Question

Estimate the fugacity of cyclopentane at 110 C and 275 bar. At 110 C the vapor pressure of cyclopentane is 5.267 bar.

This question was solved in chegg. the author used Normal boiling point (Tn) to calculate the reduced temperature (Tnr) and then to find the Saturation volume (Vsat). why didn't he use the given temperature (110 C) instead ?

Answer 1

where f is the fugacity   = fugacity coefficient , P^sat = saturated vapor pressure V = volume and T is temperature

The values at critical conditions are

Tc = critical temperature = 511.8 K

Tn = normal boiling point = 322.4 K

Pc = critical pressure = 45.02 bar

molar volume Vc = 258 cm^3/mol

Zc = 0.273 and acentric factor = 0.196

Here in the final equation T (the factor R * T ) is taken as 110 C but for calculating the above mentioned parameter we have to calculate the critical parameters respectively