Van der Waals Isotherms for Real and Ideal Gases

real gases

Ammonia

Ethanol

Water

Tetrahydrofuran

ideal gases

Xenon

Neon

Helium

Argon

minimum temperature

300

temperature range

700

The van der Waals equation of state,

P=

RT

(

V

m

-b)

-

a

2

V

m

, represents the behavior of real gases in response to pressure, molar volume, and temperature at finite concentrations. The constant

a

stands for the reduction in pressure due to the attractive forces of the molecules and the constant

b

stands for their volume. Ideal gases have smooth isotherms whereas real gases exhibit curious undulations below a certain temperature called the critical temperature.

References

[1] J. H. Noggle, Physical Chemistry, 3rd ed., New York: HarperCollins, 1996.

External Links

Van der Waals Isotherms

Permanent Citation

Kristen Aramthanapon, Wiktor Macura, Chris French

"Van der Waals Isotherms for Real and Ideal Gases"
http://demonstrations.wolfram.com/VanDerWaalsIsothermsForRealAndIdealGases/
Wolfram Demonstrations Project
Published: December 6, 2008