helium
- Formula: He
- Molecular weight: 4.002602
- IUPAC Standard InChI: InChI=1S/He
- IUPAC Standard InChIKey: SWQJXJOGLNCZEY-UHFFFAOYSA-N
- CAS Registry Number: 7440-59-7
- Chemical structure:
This structure is also available as a 2d Mol file - Permanent link for this species. Use this link for bookmarking this species for future reference.
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Gas phase thermochemistry data
Go To: Top, Phase change data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| S°gas,1 bar | 126.153 ± 0.002 | J/mol*K | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
| S°gas,1 bar | 126.15 | J/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1982 |
Gas Phase Heat Capacity (Shomate Equation)
Cp° = A + B*t + C*t2 + D*t3 +
E/t2
H° − H°298.15= A*t + B*t2/2 +
C*t3/3 + D*t4/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t2/2 + D*t3/3 −
E/(2*t2) + G
Cp = heat capacity (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 298. to 6000. |
|---|---|
| A | 20.78603 |
| B | 4.850638×10-10 |
| C | -1.582916×10-10 |
| D | 1.525102×10-11 |
| E | 3.196347×10-11 |
| F | -6.197341 |
| G | 151.3064 |
| H | 0.000000 |
| Reference | Chase, 1998 |
| Comment | Data last reviewed in March, 1982 |
Phase change data
Go To: Top, Gas phase thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| Tc | 5.2 | K | N/A | Angus, de Reuck, et al., 1977 | Uncertainty assigned by TRC = 0.0005 K; in terms of a temp. scale related to the 1958 He-4 scale, T-58 by 1.001 T-58 + 0.001 K |
| Quantity | Value | Units | Method | Reference | Comment |
| Pc | 2.274 | bar | N/A | Angus, de Reuck, et al., 1977 | Uncertainty assigned by TRC = 0.002 bar |
| Quantity | Value | Units | Method | Reference | Comment |
| ρc | 17.40 | mol/l | N/A | Angus, de Reuck, et al., 1977 | Uncertainty assigned by TRC = 0.01 mol/l |
References
Go To: Top, Gas phase thermochemistry data, Phase change data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Cox, Wagman, et al., 1984
Cox, J.D.; Wagman, D.D.; Medvedev, V.A.,
CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp., New York, 1984, 1. [all data]
Chase, 1998
Chase, M.W., Jr.,
NIST-JANAF Themochemical Tables, Fourth Edition,
J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]
Angus, de Reuck, et al., 1977
Angus, S.; de Reuck, K.M.; McCarty, R.D.,
International Thermodynamic Tables of the Fluid State - 4 Helium, Pergamon, New York, 1977. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Phase change data, References
- Symbols used in this document:
Pc Critical pressure S°gas,1 bar Entropy of gas at standard conditions (1 bar) Tc Critical temperature ρc Critical density - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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