JANAF Thermodynamic Tables

The NIST-JANAF Thermodynamics Tables are available online from the National Institute of Standards www.nist.gov/srd/monogr.htm. 

Stull, D. R. Prophet, H. "JANAF Thermodynamic Tables, Second Edition" National Bureau of Standards Washington, D.C., 1971. 

Dow Chemical Corp., JANAF Thermodynamical Tables, 2nd ed., 1971, NSRDS NBS-37. 

JANAF Thermodynamical Tables, The Dow Chemical Company, Midland,... 

Syverud, JANAF Thermodynamic Tables, 3d ed.. J. Phys. Chem. Ref. Data. 14. (1985), Supp. 1. 

JANAF Thermodynamical Tables, 2nd edition, 1971 JANAF Thermodynamical Tables, 1975, Supplement. 

In 1989 the Committee on Data for Science and Technology (CODATA) of the International Council for Science conducted a project to establish internationally agreed values for the thermodynamic properties of key chemical substances [47]. In 1959 the Dow Thermal Laboratory was commissioned to prepare the Joint Army-Navy-Air Force Thermodynamic Tables (JANAF Thermodynamic Tables) that are issued from time to time [148],... 

These data have been collated from various standard sources Kirk Othmer s Encyclopedia of Chemical Technology, Ullman s Encyclopedia of Industrial Chemistry, Handbook of Chemistry and Physics, American Institute of Physics Handbook, JANAF Thermodynamic Tables, L. Haar and J. S. Gallagher [/. Phys, Chem. Ref Data 1, 635-792] (1978), etc. 

Case MW Jr (1998) NIST-JANAF thermodynamical tables. Am. Chem. Soe., Am. Inst. Phys., NIST, Maryland... 

References D. D. Wagman, et ah, The NBS Tables of Chemical Thermodynamic Properties, in J. Phys. Chem. Ref. Data, 11 2,1982 M. W. Chase, et ah, JANAF Thermochemical Tables, 3rd ed., American Chemical Society and the American Institute of Physics, 1986 (supplements to JANAF appear in J. Phys. Chem. Ref. Data) Thermodynamic Research Center, TRC Thermodynamic Tables, Texas A M University, College Station, Texas I. Barin and O. Knacke, Thermochemical Properties of Inorganic Substances, Springer-Verlag, Berlin, 1973 J. B. Pedley, R. D. Naylor, and S. P. Kirby, Thermochemical Data of Organic Compounds, 2nd ed.. Chapman and Hall, London, 1986 V. Majer and V. Svoboda, Enthalpies of Vaporization of Organic Compounds, International Union of Pure and Applied Chemistry, Chemical Data Series No. 32, Blackwell, Oxford, 1985. 

Heat Capacity, C° Heat capacity is defined as the amount of energy required to change the temperature of a unit mass or mole one degree typical units are J/kg-K or J/kmol-K. There are many sources of ideal gas heat capacities in the hterature e.g., Daubert et al.,"" Daubert and Danner,JANAF thermochemical tables,TRC thermodynamic tables,and Stull et al. If C" values are not in the preceding sources, there are several estimation techniques that require only the molecular structure. The methods of Thinh et al. and Benson et al. " are the most accurate but are also somewhat complicated to use. The equation of Harrison and Seaton " for C" between 300 and 1500 K is almost as accurate and easy to use ... 

Ideal gas absolute entropies of many compounds may be found in Daubert et al.,"" Daubert and Danner," JANAF Thermochemical Tables,TRC Thermodynamic Tables,and Stull et al. ° Otherwise, the estimation method of Benson et al. " is reasonably accurate, with average errors of 1-2 J/mol K. Elemental standard-state absolute entropies may be found in Cox et al." Values from this source for some common elements are listed in Table 2-389. ASjoqs may also be calculated from Eq. (2-52) if values for AHjoqs and AGJoqs are known. 

We will now consider a practical example of calculating thermochemical properties for the species CH3. Actually a lot is known about the CH3 radical, and we choose it as example in order to compare the calculated results with experimental data. The NIST-JANAF Thermochemical Tables [62] are a standard source for experimental thermochemical data, as well as moments of inertia, vibrational frequencies, and the like. The NIST-JANAF Tables use the same basic approach outlined here to calculate the temperature dependence for their thermodynamic data, based on species vibrational frequencies and moments of inertia. 

Fortunately, much experimental thermochemical information exists in the literature and in data compilations. The NIST-JANAF Thermochemical Tables [62] is a particularly useful source of data. In the following, we discuss some of the data conventions adopted by the NIST-JANAF Tables in reporting this information. These compilations adopt sound and useful conventions based on fundamental thermodynamic considerations. This brief discussion offers a simple explanation of the quantities reported there. 

