Nitrogen has no color, taste, or smell. On its own it is not very active. It must be combined in compounds to be used by living things. Nitrogen compounds help plants grow and make up protein in animals.
Nitrogen becomes a liquid at very low temperatures. In that state it is useful for freeze-drying food and for keeping foods cold when they are being transported over long distances.
The two most important compounds of nitrogen that are used in factories or businesses are ammonia and nitric acid. Ammonia is a gas that is used to prepare many other nitrogen compounds. Nitric acid is a liquid that is used to produce fertilizers, dyes, drugs, and explosives.
