First semester of orgo - having a panic attack!

[fiddler]

Brett,

next time you recrystalize, add just enough hot solvent to dissolve everything. Don't cook unless you way over add. let stand to close to room temp. then place in ice water bath. mix a little water with ice. water carries heat away hundreds of times faster than air.

You shouldn't be using filter paper with a hirsch. It should have a little filter thingy at the bottom. you just vacuum filter and scrape afterwards.

read zubrick carefully several times the section you are going to be using and think about it. Basically, you need to understand what you are doing so you can optimize the procedure.

fiddler

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[mshheaddoc]

How could you like the analytical chem.?

Actually, I did like it too, []

But the worst part about the class I took was something else, which ended up giving me the grade than what I really deserved. But our Analytic lab, we had to be so precise and accurate in reporting results with fewer errors as possible while they always gave us the contaminating reagents. Then there was no way to get 100% accurate. Class in itself was not bad, but how it was taught maybe was the problem in my case.

I HATED the class. I got a D in it. The guy couldn't teach and most of us failed or got D's. Only 3 people with A's and they were in the industry and worked at Gore or Dupont! Lab I got like a A+ or something like that. Go figure. Loved the lab though. It was interesting at lesat. And you're right, 100% accurate? NEVER. Even in Ochem lab. There wasn't a chance. 7% yield would be good in our lab.

 

[mshheaddoc]

how is that book?, il be using it soon. I sure hope its good.

I wish I kept my first ochem book. I really did like it. I might have to search for it. This one is ok, see critique below.

I use Bruice also and we've had about 2 weeks of lectures and just finished chapter 1. I don't know, maybe the chapters are bigger in the Bruice book than the other o-chem books.

The Bruice books is pretty good, imo. I haven't looked through any other o-chem textbooks so I can't really compare but so far we only finished one chapter and there was maybe 1 section (of about 20) that I didn't understand after reading it. So far, so good.

Its actually pretty decent. I'm not really comfortable on its explaination of orbitals for "special circumstances". Some of our problem sets we had to do I was lost on why it would be a sp2 hybrid. Still don't know. Oh and the lewis acid/base is like 1 page and wasn't really clear. AND buffers aren't in the book. They are in the study guide. Not good if you don't get the study guide. Other than that, nomenclature for chp 2 is pretty thorough. Haven't gotten to chp 3 yet, or memorized chp 2 yet either

 

[Truman Stanford]

I just came back from Lab :goes to room to cry:
During the worst 4 hours of my life thus far, I couldn't get my sample to recrystal. I finally did at the end of lab and didn't get to filter it multiple times giving me a whopping 7% yield. Also we had to measure the melting point and pick it out from a list of unknowns. My experimental melting point was exactly in between 2 choices. I am going to have to do a bit more research to find out which I think it will be.
Lab sucks!
:end rant:

Brett, the same experiment, I believe, I got no better than 30% and that was my 3rd trial. Don't worry, when you get to chromatography you'll be a lot happier. Haha, no joke, organic lab sucks everyone.

 

[Truman Stanford]

I enjoy organic overall, however. Besides pKa, no calculations.

 

[Dave_D]

Thanks for the tips. Never heard of the seeding.

I am sure if I wanted to I could arrange to retry but it wouldn't really make a difference since I would prolly get a different unknown. I think I just had a very bad substance. I used the criteria in Zubrick in picking a solvent. Sorry I didn't clarify. Paper on the hirsch was what the TA said and told me to add DI since I think the correct solvent was a methanol/water mixture.

Wow, sounds like your TA really sent you the wrong way.(I mean adding water and using paper? That sounded strange to me but like I said we never need to do a mixed solution recrystalization.) Fiddler, thanks for confirming you guys didn't use paper either. I didn't realize Brett you were doing unknowns so you had to figure out what solvents to use.(Guess they gave us a gift by not doing too many unknowns here.) Oh a thing or 2 about ice baths. First make sure you are using an ice/water mixture.(Since I've seen so many just use straight ice and no water.) Oh, and be careful since at least our e-flasks were top heavy.(So I'd only put an 1/8" to 1/4" of icewater in my container. Anymore and my flask would flip.)

Oh I guess I shouldn't be that surprised you hadn't heard of seeding. The only place I found it besides my lab manual was in Zubrick.(If you have the 6th edition look on page 105 item 6. He's sort of talking about seeding although he's doing it through agitation.)

Oh one other tip, cool slowly. If you try to cool fast you'll get garbage in your crystals. (Something my kaplan teacher didn't know btw.)

