a membrane-like surface.

Viscosity

A measure of a liquid’s resistance to flow; increases as intermolecular forces increase.

Cohesive Forces

Intermolecular attractive forces between identical molecules of a substance.

Adhesive Forces

Intermolecular attractive forces between different molecules.

Capillary Action

The ability of a liquid to flow against gravity in a narrow tube due to adhesive and cohesive forces.

Phase Change

A transition from one phase to another, such as solid to liquid or liquid to gas.

Freezing of Water

Phase change from liquid to solid.

Melting of Ice

Phase change from solid to liquid.

Evaporation/Vaporization of Water

Phase change from liquid to gas.

Condensation of Water Vapor

Phase change from gas to liquid.

Sublimation of Dry Ice

Phase change from solid to gas.

Deposition of Iodine

Phase change from gas to solid.