Question about 'Entropy-driven'

[wangasu]

Does anybody know about the entropy-driven processes? Are they referred to the systems without enthapy change? so, all the isolated systems like the universe belong to the category. but, I also noticed that the term, entropy-driven, was used in some biological or mesoscopic systems. What is it really all about? Thank you.

 

[Andrew Mason]

Does anybody know about the entropy-driven processes? Are they referred to the systems without enthapy change? so, all the isolated systems like the universe belong to the category. but, I also noticed that the term, entropy-driven, was used in some biological or mesoscopic systems. What is it really all about? Thank you.

Entropy is not a concrete physical thing so it does not really drive anything. Energy is the ability to apply a force over a distance (work). Energy drives things. The entropy change of a process tells us whether the process will occur naturally by itself (ie. change in entropy is > 0) or whether energy must be added to make the process occur (entropy < 0). If a change in entropy of a process is > 0, the process results in energy of a system becoming more disperse. If entropy change of a system < 0, energy in the system becomes more concentrated (this can only occur if energy is added).

AM