Eurasian Science Society (ESS)Journal of Chemistry Letters2821-01231320201101Comparison of bulk modulus as Benzene dense fluid using the LIR equation of state with the extended coefficients and comparison with Peng-Robinson equation of state10311012195210.22034/jchemlett.2021.263746.1012ENMaedehKamelDepartment of Chemistry, Payame Noor University, PB BOX 19395-4697 Tehran, Iran0000-0001-6246-2954KamalMohammadifardDepartment of chemical engineering, Ferdowsi University of Mashhad, Mashhad, IranJournal Article20201225New parameters of the linear isotherm regularity, the so-called LIR equation of state, are used to calculate the bulk modulus of dense fluids. In this work, we drive an expression for the bulk modulus of dense fluids (CO, C6H6, C6H5CH3) using the linear isotherm regularity (LIR). In later stages, bulk modulus calculated by Peng - Robinson (PR) equation of state as a test of the other equation of state. Comparison of the calculated values of bulk modulus with the extended coefficients of the linear isotherm regularity with the values obtained experimentally shows the accuracy of this method to be is general, quite good.https://www.jchemlett.com/article_121952_2593e022bf5ec78e9681724d7779df23.pdf