In vapor-liquid equilibrium the relative volatility αij is defined to be the ratio of the separation or K factor for species i to that for species j, that is,
αij = Ki/Kj = (yi/xi)/(yj/xj)
In approximate distillation column calculations, the relative volatility is sometimes assumed to be a constant (independent of composition, temperature, and pressure). Test this assumption for the ethanol-ethyl acetate system using the following data:
RT ln γi = 8.163 xj2 KJ/mol
lm PvapEOH = (-4728.98/T) + 13.4643
lm PvapEOH = (-3570.58/T) + 10.4575