This article is looking at the concept of entropy in four different ways. According to the author, increase in the total entropy of one system and its surroundings may be the main cause of physico-chemical processes’ change. This means that the methods that we employ when carrying out a certain experiment and the conditions of the environment that surrounds that experiment are the ones that determine the outcome that we will get. The article proves this by providing some four different presentations.
The author then says that for all those processes that take place in a very normal condition such as the temperature and pressure, calculations are usually done using the normal Gibbs Free Energy Formula usually presented as ? G T, P < 0. Then there are the laws of dynamics where the second law governs all the spontaneous changes that are taking place in the process. It also governs the equilibrium point in the process. According to Craig, (1998), the first of these laws happens to be bookkeeping relationships, which involves exchange of energies between different parts of the environment and the reactive system.
Unlike in the second law, this first law has the equation containing an equal sign and this is an indication that energy is neither lost nor gained in the whole process. According to the author, this balance is because of an equal and opposite energy change experienced at the thermal reservoir with that experienced at the reactive system. Considering an entropy analysis of a chemical reaction, the process takes advantage of the characteristics that allow the formation of SO2 and SO3.
The two oxides happen to have relative stabilities at different temperatures and according to the author, this is the main method applied in formation of sulfuric acid and acid rain. The author also says that in some cases or rather in some temperature regime, the formation of favored product happen is usually facilitated by total entropy increase. (Craig, 1998) The second experiment employing the same concept is the heat engine. In this case, fuel burnig reactions provide the high temperature reservoirs with thermal energy.
To make use of entropy, the engine happens to have four different subsystems, which happen to have different conditions. There is a thermal reservoir with high temperature, another one with low temperature, an energy coupling device and a mechanical energy subsystem. Then there is the third experiment, which involves the dissolution of a solid in an ideal solvent. This solvent meets all the conditions that would make such dissolution react without any interference. This can be divided into two, which is the finite change in which case there is the formation of a completely new product.
In this case, the first step is the melting of the solid and then it mixes with the solvent while in liquid form. In this case, there is an entropy increase in the whole process. Then there is the second part, which is the differential change in which case one there is the production of a solution that is saturated. In this case, there is only entropy of mixing and there is no entropy of mixing. (Craig, 1998) Then there is the last of the four experiments that were to discuss entropy analysis and it is osmosis.
In this case, there is pure solvent passing through a membrane that is semi-permeable from region of low pressure to region of high pressure. This process goes on until a time when we obtain equilibrium through excess pressure and osmotic pressure impositioning on the solution phase. The reason why there is osmotic pressure is the fact that a column of the solution that has a higher gravitational field exists. It therefore has increased pressure. (Norman, 1992) Using the examples it is clear that entropy analyses can be applied different physico-chemical processes.
However, all these processes are familiar processes and they use application of the second law of thermodynamics. It is also clear that entropy analysis goes beyond the normal Gibbs analysis for spontaneous change. In my opinion, this is very difficult topic in the subject of chemistry. However, the author of the article has presented the topic in a good way such that one will fully understand entropy analysis. I would recommend the article to all those persons who have the passion for science and specifically to those students who are taking chemistry in school.
The article will help them to properly understand entropy and relate it to their daily life. According to the information that presented in this report, it is clear that the author did a thorough and viable study before writing it. He presented every detail precisely and this is a clear indication that he understood what he was doing. Other recommendable books to read are the previous book by the same author by the name of “Entropy Analysis: An Introduction to Chemical Thermodynamics” and the most recent book by Scafetta, under the title “Fractal and Diffusion Entropy Analysis of Time Series” (Scafetta, 2010)
However, I believe that the article is too scientific and may be difficult for any person without the basics of chemistry. In fact, with just the basics chemistry knowledge, it might be very difficult to understand what the author is trying to say. I believe that he would have presented the information in a more direct way and simpler way. He would have offered more information on some of those experiments rather than just stating the equations and a short explanation. Nevertheless, I can still say that though the conclusion is very short, the author supported it well using the four experiments presented.
This system would also have been studied using other real life examples such as distillation which are more available and which can be carried out in a laboratory. It may be difficult to carry out a practical example of a heat engine, as it might be very expensive. ? References Craig, N. (1998). Entropy Analyses of Four Familiar Processes. Oberlin: Oberlin College. Norman, C. (1992). Entropy Analysis: An Introduction to Chemical Thermodynamics. John Wiley & Sons: New York. Scafetta, N. (2010). Fractal and Diffusion Entropy Analysis of Time Series. London: VDM Verlag Dr. Muller Publishers.