swolebrah

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So I already finished the first chapter in Ochem II about alcohol reactions and all the ether/reagents.
Simple enough, it's just about understanding how the reactions are working and doing a bunch of practice.

Then I flip to the next chapter and I get to IR Spectroscopy. I read some of the chapter, and I have no idea what the hell I'm reading. It's such a jump from what we have been doing in organic chemistry for the past semester.

Is there any tips you guys can give in regards to learning spectroscopy? IR, NMR.
Yes I pre read before the semester starts :p.



Thanks :).
 

MedWonk

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You probably don't have to learn too much about the technical aspects of IR and NMR, but you should be able to identify molecular structure given IR and NMR data. Textbooks tend to go into way more detail than you need, which ends up confusing you, and is one of the reasons pre-reading is generally a crappy idea. Pick up an OChem MCAT review book to get a more practical idea of what you need to know re: spectroscopy. Does your textbook have problems dealing with identification from IR/NMR? Do them. All of them. Know which IR frequences correspond to what type of bond/functional group. Same with NMR. Here's a start: http://orgchem.colorado.edu/Spectroscopy/Spectroscopy.html
It's nice they give you the formula in the practice problems. Don't expect to get one on a test.
 

prettyNURSEtoMD

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I LOOOOVED IR and NMR. I made an A in OCHEM II. I am very much a visual person. So, for instance, when you look at Aldehydes, you'll see peaks at 2700-2800, those are the "sisters", or "neighbors". There is also sayings that I did...

A mean (Amine) Amide met a fine Alkyne drinking Alcohol
A real (Aryl) vinyl gets all the hide (Aldehyde) while the rest of us all kill (alkyl) to be cool (Cooh,
Carboxylic Acid)‐ that’s the end of zone 2
All kinds (Alkynes) of trees (threes/triple bonds) in the night rile (nitrile) me in zone 3
Carbonyl in zone four is the biggest peak, hard core.
If we were all keen (Alkene) we would all buy a Mercedes Benz(Benzene) to drive to zone 5

I would take pictures of the IR, and have them blank and turned them into flashcards, and remembered them that way. Hope this helps some! Good luck.
 
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Ace-Co-A

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So I already finished the first chapter in Ochem II about alcohol reactions and all the ether/reagents.
Simple enough, it's just about understanding how the reactions are working and doing a bunch of practice.

Then I flip to the next chapter and I get to IR Spectroscopy. I read some of the chapter, and I have no idea what the hell I'm reading. It's such a jump from what we have been doing in organic chemistry for the past semester.

Is there any tips you guys can give in regards to learning spectroscopy? IR, NMR.
Yes I pre read before the semester starts :p.



Thanks :).
My friends and I got pretty good at solving structures using this website through UCLA. I highly recommend this website.
 
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swolebrah

swolebrah

sup
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Oct 30, 2013
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Thanks guys!

I agree my textbook is giving a lot more information that I've seen on some youtube videos. Again thanks for the links will check them all out!
 
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swolebrah

swolebrah

sup
5+ Year Member
Oct 30, 2013
554
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I LOOOOVED IR and NMR. I made an A in OCHEM II. I am very much a visual person. So, for instance, when you look at Aldehydes, you'll see peaks at 2700-2800, those are the "sisters", or "neighbors". There is also sayings that I did...

A mean (Amine) Amide met a fine Alkyne drinking Alcohol
A real (Aryl) vinyl gets all the hide (Aldehyde) while the rest of us all kill (alkyl) to be cool (Cooh,
Carboxylic Acid)‐ that’s the end of zone 2
All kinds (Alkynes) of trees (threes/triple bonds) in the night rile (nitrile) me in zone 3
Carbonyl in zone four is the biggest peak, hard core.
If we were all keen (Alkene) we would all buy a Mercedes Benz(Benzene) to drive to zone 5

I would take pictures of the IR, and have them blank and turned them into flashcards, and remembered them that way. Hope this helps some! Good luck.
This is awesome haha. Will use for sure!
 
