Structure and States of Matter

Vocabulary flashcards reviewing fundamental concepts, phase changes, definitions, and properties of matter based on the lecture transcript.

Matter

That which occupies space and has mass.

Atom

The smallest particle of an element that cannot be further sub-divided without destroying its identity.

Molecule

The smallest particle which can exist free in nature by itself and can retain the properties of that substance.

Element

A substance which contains only one kind of atom and can neither be broken into, nor built from two or more simple substances by any known physical or chemical method.

Solid

A state of matter that has a definite shape, size, mass, and volume, in which molecules are held together by strong intermolecular forces and can only vibrate about their mean position.

Liquid

A state of matter that has a definite mass and volume but no definite shape, taking the shape of the container in which it is stored.

Gas

A state of matter that has a definite mass but no definite shape or volume, with particles far apart moving at very high speeds.

Vapour

A substance which under ordinary conditions is a solid or liquid but gaseous under specific conditions.

Fluid

Any substance which can flow, encompassing liquids and gases.

Fluidity

The ability of a substance to flow, enabled in liquids because attractive forces allow particles to move within the bulk without separating.

Intermolecular Space

The distance between any two consecutive molecules of a substance.

Intermolecular Forces

The attractive forces that hold atoms or molecules together in solids and liquids.

Diffusion

The movement of gas or liquid molecules from their region of higher concentration to their region of lower concentration until they are evenly distributed.

Melting (Fusion)

The process of transformation of a solid into the liquid state at a particular temperature.

Melting Point

The constant temperature at which a solid is transformed into the liquid state.

Boiling

The process of transformation of a liquid into the gaseous state at a particular temperature.

Boiling Point

The constant temperature at which a pure liquid is completely transformed into its vapour under normal atmospheric pressure.

Vaporisation

The process of transformation of the liquid state into the vapour or gaseous state.

Condensation (Liquefaction)

The phenomenon of conversion of a gas or a vapour to the liquid state.

Freezing (Solidification)

The process of transformation from the liquid state to the solid state at low temperatures.

Sublimation

The change of state directly from solid to gas without going through the liquid state.

Deposition

The change of state directly from gas to solid without going through the liquid state.

Triple Point

The temperature and pressure at which a substance can exist simultaneously in all three phases of matter: solid, liquid, and gas.

Interconversion of Matter

The phenomenon of changing one state of matter into another and back to the original state.

Brownian Motion

The random motion of particles suspended in a fluid resulting from their collision with fast-moving atoms or molecules in the gas or liquid.

Kinetic Molecular Theory of Matter

The theory stating that all matter is composed of atoms and molecules in constant motion possessing kinetic energy perceived as temperature.

Naphthalene

A solid substance that sublimes at standard atmospheric pressure and room temperature, and melts at $80^\circ\text{C}$ when heated.

Carbon Dioxide Compression

The process by which gaseous carbon dioxide at room temperature turns into a liquid when compressed to about $70\,\text{atm}$.