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Purpose of thermodynamics

It is therefore legitimate to postulate, for the purposes of thermodynamic reasoning, ideal septa each of which is permeable to one gas but quite impervious to all others. Such septa are called semipermeable septa. [Pg.272]

The n vs A curves obtained are shown in Figure 7. It is seen that the condensed state is realized in a very small mole fraction range. This might be attributed to the electrostatic repulsion between dodecylammonium ions. The curves in Figure 7 are more appropriate than those in Figures 6(a) and 6(b) for the purpose of thermodynamic considerations at the interface. [Pg.319]

For purposes of thermodynamic analysis, we consider the following 4 parts of the process ... [Pg.616]

In the last row are values calculated with the aid of the formula of Lindemann and myself (61), and given as the most probable values at that time. Here the agreement with Onnes may well be regarded as ample for most purposes of thermodynamical calculation. [Pg.52]

For the purposes of thermodynamic calculations, a chemical reaction represents a process in which, reactants, on the left-hand side of the reaction equation, are converted into products on the right-hand side. For example, for the formation of ammonia by reaction between nitrogen and hydrogen we write. [Pg.496]

In chemistry, the most important purpose of thermodynamics is to determine the equilibrium point of a chemical reaction and to predict whether a reaction is spontaneous under defined conditions. Thermodynamics cannot supply any information on the rate at which the reaction takes place. [Pg.52]

The mesoscopic and macroscopic models come with a number of parameters, for example, mean field potentials, friction coefficients, effective relaxation times, and so on, whose connection with molecular terms is not straightforward. It is the purpose of thermodynamically guided, systematic coarse-graining methods to address this... [Pg.360]

We continue with a brief outline of the Purpose of thermodynamics, i.e. the role that thermodynamics plays in the Chemical and Petroleum Industries, and close with a series of Examples that give a brief preview of the type of problems to be addressed in future Chapters. [Pg.2]

Remarks The aim here was not the description of the mechanism of the real methanol synthesis, where CO2 may have a significant role. Here we created the simplest mechanistic scheme requiring only that it should represent the known laws of thermodynamics, kinetics in general, and mathematics in exact form without approximations. This was done for the purpose of testing our own skills in kinetic modeling and reactor design on an exact mathematical description of a reaction rate that does not even invoke the rate-limiting step assumption. [Pg.225]

By measuring the retention volume of a solute, the distribution coefficient can be obtained. The distribution coefficient, determined over a range of temperatures, is often used to determine the thermodynamic properties of the system this will be discussed later. From a chromatography point of view, thermodynamic studies are also employed as a diagnostic tool to examine the actual nature of the distribution. The use of thermodynamics for this purpose will be a subject of discussion in the next chapter. It follows that the accurate measurement of (VV) can be extremely... [Pg.28]

Supply air Treated or untreated air entering the space. For the purpose of drawings it is color-coded to show the various thermodynamic treatments. [Pg.1479]

The existing books cover the simple, rather than the advanced, theoretical approaches to interfacial systems. This volume should fill this gap in the literature. It is the purpose of this volume to serve as a comprehensive reference source on theory and simulations of various interfacial systems. Furthermore, it shows the power of statistical thermodynamics that offers a... [Pg.958]

Sadi Carnot has been called the founder of the science of thermodynamics, In 1824, when he was twenty-eight, he first became interested in steam engines. All that time. Great Britain led the world m the design and improvement of such engines for industrial purposes. Always the French patriot, Carnot wanted his counti y to surpass the British, who had spawned the Industrial Revolution. He thought... [Pg.219]

It must be remembered that all these functions were introduced for the purpose of simplifying the mathematical operations, just as were the energy and entropy functions in the earlier stages of thermodynamics. It is only their changes which admit of physical measurement these changes can be represented as quantities of heat and external work. [Pg.102]

For the purpose of interpretation, various hypotheses have been built up around the results which have been derived from the two laws of thermodynamics. It must not be forgotten, however, that the deductions of thermodynamics would stand quite firm if the whole hypothetical system collapsed about them. [Pg.513]

