Kinetic Molecular Theory and Gas Properties

Foundational vocabulary and concepts regarding the Kinetic Molecular Theory of Matter and the physical properties of gases.

Kinetic Molecular Theory of Matter

A theory stating that the particles in all matter are in a constant state of motion.

Matter

Anything that has mass and volume.

Mass

The quantity of matter.

Volume

The amount of space taken.

Solid

A state of matter that has definite volume and definite shape.

Liquid

A state of matter that has definite volume and changing shape.

Gas

A state of matter that has changing volume and changing shape.

Particle Model of Matter

A model stating that all matter is made up of very small particles, there are spaces between them, they are always moving, and they are attracted to one another.

Ideal gas

A model of gas behavior provided by the Kinetic Molecular Theory (KMT) based on five specific assumptions.

KMT Assumption 1

Gas particles are in continuous, rapid, and random motion.

KMT Assumption 2

Gas particles are separated by great distances.

KMT Assumption 3

Collisions between gas particles and between particles and container walls are elastic collisions.

KMT Assumption 4

There are no forces of attraction or repulsion between gas particles.

KMT Assumption 5

The temperature of a gas depends on the average kinetic energy of the particles of the gas.

Expansion

A property of gases where they take the shape of their container because particles are in rapid, random, and constant motion without a definite shape or volume.

Fluidity

A property where gas particles glide past one another and flow like liquids because the attractive forces between them are slight.

Low Density

A gas property resulting from particles being spread out and far apart, making the gaseous state much less dense than the liquid or solid state.

Compressibility

The ability of gas particles to be pressed closer together, which greatly decreases the volume and makes transport easier.

Diffusion

The mixing of particles of two substances caused by the random motion of particles.

Effusion

The process of gas particles passing through a small opening.

Density Trend

Gas < Liquid < Solid, moving from less dense to more dense.

Energy and Particle Motion

The more energy particles have, the faster they move and the farther they get.