Saturday, January 20, 2007

HW #3, P11.23b - Fugacity of Subcooled Liquid Isobutylene - 8 pts

Estimate the fugacity of isobutylene liquid at its normal boiling point temperature and 200 bar.

Use the SRK EOS to determine the fugacity coefficient of saturated liquid isobutylene at TNBP. Then, use the SRK EOS to estimate the molar volume of saturated liquid isobutylene at TNBP.

4 comments:

Anonymous said...

On this problem you need to start with a vapor pressure for the normal boiling point. I looked up Tn in the book at 266.3 K but there is no corresponding Pn. I was wondering if that means the Tn is referenced to 1 atm, or do I have to apply an EOS to find it?

Dr. B said...

Trump=5 9:52 PM:
Yes. The normal boiling point means at 1 atm.

Anonymous said...

Are we supposed to be getting more than one root? I am just getting one root, and it is in the .8 range. The strange thing is that when I calculated the molar vol I get .091, and then when I calculate the fugacity USING THE SATURATION FORMULA, I get the right answer, but I know this makes no sense.

Dr. B said...

redheadjohn 2:20 PM:
I got 3 real roots. They are about: 0.0044, 0.0288 and 0.9668.
In this problem, we want to estimate the fugacity of a subcooled liquid. So, what we need to know is the fugacity coefficient of the saturateed liquid. That means we are interested in the smallest of the three roots.
If you are not getting 3 roots, then there is most likely something wrong with your A & B...and that usually means a units problem. A ~ 0.0357 and B ~ 0.0034.
I hope this helps.