Spectroscopy Absorbances

[SensesFail]

So other then the ones listed below, what absorbances should absolutely be memorized?

IR
Carbonyl = 1700
Alcohol = 3300

H NMR
Carboxylic Acid = 10.5-12
Aldehyde = 9-10
Aromatic = 6-8

I remember reading here after the August '04 MCAT that there was a very specific discrete on one of the forms which asked what ppm a hydrogen on phenol would give, or something in that ballpark.

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[DrChandy]

So other then the ones listed below, what absorbances should absolutely be memorized?

IR
Carbonyl = 1700
Alcohol = 3300

H NMR
Carboxylic Acid = 10.5-12
Aldehyde = 9-10
Aromatic = 6-8

I remember reading here after the August '04 MCAT that there was a very specific discrete on one of the forms which asked what ppm a hydrogen on phenol would give, or something in that ballpark.

IR carbon-associated-bond absorbances of

Ethers
Alkanes
Alkenes
Alkynes
Aromatics
Amines

 

[Pontifex Maximus]

Honestly, if a question asked me that I'd probably just suck it up and guess. IMO, not worth memorizing a bunch of numbers for a chance of one question. I'd know the IRs of carbonyls, and the 3000 range for alcohols and nitrogen groups. So not worth it otherwise. (by the way, unless it asks for exact specifics, if the answer choices are broad you can work through it based on withdrawing groups and whatnot)

 

[newyorkcougar]

Are you talking IR? The only one they can expect you to recognize off hand is alcohol, obvious by its shape. This was not a big issue on my MCAT and I can't imagine it will be a big issue on future ones either. The MCAT in general doesn't ask lots of small details. Rather they focus on the larger basic principles of the basic sciences. The exact spectroscopy peaks of all of the individual functional groups is not really a large, basic principle. Just my experience on my MCAT. Good luck!

 

[QofQuimica]

Might want to ask this in the Organic Chem thread of the subforum, QofQuimica is real good at this stuff and will probably be able to give you a better idea of the answer. I just knew what ever was given in my MCAT books. But ask Q. She'll give a good answer as always.

I posted this a few weeks ago: http://forums.studentdoctor.net/showthread.php?p=2721706#post2721706

 

[rtmcad2319]

So other then the ones listed below, what absorbances should absolutely be memorized?

IR
Carbonyl = 1700
Alcohol = 3300

H NMR
Carboxylic Acid = 10.5-12
Aldehyde = 9-10
Aromatic = 6-8

I remember reading here after the August '04 MCAT that there was a very specific discrete on one of the forms which asked what ppm a hydrogen on phenol would give, or something in that ballpark.

KNOW THE C13 OF -CH2- AND -NH2!!!!

 

[stoleyerscrubz]

I think AAMC 5R has a discrete on IR.

in April 2005 there was NMR on the exam. I am not sure if it was a passge though.

KNOW THE C13 OF -CH2- AND -NH2!!!!

 

[QofQuimica]

KNOW THE C13 OF -CH2- AND -NH2!!!!

I think this was a joke, guys. A CH2 can come in a range of places on a C13 depending on environment, and an NH2 won't appear on C13 at all.