pT diagram
A pT diagram is the most common form of a phase diagram in which the pressure p of a system is plotted against the temperature T.
According to Gibbs' phase rule , a pure fluid or a fluid mixture with constant composition has two degrees of freedom . From this it follows, provided that the amount of substance remains the same , that the pressure p is clearly described by the volume V and the temperature T in the function .
If you enter this relationship in a three-dimensional diagram , a pVT diagram is created . Keeping these surface into the pT-plane projected , there is obtained a pT diagram. The pressure p is the ordinate , the temperature T the abscissa and the volume V must be selected as a constant for each graph ( isochore ).
The limits of the aggregate states “solid”, “liquid” and “gaseous” or the individual phases of the substance are often entered in this diagram .
literature
- Douglas C. Giancoli: Physics. Text and exercise book, 3rd expanded edition, Pearson Education, Munich 2010, ISBN 978-3-8689-4023-7 .
- Torsten Fließbach, Hans Walliser: Workbook for Theoretical Physics. 3rd edition, Spektrum Verlag, Heidelberg 2012, ISBN 978-3-8274-2832-5 .
See also
Web links
- Chair of Thermodynamics Lecture Notes (accessed on January 21, 2016)
- Technical Thermodynamics Lecture Notes (accessed on January 21, 2016)
- Theory for the pT diagram (accessed on January 21, 2016)