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Name | HELIUM |
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Formula | He |
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CAS Number | 7440-59-7 |
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Molecular Weight | 4.003 |
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Melting point | 1.76 K , -271.39 C , -456.5 F |
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Boiling point @ 101.325 kPa (1 atm) | 4.22 K , -268.93 C , -452.07 F |
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Critical Temperature | 5.2 K , 267.95 C , -450.31 F |
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Critical Pressure | 2.28 bar , 2.25 atm , 33.07 psia |
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Critical Volume | 57.3 cm3/mol |
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Critical Density | 0.0699 g/cm3 |
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Critical Compressibility Factor | 0.302 |
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Acentric Factor | -0.390 |
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Density of Liquid @ -270 C | 0.139 g/cm3 |
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Coefficient of thermal Expansion of Liquid @ 25 C | 0.0818 1/C |
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Surface Tension @ -271 C | 0.34 dynes/cm |
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Density of Gas @ 1 atm and 70 F (21.1 C) | 0.166 kg/m3 , 0.0104 lb/ft3 |
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Relative Density of Gas @ 1 atm and 70 F (Air =1) | 0.138 |
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Enthalpy of Vaporization @ Boiling Point | 19.99 kJ/kg , 8.6 BTU/lb |
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Enthalpy of Fusion @ Melting Point | 12.49 kJ/kg , 5.37 BTU/lb |
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Heat Capacity of Gas @ 25 C , Constant Pressure (CP) | 5.193 kJ/(kg K) , 1.241 BTU/(lb R) |
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Heat Capacity of Gas @ 25 C , Constant Volume (CV) | 3.116 kJ/(kg K) , 0.745 BTU/(lb R) |
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Ratio of Heat Capacities for Gas , CP/CV | 1.667 |
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Heat capacity of Liquid @ -270 C | 2.47 kJ/(kg K) , 0.59 BTU/(lb R) |
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Heat capacity of Solid @ -272 C | 1.087 kJ/(kg K ) , 0.26 BTU/(lb R) |
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Entropy of Gas @ 25 C | 126.04 J/(mol K) |
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Entropy of Formation of Gas @ 25 C | 0 J/(mol K) |
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Enthalpy of Formation of Gas @ 25 C | 0 kJ/mol |
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Gibbs Energy of Formation of Gas @ 25 C | 0 kJ/mol |
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Solubility Parameter | 1.222 (J/cm3)^0.5 |
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Liquid Volume | 32.257 cm3/mol |
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Solubility in Water @ 25 C | 1.51 parts per million (wt) |
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Octanol-Water Partition Coefficient , log KOW |
-
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Henry's Law Constant for Compound in Water @ 25 C | 142950.4 atm/mol fraction |
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Viscosity of Gas @ 25 C | 198.57 micropoise |
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Viscosity of Liquid @ -270 C | 0.004 centipoise |
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Thermal Conductivity of Gas @ 25 C | 0.15016 watts/(m K) |
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Thermal Conductivity of Liquid @ -270 C | 0.016 watts/(m K) |
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Lower Explosion Limit in Air |
-
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Upper Explosion Limit in Air |
-
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Flash Point Temperature |
-
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Autoignition Temperature |
-
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Enthalpy of Combustion @ 25 C (77 F) |
-
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Threshold Limit Value (ACGIH) |
-
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Permissible Exposure Limit (OSHA) |
-
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Recommended Exposure Limit (NIOSH) |
-
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