Chapter 1: Solids, Liquids, and Gases

Vocabulary flashcards based on the Kinetic Particle Theory and the three states of matter (solids, liquids, and gases) as described in the lecture notes.

Matter

A word used to cover all the substances and materials from which the physical universe is composed.

States of matter

The three forms that substances can take, categorized as solids, liquids, or gases.

Expansion

The slight increase in size of a substance, such as a solid, when it is heated.

Contraction

The decrease in size of a substance when it is cooled.

Compressible

A property of liquids and gases meaning their volume can be reduced by the application of pressure.

Kinetic particle theory

A scientific model based on the idea that all matter is made up of tiny, moving particles (atoms, molecules, or ions) and explains physical properties in terms of their movement.

Solid

A state of matter where particles are held close together by attractive forces, have little freedom of movement, and can only vibrate about a fixed position in a regular manner.

Liquid

A state of matter where particles are close together but move around in a random way and often collide; the forces of attraction are weaker than those in a solid.

Gas

A state of matter where particles are relatively far apart, move randomly at very high velocities, and exert virtually no forces of attraction on each other.

X-ray crystallography

An instrument and method used for studying crystal structure to confirm how particles are arranged.

Sodium chloride

A substance that has its particles arranged to give cubic crystals.

Melting point

The temperature at which a substance changes from a solid to a liquid, such as $0^{\circ}C$ for water.

Evaporation

The process where particles at the surface of a liquid gain enough energy to overcome attractive forces and escape to form a gas.

Boiling point

The temperature at which the pressure of the gas created above a liquid equals atmospheric pressure and bubbles of gas form inside the liquid.

Condense

The process where a gas is cooled, particles move closer together, and forces of attraction cause it to become a liquid.

Freezes

The process where a liquid is cooled to form a solid.

Physical changes

Changes of state where the temperature remains constant during the change and no new substance is formed.

J.A.C. Charles

A French scientist who observed in $1781$ that when the temperature of a gas increased, the volume also increased at a fixed pressure.

Diffusion

The spreading out of a gas in a haphazard and random way to fill the space available.

Relative molecular mass

A factor affecting the rate of diffusion; lighter particles move faster and diffuse more quickly than heavier ones at a given temperature.

Intimate mixing

The term used when diffusion takes place between a liquid and a gas.