States of Matter & Intermolecular Forces Vocabulary

Vocabulary flashcards covering states of matter, intermolecular forces, phase changes, and related concepts.

Solids

State of matter with a definite shape and volume; particles are orderly and vibrate in place.

Liquids

State of matter with a definite volume that takes the shape of its container; particles are disordered yet close together.

Gases

State of matter with no definite shape or volume, filling any container; particles are highly disordered and far apart.

Intramolecular Forces

Strong forces (chemical bonds) that hold atoms together within a molecule.

Intermolecular Forces

Weaker attractive forces acting between separate molecules, atoms, or ions.

Ion-Ion Interactions

Strongest intermolecular force; electrostatic attraction between oppositely charged ions in ionic compounds.

Hydrogen Bonding

A strong dipole-dipole attraction in molecules where hydrogen is bonded to N, O, or F.

Dipole-Dipole Interactions

Attractive force between the positive end of one polar molecule and the negative end of another.

London Dispersion Forces

Weakest intermolecular force arising from temporary dipoles due to momentary electron shifts; present in all molecules, dominant in non-polar ones.

Coulomb's Law

Relationship describing electrostatic force between two charges; stronger force (larger charges or smaller distance) leads to higher melting point in ionic compounds.

Viscosity

A liquid’s resistance to flow (e.g., honey is highly viscous).

Surface Tension

Tendency of a liquid to minimize surface area due to net inward forces on surface molecules.

Capillary Action

Ability of a liquid to rise in a narrow tube when adhesive forces exceed cohesive forces.

Evaporation

Process by which molecules escape from a liquid’s surface to become gas.

Vapor Pressure

Pressure exerted by a vapor in equilibrium with its liquid in a closed system; high vapor pressure indicates volatility.

Boiling Point

Temperature at which a liquid’s vapor pressure equals external pressure; normal boiling point is measured at 1 atm.

Melting Point

Temperature at which solid and liquid phases coexist in equilibrium.

Clausius-Clapeyron Equation

Equation used to relate vapor pressure and temperature when heat of vaporization is known: ln(P1/P2) = ΔHvap/R (1/T2 – 1/T1).

Molar Heat of Fusion (ΔHfus)

Heat required to melt one mole of a solid at its melting point.

Molar Heat of Vaporization (ΔHvap)

Heat required to vaporize one mole of a liquid at its boiling point.

Phase Diagram

Graph of pressure versus temperature showing the solid, liquid, and gas regions of a substance.

Crystalline Solid

Solid with an ordered, repeating lattice structure and a sharp melting point (e.g., NaCl).

Amorphous Solid

Solid lacking long-range order, softening over a temperature range instead of having a sharp melting point (e.g., glass).