0654 Chemistry 1 Chapter 1. Kinetic Theory and the States of Matter

Matter

Anything that occupies space and has mass.

Kinetic Particle Theory

A theory describing matter as consisting of tiny particles in constant motion, explaining the properties of different states and changes between them.

Fluid

A substance that can flow; includes liquids and gases.

Intermolecular Space

The space between atoms or molecules in a liquid or gas.

Lattice

A regular three-dimensional arrangement of particles in a crystalline solid.

Pure Substance

A single element or compound with no impurities that melts and boils at fixed temperatures.

Solid

A state of matter with fixed shape and volume; particles are closely packed in a regular arrangement and vibrate in fixed positions.

Liquid

A state of matter with fixed volume but no fixed shape; particles are close together, randomly arranged, and can slide past each other.

Gas

A state of matter with no fixed shape or volume; particles are far apart and move rapidly and randomly.

Melting

The process by which a solid changes into a liquid.

Melting Point (m.p.)

The temperature at which a solid changes into a liquid.

Freezing (Solidification)

The process by which a liquid changes into a solid at the melting point.

Boiling

The change from a liquid to a gas at the boiling point, when bubbles form throughout the liquid.

Evaporation

The change of a liquid into a gas at the surface below the boiling point.

Condensation

The change of a gas or vapour into a liquid, usually caused by cooling.

Sublimation

The direct change of a solid into a gas without becoming liquid.

Volatile

A liquid that evaporates easily due to weak intermolecular forces and a low boiling point.

Exothermic Changes

State changes that release heat energy to the surroundings.

Endothermic Changes

State changes that absorb heat energy from the surroundings.

Heating and Cooling Curves

Graphs showing how temperature changes as a substance is heated or cooled during state changes.

Diffusion

The mixing of fluids caused by the random movement of particles from high to low concentration.

Relative Molecular Mass (Mr)

The mass of a molecule compared to 1/12 of the mass of a carbon-12 atom; affects diffusion rate.

Gas Pressure

The force created by gas particles colliding with container walls.

Porous Pot

An unglazed pot with tiny holes that allow gases to pass through, used to compare diffusion rates.