## Isothermal

isochoric/isometric: $\Delta V = 0$
isothermal: $\Delta T = 0$
isobaric: $\Delta P = 0$

AngieGarcia_4F
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### Isothermal

Does isothermal mean the same thing as reversible?

Kaitlyn Ang 1J
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### Re: Isothermal

Not necessarily. Isothermal means that there is no temperature change (aka deltaT = 0) whereas reversibility has to do with entropy and if total entropy is 0 (aka in a reversible system) or if entropy of the surroundings is 0 (aka in an irreversible system).

CNourian2H
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### Re: Isothermal

Kaitlyn Ang 1J wrote:Not necessarily. Isothermal means that there is no temperature change (aka deltaT = 0) whereas reversibility has to do with entropy and if total entropy is 0 (aka in a reversible system) or if entropy of the surroundings is 0 (aka in an irreversible system).

Can you explain further how entropy relates to reversible/irreversible

Sam McNeill 1E
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### Re: Isothermal

Isothermal means that the temperature is constant, which translates to delta T is 0, but isothermal is a specific pathway where the temperature is constant.

Samuel Tzeng 1B
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### Re: Isothermal

Isothermal systems have constant temperature, this does not mean the same as reversible

Posts: 102
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### Re: Isothermal

To add to the statement above, many questions in the textbook describe systems as isothermally reversible and irreversible, so it is not necessarily correct to consider an isothermal system to be only reversible.

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### Re: Isothermal

Additionally, I believe that a system being isothermal suggests that the change in internal energy for the system is 0, meaning that
dU = q + w ==> q = -w

Rebekah Alfred 1J
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### Re: Isothermal

To add to the above statement, the energy lost by the system doing work is replaced by heat flow, q, into the system, which is why q=-w.

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### Re: Isothermal

AngieGarcia_4F wrote:Does isothermal mean the same thing as reversible?

No, although isothermal reactions could very well be reversible. Isothermal means that a reaction has no change in temperature, while reversible means that there are slight changes made in pressure, and the temperature doesn't change. So, I guess that reversible reaction are isothermial, but isothermal does not mean that the reaction is reversible.

Osvaldo SanchezF -1H
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### Re: Isothermal

Something could be isothermal reversible or isothermal irreversible and the way to solve them both is the same when finding entropy as entropy is a state function but different when finding work because it is not a state function. Another difference is that in an irreversible function take into account that it is done in a vaccuum and the work for it will be 0 but this will not be the case for a reversible process.