Concise Physical Chemistry

c02 JWBS043-Rogers September 13, 2010 11:23 Printer Name: Yet to Come

32 REAL GASES: EMPIRICAL EQUATIONS

p, bar

0 20 40 60 80 100

pV

, dm barm

3

24.3

24.4

24.5

24.6

24.7

24.8

FIGURE 2.10 Quadratic real gas behavior.

Problem 2.1

The van der Waals constants forn-octane (a component of gasoline) area= 37. 81

andb= 0 .2368. FindVfor 1.00 mol ofn-octane confined at 2.0 bar pressure and

450 K.

Problem 2.3

Find all three roots in the previous problem.

Problem 2.4

What are the units of van der Waals constantsaandb?

Problem 2.5

Using commercial graphing software, produce a 3-D plot ofp–V–Tfor the van der

Waals gas N 2 , wherea= 1 .39 andb= 0 .039. What are the units ofaandb? What

happens topasVbecomes very small?