Heat capacity data

Draw the curve of Cp vs. T and Cp/T vs. T from the following heat capacity data for solid chlorine and determine the absolute entropy of solid chlorine at 70.0 K... 

The thermal conductivity of soHd iodine between 24.4 and 42.9°C has been found to remain practically constant at 0.004581 J/(cm-s-K) (33). Using the heat capacity data, the standard entropy of soHd iodine at 25°C has been evaluated as 116.81 J/ (mol-K), and that of the gaseous iodine at 25°C as 62.25 J/(mol-K), which compares satisfactorily with the 61.81 value calculated by statistical mechanics (34,35). 

A composite curve of heat of infinite dilution of oleum from reported data (3,88—90) is presented in a compiled form in the Hterature (91), where heats of formation of oleums from Hquid or gaseous SO are also reported (Tables 5 and 6). Heat of vaporization data are also available (92). Oleum heat capacity data are presented in Figure 18 (76) solubiUty data for SO2 in oleum can be found in Reference 69. 

Heat capacity data for metaborate solutions have been reported (87). The solubiUty of sodium metaborate tetrahydrate in methanol at 40°C is 26.4 wt % (61). 

The integral terms representing AH and AH can be computed if molal heat capacity data Cp(T) are available for each of the reactants (i) and products (j). When phase transitions occur between T and Tj for any of the species, proper accounting must be made by including the appropriate latent heats of phase transformations for those species in the evaluation of AHj, and AH terms. In the absence of phase changes, let Cp(T) = a + bT + cT describe the variation of (cal/g-mole °K) with absolute temperature T (°K). Assuming that constants a, b, and c are known for each species involved in the reaction, we can write... 

In the event the mean molal heat capacity data are available with a reference temperature other than = 25°C (see Table 2-46 for data with = 0°C), the following equation can be used to calculate AH (Tj) ... 

The second term on the right side of the expression for AH accounts for any phase changes that may occur between 25°C and for the final products it should be deleted if not applicable. Using molal heat capacity data C (T) for all the species present, the following equality is solved for by trial and error. 

Method 2. Use mean heat capacity data from Table 2-45 with reference conditions of P = 0 and T = 25°C for the combustion gases. Then the equation for T, becomes... 

Thus, values for C°p m T, S°m T, (H°m T - H°m 0) and (G°mT H°m0) can be obtained as a function of temperature and tabulated. Figure 4.16 summarizes values for these four quantities as a function of temperature for glucose, obtained from the low-temperature heat capacity data described earlier. Note that the enthalpy and Gibbs free energy functions are graphed as (// , T - H°m 0)/T and (G T — H q)/T. This allows all four functions to be plotted on the same scale. Figure 4.16 demonstrates the almost linear nature of the (G°m T H°m 0)/T function. This linearity allows one to easily interpolate between tabulated values of this function to obtain the value at the temperature of choice. 

Heat capacity data, from Volume 1, average values. 

PRINT "INPUT HEAT CAPACITY DATA FOR EQUATION A+BT+CT 2+DT 3"... 

The program ENERGY 1 was used to calculate the sensible heat in the inlet and outlet gas streams. The composition of the inlet stream and the heat capacity data will be the same as that for the WHB outlet given above. Outlet stream flows from flow-sheet, converted to kmol/h ... 

Heat capacity data are often available in some form of polynomial as a function of temperature, for example6 ... 

Substituting the values of temperature into Equation 6.48 leads to the results in Table 6.6. From Table 6.6, it can be seen that calculation of in Kai from heat capacity data on the basis of A Ilf maintains a good agreement with In KaT calculated from... 

Tabulated data are available for AG° and AH° at standard temperature. This can be extrapolated to other temperatures using heat capacity data. 

Table 6.19 Heat capacity data for sulfuric acid production.

Alternatively, the heat capacity data can be used to derive mean heat capacities. The mean heat capacity can be defined as18 ... 

Table 15.15 presents mean heat capacity data between 25°C and a given temperature for a range of temperatures. 

The law of Dulong and Petit states that the molar heat capacity of crystalline elements is approximately 25 J/mol deg. With this law, we can calculate approximate atomic weights from heat capacity data. 

The following heat capacity data may be employed for the temperature range of interest. (Temperatures must be expressed in degrees Kelvin.) At 1100 °F the standard heat of reaction is equal to 21.960 kcal/g mole. 

Figure 7.17 (a) Magnetic properties of [LaTb] and [Tb2] in the form of yT versus T plot per mole of Tb(lll). (b) Schematic representation of the qubit definition, weak coupling and asymmetry, as derived from magnetic and heat capacity data. 

Interestingly, this compound was known for some years [38, 39] before MCE research came back into vogue. Here, the maximum — ASM for a decoupled system is 42 J kg-1 K-1 and is almost met for AH = 0 - 7 T and 1.8 K. So, we have a reasonably high metal content, with a small, though ferromagnetic, interaction, with the appropriate high spin metals. Heat capacity data allow the adiabatic temperature change to be calculated here, this was found to be 12.7 K below 2 K, one of the best by this measure until recently. 

Fig. 12.8. Heat capacity data, showing the linearity of C/T versus T2.

The value of the heat capacity C was obtained as r G. These values were corrected subtracting the contribution Csp of the addendum. Heat capacity data are shown in Fig. 12.8, in which the ratio C/T is reported as a function of T2. 

The addendum contributions are evaluated from data in the literature [35,36], The heat capacity data for Torlon were corrected only for the Cu contribution. 

DSC measurements with a microcalorimeter played a key role in tracing the origin of the step observed in the spin transition curve of [Fe(2-pic)3]-Cl2-EtOH [24]. The mixing entropy derived from the measured heat capacity data showed a significant reduction in the region of the step. This has been... 

Table 8.3 Comparison of Debye temperatures derived from heat capacity data and from elastic properties.

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