A state of matter is a condition in which any matter may exist. In the field of physics, there are four fundamental states of matter that have been analyzed for years, including solid, liquid, plasma, and gas (Goodstein, 2014). There are also the states of matter that may exist only in some extreme situations (Fortov, 2016). Each of them has its own properties and characteristics. In this paper, gas is the state of matter for analysis. Its peculiar feature is a vast separation of particles. Still, the list of its properties is huge, and many researchers continue making their contributions to the fields of chemistry, physics, and other natural sciences and explaining how to investigate this state of matter.
Hu and Dai (2015) introduced an article “A new equation of state for studying the thermodynamic properties of real gases” where they used the compressibility effects of gases in order to develop and validate a new equation of state. The researchers made a decision to investigate the thermodynamic properties of such gases as methane, ethane, carbon dioxide, and oxygen and proved a good agreement of the gas properties with the reference at the pressure (Hu & Dai, 2015). The chosen article is interesting and informative for different readers due to the possibility to combine past and present studies, use the state of matter laws, and check the interaction of molecules of several gases. The benefits, shortages, and further implications of the article will be discussed in this paper.
Strengths
The structure of the article is one of its strongest aspects. The authors aimed not only at developing a new formula and explaining its importance in the fields of physics or chemistry but also at helping the reader to understand why this new three-parameter cubic equation of state was required. To strengthen the article, a certain attention was paid to the thermodynamic properties of gases and the way of how these properties were discussed in the Ideal Gas Law that was represented through the following formula: pV = RT. To make sure that the formula under discussion was clear to the reader, Hu and Dai (2015) explained each element, including p as pressure, V as molar volume, T as absolute temperature, and R as a universal gas constant. Due to the fact that molecular volume and interactions are not negligible for real gases, the authors used the past investigations of van der Waals and the offered equation of state where the size of molecules was taken into consideration and promoted the creation of such formula: (p + a/V2)*(V – b) = RT. There are two new parameters, including a – the molecular interactions, and b – the size of molecules (Dahm & Visco, 2015). It seems that the work of this scientist inspired Hu and Dai to make their own contribution to the science fields.
The most interesting part of the article began when the authors started discussing the effect of compressibility on gases and the level of pressure that may be used. It was proved that the volume correction could not stay constant due to the compressibility effect. This effect also depended on intermolecular force and the potential that had nothing in common with temperature (Hu & Dai, 2015). New assumptions were made to include the compressibility effect of gas molecules, and a new equation was offered with a new parameter c, constant that may be fitted from experimental data: (p + a/V2)*(V – b + c*p) = RT (Hu & Dai, 2015). With the help of this formula, it turned out to be possible to clarify some issues of the complicated behavior of the real gas and the effects of pressures on the interactions between gas molecules.
Possible Shortages
Regarding a close connection and similarities with the van der Waals’ formula, it is possible to say that Hu and Dai were not able to identify some extremely new aspects of the thermodynamic properties of gases. Similar components, the same method of calculation, and almost identical results may not impress the reader but prove the fact that has been already known. Such development of the events may be defined as the shortage of this article and question its uniqueness in research. However, this formula and a three-parameter cubic equation of state is the contribution that cannot be neglected. The study of thermodynamic properties of real gases has been improved. Clear information was given. The assumptions were proved. Though the article is not too long and mainly consists of the thoughts of the researchers, it could be improved by the use of additional sources.
Still, it is necessary to admit that new terms and definitions, as well as the use of new research and studies, may significantly influence the article and make it hard to read and understand. For example, Lo, Cessou, Bourbert, and Vervisch (2014) developed an article with a theoretical model and a number of tables and figures. Though a scientific worth of this article is great, not all readers can understand its essence and use all the ideas in a proper way. Therefore, a simple still credible and clear approach used by Hu and Dai cannot be neglected.
Further Implications
Despite a number of the existing ways to use or improve this article, its importance remains to be great. Many researchers are eager to use this formula and check their assumptions, and many scientists may benefit with this approach. For example, it is possible to combine the article under discussion with the article written by Mahmoud (2014) who also paid his attention to the factor of gas compressibility. The real gas system is complicated, and it is wrong to choose one direction and follow it all the time. It is better to discover some new ways of research even if they distinguish from other studies in one or two aspects only. Gas properties are numerous, and Hu and Dai focused on its thermodynamics proving that high pressures can change the function of gases in different ways. Its particles and may work independently and mutually, and the interaction of gas molecules under different conditions is what has to be studied in future.
Conclusion
In general, Hu and Dai’s article has clear formulas and explanations, illustrative materials, and comparisons which make it informative and educative for different readers. It is not enough to introduce new parameters and develop a formula. The authors succeeded in explaining and proving the unique nature of gases that can be exposed to higher pressures. The results of this study can be used either as separate research based on thermodynamic properties or as a part of bigger research that is devoted to the topic of the state of matter that is frequently used and developed in chemistry, physics, and natural sciences.
References
Dahm, K.D., & Visco, D.P. (2015). Fundamentals of chemical engineering thermodynamics. Stamford, CT: Cengage Learning.
Fortov, V. E. (2016). Thermodynamics and equations of state for matter: From ideal gas to quark-gluon plasma. Hackensack, NJ: World Scientific Publishing.
Goodstein, D.L. (2014). States of matter. Mineola, NY: Dover Publications.
Hu, S., & Dai, W. (2015). A new equation of state for studying the thermodynamic properties of real gases. Physics and Chemistry of Liquids, 53(1), 138-145. Web.
Lo, A., Cessou, A., Boubert, P., & Vervisch, P. (2014). Space and time analysis of the nanosecond scale discharges in atmospheric pressure air: I gas temperature and vibrational distribution function of N2 and O2. Journal of Physics D: Applied Physics, 47(11). Web.
Mahmoud, M. (2014). Development of a new correlation of gas compressibility factor (Z-factor) for high pressure gas reservoirs. Journal of Energy Resources Technology, 136(1). Web.