## Reversible vs Irreversible

$w=-P\Delta V$
and
$w=-\int_{V_{1}}^{V_{2}}PdV=-nRTln\frac{V_{2}}{V_{1}}$

Linh Vo 2J
Posts: 61
Joined: Sat Apr 28, 2018 3:00 am

### Reversible vs Irreversible

Is there a way to tell whether to use a reversible, isothermal equation or an irreversible equation to represent work?

Chloe Qiao 4C
Posts: 65
Joined: Fri Sep 28, 2018 12:27 am

### Re: Reversible vs Irreversible

It depends on the conditions that the problem gives. For example, if the question states that there is infinitesimal changes, use the reversible equation. When the change is too large(cannot by reversed by an infinitesimal change), then use the irreversible equation.

Ryan Troutman 4L
Posts: 68
Joined: Fri Sep 28, 2018 12:22 am

### Re: Reversible vs Irreversible

Only the problem can tell exactly which type of reaction it is without calculating delta G (Gibbs free energy). If there are many many changes (as stated by Chloe) then reversible is the way to go, however if it is sudden and drops quickly then it is irreversible.

Michael Novelo 4G
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Joined: Fri Sep 28, 2018 12:28 am

### Re: Reversible vs Irreversible

Usually it'll be given but the biggest difference has to do with the amount of pressure and if it changes "infinitesimal" Its a reversible process if the pressure is being slightly changed like 1 millionth less compared to the pressure of the system. If the pressure change is a large number then it's irreversible.

Michelle Nwufo 2G
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Joined: Fri May 18, 2018 3:00 am

### Re: Reversible vs Irreversible

Which of the reactions requires you to take the integral of the change in volume when calculating work?

Samantha Kwock 1D
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Joined: Fri Sep 28, 2018 12:24 am

### Re: Reversible vs Irreversible

The equation for isothermal, reversible reactions is derived from taking the integral of the change in volume.

sonalivij
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Joined: Fri Sep 28, 2018 12:27 am

### Re: Reversible vs Irreversible

Michelle Nwufo 2G wrote:Which of the reactions requires you to take the integral of the change in volume when calculating work?

The equation for an isothermal reversible expansion/compression requires you to take the integral of the change in volume when calculating work

Katelyn Phan 2A
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Joined: Fri Sep 28, 2018 12:23 am

### Re: Reversible vs Irreversible

Usually it would be told whether or not the system is reversible or irreversible.

Kaylee Kang 1G
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Joined: Fri Sep 28, 2018 12:24 am

### Re: Reversible vs Irreversible

The starting conditions should help you determine whether the reaction is reversible or irreversible.

Jonathan Pai 2I
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Joined: Fri Sep 28, 2018 12:27 am

### Re: Reversible vs Irreversible

irreversable needs to occur slowly for heat to equal out and pressure

Toru Fiberesima 1L
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Joined: Fri Apr 06, 2018 11:02 am

### Re: Reversible vs Irreversible

W for reversible isothermal expansion of an ideal gas W=-nRTln(V2/V1)