Calorimetric data, tables

Thermochemical cycles were used to test the validity of Eqs. (5a) and (7) by means of the calorimetric data (Table VI) 68). In cycle 4, the formation of gaseous carbon monoxide at the end of the sequence of adsorptions CO-O2-CO is assumed whereas, in cycle 5, the formation of adsorbed carbon dioxide is supposed. Calculations presented in Table VI show that, in the case of NiO(250°), cycle 5 is balanced for a low surface coverage whereas cycle 4 is balanced for high surface coverages. The calorimetric results confirm therefore the formation of the C03"(ads) ions and moreover they show that, when the heat of formation of this complex is high (120 kcal/mole), its interaction with carbon monoxide produces adsorbed carbon dioxide. When the heat of formation is lower (110 kcal/mole), gaseous carbon dioxide is evolved to the gas phase. 

Polymerization thermodynamics has been reviewed by Allen and Patrick,323 lvin,JM [vin and Busfield,325 Sawada326 and Busfield/27 In most radical polymerizations, the propagation steps are facile (kp typically > 102 M 1 s l -Section 4.5.2) and highly exothermic. Heats of polymerization (A//,) for addition polymerizations may be measured by analyzing the equilibrium between monomer and polymer or from calorimetric data using standard thermochemical techniques. Data for polymerization of some common monomers are collected in Table 4.10. Entropy of polymerization ( SP) data are more scarce. The scatter in experimental numbers for AHp obtained by different methods appears quite large and direct comparisons are often complicated by effects of the physical state of the monomei-and polymers (i.e whether for solid, liquid or solution, degree of crystallinity of the polymer). 

Figure 5,17 Enthalpic interactions in the various binary joins of aluminiferous garnets. calorimetric data results of interionic potential calculations. The corresponding subregular Margules interaction parameters are listed in table 5.26 (from Ottonello et al., in prep.).

Thermodynamic data on amphibole end-members are mostly derived from phase equilibria, because of the difficulty of synthesizing pure components for direct calorimetric investigation. Table 5.49 lists existing values for some pure components. Most data come from the internally consistent set of Holland and Powell... 

Interestingly, two of the other species in Table 3 are nitrolates, i.e. ethers of a-nitrooximes, an otherwise thermochemically unprecedented class of compounds. We already have briefly discussed one, 3-nitroisoxazoline, and the second is 1-nitroacetaldehyde 0-(l,l-dinitroethyl)oxime (ONo-ld-dinitroethyl acetonitronate), MeC (NOala—O—N=C(N02)Me. The latter acyclic species is a derivative of 1,1-dinitroethanol—we know of the enthalpy of formation of no other a-nitroalcohol or derivative. Nonetheless, we may ask if the two calorimetric data are internally consistent. Consider the condensed phase reaction 47, which involves formal cleavage of the O — bond in the nitroisoxazoline by the C—H bond of the dinitromethane. It is assumed that the isoxazoline has the same strain energy as the archetypal 5-atom ring species cyclopentane and cyclopentene, ca 30 kJ mol . ... 

Calorimetric data on azoles are given in Tables II and III. Figure 1 shows the linear relationship between the ionization enthalpies (AH°) and free energies (AG°). It is noteworthy that protonation and deprotonation generate two nearly parallel lines. Di- and tri-positive (or negative) ions are clearly off these lines, suggesting that the AH° — AG° relationship is sensitive to the overall charge of the ions. 

In addition to these limited procedures a number of experimental methods (vibrational spectroscopy, dipole moment measurements, electron diffraction, NMR, etc.) have been employed to determine the relative stabilities of these complexes.11,23 Intense effort has been directed towards establishing some kind of correlation between NMR parameters and stability of the borane complexes. The chemical shifts alone rarely show good correlation. However, complexation shifts (the chemical shift difference between the free and complexed borane or ligand) and various spin-spin coupling constants correlate better with calorimetric data, especially for ligands or boranes belonging to structurally similar series (Table 2).10,24... 

