Terms used in Thermodynamics

A term used in thermodynamics to designate a region separated from the rest of the universe by definite boundaries. The system is considered to be isolated if any change in the surroundings the portion of the universe outside of the boundaries of the system) does not cause any changes within the system. See Closed System Isolated System Open System... 

Retention Rejection and Reflection Retention and rejection are used almost interchangeably. A third term, reflection, includes a measure of solute-solvent coupling, and is the term used in irreversible thermodynamic descriptions of membrane separations. It is important in only a few practical cases. Rejection is the term of trade in reverse osmosis (RO) and NF, and retention is usually used in UF and MF. 

Terms used in chemical thermodynamics have not been included and reference should be made to Section 20.3. For paint terms, see Section 14.10. 

Some of the terms used in classical thermodynamics which refer to equilibrium states and closed systems have become important outside the boundaries of physics one example is the term adapted state in Darwinian evolution theory, which represents a type of equilibrium state between the organism and its environment. 

The terms adiabatic and nonadiabatic are confusing. Thus, students who approach kinetics at an electrochemical interface via studies of chemistiy will be used to the term adiabatic. In thermodynamics, adiabatic indicates a process in which no heat enters or escapes from the system, e.g., from the vessel in which the reaction... 

In terms of the selectivity to the barrier layers, the peroxide-sluriy SA system can be characterized by its mixture ratio into two zones, as shown in Fig. 1 wliich bears more or less resemblance to the phase diagram widely used in thermodynamics. Zone 1 refers to a system with the mixture ratio below 0.3. The selectivity is greatly larger than 1 and is mixture ratio dependent. While in Zone 2, the selectivity is independent of the mixture ratio and is almost equal to 1. Traditionally, the system is recommended to be used in Zone 2 with a fixed mixture ratio of 0.3 (1 3) in order to make the removal rate and consequently the process as stable as possible. 

We have looked at the meaning of some of the terms commonly used in thermodynamics and how these are interrelated in the three laws of thermodynamics. In particular, we have seen that ... 

This term is somewhat unfortunate since it implies that the Hittorf transference numbers are false. The latter are, however, the values used in thermodynamic relations, and are measures of a perfectly definite, though somewhat complex, process. The term true in this connection is, however, of too general usage to make a change advisable. 

Before proceeding, it is worthwhile to introduce a few of the terms used in applying the balance equations other, more specific thermodynamic terms and dehniiions appear elsewhere in this book. 

The concepts of work and of heat are of fundamental importance in thermodynamics, and their definitions must be thoroughly understood the use of the term work in thermodynamics is much more restricted than its use in physics generally, and the use of the term heat is quite different from the everyday meaning of the word. Again, the definitions are those given by J. A. Beattie. ... 

Any process that will actually take place with no outside intervention is spontaneous in the specialized sense used in thermodynamics. Spontaneous does not mean fast some spontaneous processes can take a long time to occur. In the last section, we used the term energetically favorable to indicate spontaneous... 

There is a wide gap between the way the terms heat and energy are used in initial chemistry education and the way that these concepts are used in thermodynamics. When we try to bridge this gap, to account for students conceptions, we need the outcomes of research in physics education. We have divided the literature in this field into three different parts (i) literature on heat and temperature, (ii) literature on a general energy concept, and (iii) literature on thermodynamics. In the next sub-sections we will briefly review these literatures. 

Comparable to genetic algorithms, there are candidate solutions that are determined in SA by the different states of the system and the energy of the state as the objective function. The control parameter in SA is called temperature, as used in thermodynamics. The Boltzmann constant is termed a cooling parameter, a, which ranges between 0 and 1. 

Both these standard states are used in thermodynamics of solutions (especially the last one also for other concentration units like (molar) concentrations or molalities, see end of this Sect. 4.8) but it is better to discuss them and other standard states in the following terms of fugacities. 

An alternative formulation of the alxtve expressions can be obtained by treating the entropy in terms of the internal energy, volume, and composition, that is, 5( /,K A )- This leads to the entropy formulation of Gibbs fundamental equation and, while not conunonly used in thermodynamics, provides certain advantages in statistic thermodynamics. The following expressions are then obtained ... 

The main independent variables are the temperamre (7), pressure (F), and composition (expressed as number of molecules, for each component molecule species, i, or through the respective molar fractions, or volume fractions, 0,). The principal thermodynamic terms are listed in Table 2.1, whereas Table 2.2 provides values of constants often used in thermodynamic calculations. 

Precise definitions of some of the terms frequently used in thermodynamics is necessary to understand the basic laws and concepts of thermodynamics. 

Prior to addressing various concepts, a limited number of terms often used in thermodynamics will be defined. 

Table 1.2 lists derived units for some additional physical quantities used in thermodynamics. The derived units have exact definitions in terms of SI base units, as given in the last column of the table. 

The units listed in Table 1.3 are sometimes used in thermodynamics but are not part of the SI. They do, however, have exact definitions in terms of SI units and so offer no problems of numerical conversion to or from SI units. 

---