# Questions tagged [equation-of-state]

Questions related to a thermodynamic equation describing the state of matter under a given set of physical conditions.

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### Equation of state for gas and liquid

If I'm correct, one and the same EoS is used for both liquid and gas phase. I'm trying the classical Peng-Robinson equation to get pressure from temperature and density: when using values for the gas ...
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### equation of state for a liquid in small ranges of temperature and pressure

consider the following question from Physical chemistry by Robert J. Silbey Robert A. Alberty Moungi G. Bawendi the answer is given to be $$V=Ke^{\alpha T}e^{-kp}$$ But I do not understand how this ...
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### Number of state variables in the general expression for a state function

In the tenth addition of Physical Chemistry: Thermodynamics, Structure, and Change by Peter Atkins and Julio de Paula, it is given, in section 2E, that the general expression for the differential of ...
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### How to convert molar volume to volume?

This seems like a simple question that people must have asked already, but I can't find an answer online. I'm not a chemist, but need to use a code that deals with thermodynamics. I am trying to use ...
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### What’s the physical meaning of (∂v/∂T )P?

I'm solving this exersice: The equation of state of a Van der Waals gas is $$\left(P + \frac{a}{v^2}\right)(v-b) = RT \tag{1}$$ Where $a$,$b$ and $R$ are constants. ...
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### Getting the pressure using the equation of states - will the answer be the same?

When I get the pressure using the different equations of state (e.g. van der Waals, Redlich-Kwong, etc.), will the answer still be the same?
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### Determining the boiling point of a substance given the triple point and critical point

If I have the pressure and temperature of a substance in its triple point, as well as its pressure and temperature in the critical point, how can I determine the boiling point of the substance at 1 ...
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### Theoretical versus empirical equations

I'm familiar with the fact that theoretical formulae are based on already known theory and are very frequently simplified (some equations don't include interactions between molecules for example) ...
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1 vote
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### Cohesive Energy Density table request

Quick question: Any one knows a resource for Cohesive Energy Density of some organic materials ? I am not looking for any specific molecule, actually I want to plan my project based on available ...
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### Why does small value of van der Waals gas constant "b" ensure easier liquefication?

Larger value of b signifies that the size of the molecules is larger and hence the forces acting should become larger due to increased surface area.This should ensure easier liquefication. But my book ...
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### Relation between the virial coefficients and van der Waals constants

I don't know where to begin with this question. A function $f(x)$ can be expressed as a special power series called the Taylor expansion. The common expansion is $(1-x)^{-1}=1+x+x^2$ Note that the ...
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### How much pressure is needed to make dry ice?

By compressing $\ce{CO2 (g)}$ the gas gains a lot of heat. When the hot compressed carbon dioxide is left to cool, it attains the temperature of the surrounding material. When it is released into the ...
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Let's say I truncate the virial equation after the third term for use as my equation of state: $${P\over\rho RT}=1+B\rho+C\rho^2$$ I have tabulated values for $B(T)$ and $C(T)$. I know $P$ and $T$ ...
I am confused about the justification for the corrections to the ideal gas law in the Van der Waals equation: $$p=\frac{nRT}{V-nb}-a\left(\frac{n}{V}\right)^2$$ I understand that the equation ...