The forcefield has been successfully extended to treat fluorocarbons and chlorofluorocarbons in faujasite zeolites [13]. (N,V,T) Monte Carlo simulations on the adsorption of a series of fluoro-, chlorofluoro- and hydrofluoro-carbons (CF CF,C1, CF,C1, CFC1, CHFj) in siliceous Y and NaY zeolites were performed and compared with available calorimetric data on the same host-guest systems. They predict adsorption heats with good accuracy (Table 3), while yielding a first validation of our forcefield parameters. 

Table 16.3 Summary of optical and calorimetric data for the duplex melting of d(CGCGAATTCGCG) at different salt and... 

For the purposes of fitting microcalorimetric data, one equation is perhaps of more interest than most. That is the Ng equation (19), given in Table 4, which is stated to describe all two-state solid phase reactions. If the calorimetric form of the Ng equation is used to fit suitable calorimetric data then it is possible, from knowledge of the values of the constants m and n, to infer... 

A characteristic feature of the hydrophobic interaction is that it is dominated by entropy effects. Both the temperature dependence of alkane solubilities in water126,127) and direct calorimetric measurements128 show that Iihf is close to zero at room temperature. Some calorimetric data for heats of solution of hydrocarbons in water are shown in Table 3.2. A further noticeable feature is that Iihf is temperature dependent due to the rather large heat capacity, Cp F, associated with the hydrophobic interaction. From a systematic calorimetric study of a series of compounds with rather short alkyl chains129 it was found that... 

The most reliable calorimetric data on the enthalpy of dissolution of various nonpolar gases, the noble gases and hydrocarbons, are collected in Table II. The very small gaseous molecules (helium and neon) were not included. The surface area of the considered molecules, As, have been calculated from the known spatial structure of the molecule and represented either in terms of A2 or the number of contacting water molecules, Nt, assuming that each water molecule occupies an area of about 9 A2 (Hermann, 1972). The direct correlation between the enthalpy of dissolution of a gas in water, A H, and the surface area of the solute molecule, At, or the number of water molecules contacting the solute molecule, Ns, is seen from column flve in Table II. 

The calorimetric data obtained for the addition of water and ether to acid solutions are summarized in Tables I and II, respectively. The addition of water or ether (R20) to the solutions of acid (HA) in sulfolane gives rise to a series of reactions. We have considered the following... 

Two typical sets of the calorimetric data are presented in Table IV. The enthalpies of complexation were calculated as described previously (6). The heat of dilution of the lanthanide perchlorate was checked by titrating two of the lanthanides (/ = IM, pH = 3.0) with NaC104 (jn = IM, pH = 3.0). No heat was observed. The heat of dilution of the sodium fluoride was checked by titrating IM NaC104 (pH = 3.0) with NaF fx = IM, pH = 3.0). A small heat of dilution was observed for the first two points in the titration after this it was negligible. The heats of dilution of the sodium fluoride were accounted for in the calculations. 

Calorimetric data for human aFGF at neutral pH (50 mM HEPES, 0.5 mM DTT and 2 mM EDTA) with and without the addition of 10 mM Phosphate or Sulfate ion, are listed in table I. Also listed in this table are the calorimetric data for the addition of 0.6 M GuHCl to phosphate buffered saline (plus 0.5 mM EDTA and 2.0 mM DTT) in the presence of 10 mM (NH4)2S04. 

Botli tile classical and statistical equations [Eqs. (5.40) and (16.20)] yield absolute values of entropy. As is evidentfrom Table 16.3, good agreementbetween the statistical calculations and those based on calorimetric data is obtained. Results such as these provide impressive evidence for tile validity of statistical mechanics and quantum theory. In some instances results based on Eq. (16.20) are considered more reliable because of uncertainties in heat-capacity data or about tlie crystallinity of the substance near absolute zero. Absolute entropies provide much of tile data base for calculation of the equilibrium conversions of chemical reactions, as discussed in Chap. 13. 

