Heat capacity above

The heat capacity measurements of Wallace [1960WAL] from 298.15 to 1273 K merge smoothly with the low temperature data of [1953GRI/SKO]. However, Nakamura et al. [1980NAK/TAK] measured the heat capacity of thorium containing 0.05 mass% impurities using a laser-flash technique. This a valuable study, as not only 

The only reliable enthalpy increment measurements are those of Levinson [1966LEV] from 1269 to 2100 K, although Jaeger and Veenstra [1934JAEAffiE] reported measurements on thorium containing 6 mass% Th02, which are clearly too high. 

As noted earlier, the assessments of the reviews of [1982GLU/GUR] and [1986WAR/KLE] (and the unpublished assessment of Aiblaster) have relied heavily on the extensive and well-documented data of Nakamura et al. [1980NAK/TAK] from 80 to 1000 K, since these merge extremely well with the high temperature enthalpy data of Levinson [1966LEV] and we have adopted the same philosophy. 

The selected values above 298.15 K are those of [1982GLU/GUR], but with a transformation temperature of (1633 + 20) K rather than (1650 + 20) K, as discussed earlier. These values are essentially identical to the assessment of [1986WAR/1CLE] up to 1000 K, but above this temperature, the equation of [1982GLU/GUR] 

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Product Specific heat capacity above freezing Highest freezing point (°C) Latent heat of freezing Specific heat capacity below freezing... 

Criss, C. M. Cobble, J. W. "The Thermodynamic Properties of High Temperature Aqueous Solutions. V. The Calculation of Ionic Heat Capacities up to 200OC. Entropies and Heat Capacities above 200 C" J. An. Chan. Soc., 1964, 86, 5390. 

The low temperature (16-298.15 K) heat capacities were reported by Johnston and Kerr (5). The heat capacities above 300 K were estimated with those of Its constituent oxides. S (298.15 K) was obtained from Johnston and Kerr using S (17 K) = 0.18 kcal mol". ... 

Westrum and Felck s 5) values were adopted to 350 K. The disparities in heat capacities above room temperatures seem too great to be errors in measurement and are probably due to sample differences. Since the samples used by Westrum and Feick ( ) and by Valentine et al. (6) were from the same batch, Valentine s data were used above 350 K. The two sets of data were fitted to a Shomate plot which was extrapolated to 4000 K. However, in consideration of the results of Mezsakl (7), Prophet (8) and Neel et... 

Cp(60 to 371.93 K) was given by Purukawa and Park ( ). The heat capacity above 371.93 K is estimated by comparison with that of the liquid decarborane. Heat capacity (14 to 205 K) was also reported by Kerr, Haliett and Johnston (4). The value of S (298.15 K) was taken from Purukawa and Park (3). 

The heat capacity and entropy of TiBr Ccr) have been measured over the temperature range 51 to 800 K by King et al. (2). Heat capacities above 800 K are estimated from graphical extrapolation. The value of S"(298.15 K) is derived from these data, based on S (51 K) - 8.60 cal K mol. The value of S (51 K) is estimated from a Debye-Einsteln extrapolation of the measured heat capacities, the equation being C - D(70.0/T) + E(120/T) + 2E(306/T). It is assumed that all electronic entropy is... 

The low temperature heat capacity, 14.0-315 K was measured by Getting (7). Janz et al. (8) measured the heat content by drop calorimetry in the temperature range 630-1250 K, and gave enthalpy and heat capacity equations based on their measurements. The above information was used in a Shomate analysis in order to smooth the enthalpy and calculate heat capacity above 298.15 K. The values from the low and high temperature sources join smoothly at 298.15 K. The heat capacity was graphically extrapolated above the melting point. The entropy at 14.0 K was calculated from the extrapolated low temperature... 

The constant heat capacity above the assumed glass transition at 700 K is derived from high temperature enthalpy data in a... 

The entropy of CuCl was obtained from the several pieces of equilibrium data reported above and the adopted A.H (298J.5 K). A -1 -1 weighted average of 20.8 1 cal K mol was adopted for S CCuCl, cr, 298.15 K). The enthalpy and heat capacity above 298.15 K have... 

The low temperature heat capacities (12.53-298.07 K) were measured by Latimer and Ahlberg (5). The heat capacities above... 

Heat capacities above 300 K are estimated from those... 

Formation," for details. Therefore the value, S (298,15 K) = 25.71 + 3.2 = 28.91 cal K mol for FeSO (cr), was adopted. The heat capacities above 294.9 K were estimated by comparison with those for MnSO (cr). The high temperature heat capacities, 870.3-1082.3 K, were determined by Southard and Shomate (7). The two sets of data were joined smoothly at 298.15 K by use of Shomate-function plot. 

