• Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

Search Issue | RSS Feeds RSS
Previous Issue

Nov 1997

Volume 26, Issue 6, pp. 1273-1505


An International Standard Equation of State for Difluoromethane (R-32) for Temperatures from the Triple Point at 136.34 K to 435 K and Pressures up to 70 MPa

Reiner Tillner-Roth and Akimichi Yokozeki

J. Phys. Chem. Ref. Data 26, 1273 (1997); http://dx.doi.org/10.1063/1.556002 (56 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
A fundamental equation of state for the Helmholtz free energy of R-32 (difluoromethane) is presented which is valid from the triple point at 136.34 K to 435 K and pressures up to 70 MPa. It is based on accurate measurements of pressure-density-temperature (p,,T), speed of sound, heat capacity, and vapor pressure currently available. New values for the isobaric heat capacity cp of the ideal gas calculated from spectroscopic data taking into account also first order anharmonicity corrections are presented. The Helmholtz free energy equation of state has 19 coefficients and represents all selected experimental data within their estimated accuracy with the exception for heat capacities and speed of sound in the region close to the critical point. Typical uncertainties are ±0.05% for density, ±0.02% for the vapor pressure and ±0.5%–1% for the heat capacity. This equation of state has been compared to equations developed by other research groups by Annex 18 of the International Energy Agency and has been selected as an international standard formulation for the thermodynamic properties of R-32 by this group. © 1997 American Institute of Physics and American Chemical Society.
Show PACS
01.30.Kj Handbooks, dictionaries, tables, and data compilations
06.20.F- Units and standards
64.10.+h General theory of equations of state and phase equilibria
65.20.-w Thermal properties of liquids
65.40.gd Entropy
51.30.+i Thermodynamic properties, equations of state
51.10.+y Kinetic and transport theory of gases
62.60.+v Acoustical properties of liquids
62.65.+k Acoustical properties of solids

Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry: Supplement VI. IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry

R. Atkinson, D. L. Baulch, R. A. Cox, R. F. Hampson, J. A. Kerr, M. J. Rossi, and J. Troe

J. Phys. Chem. Ref. Data 26, 1329 (1997); http://dx.doi.org/10.1063/1.556010 (171 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photochemistry of gas-phase chemical reactions of neutral species involved in atmospheric chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997)]. The present evaluation is limited to the following families of atmospherically important reactions: Ox, HOx, NOx, and SOx. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 151 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross-sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model atmospheric chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available data on enthalpies of formation of the reactant and product species. © 1997 American Institute of Physics and American Chemical Society.
Show PACS
01.30.Kj Handbooks, dictionaries, tables, and data compilations
82.33.Tb Atmospheric chemistry
92.60.H- Atmospheric composition, structure, and properties
82.50.-m Photochemistry
82.20.Pm Rate constants, reaction cross sections, and activation energies
82.60.Cx Enthalpies of combustion, reaction, and formation

Erratum: Heat Capacities and Entropies of Organic Compounds in the Condensed Phase, Volume III [J. Phys. Chem. Ref. Data 25, 1–525 (1996)]

Eugene S. Domalski and Elizabeth D. Hearing

J. Phys. Chem. Ref. Data 26, 1501 (1997); http://dx.doi.org/10.1063/1.556003 (5 pages)

Full Text: | Download PDF

Show Abstract
The errata are arranged in the format shown below and are listed as found according to successive pages in the 1996 publication, J. Phys. Chem. Ref. Data 25, 1–525 (1996). After the page number for a specific erratum, which is shown on the extreme left side of the first line, information is provided regarding its location on a given page, such as: compound formula, compound name, reference squib, or other pertinent information. On the second line, the erratum appears as found in the publication. On the third line, one finds the correction. The last line offers a comment or explanation about the erratum. © 1997 American Institute of Physics and American Chemical Society.
Show PACS
65.40.-b Thermal properties of crystalline solids
65.60.+a Thermal properties of amorphous solids and glasses: heat capacity, thermal expansion, etc.
65.80.-g Thermal properties of small particles, nanocrystals, nanotubes, and other related systems
65.20.-w Thermal properties of liquids
65.40.gd Entropy
99.10.Cd Errata
Close
Google Calendar
ADVERTISEMENT

close