q vs delta H to calculate delta S


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Payton Kammerer 2B
Posts: 49
Joined: Tue May 01, 2018 3:00 am

q vs delta H to calculate delta S

Postby Payton Kammerer 2B » Tue Mar 10, 2020 10:30 pm

4F.1 A human body generates heat at the rate of about 100. W
(1 W 5 1 J?s21). (a) At what rate does your body heat generate entropy in your surroundings, taken to be at 20. 8C? (b) How much entropy do you generate each day? (c) Would the entropy generated be greater or less if you were in a room kept at 30. 8C? Explain your answer.

In the solution manual, their explanation for c) said that the equation was delta S= delta H / T

why were they using delta H instead of q there? Would it also be okay to use q? When can/should the two be flipped, apart from phase changes?

JasonLiu_2J
Posts: 109
Joined: Sat Aug 24, 2019 12:17 am

Re: q vs delta H to calculate delta S

Postby JasonLiu_2J » Wed Mar 11, 2020 10:56 am

Remember that under conditions of constant pressure, delta H equals q. I think in this situation, they simply substituted in delta H for q in the change in entropy equation. Whether you call the heat generated delta H or q in this question does not matter, since it will still give you the same change in entropy from delta S = delta H/T or delta S = q/T.


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