:This page is about the physical properties of gas as a state of matter. For the uses of gases, and other meanings, see Gas (disambiguation). A gas is a state of matter, consisting of a collection of particles (molecules, atoms, ions, electrons, etc.) without a definite shape or volume that are in more or less random motion. Physical characteristics Due to the electronic nature of the aforementioned particles, a "force field" is present throughout the space around them. Interactions between th… (More on Gases)