Estimate the latent heat of water with Van der Waals

[It's me]

Homework Statement

Try to estimate the latent heat of vaporization of water and nitrogen using the Van der Waals model. What happens?

Homework Equations

$$\Delta Q = T\Delta S=L$$
$$S=nR\left[ \ln\left(\frac{(V-nb)T^{3/2}}{n\Phi}\right)+\frac{5}{2} \right]$$

The Attempt at a Solution

I predict the latent heat of vaporization of water will be wrongly approximated by the Van der Waals model. By looking at the equation for entropy I think the $\Delta S$ is going to be zero, so the latent heat would be zero also. But I am not sure if I am looking at the problem in the wrong way.

 

[BvU]

Hi me,
I had already replied with : why do you think $\Delta S = 0$ ?

didn't come across ?