Technology & Engineering
Entropy of Mixing
Entropy of mixing refers to the measure of disorder or randomness that occurs when different substances are mixed together. It is a concept in thermodynamics that quantifies the extent of mixing in a system. When substances are mixed, the entropy of the system increases, reflecting the increase in disorder and the tendency of the system to move towards a more disordered state.
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6 Key excerpts on "Entropy of Mixing"
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
Energy dispersal The concept of entropy can be described qualitatively as a measure of energy dispersal at a specific temperature. Similar terms have been in use from early in the history of classical thermodynamics, and with the development of statistical thermodynamics and quantum theory, entropy changes have been described in terms of the mixing or spreading of the total energy of each constituent of a system over its particular quantized energy levels. Ambiguities in the terms disorder and chaos , which usually have meanings directly opposed to equilibrium, contribute to widespread confusion and hamper comprehension of entropy for most students. As the second law of thermodynamics shows, in an isolated system internal portions at different temperatures will tend to adjust to a single uniform temperature and thus produce equilibrium. A recently developed educational approach ________________________ WORLD TECHNOLOGIES ________________________ avoids ambiguous terms and describes such spreading out of energy as dispersal, which leads to loss of the differentials required for work even though the total energy remains constant in accordance with the first law of thermodynamics (compare discussion in next section). Physical chemist Peter Atkins, for example, who previously wrote of dispersal leading to a disordered state, now writes that spontaneous changes are always accompanied by a dispersal of energy. Relating entropy to energy usefulness Following on from the above, it is possible (in a thermal context) to regard entropy as an indicator or measure of the effectiveness or usefulness of a particular quantity of energy. This is because energy supplied at a high temperature (i.e. with low entropy) tends to be more useful than the same amount of energy available at room temperature. Mixing a hot parcel of a fluid with a cold one produces a parcel of intermediate temperature, in which the overall increase in entropy represents a “loss” which can never be replaced.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- White Word Publications(Publisher)
Energy dispersal The concept of entropy can be described qualitatively as a measure of energy dispersal at a specific temperature. Similar terms have been in use from early in the history of classical thermodynamics, and with the development of statistical thermodynamics and quantum theory, entropy changes have been described in terms of the mixing or spreading of the total energy of each constituent of a system over its particular quantized energy levels. Ambiguities in the terms disorder and chaos , which usually have meanings directly opposed to equilibrium, contribute to widespread confusion and hamper comprehension of entropy for most students. As the second law of thermodynamics shows, in an isolated system internal portions at different temperatures will tend to adjust to a single uniform temperature and thus produce equilibrium. A recently developed educational approach avoids ambiguous terms and describes such spreading out of energy as dispersal, which leads to loss of the differentials required for work even though the total energy remains constant in accordance with the first law of thermodynamics (compare discussion in next section). Physical chemist Peter Atkins, for example, who previously wrote of dispersal leading to a disordered state, now writes that spontaneous changes are always accompanied by a dispersal of energy. Relating entropy to energy usefulness Following on from the above, it is possible (in a thermal context) to regard entropy as an indicator or measure of the effectiveness or usefulness of a particular quantity of energy. This is because energy supplied at a high temperature (i.e. with low entropy) tends to be more useful than the same amount of energy available at room temperature. Mixing a hot parcel of a fluid with a cold one produces a parcel of intermediate temperature, in which the overall increase in entropy represents a “loss” which can never be replaced.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Learning Press(Publisher)
Energy dispersal The concept of entropy can be described qualitatively as a measure of energy dispersal at a specific temperature. Similar terms have been in use from early in the history of classical thermodynamics, and with the development of statistical thermodynamics and quantum theory, entropy changes have been described in terms of the mixing or spreading of the total energy of each constituent of a system over its particular quantized energy levels. Ambiguities in the terms disorder and chaos , which usually have meanings directly opposed to equilibrium, contribute to widespread confusion and hamper comprehension of entropy for most students. As the second law of thermodynamics shows, in an isolated system internal portions at different temperatures will tend to adjust to a single uniform temperature and thus produce equilibrium. A recently developed educational approach avoids ambiguous terms and describes such spreading out of energy as dispersal, which leads to loss of the differentials required for work even though the total energy remains constant in accordance with the first law of thermodynamics (compare discussion in next section). Physical chemist Peter Atkins, for example, who previously wrote of dispersal leading to a disordered state, now writes that spontaneous changes are always accompanied by a dispersal of energy. ________________________ WORLD TECHNOLOGIES ________________________ Relating entropy to energy usefulness Following on from the above, it is possible (in a thermal context) to regard entropy as an indicator or measure of the effectiveness or usefulness of a particular quantity of energy. This is because energy supplied at a high temperature (i.e. with low entropy) tends to be more useful than the same amount of energy available at room temperature. Mixing a hot parcel of a fluid with a cold one produces a parcel of intermediate temperature, in which the overall increase in entropy represents a “loss” which can never be replaced.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
