### units for calculating work

Posted:

**Thu Jan 18, 2018 10:10 pm**when calculating the work using w=-P∆V, what units are best to use for pressure and volume in order to get work in joules?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=129&t=25798

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Posted: **Thu Jan 18, 2018 10:10 pm**

when calculating the work using w=-P∆V, what units are best to use for pressure and volume in order to get work in joules?

Posted: **Thu Jan 18, 2018 10:15 pm**

I would stick with atm for pressure and liters (L) for volume when calculating work using w=-P*deltaV.

Posted: **Thu Jan 18, 2018 10:16 pm**

I'll say use liter for volume and atm for pressure.

Posted: **Fri Jan 19, 2018 1:20 pm**

I think that atm is best for pressure and L is best for volume because then you can just convert from L.atm to J (1 L.atm = 101.325 J).

Posted: **Fri Jan 19, 2018 2:03 pm**

atm and liters would probably be the best units since the conversion of L.atm to joules will be given to us on the constants and formulas sheet.

Posted: **Fri Jan 19, 2018 2:16 pm**

Use for volume and atm for pressure. Even if the question gives you a pressure unit that is not in atm, converting to atm might help make answering easier. The conversion between the various pressure units will be on the formula sheet.

Posted: **Fri Jan 19, 2018 2:27 pm**

If you use the equation w = -P∆V, the units are kg/m⋅s² (m³) ,which is equal to kg⋅m²/s², which is the equivalent of Joules. Alternatively, you could multiply by 101.325 J/L⋅atm, which would result in work with units of Joules.