Aug 22, 2013
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So I already finished the first chapter in Ochem II about alcohol reactions and all the ether/reagents.
Simple enough, it's just about understanding how the reactions are working and doing a bunch of practice.

Then I flip to the next chapter and I get to IR Spectroscopy. I read some of the chapter, and I have no idea what the hell I'm reading. It's such a jump from what we have been doing in organic chemistry for the past semester.

Is there any tips you guys can give in regards to learning spectroscopy? IR, NMR.
Yes I pre read before the semester starts :p.



Thanks :).
Textbooks go into the explanation of how the machines work to measure the vibrations of diff functional groups, blah blah... Organic chemists don't really care too much about how the instruments work, that's more for analytical chemists. My recommendation:

For IR just make sure to memorize the peaks for very important functional groups.

Examples:
Alcohols (OH) have big broad peaks 32-3600cm^-1
Carbonyls (C=O) have strong sharp peaks around 1650cm^-1
Those two groups are the only MCAT relevant ones, but for class know sp3 C-H bond, sp2 C-H, C=C, C=_C, C-N, and whatever else your prof emphasizes

Remember to avoid answer choices in the fingerprint region, anything below 1550cm^-1. PhDs reference books to figure out what's going on in there.

For NMR do lots of practice problems in order to understand: splitting (n+1 where n= number of hydrogens); recognize equivalent protons; how electro withdrawing groups deshield protons while electron donating shield; deshielding pulls electrons downfield while shielded saty upfield( exception being benzene).

NMR is one of the more likely types of lab questions for the MCAT, and it can often be as simple as recognizing which protons are equivalent or how many signals will result from the molecule.

The other two types of spectroscopy are not too MCAT relevant, but I'm sure you are expected to know them or class.

UV/Vis is only important if you are looking at a molecule that has a large, conjugated pi system. Look up beta-keratine to see what I mean.

And Mass-spec is prob the least important, but it looks at where cleavage will most likely occur if you energize the molecule. Here just remember how inductive effects work and you will e find. Note the special peaks for bromine and chlorine.

Best of luck!!!
 
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swolebrah

swolebrah

sup
5+ Year Member
Oct 30, 2013
554
269
Status
Medical Student
Textbooks go into the explanation of how the machines work to measure the vibrations of diff functional groups, blah blah... Organic chemists don't really care too much about how the instruments work, that's more for analytical chemists. My recommendation:

For IR just make sure to memorize the peaks for very important functional groups.

Examples:
Alcohols (OH) have big broad peaks 32-3600cm^-1
Carbonyls (C=O) have strong sharp peaks around 1650cm^-1
Those two groups are the only MCAT relevant ones, but for class know sp3 C-H bond, sp2 C-H, C=C, C=_C, C-N, and whatever else your prof emphasizes

Remember to avoid answer choices in the fingerprint region, anything below 1550cm^-1. PhDs reference books to figure out what's going on in there.

For NMR do lots of practice problems in order to understand: splitting (n+1 where n= number of hydrogens); recognize equivalent protons; how electro withdrawing groups deshield protons while electron donating shield; deshielding pulls electrons downfield while shielded saty upfield( exception being benzene).

NMR is one of the more likely types of lab questions for the MCAT, and it can often be as simple as recognizing which protons are equivalent or how many signals will result from the molecule.

The other two types of spectroscopy are not too MCAT relevant, but I'm sure you are expected to know them or class.

UV/Vis is only important if you are looking at a molecule that has a large, conjugated pi system. Look up beta-keratine to see what I mean.

And Mass-spec is prob the least important, but it looks at where cleavage will most likely occur if you energize the molecule. Here just remember how inductive effects work and you will e find. Note the special peaks for bromine and chlorine.

Best of luck!!!
Thank you !
 
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swolebrah

swolebrah

sup
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Oct 30, 2013
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Medical Student
Damn NMR is kicking my ass. I working hard, but the ranges are so blurry. Sometimes the CH3 is in the .9 area then its in the 1.7 area due to a allylic...#$#[email protected]#