Equation of State: Internal Interventions

[M. next]

It is known that the combination of (p, v, t) gives Equation if State. Okay, what if we have the intervention of the internal as well, i.e, U=cte*PV for example. Can this be also considered as an equation of state?

 

[mikeph]

How do we know what U or cte are?

 

[M. next]

Excuse me, U: internal energy. Cte any constant relating those variables. My case was cte=3/2

 

[DrClaude]

An equations of state is an equation that relates state variables, so yes, that would be an equation of state. Note that your example is just a trivial modification of the usual equation of state, due to the fact that there is a direct linear relation between U and T.

 

[fluidistic]

It is known that the combination of (p, v, t) gives Equation if State. Okay, what if we have the intervention of the internal as well, i.e, U=cte*PV for example. Can this be also considered as an equation of state?

If you give such a U (notice that it depends explicitly on some intensive parameters), it would be an equation of state. If you however give U in function of S, V and n (extensive parameters), you have all the information of the system and in such a case you'd have a fundamental equation from which you could derive up 3 equations of state.

 

[M. next]

Thank you both for clearing things up!