Table 1.

Properties of H₂, CH₄, and CO₂¹²⁴

Properties	H2	CH4	CO2
Molecular mass (g/mol)	2.016	16.043	44.009
Density (kg/m3)	0.08375	0.6682	1.842
Dynamic viscosity at 293.15 K (10-5 Pa s)	0.88	1.10	1.47
Specific gravity (air = 1)	0.07	0.55	1.52
Diffusion coefficient in air (cm2/s)	0.756	0.21	0.16
Solubility in water (g/100 g)	0.00016	0.0023	0.169
Net heating value (kJ/g)	120–141.7	50–55	/