Chemistry: Van Der Waals' Equation

[candiishop]

Which of the following properties of a real gas is related to the 'b' coefficient in the van der Waals' equation?

 

(P + n2a/V2)(V - nb) = nRT

 

a) There are attractive forces between atoms or molecules of a real gas

b) The rate of effusion of a gas is inversely proportional to the square root of the molecular weight of the gas

c) Real gases consist of molecules or atoms which have volume

d) The average speed of the molecules of a real gas increases with temperature

e) None of the above

 

Do you think the answer is c? Thanks

[ecoli]

yup, it's 'c'. The ideal gas law does not account for the fact that molecules are not point particles. They have volume, and thus can interact with each other. The ideal gas law justs considers the volume of the occupying space, and not the volume of the molecules, unlike the corrected gas law.

[Cap'n Refsmmat]

http://www.wisci.org/wiki/Van_Der_Waals_equation_of_state