Why does entropy never decrease in a closed system?
A closed system simply describes a system in which no exchange of substances takes place, but energy exchange does.
In the case of a closed/isolated system, I would understand the statement mentioned in the question, since no energy exchange takes place there. But in a closed system, heat, for example, can be released back into the environment, right? Or does "closed" mean that energy can be added but not removed?
(1 votes)
Loading...
In a fromclosed system never decreases the entropy, since neither entropy is dissipated by mass or heat flows and irreversible entropy production is never negative. In a closed system the entropy can decrease, by heat dissipation via the system boundary
Consider the exact definitions:
closed system: no material exchange takes place at the system boundary. The mass conservation rate applies. Energy and entropy can exceed the system limit and become both more and less.
adiabates system: no heat exchange takes place at the system boundary. However, other forms of energy such as work or matter can be overreacted. Typical example: Insulating pot.
closed system: neither energy nor matter can exceed the system limit. The system applies both the mass conservation rate and the energy conservation rate. Entropy can’t be less.
open system: Energy and matter can exceed the system limit.
No. Closed means closed. In the thermodynamically closed system, the energy remains constant, but the entropy cannot decrease, only increase. Thermodynamics does not know any difference between closed and closed, since it is only about energy flow anyway. Technical installations and machines can possibly make such a difference, but for the entropy term the thermodynamics is leading.
Illustrative example: a glass is filled with half white powder, black powder. This is a state of low entropy=high order, because the color of a grain can easily be determined from the position. Now the mixture is stirred 10 times clockwise and has gray powder, a state of high entropy = disorder. In order to restore the separate state of origin, it now does not help to stir ten times counterclockwise, the entropy remains high and no longer decreases.
The increase in entropy in closed systems is caused by the absorbed heat and by “dissipated” work, i.e. by the conversion of other energy forms into heat energy which can no longer be used without loss.
https://de.wikipedia.org/wiki/ Closed_System
https://de.wikipedia.org/wiki/Zmore_Main set_der_Thermodynamics