BTW, what school are you taking this course at?(Ok, I'm curious but it sounds like they're really making you work in lab.)

 

[DrBowtie]

I know the ice bath is an ice-water bath. I guess I made the mistake of adding too much solvent. Oh well - Live and Learn. If I didn't put paper in the hirsch my particulate would have flown right through. It was that small.

I'm at U of Louisville.

 

[jimkat]

I was out of school for 10 years and hadn't looked at a single chemistry book until 3 days before I enrolled in the middle quarter (2nd quarter) of a 3 quarter ochem sequence. Luckily I dug up my old book by Morrison & Boyd. This book saved me and I got an A+ and then an A in the 3rd quarter of the sequence. I would highly recommend this book because everything is explained so well. The mechanisms and graphics aren't as nice as the newer books but the explanations make it so you know what the hell is going on. BTW, both of my professors had this textbook on their shelves and refered to it as the bible of ochem.

 

[Dave_D]

I know the ice bath is an ice-water bath. I guess I made the mistake of adding too much solvent. Oh well - Live and Learn. If I didn't put paper in the hirsch my particulate would have flown right through. It was that small.

I'm at U of Louisville.

Ok, I'm thinking you have a funnel that has small holes and not a filter disk. If you care here's a drawing of a funnel with a disk http://fp.academic.venturacollege.edu/doliver/chem12b/lab/MicroscaleAddendums.htm
Just wanted to clear that up.(Basically we used funnels with built in disks and particulate wouldn't go through them. It was basically like it had a built in filter paper.)

Yeah, sounds like you put in too much solvent. Only advice I can say when this happens is if your filter flask is clean you can always take out the solution, boil off the solvent and try again.

 

[beastly115]

Not good if you don't get the study guide. Other than that, nomenclature for chp 2 is pretty thorough. Haven't gotten to chp 3 yet, or memorized chp 2 yet either

At our school the Study Guide and Textbook came wrapped as a package. Basically we had to buy both. I think it has a good study guide. It actually explains the answers. My gen chem book last year only gave the answers and most of them were wrong

 

[DrBowtie]

Ok, I'm thinking you have a funnel that has small holes and not a filter disk. If you care here's a drawing of a funnel with a disk http://fp.academic.venturacollege.edu/doliver/chem12b/lab/MicroscaleAddendums.htm
Just wanted to clear that up.(Basically we used funnels with built in disks and particulate wouldn't go through them. It was basically like it had a built in filter paper.)

Yeah, sounds like you put in too much solvent. Only advice I can say when this happens is if your filter flask is clean you can always take out the solution, boil off the solvent and try again.

We use a small filter paper in combo with this.

 

[mshheaddoc]

At our school the Study Guide and Textbook came wrapped as a package. Basically we had to buy both. I think it has a good study guide. It actually explains the answers. My gen chem book last year only gave the answers and most of them were wrong

The book does have some typos in it though. Just so you know. My prof compiled a list of them for us. Additionally I bought on half.com/amazon. I never buy books from the school book store when I can save at least $25/book online used

 

[fiddler]

We use a small filter paper in combo with this.

you poor soul, that's not a hirsch funnel!!!

go buy one. it is fairly cheap and will make your life much much easier. I can't imagine trying to do micro orgo with that thing and a filter paper. gah!

fiddler

 

[JustR]

And you're right, 100% accurate? NEVER. Even in Ochem lab. There wasn't a chance. 7% yield would be good in our lab.

 

[DrBowtie]

you poor soul, that's not a hirsch funnel!!!

go buy one. it is fairly cheap and will make your life much much easier. I can't imagine trying to do micro orgo with that thing and a filter paper. gah!

fiddler

Link to a pic or website for purchase? I'm confused as this is what zubrick called a hirsch funnel as well.

 

[fiddler]

Link to a pic or website for purchase? I'm confused as this is what zubrick called a hirsch funnel as well.

I sure hope this works. this is what we use.

http://www.uncp.edu/home/pwf/251l2f1.jpg

if you get one, don't bother with the filter paper. it works well without it. just make sure you clean it well afterwards.

fiddler

i'll see if i can find a link to a website that sells it because you're just using a smaller version of the buchner which sucks.

 

[DrBowtie]

I sure hope this works. this is what we use.

http://www.uncp.edu/home/pwf/251l2f1.jpg

fiddler

i'll see if i can find a link to a website that sells it because you're just using a smaller version of the buchner which sucks.

