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What is difference between perfect gas and ideal gas?
I want to know about it used in engineeringThere is a difference between usage in physics and in engineering. While physicists often use both terms interchangeably, this is not the case for engineers.
@Chestermiller can fill in the details better than me.
Yes, that's correct. And I considered not including #3, but, for a neophyte to thermodynamics, I felt it would helpful to include.For a gas whose equation of state is exactly given by ##pV = nRT##, the specific internal energy depends only on temperature. Thus, if definition (1.) holds, definition (3.) is redundant.
We're still waiting for a Physicist to respond with their version of an ideal gas and perfect gas. We engineers use ideal gas and perfect gas interchangeably. Anyway, you said you were more interested in the engineering definition (which I gave).I haven't got the difference between ideal gas and perfect gas?
You have given the characterstics of ideal gas, they are true but I needed how can we differentiate between ideal and perfect gas?We're still waiting for a Physicist to respond with their version of an ideal gas and perfect gas. We engineers use ideal gas and perfect gas interchangeably. Anyway, you said you were more interested in the engineering definition (which I gave).
Like I said, I'll leave it up to Physicists to provide their version of things. You have our answer from us engineers.You have given the characterstics of ideal gas, they are true but I needed how can we differentiate between ideal and perfect gas?
I know one of the difference, it is that in ideal gases specific heat vary with temperature but in perfect gas specific heat is constant. I wanted to know more about it.
Indeed, at least in my community (relativistic heavy-ion physics, which uses relativistic statistical physics, including transport theory, thermal QFT, hydrodynamics, as one of its most important tools), there's no difference made between a "perfect" and an "ideal" gas. In fact, the expression "perfect gas" is never used.
From point of view of kinetic theory, one can define an ideal gas as a gas whose consituent particles have a mean free path which is much shorter than the typical space-time scales upon which the macroscopic properties of the gas changes. This implies equilibration (or relaxation) times much shorther than the typical timescales for changes of the macroscopic properties. Then the motion of the gas can be described well with ideal hydrodynamics, which implies that the gas is, on the resolution of macroscopic space-time scales, always in local thermal equilibrium.
Yikes. This is the same as what we engineers assume.Indeed, at least in my community (relativistic heavy-ion physics, which uses relativistic statistical physics, including transport theory, thermal QFT, hydrodynamics, as one of its most important tools), there's no difference made between a "perfect" and an "ideal" gas. In fact, the expression "perfect gas" is never used.
From point of view of kinetic theory, one can define an ideal gas as a gas whose consituent particles have a mean free path which is much shorter than the typical space-time scales upon which the macroscopic properties of the gas changes. This implies equilibration (or relaxation) times much shorther than the typical timescales for changes of the macroscopic properties. Then the motion of the gas can be described well with ideal hydrodynamics, which implies that the gas is, on the resolution of macroscopic space-time scales, always in local thermal equilibrium.
According to the author your book, he defines a perfect gas as an ideal gas with constant heat capacity.View attachment 231708
I am confused after reading. I don't know what it is trying to say.
Now I am more confused. What is perfect gas?According to the author your book, he defines a perfect gas as an ideal gas with constant heat capacity.
I don't know how I can say this more precisely. Sorry. My advise is to not obsess over the difference, and to continue on with your learning.Now I am more confused. What is perfect gas?
Ok, thanks any way for your tineI don't know how I can say this more precisely. Sorry. My advise is to not obsess over the difference, and to continue on with your learning.
In Chapter III “SYSTEMS OF ONE COMPONENT” of the book “MODERN THERMODYNAMICS BY THE METHODS OF WILLARD GIBBS” by E. A. Guggenheim one finds:Now I am more confused. What is perfect gas?