## Final 2015 Question #3

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

JukaKim_1D
Posts: 24
Joined: Fri Sep 25, 2015 3:00 am

### Final 2015 Question #3

When the question asks, what is the work DONE by the air in the lungs as it expands on going from 20C to 37C,
even though the calculation would be -3.9J (in terms of the system), shouldn't the answer be 3.9J? Because "doing work" and the negative sign cancels out each other in terms of definition?

Chem_Mod
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### Re: Final 2015 Question #3

Remember that work DONE by something meaning it's losing its energy to do work which is demonstrated by the "-" sign.

JukaKim_1D
Posts: 24
Joined: Fri Sep 25, 2015 3:00 am

### Re: Final 2015 Question #3

yeah so wouldn't it make sense to say 3.9J of work was done?