GENERAL CHEMISTRY I Unit 12: gases

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Gases are one of the three main states of matter, along with solids and liquids. A gas is a type of matter that has no defined shape or volume and expands to fill the entire space available to it. In gases, the particles (atoms, molecules, or ions) are widely separated and in constant, random motion. The intermolecular forces between the particles in a gas are relatively weak, so the particles are free to move and spread out. This gives gases their characteristic low density and high compressibility, meaning that their volume changes significantly under pressure. Gases are often described by their pressure, volume, and temperature, which are related by the ideal gas law. Some common examples of gases include air, hydrogen, and carbon dioxide. Gases play an important role in our daily lives, as they are used for a variety of purposes, including as fuels, refrigerants, and lifting agents.