# Questions tagged [van-der-waals-behavior]

Questions with substantial discussion on the behavior of real gases using the van der Waals model (as opposed to just calculations with the van der Waals equation, or a casual reference to the van der Waals model).

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### How should I evaluate $\left(\frac{\partial U}{\partial V}\right)_T$ with van der waals equation: $P = \frac{nRT}{V-nb}-a(\frac{n}{V})^2$?

So in my homework I was able to get this- $\left(\frac{\partial U}{\partial V}\right)_T = T(\frac{\partial P}{\partial T})_V - P$ but now I'm trying to plug in $P = \frac{nRT}{V-nb}-a(\frac{n}{V})^2$ ...
96 views

### Cubic nature of van der Waals' gas equation

$V_m^3-\dfrac{RT+bP}{P}V_m^2+\dfrac{a}{P}V_m-\dfrac{ab}{P}=0$ So, At $T<T_c$ the above equation has three real roots say $V_1,V_2,V_3$, my doubt is what does this mean physically because for some ...
29 views

### Experimental Verification of Van der Waals parameters?

I am currently trying to find an academic paper that experimentally verifies the a and b values of Van der Waals forces for carbon dioxide. I can't seem to find this, and am wondering if I am missing ...
41 views

### Best description of forces/ mechanisms that stabilize the interaction between a hydrophobic protein binding pocket and a hydrophobic ligand

This is a more theoretical or definition question that is related to the terms "hydrophobic effect", "hydrophilic interaction", and "van der Waals' forces" (and others I ...
49 views

### Why do we use the ratio of Critical Pressure and Critical Temperature to calculate size of a gas molecule?

Our teacher explained that using the ratio of Critical Pressure and Critical Temperature is preferred over Critical Volume to calculate the size of a gas molecule when all these quantities are taken ...
360 views

### If a = 0 for a Van der Waals gas, what does that signify?

I know that if $a = 0$ for a gas at certain temperature and pressure, it means that the molecules of gas have almost no attractive forces acting between them. But does that also mean that the ...
1 vote
47 views

### What happens when $V=Nb$ in the Van der Waals equation (divergent)?

The VdW equation: $$\left(P+a\left(\frac{N^2}{V^2}\right) \right)\left(V-Nb\right)=Nk_BT$$ when the intermolecular forces are zero $a=0$, so $P=\frac{Nk_BT}{V-Nb}$ which diverges at $V=Nb$ for fixed ...
41 views

### Should there be a better explanation on Van Der Waals force? [duplicate]

The explanation on how Van der Waals force forms is this: Van der Waals forces consist of induced, temporary dipoles between neighbouring molecules. These are caused by constantly shifting electron ...