Calculating entropy using an EOS

Good morning,

I am writing a code to simulating thermodynamic properties, like Winprop, and I am facing a problem in the entropy calculus.

The main problem is, using a EOS is easy to calculate the excess entropy (In my case I am using PR equation), so the entropy is obtained adding the Ideal Gas Entropy:

S = Excess_S + IG_S

So my problem is to calculate the ideal gas entropy. I don't know if I have to calculate the pressure part of the equation, given by ln(p/pref). The thermodyinamical path chosen was the heating of the Ideal Gas, so I believe that the process is made a constant pressure and this term does not exist.

If someone could help me I will be really thankful because I am stopped in this part.

Thanks

Hello. You can post your code here . Also describe the problem in details

[QUOTE=temr;322057]Hello. You can post your code here . Also describe the problem in details[/QUOTE]

Hello,

I have solved my problem yesterday. In the Poling's book (Thermodynamical Properties), it is explained how to calculate the excess entropy of a real substance, and the software is now agreeing with NIST data.

Thanks