# I A proper Thermodynamic system

#### MathematicalPhysicist

Gold Member
I have this question that in it there's this expression "A proper Thermodynamic system".

I thought that means that the first law (or is it the second) that $dS \ge 0$, i.e. the change of entropy always increase.

But I am not sure, can someone clear to me this matter?

Thanks in advance.

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#### Khashishi

Science Advisor
Have you tried looking it up? Your question can be answered in a second of searching on the internet.

• Chestermiller

#### MathematicalPhysicist

Gold Member
I tried searching google, and didn't find the exact phrasing:"A proper Thermodynamic system" then what is it?

#### Khashishi

Science Advisor
I guess I didn't understand your question. I thought you were confused by what the first and second laws of thermodynamics are, since you got them mixed up above. You still should look them up for that reason.
I think you are expecting a technical definition for "proper thermodynamic system", when it just means proper "thermodynamic system", where proper is just a non-technical English word, and thermodynamic system is just a system that obeys thermodynamics, which is basically anything that isn't some make-believe model.

#### MathematicalPhysicist

Gold Member
I have this question which I don't know how to start with and the teacher assistant isn't well responsive in the email.

Maybe you know better than me:

We have: the equations of system: $u =3/2 pv , p=av T^n$, I first was ask to find $T(u,v), p(u,v)$ which I found ($n$ is an integer and $a$ some constant).
Now I am asked to find for which values of $n$ is the system a proper theormodynamic system?

I thought of using $dS \ge 0$ in the end I got that: $n \ge constant/ (av^3 \ln T)$, I thought that since should be valid for every $T>0$ then when $T\ to \infty$ we get: $n \ge 0$, but I am not sure.

Do you know of this problem before?
I searched my reference with no help.

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