Show that if the polymer fiber of Problem 6.26 is to be thermodynamically stable at all temperatures, the parameters α, β, and γ must be positive.

Problem 6.26

Nitrogen is to be isothermally compressed at 0°C from 1 bar to 100 bar. Compute the work required for this compression; the change in internal energy, enthalpy; Helmholtz and Gibbs energies of the gas; and the heat that must be removed to keep the gas at constant temperature if

a. The gas is an ideal gas. 

b. The gas obeys the virial equation of state

c. The gas is described by the van der Waals equation

d. The gas is described by the Peng-Robinson equation of state.

Transcribed Image Text:

PV RT 1+ B V C V² with B = -10.3 x 10-6 m³/mol and C = 1517 x 10-12 m6/mol².