Cubic equations of state are able to predict the liquid-vapour coexistence curve of volatile substances. However, this property is rarely used to teach Physical Chemistry because solving the resulting equations require numerical technics and many mathematical operations. In this report was shown how the interactive method for finding the root of an equation can be applied with the Excel to determine the vapour pressure of the liquid, as well as the molar volumes of the gas and liquid phases. The generated points was used to build the curves of phase transition in the P ´ V and P ´ T graphics.
Keywords:
Maxwell equal-area rule; vapour pressure; van der Waals equation; Redlich-Kwong equation; iterative method
