# Estimate the latent heat of water with Van der Waals

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1. May 22, 2015

### It's me

1. The problem statement, all variables and given/known data

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

2. Relevant equations

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

3. 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.

2. May 27, 2015

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

3. May 28, 2015

### BvU

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

didn't come across ?