Molecular Comparison of Gases, Liquids, and Solids

All matter is composed of a very large number of molecules that move in a constant, random motion. Even in ice and metals, atoms still move.

There are three different states of matter: solids, liquids, and gases. In all these states molecules, atoms, or ions are in motion with a specific amount of kinetic energy, which determines the state of matter.

In the gaseous state, molecules have a high kinetic energy. The high energy molecules move quickly past each other and are widely separated, making it harder for them to intersect frequently. As a result the attractive forces in gases are weak.

With this negligible force of attraction, gases have no definite volume or shape and expand freely to fill in the entire volume of its container. With a lot of space around the molecules, gases have low densities making them easy to compress.

When gases are compressed or cooled, their kinetic energy is reduced and consequently the molecules slow down. The molecules move past each other more often and come closer together.

This increases the amount of intermolecular forces and transforms the gas to a liquid state.

Molecules within liquids are bound by stronger attractive forces, leaving little sp