> A closed system has fixed energy in classical. Wrong again! https://en.wikipedia.org/wiki/Closed_system https://en.wikipedia.org/wiki/Closed_system "In the

> A closed system has fixed energy in classical. Wrong again! https://en.wikipedia.org/wiki/Closed_system https://en.wikipedia.org/wiki/Closed_system "In thermodynamics, a closed system can exchange energy (as heat or work) but not matter, with its surroundings." Maybe you meant "isolated" instead of "closed" - but then I don't know what we have been talking about. (When I say "we" I mean "you".) > It doesn't make sense to count the microstates for a volume of gas at some pressure and temperature. A volume of gas at some pressure and temperature is a closed system but not an isolated system. > I can have a container with 1l of some gas at room temperature T1 and proceed to heat the room - and the container - to temperature T2. The containers in that example are closed systems but not isolated systems. > the microstates of that sample of gas at some fixed temperature don't have all the same energy That sample of gas at some fixed temperature is a closed system but not an isolated system. Hopefully you'll agree with everything I wrote with the understanding that we were not talking about isolated systems. [ have _you_ tried reading a physics book? :-) ]