6) Using the composition given below, calculate the density (at 4000 Psi and 160 F) of the gas phase and liquid phase by using the Peng-Robinson EOS. Assume kij = 0. C1 C2 C3 C4 C5 C6 C7+ xi 0.45 0.05 0.05 0.03 0.01 0.01 0.4 yi 0.8 0.05 0.05 0.02 0.01 0.005 0.065 ee) The heptane's-plus fraction has the following properties: (M = 215 Pc = 285 psia Tc= 700F W = 0.52)