Are V_l and V_g specific volumes in the Clausius-Clapeyron formula?

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Sebas4
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Hey, I have a question about the meaning of a variable in the Clausius-Clapeyron formula.

My textbook (Daniel v. Schroeder) says that the Clausius-Clapeyron formula is (for phase boundary between liquid and gas)
[tex]\frac{dP}{dT} = \frac{L}{T\left(V_{g} - V_{l} \right)}[/tex].

What is [itex]V_{l}[/itex] or [itex]V_{g}[/itex]? It's not volume. I looked on Wikipedia, they say that [itex]V_{g} - V_{l}[/itex] is the difference in specific volume of gas and liquid.
Specific volume is defined as [tex]\nu = \rho^{-1}[/tex].

My question is, is [itex]V_{l}[/itex] and [itex]V_{g}[/itex] specific volumes for gas and liquid, or I mean is it correct?
I want to ask just to be sure.

Thank you in advance for responding,

-Sebas4.
 
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Sebas4 said:
What is [itex]V_{l}[/itex] or [itex]V_{g}[/itex]? It's not volume.
It is volume. Schroeder writes the equation in terms of extensive quantities (total latent heat for a given system of a given size) whereas in Wikipedia the equation is written in terms of the specific latent heat and the specific volume.
 
It doesn't matter as long as you are consistent, i.e. L and V are both specific (J/kg and m3/kg), or both molar (J/mol and m3/mol), or both extensive (J and m3). In each case the expression has units J m-3 K-1 ≡ Pa K-1.
 
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