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Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System.
Liquid nitrogen is a compact and readily transported source of dry nitrogen gas, as it does not require pressurization. Further, its ability to maintain temperatures far below the freezing point of water, specific heat of 1040 J ⋅kg −1 ⋅K −1 and heat of vaporization of 200 kJ⋅kg −1 makes it extremely useful in a wide range of ...
It burns quickly and completely in air very exothermically to give nitrogen and water vapour. It is a very useful and versatile reducing agent and is a weaker base than ammonia. [7] It is also commonly used as a rocket fuel. [8] Hydrazine is generally made by reaction of ammonia with alkaline sodium hypochlorite in the presence of gelatin or ...
Food is mainly composed of water, lipids, proteins, and carbohydrates. Minerals (e.g., salts) and organic substances (e.g., vitamins) can also be found in food. [4] Plants, algae, and some microorganisms use photosynthesis to make some of their own nutrients. [5] Water is found in many foods and has been defined as food by itself. [6]
It does not, however, give a measure of true protein content, as it measures nonprotein nitrogen in addition to the nitrogen in proteins. This is evidenced by the 2007 pet food incident and the 2008 Chinese milk powder scandal, when melamine, a nitrogen-rich chemical, was added to raw materials to fake high protein contents. Also, different ...
Ammonia is found throughout the Solar System on Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto, among other places: on smaller, icy bodies such as Pluto, ammonia can act as a geologically important antifreeze, as a mixture of water and ammonia can have a melting point as low as −100 °C (−148 °F; 173 K) if the ammonia concentration is ...
Therefore, nitrogen is often the limiting factor for growth and biomass production in all environments where there is a suitable climate and availability of water to support life. Microorganisms have a central role in almost all aspects of nitrogen availability, and therefore for life support on earth.
The lighter isotope of nitrogen, 14 N, is preferred during denitrification, leaving the heavier nitrogen isotope, 15 N, in the residual matter. This selectivity leads to the enrichment of 14 N in the biomass compared to 15 N. [ 27 ] Moreover, the relative abundance of 14 N can be analyzed to distinguish denitrification apart from other ...