Gases, heat capacities table

Values for the free energy and enthalpy of formation, entropy, and ideal gas heat capacity of carbon monoxide as a function of temperature are listed in Table 2 (1). Thermodynamic properties have been reported from 70—300 K at pressures from 0.1—30 MPa (1—300 atm) (8,9) and from 0.1—120 MPa (1—1200 atm) (10). 

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 ... 

Table 8.4. Group contributions to ideal gas heat capacities, kJ/kmol°C (Rihani and Doraiswamy, 1965)...

Table 10-3 Ideal Gas Heat Capacity Coefficients for Common Fnel Cell Gases...

Vapour phase enthalpies were calculated using ideal gas heat capacity values and the liquid phase enthalpies were calculated by subtracting heat of vaporisation from the vapour enthalpies. The input data required to evaluate these thermodynamic properties were taken from Reid et al. (1977). Initialisation of the plate and condenser compositions (differential variables) was done using the fresh feed composition according to the policy described in section 4.1.1.(a). The simulation results are presented in Table 4.8. It shows that the product composition obtained by both ideal and nonideal phase equilibrium models are very close those obtained experimentally. However, the computation times for the two cases are considerably different. As can be seen from Table 4.8 about 67% time saving (compared to nonideal case) is possible when ideal equilibrium is used. 

The minimum information covers chemical formula, molecular weight, normal boiling point, freezing point, liquid density, water solubility and critical properties. Additional properties are enthalpies of phase transitions, heat capacity of ideal gas, heat capacity of liquid, viscosity and thermal conductivity of liquid. Computer simulation can estimate missing values. The use of graphs and tables of properties offers a wider view and is strongly recommended. 

TABLE 1.3 Group Contributions to Ideal-Gas Heat Capacity... 

Table 2.6 Ideal gas heat capacity correlation coefficients for use with equation (2.3).

The table below summarizes the calculations from the three approaches. Again, the use of the ideal gas heat capacities results in a better estimate of the result obtained by the rigorous calculation. Furthermore, this has nothing to do with efficiencies because in each case all of the efficiencies are assumed to be 100%. 

Valuesof the parametersare givenin Table C. 1 of App. Cfora numberof common organic and inorganic gases. More accurate but more complex equations are found in the hterature. As a result of Eq. (3.18), the two ideal-gas heat capacities are related ... 

Classical tliennody namics is a deductive science, in which the general features of macroscopic-system beliaviorfollow from a few laws and postulates. However, the practical application of thermodynamics requires values for the properties of individual chemical species and their mixtures. These may be presented either as numerical data (e.g., the steam tables for water) or as correlating equations (e.g., a P VT equation of state and expressions for the temperatnre dependence of ideal-gas heat capacities). 

Constants in this table can be used in the following equation to calculate the ideal gas heat capacity Cp. 

TABLE 2-347 Benson and CHETAHt Group Contributions for Ideal Gas Heat Capacity [Continued)... 

The NIST s Thermodynamics Research Center (TRC) has a large collection of pure-fluid thermodynamic and transport properties tables of recommended values and correlations exist both in paper form and in a computer database [12], The TRC has also produced books with comprehensive compilations for organic compounds (sometimes also available as software) for vapor pressure [17], liquid density [18], and ideal-gas heat capacity [29], in addition to a compilation on virial coefficients [32]. Their major archival database of experimental pure-component and mixture data is called Source [97] it is currently available only to members of their consortium. Some data for mixtures of organic compounds are published in the periodical Selected Data on Mixtures [49]. More information is at http //trc.nist.gov. 

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