Van der Waals equation of state: Difference between revisions

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m (New page: The van der Waals equation is <math> \left. p = \frac{ n R T}{V - n b } - a \left( \frac{ n}{V} \right)^2 \right. </math>. where: * <math> p </math> is the pressure * <math> V </math> ...)
 
mNo edit summary
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The van der Waals equation is
The van der Waals (VDW) equation is


<math> \left. p = \frac{ n R T}{V - n b } - a \left( \frac{ n}{V} \right)^2  \right. </math>.
<math> \left. p = \frac{ n R T}{V - n b } - a \left( \frac{ n}{V} \right)^2  \right. </math>.
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* <math> V </math> is the volume
* <math> V </math> is the volume


* <math> N </math> is the number of molecules
* <math> n </math> is the number of moles


* <math
* <math> T </math> is the absolute temperature


* <math> T </math> is the absolute temperature
* <math> </math> is the Gas constant; <math> R = N_A k_B </math>, with <math> N_A </math> being [[Avogadro constant]]
 
The VDW equation of state (EoS) takes into account two features that are absent in the Ideal Gas (EoS):


* <math> k_B </math> is the [[Boltzmann constant]]
The parameter <math> b </math> introduces somehow the '''repulsive behavior between pairs of molecules at short distances''',
it represents the minimum molar volume of the system.


* <math> </math> is the Gas constant; <math> R = N_A k_B </math>, with <math> N_A </math> being [[Avogadro constant]]
whereas <math> a </math> measures the '''attractive interactions''' between the molecules

Revision as of 19:58, 21 February 2007

The van der Waals (VDW) equation is

.

where:

  • is the pressure
  • is the volume
  • is the number of moles
  • is the absolute temperature
  • is the Gas constant; , with being Avogadro constant

The VDW equation of state (EoS) takes into account two features that are absent in the Ideal Gas (EoS):

The parameter introduces somehow the repulsive behavior between pairs of molecules at short distances, it represents the minimum molar volume of the system.

whereas measures the attractive interactions between the molecules