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Trying to grasp Entropy not from the combinatorics point of view (I understand the micro-macro states thing pretty good now), but from the phenomenological point of view.

So Entropy is:

What entropy measures is how much energy is spread out in a process/T OR how spread out the initial energy of a system becomes in that system (at constant temperature).

Now that makes some sence and it almost sinks in my mind. But there is one small thing I can't comprehend. The units of entropy.

If we say that 10 Joules of energy got dispersed in 10 qubic meters of volume then the measure of such dispersion would be Energy/Volume.

But in the case of Entropy we have Energy/Temperature. Why is it so? I mean do we measure of the spread in the "temperature"? How many Joules got spreaded in each degree of T? Why the temperature? Why not the volume?

Is Temperature being treated here as a kind of a universal "volume"? I now that math checks out and stuff... I'm talking here about intuition though.

P.S. I feel that dividing by temperature here has something to do with heat capacity of the substance. The more the heat capacity the more there is "volume" for the energy to spread inside the substance...

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coobit
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Entropy change is related to reversibility. In layman's term it is related to the degree of disorder introduced to the system, relative to its initial disorder. Now recall that temperature is actually a measure of molecular (or particle) agitation. Greater the temperature, grater the agitation. On the other hand when energy is transferred as heat it means there are disordered works done at the molecular level. Since we are not able to keep track of all these molecular works we add them up all and call it heat. It is disordered in the sense that the molecules which received heat move randomly.

The unit of entropy is unit of heat by unit of temperature. It actually measures how much energy in form of disordered motion is delivered to the system (heat) taking into account how much disordered motion the system already has (temperature). A small quantity of the first (heat) into a system which already has a lot of disorder (high temperature) will not make much difference. Hence it shall represent a small entropy change.

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