Isochoric Heat capacity
The isochoric heat capacity , which one generally notes , is defined by the Dérivée partial of the internal energy U compared to the Température T calculated in constant volume V , that is to say:
Like energy interns, it is an extensive size , which is expressed in Joule by Kelvin. It depends in general on the temperature T and volume V .
Example
For N moles of a monoatomic perfect gas, energy interns is calculated explicitly:
where R is the Constante perfect gases. Internal energy is here independent of volume V , and the isochoric heat capacity is in this particular case equal to a constant:
Property
The energy interns U (T, V) being in general a function of the temperature T and volume V , the isochoric heat capacity is naturally introduced into the differential Forme:
where L is a calorimetric Coefficient.
Variation with volume
Energy interns U being a Fonction of state, the preceding differential form is a exact Différentielle, and one from of deduced the relation:
Thermodynamics makes it possible to show in addition that the calorimetric coefficient L is equal to:
One from of deduced the derivative partial of the isochoric heat capacity compared to volume at constant temperature:
If one knows the equation of state of the studied system, one can thus calculate this partial derivative.
Variation with the temperature
Thermodynamics does not make it possible alas to calculate the derivative partial of the isochoric heat capacity compared to the temperature with constant volume:
This variation must thus be measured in experiments for each system.
Related articles
-
Thermodynamique
- Énergie interns
- isobar Heat capacity
Category: Thermodynamics
| Random links: | Adıyaman | Farmhouse Soubeyran | Xavier Lesage | Alex Mineiro | Garriga handbook | Taang_!_Disques |