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### U:Internal Energy

Posted: Thu Jan 31, 2019 9:06 pm
What's the difference between
1) deltaU= q+w
and
2) deltaU= deltaH -PV

Is the second equation only for constant pressure? Are there certain circumstances to use each equation or are they interchangeable?

### Re: U:Internal Energy

Posted: Thu Jan 31, 2019 11:14 pm
They are essentially the same. It just depends which values you are given in the question, and which you can plug into the equation.

### Re: U:Internal Energy

Posted: Sat Feb 02, 2019 1:35 pm
They can both be used to find delta U depending on what's given in the problem. We also went over that when there is no volume change (in most of biology) then delta U = delta H.

### Re: U:Internal Energy

Posted: Sat Feb 02, 2019 4:16 pm
They are basically the same, you just pick which one you use based on what information you are given in the question.

### Re: U:Internal Energy

Posted: Sat Feb 02, 2019 4:50 pm
Essentially they are the same equation you would just use one or the other depending on the information that is given in the problem.