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### Entropy of the System for irreversible expansions

Posted: Tue Feb 11, 2020 9:19 pm
What is the difference between the change in entropy for a reversible isothermal expansion vs an irreversible expansion? Are they exactly the same?

### Re: Entropy of the System for irreversible expansions

Posted: Tue Feb 11, 2020 10:00 pm
Yes, they are the same because entropy is a state function.

### Re: Entropy of the System for irreversible expansions

Posted: Tue Feb 11, 2020 10:04 pm
State functions means that the path doesn't matter so it is the same.

### Re: Entropy of the System for irreversible expansions

Posted: Wed Feb 12, 2020 3:29 pm
Also,

When is the change in internal energy zero for an irreversible expansion?

### Re: Entropy of the System for irreversible expansions

Posted: Wed Feb 12, 2020 4:24 pm
Amir Bayat wrote:Also,

When is the change in internal energy zero for an irreversible expansion?

Internal energy is zero when Temperature is constant because there is no energy transfer if there is no change in temperature ( Internal energy measure the heat transfer) so there is none if temperature isn't changing. DeltaU= DeltaH-Deltan*R*T so if there is no temp change it all comes to be deltaU=0

### Re: Entropy of the System for irreversible expansions

Posted: Wed Feb 12, 2020 5:03 pm
i believe they are the same, or at least you assume its always reversible

### Re: Entropy of the System for irreversible expansions

Posted: Sun Feb 16, 2020 10:25 pm
Since entropy is a state function, that means the path you take does not matter, so they will technically be the same.

### Re: Entropy of the System for irreversible expansions

Posted: Sun Mar 01, 2020 12:06 pm
entropy is the same in both scenarios because entropy is a state function. It doesn't matter what path you take to get the change in entropy, it will be the same.