The low temperature heat capacities in the temperature range from 52-298 K are obtained from Todd s measurements (7). Two peaks at 193.5 K and 230.9 K were found in his heat capacity data. Below 50 K, the heat capacities were extrapolated using a combination of 1 Debye (0 = 139) and 2 Einstein (0 = 260) functions as suggested by Todd. This extrapolation yields the entropy from lattice contribution as 3.278 cal k" mol at 50 K. By neutron diffraction. Smith et al. ( ) found an antiferromagnetic transition at 7 K which indicates the existence of an unpaired electron in KOgCcr). We tentatively adopt S (50 K) = 4.656 1 cal K" mol" which includes both lattice (3.278 cal k" mol" ) and unpaired electron (Rtn2) contributions. Heat capacities above 298 K are estimated graphically. 

Low temperature heat capacities, 52.92 - 296.09 K, were measured calorimetrically by King and Weller (3). The heat capacities above 300 K are estimated by comparison with those of CaWO (cr) (4), CaO(cr) (5) and MgO(cr) (6). These two se data are joined smoothly at 298.15 K by a graphical method. 

The heat capacity above 900 K is derived as constant from the high temperature enthalpy data, 1414 - 1747 K, measured by Naylor (1 ). A glass transition temperature is assumed at 900 K, i.e., the heat capacities below 900 K are taken to be those for... 

High temperature enthalpy data have been reported by Palmaer (6) and Bousquet et al. (7) but these data suffer from unknown amounts of impurity, for which the correction is probably substantial, and decomposition to intermediate oxides. Thus, the heat capacity above room temperature was estimated by a graphical extrapolation of the low temperature heat capacity. 

High temperature studies are summarized below along with the pertinent low temperatures studies. The selected heat capacities above 300 K are obtained from a Shomate plot of the adopted low temperature heat capacities and the enthalpies reported or derived from the work of Dennison (5), Kantor et al. (6), Olette (7), Serebrennikov and Gel d (8) and Magnus (9). 

Low temperature heat capacity measurements by Anderson 10) y Bronson and MacHattie 42) y Keesom and van den Ende 176) y and Armstrong and Grayson-Smith 16) were used to calculate an entropy and enthalpy at 298 K. of 13.58 e. u. and 1536 cal./gram atom, respectively. From many sources, Kelley 186) derives an equation for the solid heat capacity above 298 K. Kubaschewski and coworkers 206) select 544.5 K. as the melting point and 2600 50 cal./gram atom for the heat of melting. Data on... 

Kelley 186) estimates the entropy at 298 K. as 12.5 =t 0.5 e. u. The solid heat capacity above room temperature was estimated by comparison with calcium. Eastman, Cubicciotti, and Thurmond 93) have reported a transition point at 862 K. and a melting point of 1043 K., in good agreement with the review of Kubaschewski, Brizgys, Huchler, Jauch, and Reinartz 306). Kubaschewski and coworkers 306) have estimated... 

The uncertainties are approximately 0.2% in density at temperatures up to 320 K, 0.5% in density at higher temperatures, 2% in heat capacity above 250 K, 4% in heat capacity at lower temperatures, 0.1% in the vapor phase speed of sound, 3% in the liquid-phase speed of sound, and 0.4% in vapor pressure at temperatures above 200 K. For viscosity, estimated uncertainty is 2%. For thermal conductivity, estimated uncertainty, except near the critical region, is 4-6%... 

The temperature dependence of the heat capacity above 298.15 K was only presented as graphs in all publications except in [78BLA/GUN] and [2003GRO/STO] in which also numerical values were presented. No analytical expression for the temperature dependence of the heat capacity was derived by the review because the numerical values in the two series of measurements differ by several J-K -moP. ... 

There are no published experimental data on the heat capacities above 298.15 K, but [1977WAG/SCH] give values based on preliminary high temperature enthalpy measurements by Dworkin from 1200 to 1420 K. We have refitted these so that they reproduce more precisely the value of C° (298.15 K) measured by [1954LOH/OSB] and these are the selected values ... 

However, the noticeable decrease in the heat capacity above 3100 K is not consistent with the more accurate enthalpy data of Fisher et al. [1981FIS/FIN] who made... 

CRI/COB2] Criss, C. M., Cobble, J. W., The thermodynamic properties of high temperatirre aqueous solutions. V. The calculation of ionic heat capacities up to 200°C. Entropies and heat capacities above 200°C, J. Am. Chem. Soc., 86, (1964), 5390-5393. Cited on page 643. 

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