Is my understanding of Entropy correct?

Question

I keep reading a bunch of information on entropy that doesn't really tell me what's happening when a system increases in entropy.  For example the "degree of disorder increases", what does Disorder mean?

Tell me if my explanation of entropy is correct:
Entropy is vibration of atoms (heat) dispersed among a thermodynamic system.  The higher the entropy, the more evenly dispersed the vibration among all the atoms in the thermodynamic system is.  In perfect, or absolute, entropy, the vibration among atoms is perfectly similar among all atoms in the entire system.

Do I have the correct understanding?  If not please explain what happens at the atomic level.

Huh · Answer

Entropy is not disorder. Entropy is described as disorder because that seems to be the way in which students can understand it. Entropy according according to statistical mechanics is the number accessible microstates for particles in a system.

In solid the particles can only vibrate. They are restricted; they cannot zoom from one side to another. In a liquid the particles can roll over each other and they can go from east to west if there is such a thing as east and west on the molecular level, so they have more entropy because there are more available microstates (miniature places) for a particles to swap with. In gas, there is even more entropy because there is a lot of open space between each of the particles; they are not generally touching each other unless they crash into each other bouncing between the walls of a containing. There is more void spaces so there is more entropy. If you open the container there is still more entropy because the volume of the gas expands creating more microstates within the system, as the surroundings is all the chemicals in the atmosphere that are not the gas particles of interest.

If you consider the entropies of individual molecules you should look at the standard entropies of formation typically measured at room temperature (25 degrees celsius). You need to consider a few things like what state the molecule is in (solid, liquid, gas) at Standard Temperature and Pressure, if any pi bonds tight are present, how many particles (being the nuclei of each atom are present) in the molecule. It's pretty complicated stuff. Fortunately there is a data table, but it seems like chemists haven't measure the entropy of formation for a lot of molecules.

http://www.update.uu.se/~jolkkonen/pdf/CRC_TD.pdf

It seems that the simplest explanation of entropy is Boltzmann's entropy formula:

S = 1.38065 × 10−23 J/K * ln(W),
where "W" is the number of micro-states in the system, and that number is Boltzmann's constant. 
However, this is too simple. It's not that easy to just know W. You need some experiments.

I think your explanation of entropy has some entropy factors in it, but it seems to explain temperature more than entropy in which temperature measures the kinetic energy of a system. However, as temperature increases entropy also increases. Enthalpy is more like the frictional heat of bond formation and bond breaking, and also a indicator of the intermolecular forces of attraction (especially in the case of hydrogen bonding molecules).

Is my understanding of Entropy correct?

1 Answer