An inert gas is a gas that does not readily undergo chemical reactions with other chemical substances and therefore does not readily form chemical compounds. Though inert gases have a variety of applications, they are generally used to prevent unwanted chemical reactions with the oxygen (oxidation) and moisture (hydrolysis) in the air from degrading a sample. Generally, nitrogen, carbon dioxide, and all noble gases except oganesson are considered inert gases. The term inert gas is context-dependent because several of the inert gases, including nitrogen and carbon dioxide, can be made to react under certain conditions.