About H2

Under normal conditions (at the temperature of 273.15 K and pressure of 101325 Pa) hydrogen is a flammable, colourless, tasteless and scentless gas.

It is approximately 14.5 fold lighter than air (0.0899 kg m–3) and due to its low molecular weight it is hardly coercible. In the air it creates an explosive mixture..

Review of physical-chemical properties:

Crystal structure
Melting temperature
14,025 K
Boiling temperature
20,268 K
Molar volume
11,42 · 10−6m3 (½ mol H2 at 2 K)
Saturated vapour pressure
209 Pa at 23 K
Speed of sound
1270 m/s at 298,15 K
Specific heat capacity
14304 J/(kg K)
Thermal conductivityt
0,1815 W/(m K)
Hydrogen combustion heat
72 kJ/mol
Heating power
59,775 kJ/mol