Properties of Matter & Kinetic Molecular Theory

Vocabulary flashcards covering key terms from the lecture on properties of solids, liquids, gases, and the Kinetic Molecular Theory.

Solid

State of matter with fixed volume, definite shape, least intermolecular space, and strong intermolecular forces; particles vibrate slowly and cannot flow or be compressed easily.

Liquid

State of matter with fixed volume but no definite shape, moderate intermolecular space and weak intermolecular forces; particles slide past one another, can flow, and are slightly compressible.

Gas

State of matter with no fixed volume or shape, maximum intermolecular space, very weak intermolecular forces; particles move rapidly in random directions, can flow, and are easily compressed.

Volume (in matter)

The amount of three-dimensional space occupied by a substance; fixed for solids and liquids, variable for gases.

Shape (in matter)

The external form a substance takes; definite for solids, container-dependent for liquids, and entire-space-filling for gases.

Intermolecular Space

The distance between particles in a substance; least in solids, moderate in liquids, greatest in gases.

Intermolecular Forces of Attraction

Forces that pull particles toward each other; strongest in solids, weaker in liquids, weakest in gases.

Movement of Particles

Speed and pattern of particle motion: very slow vibration in solids, moderate sliding in liquids, very fast random motion in gases.

Fluidity

Ability of a substance to flow; absent in solids, present in liquids and gases.

Compressibility

Extent to which a substance’s volume can be reduced by pressure; negligible in solids, slight in liquids, high in gases.

Diffusion

Spontaneous mixing of particles due to motion; none in solids, slight in liquids, high in gases.

Kinetic Molecular Theory (KMT)

Model stating that matter is made of tiny particles in constant motion whose kinetic energy explains states, properties, and changes of matter.

Kinetic Energy (in KMT)

Energy possessed by particles because of motion; increases with particle speed and temperature.

Temperature (KMT context)

Measure of the average kinetic energy of particles in a substance; higher temperature means faster particle motion.

Phase Change

Transition between states of matter (e.g., melting, evaporation) that occurs when temperature changes sufficiently.

Attractive Forces Between Particles

Intermolecular forces that become stronger as particles move closer, influencing state and phase changes.

States of Matter

Distinct physical forms—solid, liquid, gas—characterized by different particle arrangements, energies, and properties.

Model (Scientific)

A conceptual representation—such as KMT—used to explain and predict behavior of physical systems.

Particle

The minute unit (atom, molecule, or ion) composing matter, always in motion according to KMT.

Diffusibility Gradient

Comparative tendency of substances to diffuse: none in solids, slight in liquids, high in gases.