Chemistry Reference and Research
           
 
Periodic Table
- standard table
- large table
 
Chemical Elements
- by name
- by symbol
- by atomic number
 
Chemical Properties
 
Chemical Reactions
 
Organic Chemistry
 
Branches of Chemistry
Analytical chemistry
Biochemistry
Computational Chemistry
Electrochemistry
Environmental chemistry
Geochemistry
Inorganic chemistry
Materials science
Medicinal chemistry
Nuclear chemistry
Organic chemistry
Pharmacology
Physical chemistry
Polymer chemistry
Supramolecular Chemistry
Thermochemistry

Critical variable

(Redirected from Critical variables)

Critical variables are defined, for example in thermodynamics, in terms of the values of variables at the critical point.

On a PV diagram, the critical point is an inflection point. Thus:

\left(\frac{\partial P}{\partial V}\right)_{C}=0
\left(\frac{\partial^2 P}{\partial V^2}\right)_{C}=0

For the van der Waals equation, the above yields:

P_C=\frac{a}{27b^2}
vC = 3b
T_C=\frac{8a}{27bR}
01-04-2007 01:16:19
The contents of this article are licensed from Wikipedia.org under the GNU Free Documentation License. How to see transparent copy