Standard Conditions

[DrRoyal Pains]

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Under Chad's quizzes for section G6.7, there is a question asking to solve for Delta S (vap.) and you are given Delta H (vap.), which equals 40.67 KJ/mol. In the solution, he uses 373K as the temperature, which I understand because he just added 100 to 273 because vaporization of H2O occurs at 100 C, but I thought under STANDARD CONDITIONS, the temp was 298k? Meaning he should have used 398 K rather than 373 K? Im confusing myself ha.

 

[2PacClone23]

STP is 1atm/25C

Standard Conditions is 1atm/0C


I might have these two confused lol.

 

[DrRoyal Pains]

Its the other around, STP is 1 atm/0C (or 273 K). Standard conditions i 1 atm/25 C (or 298K). When's D-day by the way? Didn't you say you were writing it soon?

 

[2PacClone23]

21st 🙂

I just took CDP4 and gave up midway. I wasn't in the mood and was super tired. It's also 10x harder than CDP1-3 for some odd reason. Anyway, from now until 21st, I got just review.

 

[DrRoyal Pains]

Some of their questions are RIDICULOUS. A lot of the cube counting questions on their practice tests have illusions. The real PAT better not have that ish. Im shooting to take mine either at the end of this month or beginning/middle of next.

 

[jwnichols21]

You resolved this, yes?

 

[DrRoyal Pains]

Not yet. Do you see what I mean though?

 

[jwnichols21]

Yeah...they didn't explicitly state standard conditions though. But I guess it's implied because of the circle. Hmmmmmm

 

[DrRoyal Pains]

Even if it is implied, he still used the wrong value. He got 373 by adding 100 to 273 which is STP, not Standard Conditions. If it was under Standard Conditions, which it is, he should have gotten 398K, not 373K.