## SI unit for P

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

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

### SI unit for P

Can anyone tell me what is the SI unit we use for pressure? Is it atm or pa?

aisteles1G
Posts: 117
Joined: Fri Sep 28, 2018 12:15 am

### Re: SI unit for P

The SI unit for Pressure is technically Pascals but the book uses atm for most calculations, and I don't think they expect you to know the conversion factor from atm to pascals which is 1 atm = 101325 Pa

Jonathan Omens 1K
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### Re: SI unit for P

In this class, use atm when reporting pressures.

Albert Duong 4C
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### Re: SI unit for P

Since atm is mostly used, the other gas constant R=.08206 L x atm/K/mol would most likely be used in questions involving PV=nRT.

Porus_Karwa_2E
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### Re: SI unit for P

Our textbook uses bar mostly, but atm is technically the proper SI unite for pressure. Since there is only a 1% difference between bar and atm they are interchangeable though.

Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

### Re: SI unit for P

I think we are supposed to use atm for pressure, and since there's a very small difference between atm and bars, the value with either of these units will be pretty much the same.

Alexandra Albers 1D
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Joined: Fri Sep 28, 2018 12:18 am

### Re: SI unit for P

So far, we have largely used atm for pressure measurements and have occasionally seen bar as well. From what I've seen, the units are only important for figuring out which version of the gas constant (R) we should use in calculations.