Definitions for "Gases"
are easily compressible fluids that expand to fill their containers, and expand indefinitely in the absence of boundary restraints, As a result of their compressibility, gases may have large change in volume and density. However, under conditions of relatively constant pressure and temperature, gases will have relatively constant volumes.
formless fluids that expand to occupy the space or enclosure in which they are confined. Examples are nitrogen, oxygen and carbon dioxide of the air.
A aeriform fluid consisting of fine particles as suspended in air, having an indefinite expansion or shape, gaseous particles will expand by their same fraction for every degree that the temperature rises.
Volcanic gases are dissolved in the magma at depth in the chamber and are released in the low-pressure environment of the earth's surface. The main volcanic gas is usually water with minor amounts of sulphur dioxide, carbon dioxide and halogen gases such as chlorine and fluorine.
Substances that become airborne at room temperature. They may or may not mix with air.