Benedict-Webb-Rubin constants and hydrogen?

Question

Hi everybody,

I searced the most popular thermodynamics book but every of them include constants for only 5 gas (n-butane, CO2, CO,CH4 and N2)...

I need hydrogen right now but I wonder the other gas either...for ex., O2, H2O(vapor), etc...

why there is no constant about these gaseous?

Thank you ...

Answer 1

I believe it has to with the fact that the assumptions made about the mathematical form of intermolecular forces for certain gases allows you to develop theoretical expressions for each of the coefficients or constants in the Benedict-Webb-Rubin equation of state.

However, the assumptions made for calculating those constants for gases such as n-butane, CO2, CO,CH4 and N2 are most likely NOT applicable to H2, H2O, or O2.