1. Given that the vapor pressure of n-butane at 350 K is 9.4573 bar, please follow the generic cubic equation of state and the recommended initial guess for Z to solve the following problems. (Solver must be used to find the roots. Turn in your spreadsheet as the appendix.) a) At 350 K and 6 bar, what is the physical state of the n-butane, liquid, vapor, or liquid- vapor coexisting? Calculate the molar volumes and the compressibility factor of n- butane at this state by using Redlich-Kwong EOS. (20 points) b) At 350 K and 12 bar, what is the physical state of the n-butane, liquid, vapor, or liquid- vapor coexisting? Calculate the molar volumes and the compressibility factor of n- butane at 350 K and 12 bar by using Peng-Robinson EOS. (15 points) c) At 350 K and 9.4573 bar, find the molar volume and the compressibility factor of the saturated vapor by using Peng-Robinson EOS. (15 points)