In the BR molecular structure chapter, phase 2, number 20 (a discrete), it stated that the most unstable molecule releases the most energy upon combustion in the answer explanation. However, in aamc3, number 123, it said that the most stable molecule releases the most energy upon combustion. I am agreeing more with aamc because it makes the most sense, but also because the mcat write wrote it. AAMC is correct right?
BR molecular structure vs aamc
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If you are going to ask about questions on an AAMC practice test, you need to put a spoiler tag in your title.
Anyways, you misread both sources.
A more unstable organic molecule has a higher heat of combustion per carbon. For two structures of equal number of carbons, the more unstable one releases more energy per mole. If they are not of the same size, then you need more information to know which releases more energy. This is pretty much what both sources said.
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And you can come to this conclusion because higher energy = more unstable, correct?
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Higher energy per molecule of carbon, yes.
You can see this when comparing carbons under ring strain and comparing alkenes.
More ring strain=higher energy release per carbon when it is combusted compared to carbons under less strain.
Conjugated double bonds=less energy release when hydrogenated compared to isolated double bonds.
