Physical properties of hydrogen (H2)
Release time:
2018-11-05
Physical properties of hydrogen (H2)
1. Hydrogen is a colorless, odorless, tasteless gas. Under standard conditions (temperature 0℃, pressure 101.325 kPa), its density is 0.08987 g/L, which is 2/29 of the density of air.
2. Hydrogen molecules move at the fastest speed, thus possessing the highest diffusivity and thermal conductivity, seven times that of air.
3. The boiling point of hydrogen is -252.78℃, and its melting point is -259.24℃.
4. Liquid hydrogen is a colorless and transparent liquid with a specific gravity of 0.070 g/cm³ (-252℃). Solid hydrogen is a snow-like solid with a specific gravity of 0.0807 g/cm³ (-262℃).
5. Hydrogen has a relatively high ignition point of 574℃, but its ignition energy is very low, making it easily ignited, even by a small electrostatic spark. When hydrogen burns, it produces a pale blue flame, generating water and releasing a large amount of heat: 2H2+02=2H2O+572.8KJ. The flammable range of hydrogen in air (20℃, 101.325 Kpa) is 4.0-74.5%, and in oxygen (20℃, 101.325 Kpa) it is 4.0-94%.
6. Hydrogen has reducing properties. At high temperatures, hydrogen can extract oxygen, phosphorus, sulfur, nitrogen, chlorine, and carbon from many compounds, thus reducing the compounds.
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