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Final 2015 Question #3

Posted: Thu Mar 10, 2016 10:59 am
by JukaKim_1D
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?

Re: Final 2015 Question #3

Posted: Thu Mar 10, 2016 12:22 pm
by Chem_Mod
Remember that work DONE by something meaning it's losing its energy to do work which is demonstrated by the "-" sign.

Re: Final 2015 Question #3

Posted: Thu Mar 10, 2016 12:24 pm
by JukaKim_1D
yeah so wouldn't it make sense to say 3.9J of work was done?