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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.
For instance, at STP nitrogen is a transparent non-metallic gas, while bismuth is a silvery-white metal. [12] The densities of the pnictogens increase towards the heavier pnictogens. Nitrogen's density is 0.001251 g/cm 3 at STP. [12] Phosphorus's density is 1.82 g/cm 3 at STP, arsenic's is 5.72 g/cm 3, antimony's is 6.68 g/cm 3, and bismuth's ...
Nitrogen frost has a density of 0.85 g cm −3. [49] As a bulk material the crystals are pressed together and density is near that of water. It is temperature dependent and given by ρ = 0.0134T 2 − 0.6981T + 1038.1 kg/m 3. [48] The volume coefficient of expansion is given by 2×10 −6 T 2 − 0.0002T + 0.006 K −1. [48]
The temperature of liquid nitrogen can readily be reduced to its freezing point −210 °C (−346 °F; 63 K) by placing it in a vacuum chamber pumped by a vacuum pump. [2] Liquid nitrogen's efficiency as a coolant is limited by the fact that it boils immediately on contact with a warmer object, enveloping the object in an insulating layer of ...
The ammonia molecule readily undergoes nitrogen inversion at room temperature; a useful analogy is an umbrella turning itself inside out in a strong wind. The energy barrier to this inversion is 24.7 kJ/mol, and the resonance frequency is 23.79 GHz , corresponding to microwave radiation of a wavelength of 1.260 cm.
Specific volume is the inverse of the density of a substance; therefore, careful consideration must be taken account when dealing with situations that involve gases. Small changes in temperature will have a noticeable effect on specific volumes. The average density of human blood is 1060 kg/m 3.
For carbon dioxide at 400 K, the density increases almost linearly with pressure. Many pressurized gases are actually supercritical fluids. For example, nitrogen has a critical point of 126.2 K (−147 °C) and 3.4 MPa (34 bar). Therefore, nitrogen (or compressed air) in a gas cylinder above this pressure is actually a supercritical fluid.
One interstitial compound of argon, Ar 1 C 60, is a stable solid at room temperature. A Kr-shaped krypton discharge tube. Krypton has a density of 3.749 × 10 −3 g/cm 3, liquifies at −153.415 °C, and solidifies at −157.37 °C. It has a high ionisation energy (1350.8 kJ/mol), low electron affinity (estimated at −60 kJ/mol), and high ...