Nitrogen can be found in a variety of compounds, including ammonia, nitric acid and organic nitrates. It is a gas that forms approximately 78 percent of the Earth’s atmosphere.
Nitrogen, along with carbon and oxygen, is one of the elements that is essential to life. It is required to make plants grow, and it is used to refine oil. Once oil comes out of the ground, it needs nitrogen to become gasoline. Nitrogen is also used as a refrigerant because, when it is in liquid form, it becomes extremely cold. Liquid nitrogen is often used by scientists to keep things frozen.