Liquid Helium Physical Properties:

• Molecular Symbol: He
• Molecular Weight: 4.003
• Boiling Point 1 atm: -452.1°F (-268.9°C, 4oK)
• Freezing Point 367 psia: -459.7°F (-272.2°C, 0oK)
• Critical Temperature: -450.3°F (-268.0°C)
• Critical Pressure 33.0 psia: (2.26 atm)
• Density, Liquid B.P., 1 atm: 7.798 lb./cu.ft.
• Density, Gas 32°F (0°C), 1 atm: 0.0103 lb./cu.ft.
• Specific Gravity, Gas (Air = 1) 32°F (0°C), 1 atm: 0.138
• Specific c Gravity, Liquid B.P., 1 atm: 0.125
• Specific c Volume 32°F (0°C), 1 atm: 89.77 cu.ft./lb.
• Specific c Volume 68°F (20°C), 1 atm: 96.67 cu.ft./lb.
• Latent Heat of Vaporization: 34.9 Btu/lb. mole
• Expansion Ratio, Liquid to Gas, B.P. to 32°F (0°C): 1 to 754