For thermodynamic data, see N. Jacobson, Use of Tabulated Thermochemical Data for Pure Compounds, J. Chem. Ed. 2001, 78, 814 http //webbook.nist.gov/chemistry/ and http //www.crct.polymtl.ca/fact/ websites.htm M. W. Chase, Jr., NIST-JANAF Thermochemical Tables, 4th ed ... 

In the JANAF Thermochemical Tables [U.S. National Bureau Standards, NSRDS-NBS Pub. 37 (1971 and later)], thermodynamic data are tabulated at many different temperatures. 

The thermochemical data for the product species are critical in the calculation of propellant performance. The methods of statistical thermodynamics have provided a reliable technique of establishing most of the thermochemical data required for propellant performance calculations. Again, the JANAF Thermochemical Tables (18) represent an extensive and widely used compilation of these data. 

The process of the calculation involves a reformer which gets its exergy not from combustion, but as electrical power generated by supplying CO and Fi2 to separate fuel cells which are able to create an excess above the need of the reformer. The invaluable JANAF thermochemical tables (Chase etah, 1985) provided the thermodynamic data. The excess is the chemical exergy of methane. 

Historically, the defined pressure for the standard state, i.e., the standard-state pressure, has been one standard atmosphere (101 325 Pa) and most existing data use this pressure. With the growing use of SI units, continued use of the atmosphere is inconvenient. lUPAC has recommended that the thermodynamic data should be reported for a defined standard-state pressure of 100 000 Pa. The standard-state pressure in general is symbolized as Previously in all JANAF thermochemical publications, was taken as 1 atm. In the current set of JANAF Thermochemical Tables p"" is taken as 100 000 Pa (1 bar). It should be understood that the present change in the standard-state pressure carries no implication for standard pressures used in other contexts, e.g., the convention that normal boiling points refer to a pressure of 101 325 Pa (1 atm). 

Our concern in the preparation of the JANAF Thermochemical Tables is to adjust any experimental measurements to the thermodynamic scale. In practice, this means converting to the IPTS-68 scale since it is the currently accepted closest approximation to the thermodynamic scale. 

In all previous JANAF Thermochemical Tables, the standard-state pressure was one atmosphere (101 325 Pa) and the unit of energy was the thermochemical calorie (4.184 J). For this publication, the standard-state pressure is changed to one bar (100 000 Pa) and the energy unit to the joule. The values from previous JANAF tabulations have been converted as described below. This information is provided not only to make clear the correspondence between this publication and previous JANAF Thermochemical Tables but also to assist the reader in making comparisons with other tables. This information is the same as that provided in The NBS Tables of Chemical Thermodynamic Proper-... 

L. V. Gurvich, I. V. Veits, et al., "Thermodynamic Properties of Individual Substances", Vol. 3, Nauka, Moscow, 1981. JANAF Thermochemical Tables (1983). 

J. D. Cox, chairman, CODATA Task Group on Key Values for Thermodynamics, J. Chem. Thermodynamics J, 903 (1978). JANAF Thermochemical Tables P (g), 12-30-82. 

The reverse rate constants for the elementary reactions used in the present work were caJculated from the forward rate constants and the equilibrium constant by assuming microscopic reversibility. Standard states used in tabulations of thermodynamic data are invariably at 1 atm and the temperature of the system. Since concentration units were required for rate constant calculations, a conversion between Kp and Kc was necessary. Values of Kp were taken from the JANAF Thermochemical tables (1984). Kc was calculated from the expression ... 

Thermodynamic properties of the Si3N4 compound were also reassessed based on the JANAF thermochemical tables [61]. 

The thermodynamic parameters for Reaction (8.2) in the gas phase, as calculated from the JANAF Thermochemical Tables [359aa], are detailed in Table 8.1, and illustrated in Figures 8.3 and 8.4 [1825a]. Further details of this dissociation reaction are given in Sections 5.1.2 and 6.1.4. 

Selenium forms compounds with most elements of the Periodic Table. NEA-TDB selected data for a number of these elements are not available for use as auxiliary data in the evaluation of formation data and entropies of their selenium compounds from reaction data. It would not have been a realistic task for the selenium project to assess all non-selected auxiliary data needed according to the NEA-TDB Guidelines. Instead the information required was obtained from compilations of thermochemical data such as The NBS tables of chemical thermodynamic properties and JANAF thermochemical tables supplemented by Critical reviews of. .. published in chemical Journals. The review of the literature on selenium and its compounds has thus resulted in two thermochemical data sets. One set of data is in accord with the NEA-TDB Guidelines and compatible with the requirements for addition to the NEA-TDB Data Bank. The other set, obtained with non-TDB auxiliary data, does not fulfil the requirements of the Data Bank. These facts created a problem in the presentation of the results of the selenium project, which was solved by the... 

Rossini, F. D. Selected values of physical and thermodynamic properties of hydrocarbons and related compounds. Pitsburgh Carnegie Press 1953 JANAF thermochemical tables, Stull, D. R. (project director). Midland, Michigan Dow Chemical Company 1965... 

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