2nd law of Thermodynamics


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JeremyPark14B
Posts: 29
Joined: Fri Sep 28, 2018 12:19 am

2nd law of Thermodynamics

Postby JeremyPark14B » Tue Feb 12, 2019 12:48 am

How does the 2nd law of thermodynamics relate to the equation of delta S = q(rev) / T ?

The 2nd law states that spontaneous processes lead to an increase in entropy. However, if q is negative, isn't the change in entropy negative? How does this make sense?

ThomasLai1D
Posts: 61
Joined: Fri Sep 28, 2018 12:17 am

Re: 2nd law of Thermodynamics

Postby ThomasLai1D » Tue Feb 12, 2019 5:19 pm

q refers to the heat you are adding to or taking out of the system. A positive q means you are adding heat to the system, which increases energy. I think you are confusing this with when delta H is negative, which is not the same as removing heat from the system. When delta H is given, spontaneity is determined when delta G is negative, and delta G = delta H - T delta S.


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