Orthobaric

Alejandre J, Tildesley D J and Chapela G A 1995 Molecular dynamics simulation of the orthobaric densities and surface tension of water J. Chem. Phys. 102 4574-83... 

Fig. 13.2 Vapor pressures (PV,T) and liquid molar volumes (Vm,T) along the orthobaric LV equilibrium line for reference isotopomer pairs, showing their distinctly different behaviors (schematic). The thicker lines label the heavier isotopomers. The curves begin at the triple points and end at the critical points (except for He which has no triple point under orthobaric conditions). Not to scale, isotopic differences are exaggerated (Reprinted from Van Hook, W. A., Rebelo, L. P. N. and Wolfsberg, M., Fluid Phase Equilib. 257, 35 (2007), copyright 2007, with permission from Elsevier)...

The orthobaric density of incchylmtune has been reported from 0°C to the eritica] temperature.1,1111 The densities ct the other three compounds have been measured Usmii OX to 80X.1111,0144 The Lydersen technique an used to calculate the densities up to the critical point 1 When compared with I 3 experimental points, this method gave an average error ot fl.81 and a maximum error of 2 4X Figure 33-h shows the density of aqueous ethylcnediamine solutions over the 10-... 

Note The volume measured at the same temperature and pressure, i.e., Vv and VL are sometimes known as orthobaric volumes. ... 

Anal Chem 19, 602-3(1947) (Graphical methods for predicting effect of pressure on azeotropic systems 7)M.Lecat, "Tables Azeo-tropiques, tome I (Azeotropes binaires orthobares), Bruxelles (1949) may be obtained from the author 29, rue Auguste Danse, Ucele-Bruxelles, Belgium(Data for 230 azeotropes of nitrocompds with other org compds)... 

Onsager and Fuoss viscosity equation, 125 order in liquids, 1 oriented molecules, 152, 155 0rsted s piezometer, 58 orthobaric density, 48, 327 Oseen correction for falling sphere equation, 87... 

Enthalpy of Formation Pohland (2) has studied the vaporization of SiBr from 260-426 K (0.8-755.5 mm Hg). This vapor pressure data (20 points) is corrected for vapor non-ideality by means of the equation AG /T -R In p - Bp/T. The Berthelot equation of state and critical constants T - 656 K and P 41.3 atm as suggested in the review article by Lapldus et al. (2) are used to calculate B. The recent study on orthobaric densities by Nisei son et al. ( ) reported T = 663 K. The use of this latter value does not signficantly affect the results. 

Johnson and Cubicciotti (6), in their study of the orthobaric densities of NbCl ... 

At its normal boiling point (77.15° C) the orthobaric densities of ethyl acetate are 0.828 (liquid) and 0.00323 (vapor) g. cc. . The rate of change of vapor pressure with temperature in the vicinity of the boiling point is 23.0 mm. deg.-h Calculate the heat of vaporization by (i) the Clapeyron equation, (ii) the Clapeyron-Clausius equation. 

ORTHOBARIC DENSITIES OF PHOSGENE ABOVE STANDARD PRESSURE [739]... 

This statement is, of course, in a contradiction with the conventional mean-field assumption that the orthobaric curve forms a line along which e,s,v all increase monotonically on passing from liquid, through the critical point, to the gas. 

We have applied the model over an extended range of external conditions from the triple point up to the critical point of water. Figure 2.24 compares the experimental " (steam tables) vapor pressures with the calculated ones. The two sets of values are practically identical. Figure 2.25 compares the corresponding values for the orthobaric densities of water. As observed, the density is well described over the full range. 

FIGURE 2.25 Orthobaric densities of water as calculated (line) by tbe cooperativity model. Symbols are experimental data. ... 

These observations are in agreement with the idea that the critical point is a single temperature and not a range of temperatures. It does appear, however, that the coexistence curve for gas and liquid has a very flat top. This is responsible for the rather large differences in critical densities which have been reported. Orthobaric densities for liquid and vapor (Table III) have been determined by Miller et al. (212) from 9° to 43°. In this work liquid sulfur hexafluoride was found to be a good solvent for nitrogen. 

An isochoric equation has been developed for computing thermodynamic functions of pure fluids. It has its origin on a given liquid-vapor coexistence boundary, and it is structured to be consistent with the known behavior of specific heats, especially about the critical point. The number of adjustable, least-squares coefficients has been minimized to avoid irregularities in the calculated P(p,T) surface by using selected, temperature-dependent functions which are qualitatively consistent with isochores and specific heats over the entire surface. Several nonlinear parameters appear in these functions. Approximately fourteen additional constants appear in auxiliary equations, namely the vapor-pressure and orthobaric-densities equations, which provide the boundary for the P(p,T) equation-of-state surface. 

Iteration for Coexisting Densities. Orthobaric densities near the critical point generally cannot be obtained accurately from isochoric PpT data by extrapolation to the vapor-pressure curve because the isochore curvatures become extremely large near the critical point. The present, nonanalytic equation of state, however, can be used to estimate these densities by a simple, iterative procedure. Assume that nonlinear parameters in the equation of state have been estimated in preliminary work. For data along a given experimental isochore (density), it is necessary merely to find the coexistence temperature, Ta(p), by trial (iteration) for a best, least-squares fit of these data. 

Cook, D. The Vapour Pressure and Orthobaric Density of Nitrous Oxide, ... 

To fit the orthobaric densities of caxbon monoxide by the empirical formula... 

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