Please Help me with Organic Here:(

[annygirl]

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Hi everybody, this is my first post.

I know this a little awkward maybe, but I need some help big time. Not in the application process, even though, I doul love to answer anyone could have about the process since I've already applied to medical schools this year, but I have an organic chemistry exam on tuesday, and the professor gave us a little under 30 practice questions. I have answered almost all of them, actually i answered two thirds of them, and I have exactly ten to go 🙁
I'm gonna go nuts here, because I have used every single reference I could get my hands on, and the questions are still not working out. I thought you guys are really smart people, and maybe you could help me answer them. Please don't answer them unless you are possitive your answer is correct, I can't afford to lose any points on tuesday's final....he promised us that atleast 4 of them are going to be on the final, and the final has a total of 10 questions. Please help me, I'm also oing to post this on the MCAT discussion....geez, I just hope the mods won't get pissed. Mods, can you please leave this on the preallo just for another day or so, PLEASE...because I know most people don't visit the mcat discussions, most are here...please anyone help me, im going insane here!!
thanks a lot guys and gals...i appreciate this..

 

[uic1999]

Okay, those problems are not hard and any introductory organic chemistry book will be more than adequate in helping you answer them. I don't think SDN is the place to be posting this...

Your prof was nice enough to give you some problems that are indicative of what will be on the exam, maybe you should sit down and do them...SDN won't help you on the exam.

 

[annygirl]

uic, thanks for your reply....actally i did 16 of them....i copied and pasted these on another .DOC for someone to help me. I'm still taking orgo 1, but I got a 31 on my MCAT...which isn't good, but isn't bad either...what I mean is that I'm not stupid...so if someone can please help me, i would appreciate it...if someone can't help me like uic, can you please refrain from insulting me?

SDN isn't the place to be posting these kinds of things? i'll be damed if thats true...if we're not here to help each other, i think im in the wrong place....i apologize if I haven't contributed to SDN like the other members have, and I also have the audacity to ask everyone with this big favor...but wtf? u know...

 

[phosphorylation]

hey annygirl, i just PMed you the first one; i'm lost with the others ; maybe im just stupid or sth. Good luck.

 

[dmoney41]

He has a point. These are not off the wall problems - they're pretty basic organic that you should be able to figure out just from the lectures.

I skimmed a couple ... #9 is basic Sn1/E1, #10 is a basic synthesis, 6 is a basic intramolecular ring closing, etc. I didn't really see anything "trick" on there, just the basics that you need to know if you're going to pass the class.

Oops, I just noticed you need to lose a extra carbon in 10. Still, that's what those 800 reactions you have to memorize in the alkene/alkyne chapter are for.

 

[uic1999]

You're obviously not stupid if you can get a 31 without having taken organic chemistry. That's my point, though, in the time it took you to type up those questions and check SDN, they could be done.

I'm not insulting you, either, trying to help you. Working through problems and recognizing trends is the best way to learn orgo, not getting answers from other people and trying to memorize specific questions.

Just go do them, trust me, it will pay off. To get you started, though, most of those problems can be easily solved if you simply identify electrophilic and nucleophilic species.

 

[shadowy onion]

Anny, for your first ever post this is asking a bit much, don't you think?
I tend to agree with the other posters, but I'm sure you anticipated these kinds of responses. I hope there are people out there who can help you.
Good luck on tuesday.

 

[IndyZX]

I hope you find someone to do your work for you.

 

[Haybrant]

agreed. these problems aren't really all that backhanded. I would suggest trying them till you get them b.c organic chem is really a subject that requires a certain amount of mind-shaping if you wish to get anything out of it. Or work on them with other students in class. If you have any more questions on how to do well in the subject let me know, but i think you'll be able to get these questions on your own if you work hard enough.

