NOTES (kap. 1,3,2)

Question 1

What is the van der Waals equation used for?

Answer 1

Real gases exhibit deviations from the ideal gas law. If there were no interactions between
the gas molecules, gases would not be able to condensate into liquids.

real gases do have intermolecular forces (attractive or repulsive) and take up a finite volume. Van der Waals equation corrects for these real-world deviations.

Question 2

what does the a and b mean in the van der Waals equation?

Also Vm?

Answer 2

a = a constant related to the attractive forces between molecules

b = a constant related to the volume occupied by the molecules

Vm = molar volume, and is found by (V/n).

Question 3

A table of BP and the van der Waals constants (a and b) for some selected substances can be found on page 1-5

Answer 3

page 1-5