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Properties of substance:

helium

Group of substances:

inorganic

Physical appearance:

colorless gas

Empirical formula (Hill's system for organic substances):

He

Structural formula as text:

He

Molar/atomic mass: 4.0026

Boiling point (°C):

-268.93

Solubility (g/100 g of solvent):

acetone: 0.0007 (20°C) [Ref.]
benzene: 0.000365 (20°C) [Ref.]
cyclohexane: 0.00054 (20°C) [Ref.]
ethanol: 0.0005 (15°C) [Ref.]
ethanol: 0.00057 (25°C) [Ref.]
methanol: 0.000707 (20°C) [Ref.]
perfluoro-n-heptane: 0.0008583 (18.25°C) [Ref.]
perfluoro-n-heptane: 0.0008858 (22.32°C) [Ref.]
perfluoro-n-heptane: 0.0009188 (25°C) [Ref.]
perfluoro-n-heptane: 0.0009282 (26.09°C) [Ref.]
perfluoro-n-heptane: 0.0009595 (30.08°C) [Ref.]
water: 0.000173 (0°C) [Ref.]
water: 0.000177 (10°C) [Ref.]
water: 0.000179 (30°C) [Ref.]
water: 0.000191 (50°C) [Ref.]
water: 0.000216 (75°C) [Ref.]

Numerical data:

Year of discovery: 1868 (открыт по желтой спектральной линии в атмосфере Солнца)
Thermal conductivity (W/m·K): 0.1557
Magnetic susceptibility (mm3/kg): -0.47
Ionization Potentials (Electronvolts): 24.588

Density:

0.145 (-273.15°C, g/cm3)
0.13 (-269°C, g/cm3)
0.000178467 (0°C, g/cm3)

Half-life:

102He = 260 ys (2n (100%))
32He = stable (mass excess 14931 keV (isotopic abundance 0,000137%))
42He = stable (mass excess 2424,9156 keV (isotopic abundance 99,999863%))
52He = 602 ys (αn; mass excess 11231 keV)
62He = 0.80692 s (β- (100%); β-d (0.00278%); mass excess 17592,1 keV)
72He = 2.51 zs (n (100%); mass excess 26073 keV)
82He = 0.119 s (β-t (88%); n (12%); mass excess 31598 keV)
92He = 2.5 zs (n (100%))

Vapour pressure (Torr):

1 (-271.9°C)
10 (-271.4°C)
100 (-270.5°C)

Permittivity (dielectric constant):

1.000068 (0°C)
1.0555 (-271.095°C)

Viscosity (mPa·s):

0.0188 (0°C)
0.0229 (100°C)
0.0269 (200°C)
0.0342 (400°C)
0.0407 (600°C)

Speed sound (m/s):

1056 (30°C, aggregative state - gas)
965 (0°C, aggregative state - gas)
237.66 (-272.165°C, aggregative state - liquid)
231.4 (-271.39°C, aggregative state - liquid)
221.7 (-270.97°C, aggregative state - liquid)
223.3 (-270.65°C, aggregative state - liquid)
179.8 (-268.93°C, aggregative state - liquid)

Standard molar enthalpy (heat) of formation ΔfH0 (298.15 K, kJ/mol):

0 (g)

Standard molar Gibbs energy of formation ΔfG0 (298.15 K, kJ/mol):

0 (g)

Standard molar entropy S0 (298.15 K, J/(mol·K)):

126.04 (g)

Molar heat capacity at constant pressure Cp (298.15 K, J/(mol·K)):

20.79 (g)

Molar enthalpy (heat) of fusion ΔfusH (kJ/mol):

0.00723

Enthalpy (heat) of vaporization ΔvapH (kJ/mol):

0.084

Critical temperature (°C):

-267.95

Critical pressure (MPa):

0.229

Critical density (g/cm3):

0.0693

References:

  1. Handbook of Chemistry and Physics. - CRC Press, Inc., 2002. - pp. 11-51
  2. Seidell A. Solubilities of inorganic and metal organic compounds. - 3ed., vol.1. - New York: D. Van Nostrand Company, 1940. - pp. 601-604
  3. Гринвуд Н., Эрншо А. Химия элементов. - Т.2. - М.: БИНОМ. Лаборатория знаний, 2008. - pp. 235 [Russian]
  4. Гурвич Я.А. Справочник молодого аппаратчика-химика. - М.: Химия, 1991. - pp. 50 [Russian]
  5. Девяткин В.В., Ляхова Ю.М. Химия для любознательных, или о чем не узнаешь на уроке. - Ярославль: Академия Холдинг, 2000. - pp. 36 [Russian]
  6. Краткая химическая энциклопедия. - Т. 1: А-Е. - М.: Советская энциклопедия, 1961. - pp. 827-832 [Russian]
  7. Некрасов Б.В. Основы общей химии. - Т.1. - М.: Химия, 1973. - pp. 44-46 [Russian]
  8. Некрасов Б.В. Основы общей химии. - Т.2. - М.: Химия, 1973. - pp. 540-541 [Russian]
  9. Рабинович В.А., Хавин З.Я. Краткий химический справочник. - Л.: Химия, 1977. - pp. 24, 61 [Russian]
  10. Справочник по растворимости. - Т.1, Кн.1. - М.-Л.: ИАН СССР, 1961. - pp. 553-557 [Russian]
  11. Фастовский В.Г., Ровинский А.Е., Петровский Ю.В. Инертные газы. - М.: Атомиздат, 1972 [Russian]
  12. Физические величины. - Под ред. Григорьева И.С., Мейлихова Е.З. - М.: Энергоатомиздат, 1991. - pp. 994 [Russian]
  13. Химическая энциклопедия. - Т. 1. - М.: Советская энциклопедия, 1988. - pp. 513-514 [Russian]

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    © Collected Ruslan Anatolievich Kiper, burewestnik@mail.ru