______________________________ WORLD TECHNOLOGIES ______________________________ Chapter 13 Entropy Ice melting in a warm room is a common example of increasing entropy, described in 1862 by Rudolf Clausius as an increase in the disgregation of the molecules of ice. Entropy is a thermodynamic property that is a measure of the energy not available for useful work in a thermodynamic process, such as in energy conversion devices, engines, or machines. Such devices can only be driven by convertible energy, and have a theoretical maximum efficiency when converting energy to work. During this work entropy accumulates in the system, but has to be removed by dissipation in the form of waste heat. ______________________________ WORLD TECHNOLOGIES ______________________________ The concept of entropy is defined by the second law of thermodynamics, which states that the entropy of a closed system always increases or remains constant. Thus, entropy is also a measure of the tendency of a process, such as a chemical reaction, to be entropically favored , or to proceed in a particular direction. It determines that thermal energy always flows spontaneously from regions of higher temperature to regions of lower temperature, in the form of heat. These processes reduce the state of order of the initial systems, and therefore entropy is an expression of disorder or randomness. This model is the basis of the microscopic interpretation of entropy in statistical mechanics describing the probability of the constituents of a thermodynamic system to be occupying accessible quantum mechanical states, a model directly related to the information entropy. Thermodynamic entropy has the dimension of energy divided by temperature, and a unit of joules per kelvin (J/K) in the International System of Units. The term entropy was coined in 1865 by Rudolf Clausius based on the Gr eek εντροπία [entropía], a turning toward , from εν - [en-] (in) and τροπή [tropē] (turn, conversion).
eBook - PDFBios: A Study Of Creation (With Cd-rom)
A Study of Creation (With CD-ROM)
- Hector Sabelli(Author)
- 2005(Publication Date)
- World Scientific(Publisher)
These assumptions seem acceptable to some physicists. 11.1 Definition of Entropy The term entropy has been given many different and contradictory definitions. 3 Currently, some scientists and most laymen use the term to mean disorder, while many other scientists regard entropy as a measure of complexity (e.g. of an ecological community). In the course of its history, the term entropy, meaning transformation in Greek, has been given four distinct meanings: physical, statistical, informational, and philosophical. (1) Physical entropy: The physical concept of entropy emerged in the 19 th century from work on the efficiency of steam engines 4 and was heated by national rivalry. 5 Thermodynamics defines the change AS in entropy S, AS = dQ/T, (ll.l) in which dQ is the flow of heat, and T is the absolute temperature. The second law postulates dS>0, (11.2) where 0 occurs when there is no action. Actions are never at equilibrium (although standard thermodynamics assumes that they can be), and whenever there is a change in heat, there must be a change in temperature (although the definition of entropy asks us to assume that there is none). Note that only changes in entropy can be measured; 3 Bunge, M. (1986). Review of C. Truesdell Rational Thermodynamics. Philosophy of Science 53:305-3-6; Corning, P. A. and Kline S. (1998). Thermodynamics, Information and Life Revisited, Part I: 'To Be or Entropy'. Systems Research and Behavioral Science 15: 273-295. 4 The modern steam engine was invented by the English military engineer Thomas Savery in 1698; its efficiency was improved by the Scottish engineer James Watts, who made a fortune charging his customers a percentage of the cost of maintaining the number horses necessary to perform the same task (hence the expression horsepower).
eBook - PDF- Lokesh Pandey(Author)
- 2020(Publication Date)
- Arcler Press(Publisher)
This can be understood as the distribution of the thermal energy among the thermal microparticles that may be moving randomly in space. The entropy can be considered as the measure of the thermal energy in its random and redistributed form which has been integrated over a certain range of temperature. The redistribution may have taken due to the transfer of heat or a heat generation which is irreversible in nature and has taken place due to the degradation of energy. The generation of heat may have more than one aspect to look forward to and may be elusive in nature. This redistribution may take place within a structure of material system in space as per the absolute temperature level and may be given by: dS = dQ sys /T = m C sys dT/T The unit of this may be J/K. The entropy of a system may also be given as the measure of the thermal disorder which is given in relation to the logarithm of the number of all the thermal and dynamic microstates, given by W, which is based on the position and the moment of the microparticles and expressed as S = k B ln W Some people like to introduce the concept of entropy as the measure of the disorder or the randomness and state that the destruction of entropy is brought about when some order is created, giving the example of the manner in which life evolved. However, it may be noted that at the time of any of the processes, which may be natural or man-made and which may be of creating or destroying any order or disorder, that is the transformation of any structure of material, the work potential may be regarded as always being dissipated into heat and in such a case the generation of entropy will always be there.
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