Clausius equation of state: Difference between revisions

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(Corrected T_c to be T_c^3 not T_c^2)
 
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The '''Clausius''' [[Equations of state | equation of state]], proposed in 1880 by [[Rudolf Julius Emanuel Clausius]] <ref>[http://dx.doi.org/10.1002/andp.18802450302 R. Clausius "&Uuml;ber das Verhalten der Kohlens&auml;ure in Bezug auf Druck, Volumen und Temperatur", Annalen der Physik und Chemie '''9''' pp. 337-357 (1880)]</ref>  is given by (Equations 3 and 4 in <ref>[http://dx.doi.org/10.1021/ie50663a005 K. K. Shah and G. Thodos "A Comparison of Equations of State", Industrial & Engineering Chemistry '''57''' pp. 30-37 (1965)]</ref>)
The '''Clausius''' [[Equations of state | equation of state]], proposed in 1880 by [[Rudolf Julius Emanuel Clausius]] <ref>[http://dx.doi.org/10.1002/andp.18802450302 R. Clausius "&Uuml;ber das Verhalten der Kohlens&auml;ure in Bezug auf Druck, Volumen und Temperatur", Annalen der Physik und Chemie '''9''' pp. 337-357 (1880)]</ref> <ref>[http://dx.doi.org/10.1002/andp.18812501007 R. Clausius "Ueber die theoretische Bestimmung des Dampfdruckes und der Volumina des Dampfes und der Flüssigkeit", Annalen der Physik und Chemie '''14''' pp. 279-290 (1881)]</ref> is given by (Eq. 1 <ref>[http://gallica.bnf.fr/ark:/12148/bpt6k30574.pleinepage.f941.N4 E. Sarrau "Sur la compressibilité des fluides", Comptes Rendus des Séances de l'Académie des Sciences. Paris '''101''' pp. 941-944 (1885)]</ref>)


:<math>\left[ p + \frac{a}{T(v+c)^2}\right] (v-b) =RT.</math>
:<math>\left[ p + \frac{a}{T(v+c)^2}\right] (v-b) =RT.</math>
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where <math>p</math> is the [[pressure]], <math>T</math> is the [[temperature]], <math> v </math> is the volume per mol,  and <math>R</math> is the [[molar gas constant]]. <math>T_c</math> is the [[critical points | critical]] temperature and <math>P_c</math> is the [[pressure]] at the critical point, and <math> v_c </math> is the critical volume per mol.
where <math>p</math> is the [[pressure]], <math>T</math> is the [[temperature]], <math> v </math> is the volume per mol,  and <math>R</math> is the [[molar gas constant]]. <math>T_c</math> is the [[critical points | critical]] temperature and <math>P_c</math> is the [[pressure]] at the critical point, and <math> v_c </math> is the critical volume per mol.


At the [[critical points | critical point]] one has <math>\left.\frac{\partial p}{\partial v}\right|_{T=T_c}=0 </math>, and <math>\left.\frac{\partial^2 p}{\partial v^2}\right|_{T=T_c}=0 </math>, which leads to
At the [[critical points | critical point]] one has <math>\left.\frac{\partial p}{\partial v}\right|_{T=T_c}=0 </math>, and <math>\left.\frac{\partial^2 p}{\partial v^2}\right|_{T=T_c}=0 </math>, which leads to <ref>For details see the [[Mathematica]] [http://urey.uoregon.edu/~pchemlab/CH417/Lect2009/Clausius%20equation%20of%20state%20to%20evaluate%20a%20b%20c.pdf printout] produced by [http://www.uoregon.edu/~chem/hardwick.html Dr. John L. Hardwick].</ref>


:<math>a = v_c - \frac{RT_c}{4P_c}</math>
:<math>a = \frac{27R^2T_c^3}{64P_c}</math>


:<math>b= \frac{3RT_c}{8P_c}-v_c</math>
:<math>b= v_c - \frac{RT_c}{4P_c}</math>


and
and


:<math>c= \frac{27R^2T_c^2}{64P_c}</math>
:<math>c= \frac{3RT_c}{8P_c}-v_c</math>  
==References==
==References==
<references/>
<references/>
[[category: equations of state]]
[[category: equations of state]]

Latest revision as of 09:52, 7 September 2012

The Clausius equation of state, proposed in 1880 by Rudolf Julius Emanuel Clausius [1] [2] is given by (Eq. 1 [3])

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

At the critical point one has , and , which leads to [4]

and

References[edit]