Berthelot equation of state: Difference between revisions

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where <math>p</math> is the [[pressure]], <math>T</math> is the [[temperature]] and <math>R</math> is the [[molar gas constant]]. <math>T_c</math> is the [[critical points | critical]] temperature, <math>p_c</math> is the pressure and <math>v_c</math> is the volume at the critical point.
where <math>p</math> is the [[pressure]], <math>T</math> is the [[temperature]] and <math>R</math> is the [[molar gas constant]]. <math>T_c</math> is the [[critical points | critical]] temperature, <math>p_c</math> is the pressure and <math>v_c</math> is the volume at the critical point.
==Low pressure variant==
==Low pressure variant==
Berthelot also proposed an [[Equations of state |equation of state]] for use at low pressures:
Berthelot also proposed an [[Equations of state |equation of state]] for use at low pressures{{reference needed}}:




:<math>p = \frac{RT}{v} \left( 1 + \frac{9}{128} \frac{pT_c}{p_c T} \left( 1- \frac{6T_c^2}{T^2} \right)  \right)</math>  
:<math>p = \frac{RT}{v} \left( 1 + \frac{9}{128} \frac{pT_c}{p_c T} \left( 1- \frac{6T_c^2}{T^2} \right)  \right)</math>
 
==References==
==References==
<references/>
<references/>
[[category: equations of state]]
[[category: equations of state]]

Revision as of 17:41, 29 September 2010

The Berthelot equation of state [1][2] can be written as

.

At the critical point one has , and ,

which leads to (Eqs. 4.1 - 4.3 [3][4])



and giving a critical compressibility factor of



where is the pressure, is the temperature and is the molar gas constant. is the critical temperature, is the pressure and is the volume at the critical point.

Low pressure variant

Berthelot also proposed an equation of state for use at low pressures[?]


References