## Identifying constant pressure in a question

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

Riya Sood 4G
Posts: 160
Joined: Sat Aug 24, 2019 12:18 am

### Identifying constant pressure in a question

What are some key indicators in a question to identify whether pressure is constant or not to calculate the work when the question does not explicitly use the words "constant external pressure"?

KeyaV1C
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### Re: Identifying constant pressure in a question

Non-expansion work is one way of knowing that the pressure is constant

Brooke Yasuda 2J
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Joined: Sat Jul 20, 2019 12:17 am

### Re: Identifying constant pressure in a question

if it says anything about the system being in equilibrium or being reversible, you know that the external pressure can change

Daniel Toscano 1L
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Joined: Tue Nov 13, 2018 12:18 am

### Re: Identifying constant pressure in a question

also, be aware that if it just says "an external pressure of [blank]" then it will be constant