Hii have a few questions about entropy:why does the definition

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In summary, entropy is a measure of the amount of energy in a system that is no longer available to do work. It is often referred to as "disorder" or "randomness" because as a system's energy becomes more spread out and less organized, it becomes less useful for performing work. Entropy is related to the second law of thermodynamics, which states that the total entropy of a closed system will always increase over time. The definition of entropy includes the concept of probability because the more uncertain and disordered a system is, the higher the number of possible arrangements or states it can have, and therefore the higher the entropy. As entropy increases in a system, it becomes more difficult to predict its behavior, leading to lower predict
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hi

i have a few questions about entropy:

why does the definition of entropy stress the fact that the heat exchange by the system is reversible(dS=dQ_rev/T)?

am i right, that processes are only reversible iff ΔS=0 and therefore e.g. isothermic, isobaric and isochoric processes even of ideal gases are irreversible in general?
 
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FAQ: Hii have a few questions about entropy:why does the definition

Why is entropy often referred to as "disorder" or "randomness"?

Entropy is a measure of the amount of energy in a system that is no longer available to do work. In simpler terms, it is a measure of the system's disorder or randomness. This is because as a system's energy becomes more spread out and less organized, it becomes less useful for performing work.

How is entropy related to the second law of thermodynamics?

The second law of thermodynamics states that the total entropy of a closed system will always increase over time. This means that as energy is transferred and transformed within a system, it will ultimately become more dispersed and less organized, leading to an increase in entropy.

Why does the definition of entropy include the concept of probability?

The definition of entropy states that it is a measure of the number of possible arrangements or states that a system can have. This involves the concept of probability, as the more uncertain and disordered a system is, the higher the number of possible arrangements or states it can have, and therefore the higher the entropy.

How does entropy impact the predictability of a system?

As a system's entropy increases, the number of possible arrangements or states it can have also increases. This makes it more difficult to predict the exact state or behavior of the system, as there are more possibilities to consider. Therefore, higher entropy leads to lower predictability.

Can entropy ever decrease in a system?

According to the second law of thermodynamics, the total entropy of a closed system will always increase over time. However, in a localized or open system, it is possible for entropy to decrease in one part while increasing in another, as long as the overall entropy of the entire system still increases. This is known as the local decrease of entropy, and it is often seen in living organisms that are able to maintain a high level of organization and complexity while increasing the entropy of their surroundings.

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