23 7.6 From experimental data it is known that at moderate pressures the volumetric equation of state may be written as PV = RT + B P, where the second virial coefficient B is a function of temperature only. Data for methane are given by Dymond and Smith (1969) as, T(K) 120 140 160 200 250 300 350 400 500 1600 B(cm/mole) -284 -217 -169 -133 -107 -67 -42 1-27.0 -15.5 -0.5 8.5 60 | 180 = (a) Identify the Boyle temperature (the temperature at which B = 0) and the inversion tem- perature (the temperature at which (atlP)h = 0) for gaseous methane. (Hint: Plot B versus T-1 and regress a trendline, then differentiate analytically.] (b) Plot these data versus T-1 and compare to the curve generated from Eqn. 7.7. Use points without lines for the experimental data and lines without points for the theoretical curve