If the present volume will help towards the comprehension of the fundamental principles on which the science of thermodynamics rests, and also serve to bring home the importance of a knowledge of these principles in the suggestion and interpretation of experimental work, the purpose which has been kept in view during its preparation will have been amply fulfilled. In any case, it is hoped that neither the extreme view that thermodynamic principles alone suffice in the construction of a systematic physical or chemical science, nor the equally mistaken opinion that they are of little practical utility to the experimental worker, can fairly result from its study. [Pg.562]

For purposes of simulation and illustration we have chosen a batch reactor, solution polymerization of methylmethacrylate (MMA). Kinetic data were taken from Schmidt and Ray (1981) and thermodynamic data from Bywater (1955). We do not here consider the influence of diffusion control on the termination or other rate processes because such effects may be small when in a solution which is siifHciently dilute or when the polymer is of low molecular weight. [Pg.323]

For the purpose of illustrating the application of the thermodynamic equation of state to experimental data, consider the plot given in Fig. 84 for the retractive force, measured at fixed length, against the absolute temperature for a hypothetical elastic substance. The slope at any temperature T gives the important quantity —(dS/dL)T,p according to Eq. (12) an increase in / with T at constant L shows immediately, therefore, that the entropy decreases with increase in length... [Pg.442]

The formal thermodynamic analogy existing between an ideal rubber and an ideal gas carries over to the statistical derivation of the force of retraction of stretched rubber, which we undertake in this section. This derivation parallels so closely the statistical-thermodynamic deduction of the pressure of a perfect gas that it seems worth while to set forth the latter briefly here for the purpose of illustrating clearly the subsequent derivation of the basic relations of rubber elasticity theory. [Pg.464]

The purpose of this compilation is to tabulate the densities of compounds, hence only minimal description of experimental methods used to measure the density of liquids or solids appears. Detailed descriptions of methods for density determination of solids, liquids and gases, along with appropriate density reference standards, appear in a chapter by Davis and Koch in Physical Methods of Chemistry, Volume VI, Determination of Thermodynamic Properties [86-ros/bae],... [Pg.8]

Principal component regression (PCR) is an extension of PCA with the purpose of creating a predictive model of the Y-data using the X or measurement data. For example, if X is composed of temperatures and pressures, Y may be the set of compositions that results from thermodynamic considerations. Piovoso and Kosanovich (1994) used PCR and a priori process knowledge to correlate routine pressure and temperature measurements with laboratory composition measurements to develop a predictive model of the volatile bottoms composition on a vacuum tower. [Pg.35]

The present theory can be placed in some sort of perspective by dividing the nonequilibrium field into thermodynamics and statistical mechanics. As will become clearer later, the division between the two is fuzzy, but for the present purposes nonequilibrium thermodynamics will be considered that phenomenological theory that takes the existence of the transport coefficients and laws as axiomatic. Nonequilibrium statistical mechanics will be taken to be that field that deals with molecular-level (i.e., phase space) quantities such as probabilities and time correlation functions. The probability, fluctuations, and evolution of macrostates belong to the overlap of the two fields. [Pg.4]

It is not the purpose of chemistry, but rather of statistical thermodynamics, to formulate a theory of the structure of water. Such a theory should be able to calculate the properties of water, especially with regard to their dependence on temperature. So far, no theory has been formulated whose equations do not contain adjustable parameters (up to eight in some theories). These include continuum and mixture theories. The continuum theory is based on the concept of a continuous change of the parameters of the water molecule with temperature. Recently, however, theories based on a model of a mixture have become more popular. It is assumed that liquid water is a mixture of structurally different species with various densities. With increasing temperature, there is a decrease in the number of low-density species, compensated by the usual thermal expansion of liquids, leading to the formation of the well-known maximum on the temperature dependence of the density of water (0.999973 g cm-3 at 3.98°C). [Pg.25]

Computing thermodynamic properties is the most important validation of simulations of solutions and biophysical materials. The potential distribution theorem (PDT) presents a partition function to be evaluated for the excess chemical potential of a molecular component which is part of a general thermodynamic system. The excess chemical potential of a component a is that part of the chemical potential of Gibbs which would vanish if the intermolecular interactions were to vanish. Therefore, it is just the part of that chemical potential that is interesting for consideration of a complex solution from a molecular basis. Since the excess chemical potential is measurable, it also serves the purpose of validating molecular simulations. [Pg.323]


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See also in sourсe #XX -- [ Pg.20 , Pg.21 , Pg.22 , Pg.23 ]




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