NITROGEN (N)
1. Overview
Nitrogen is a chemical element with the symbol N and atomic number 7. Under normal conditions, it is a colorless, odorless, tasteless, and quite inert gas in its molecular form, N2, also known as nitrogen gas. It makes up about 78% of Earths atmosphere and is a component of all living organisms. Nitrogen produces many important compounds such as amino acids, ammonia, nitric acid, and cyanides.
2. Properties
Nitrogen is a nonmetal with an electronegativity of 3.04. It has five electrons in its outermost shell, making it typically trivalent in most compounds. Pure nitrogen is a colorless molecular gas that only participates in chemical reactions at room temperature when reacting with lithium. It liquefies at 77 K (-196°C) under atmospheric pressure and freezes at 63 K (-210°C). Liquid nitrogen is commonly used as a refrigerant.
At normal temperature and air pressure, nitrogen is almost chemically inert. It is a colorless, odorless, tasteless, non-toxic, and non-flammable gas. In the air, nitrogen accounts for 78.03% by volume.
3. Applications
Nitrogen has two special features: it is an inert, non-toxic, and non-flammable gas, and liquid nitrogen at standard pressure (1.013 bar) has a very cold temperature (-196°C). As a major component of Earths atmosphere, nitrogen is produced on an industrial scale in large quantities. Because of this, nitrogen is used more than any other industrial gas.
• Preserving the freshness of packaged foods
• Ensuring safety on top of liquid explosives
• Production of electronic components
• Stainless steel production
• Inflating car and airplane tires
• Heat treatment
• Welding or laser cutting
• Liquid nitrogen is extremely useful in various applications
• Refrigerating, freezing, or controlling the temperature of food products
• Temperature control during transportation and distribution by indirect liquid nitrogen spraying
• Preserving body parts, sperm and egg cells, samples, and biological products
• Medical applications (dermatology)
4. Characteristics
— Main risks: suffocation, high-pressure risk
— Explosion limit: None
— Flammability: None
— Smell: None
— Molecular weight: 28.1
— Specific capacity at 20°C: 0.858 m³/kg
— Specific gravity (Air = 1) at 20°C: 0.967
— Critical temperature: -146.9°C
— Critical pressure: 34.7 bar
— Purity levels: Depending on usage requirements, nitrogen is available in the following purities: N2 4.0, N2 5.0, N2 6.0.
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