 

[dmoney41]

the only one here where you might really need a hint is #7, because the only example of anti-markovnikov radical additions off an alkene we ever saw was Br2, although perhaps other departments cover di-tbutyl-peroxide as a reagent. although actually come to think of it i think there was one of these on a later exam, so perhaps they like to see if you can think outside the box as far as generalizing the idea of a radical abstraction. when i first saw it i thought it was a variant of TFPAA and had unpleasant memories of organic 2.

the obvious hint being it's a radical addition.

 

[Pinkertinkle]

Wow, I don't remember any of that stuff, and it's only been a semester.

 

[bella_dottoressa]

Chem 251...You don't go to OSU by chance do you?

 

[SanDiegoSOD]

If you post this on the MCAT forum, you might get some crazy gunner who wants to impress everyone to do it for you. BTW, I havnt taken o-chem for a year, but I have to say - theses are definitely basic problems. You should really try and learn how to answer them yourself. Sorry I can't (actually, won't) help more.

 

[annygirl]

Thanks guys, I do appreciate the advice. From Everyone.

 

[jlee9531]

i remember last year, we had some ochem lovers that would help out people in need all the time on sdn. too bad we are all too busy getting ready for med...
i'll take a look at em later if i have a chance.

 

[jlee9531]

i just took a look at it real quick, and doesn't seem too hard. ill see if i can help you later once i get my **** settled.

 

[SanDiegoSOD]

Ok, because of Jlee's post, I'll be a little nicer.
When you are dealing with an O-chem problem, the first thing you have to do is realize what type of molecule you are dealing with. In the case of number two, you start with 1-methyl-cyclohexanol. That means you have an alchohol attached to a tertiary carbon, which just happens to be in an acidic solution. So what are the possiblities? Sn2 reactions cannot happen with tertiary carbons. The best bet is an E1 - a free proton attacks the OH group, which turns a poor leaving group into an good one as you create a substrate of H2O. Due to random thermal energy, the H2O leaves the carbon, creating a tertiary carbocation. Now, carbocations are of course extremely electrophilic, and desire to connect with a source of electrons - which just happens to be present on the CH30H. The carbocation attacks the oxygen of the methanol and forms a bond with the oxygen, while the Hydrogen on the methanol leaves into solution, replenishing the original catalyst. You now have your product.
This is the way you have to look at Ochem - look at your beginning reactant, determine its reactive possiblities due to the starting solute and the molecules present, and then take it one step at a time. Good luck.

 

[LUBDUBB]

I'm still taking orgo 1, but I got a 31 on my MCAT...which isn't good, but isn't bad either...

I was about this close to clicking on that attachment to help you..until I read this line.

 

[annygirl]

lubdubb, not sure how that line offended you or made something look like something it wasn't. But I apologize for that. But if you can help me out, I would really appreciate it. I'm not that smart, as a lot of ppl have already put it in many different forms on this thread. I'm having a nervous breakdown here....I really want to know these questions before my final on tuesday...
I would appreciate any help...especially for numbers 3 and 7...i've done some of the other ones, ive been working on them all day....

anny

 

[SanDiegoSOD]

Damn anny, if you spent as much time hitting the books as you do watching this thread, then your questions would be answered and you'd be on your way to an A! You gotta take this matter into your own hands, and besides, the questions answered here wont be on your exam.

 

[dmoney41]

I find that difficult to believe because 3 has to be the easiest of them all, but I'm bored and have 5 minutes to waste before I go, so:

3 - it's an Sn2, think of a way to make a good leaving group with what you've got in the solution

7 - it's a radical abstraction off a double bond, it should be in the alkenes chapter somewhere, the standard example is Br2 breaking down into Br* + Br*

 

[euromd]

i wonder if adcoms read SDN. this thread in particular should be highlighted. where are you taking you class again? i don't think i caught that info...

31 on MCAT and still can't figure out basic org chem!!!

-S

 

[jlee9531]

adcoms do read SDN. some of them openly mention this site. now they dont really waste their time on the forums but instead on the interview feedback so they know how the kids they invited felt about their school.