Download the information in Excel format: Hydrogen Properties

Properties Values Units

Autoignition temperature

500 °C
  932 °F
Boiling point (1 atm) -252.9 °C
  -423.2 °F
Density (NTP) 0.08375 kg/m³
  0.005229 lb/ft³
Diffusion coefficient in air (NTP) 0.610 cm²/s
  6.57 E-4 ft²/s
Enthalpy (NTP) 3858.1 kJ/kg
  1659.8 Btu/lb
Entropy 53.14 J/g-K
  12.70 Btu/lb-°R
Flame temperature in air 2045 °C
  3713 °F
Flammable range in air 4.0 - 75.0 vol%
Ignition energy in air 2.0 E-5 J
  1.9 E-8 Btu
Internal Energy (NTP) 2648.3 kJ/kg
  1139.3 Btu/lb
Molecular weight 2.02  
Specific gravity (air = 1) (NTP) 0.0696  
Specific volume (NTP) 11.94 m³/kg
  191.26 ft³/lb
Specific heat at constant pressure, Cp (NTP) 14.29 J/g-K
  3.415 Btu/lb-°R
Specific heat at constant volume, Cv (NTP) 10.16 J/g-K
  2.428 Btu/lb-°R
Thermal conductivity (NTP) 0.1825 W/m-K
  0.1054 Btu/ft-h-°R
Viscosity (NTP) 8.813 E-5 g/cm-sec
  5.922 E-6 lb/ft-sec

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