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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Dawek on August 27, 2017, 01:48:44 PM

Title: Physical Chemestry problem - Corresponding States
Post by: Dawek on August 27, 2017, 01:48:44 PM
That problem was taken of McQuarrie Physical Chemestry book, which answer is V ≈ 78.5cm³·mol-1

Use the following figure to estimate the volume of CO at 200K and 180bar. An accurate experimental value is 78.3 cm³·mol-1.
Figure: http://prntscr.com/gdoohm (http://prntscr.com/gdoohm)

Can anyone solve this for me?
Thank you!  ;D
Title: Re: Physical Chemestry problem - Corresponding States
Post by: Borek on August 27, 2017, 02:45:27 PM
Can anyone solve this for me?

No.

Please read the forum rules (http://www.chemicalforums.com/index.php?topic=65859.0).
Title: Gases properties - The Law of Corresponding States
Post by: Dawek on August 27, 2017, 07:21:30 PM
That problem was taken of McQuarrie Physical Chemestry book, which answer is V ≈ 78.5cm³·mol-1

Use the following figure to estimate the volume of CO at 200K and 180bar. An accurate experimental value is 78.3 cm³·mol-1.
Figure: http://prntscr.com/gdoohm (http://prntscr.com/gdoohm)


I know that all gases at corresponding states should behave similary, so  gases at the same reduced pressure and at the same reduced temperature should have the same reduced volume.

Reduced temperature, Tr, and reduced pressure, Pr, can be written as:

Tr = T/Tc = 27RbT/8a
Pr = P/Pc = 27b²p/a

Where a and b are van der Waals parameters.

Pr and Tr are easily taken from the figure, and: Pr/Tr = 8bp/RT

We now Vc = 3b, where Vc é the critical volume. Then, Vc = 3(Pr/Tr) x (TR/8P).

But now have no ideia how could i proceed,i hope anyone to guide me through this problem. If a went wrong above, please tell-me.
Thanks!