Valentine (1.)] used low-temperature calorimetric data to derive the ideal gas entropy at the normal boiling point of 190.97 K. The experimental value of 57.18 cal K mol is in good agreement with 57.216 cal K mol obtained from this table. Schwing ( ) measured C for CHFg vapor (25-100 C) and confirmed that the vibrational assignment is adequate. 

AjG data for B-TiO are reviewed on the table for a-TiO (9). Values of A H derived from a G" depend on the value of S (see Entropy). There are additional references on the A G which deserve comment. Solid-state emf data of Hoch et al. ( ) are insufficient to yield AjG (B), especially in the direct way used by Drowart et al. (19). Their interpretation is inconsistent with phase diagrams (, 1 ) and extensive emf data (7) which show bivariant behavior in which A C(02) is a strong function of (0/Tl). It is not useful to reinterpret the emf data ( 8) they show a temperature dependence of the wrong sign and we do not know the necessary electrode compositions. The often quoted A G of Kubaschewski and Dench (2 1) is not an independent value since it assumes the correctness of the calorimetric data of the Bureau of Mines (, 1 ). Kubaschewski s reassessment (, 8) of... 

The dependence of the curvature of the freezing point curve at the origin upon the entropy of fusion of the solvent was first pointed out by van Laar. The most common case corresponds to (22.17) and fig. 22.1 (c/. chap. XIV, 5, table 14.6). On the other hand, for spherical solvent molecules (c/. table 14.5) for which the entropy of fusion is abnormally small, the case (22.18) is realized. The form of the freezing point curve at the origin is thus a useful criterion, in the absence of calorimetric data, for the identification of those compounds which have a low entropy of fusion, f... 

Calculated values for the heat of the homogeneous process (Table III) are close to 68 kcal/mole for cycle 1 (formation of adsorbed carbon dioxide) but not for cycle 2 (formation of gaseous carbon dioxide). It is, therefore, concluded from the calorimetric data, that the interaction between carbon monoxide and oxygen ions adsorbed on NiO(200°) yields adsorbed carbon dioxide exclusively. 

It ought to be remarked that, in both cases, the quantity of carbon monoxide which interacts with C03"(ads) ions (second adsorption of carbon monoxide. Table V) is not large enough to convert all C03 (ads) ions into carbon dioxide. This was explained, in the case of NiO(200°) by the stability of C03"(ads) ions formed on the most active sites of the surface when the heat produced is 134 kcal/mole. In the case of NiO(250°), calorimetric data do not explain the nonreactivity of a fraction of C03 (ads) ions. However, calorimetric curves (for examples of such curves, see Figs. 34 and 36), as well as the variation of the electrical conductivity of the sample with time (25), show that, in both cases, interaction (7) is very slow compared to interaction (5a). We believe therefore that the nonreactivity of a fraction of C03"(ads) ions is related to equilibrium of interaction (7). The conversion of C03 (ads) by carbon monoxide into carbon dioxide is indeed increased for an increased pressure of carbon monoxide (42). 

Table 1. Comparison of Photoionization Mass Spectrometric and Calorimetric Data on KrF2 and XeF2...

The authors also measured the enthalpy change of the reaction between AgN03(cr) and a solution of sodium selenite with formation of crystalline silver selenite as verified by chemical analysis and X-ray diffraction. The calorimeter was calibrated by electrical resistance heating. The calorimetric data are evaluated in Table A-25. 

Crystalline K2Se03 was prepared and chemical analysis of the very hygroscopic substance agreed reasonably well with the expected composition for K2Se03. A specimen of the preparation was reacted with a lead nitrate solution in an electrically calibrated calorimeter. Crystalline PbSeOs was formed. The calorimetric data have been used to estimate the enthalpy change of the reaction K2Se03(cr) -i- Pb PbSe03(cr) -i- 2K in Table A-60. 

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