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qp=deltaH

Posted: Wed Jan 10, 2018 3:33 pm
So I understand that qp is essentially delta h and that is enthalpy, but for notation, is there going to be any instances when we would use qp?

Re: qp=deltaH

Posted: Wed Jan 10, 2018 3:36 pm
Since they are interchangeable, I do not believe it matters which notation you use. However, since Dr. Lavelle has been using deltaH almost exclusively in lecture so far, I take it that we would mainly use deltaH.

Re: qp=deltaH

Posted: Wed Jan 10, 2018 3:50 pm
DeltaH is what people usually use, so I don't think we will use qp

Re: qp=deltaH

Posted: Wed Jan 10, 2018 6:19 pm
The textbook uses q for heat and H for enthalpy

Re: qp=deltaH

Posted: Wed Jan 10, 2018 9:27 pm
For all intents and purposes, I think it is just important to know the concept behind their interchangeability. q is used to describe values of released or absorbed heat, and using the subscript p to create "qp" just means you are looking at the change in heat at a constant pressure. This is the definition behind enthalpy, as enthalpy can be described in terms of heat (q).

Re: qp=deltaH

Posted: Wed Jan 10, 2018 11:54 pm
I think you should focus mostly on deltaH

Re: qp=deltaH

Posted: Thu Jan 11, 2018 9:19 am
Both would probably be acceptable, but it may be best to stick to whatever Dr. Lavelle prefers to use in lecture.

Re: qp=deltaH

Posted: Thu Jan 11, 2018 10:06 am
I do not think there will be a specific case where you are obligated to use "qp" instead of the deltaH notation but it is still important to understand the concept that they are equal to each other since it provides you with a definition of what the meaning of deltaH actually is.

Re: qp=deltaH

Posted: Thu Jan 11, 2018 10:10 am
qp is the heat released or absorbed at constant pressure, you would use this format in certain situations when looking at systems at constant pressure whereas the other equation where it is just q is the heat released or absorbed under certain conditions not necessarily at constant pressure. I recommend looking into it and asking a TA just to be sure, I think the previous replies do a good job of explaining all of this.