Thats how I use mine. With a vacuum filter. The pic shows filter paper too. I guess I found a poor picture earlier.

 

[fiddler]

Thats how I use mine. With a vacuum filter. The pic shows filter paper too. I guess I found a poor picture earlier.

nope, yours is a smaller version of the buchner. ours don't have any little holes int he bottom. it takes a little filter disk and that is all you need. It is made of some plastic or something and the filtration is top rate without the paper.

the filter disk never comes out and lasts all year long.

go take a close look at that picture. there are no llittle holes at the bottom. there is a big one where the filter disk goes into and thats it. it looks like its plugged up.

fiddler

 

[fiddler]

Thats how I use mine. With a vacuum filter. The pic shows filter paper too. I guess I found a poor picture earlier.

take a look at this.

http://www.sigmaaldrich.com/Area_of...Books/Glassware_Catalog/Kits__Microscale.html

item N. and read desctiption.

do a seach on their website and you will be able to buy one. at worst i can get you one from my chemistry stock room.

fiddler

 

[Dave_D]

Damn Brett, that looks like a pain in the a** to use. The kind we used were like fiddler showed.(Really nice and if you've got good technique you could just transfer your product to a massed vial. No bothering with weighing paper.) Anyway I found this link
http://www.kimble-kontes.com/html/pg-748100.html
I think this might actually be the company we used in the first place. Fiddler, tell me if you think that looks right. Anyway I'd double check with the lab TA but it might be worth it to you.(And come to think of it if it works out you can just sell the extra ones to your classmates

 

[fiddler]

Damn Brett, that looks like a pain in the a** to use. The kind we used were like fiddler showed.(Really nice and if you've got good technique you could just transfer your product to a massed vial. No bothering with weighing paper.) Anyway I found this link
http://www.kimble-kontes.com/html/pg-748100.html
I think this might actually be the company we used in the first place. Fiddler, tell me if you think that looks right. Anyway I'd double check with the lab TA but it might be worth it to you.(And come to think of it if it works out you can just sell the extra ones to your classmates

that's it. hirsch funnel with pe disk, 20 um porosity.

brett, you can see the holes in yours, no way they're 20 microns. lol

if you look carefully at zubrick's book, you will notice that his hirsch funnels look like these.

fiddler

 

[girlsporty]

I took both semesters of Orgo for the first time this past summer, and I actually ended up liking it. We used Bruice's textbook. I will say, I was far more impressed with this textbook than almost any other science textbook. Bias might have crept in as I'm now pre-med, but I thought the author did a very good job.

The biggest help -- check out the Bruice website on the prentice hall webpage. They make you download Chyme, but being able to picture the molecules and practice reactions made all the difference in the world. Whenever there's a little www symbol in the book, you can find a bit on the website. I LOVED their "tutorials" because you could run through a reaction and they'd tell you what was right and wrong. Anyone can access these, actually....

http://wps.prenhall.com/esm_bruice_organic_4

Good luck!!

 

[DrBowtie]

that's it. hirsch funnel with pe disk, 20 um porosity.

brett, you can see the holes in yours, no way they're 20 microns. lol

if you look carefully at zubrick's book, you will notice that his hirsch funnels look like these.

fiddler

So the solid just cakes on top of the disk allowing you to scrape it of a non absorbant material? If so, sounds like it could have been useful.

 

[Dave_D]

So the solid just cakes on top of the disk allowing you to scrape it of a non absorbant material? If so, sounds like it could have been useful.

Yup, exactly how it worked for me.(And given how little product we generally made every little bit helped.)

 

[fiddler]

Yup, exactly how it worked for me.(And given how little product we generally made every little bit helped.)

Can you imagine using a buchner funnel for micro orgo?!? gah!

fiddler

 

[Dave_D]

Can you imagine using a buchner funnel for micro orgo?!? gah!

fiddler

Please, you're going to give me nightmares Seriously though considering I'd usually get between 0.1 and 0.5 gram of product using a buchner funnel would be a bear to deal with.

 

[Anastasis]

To everyone using Solomon's book - what chapter are you on? We're still on Ch 1 - 3rd week of lectures. Apparently we're only doing the first 6 chapters in the first semester. Is that normal? It seems REALLY slow. Am I going to get thru all the stuff I need for the MCAT by April?

 

[DrBowtie]

Hey, Brett! How did you do on your Orgo exam?

Ours is Friday- looks like the same stuff - probably lots of isomer drawings and naming, the rest is multiple choice.

88 but it will be 93 since one question was messed up.

we started the last week of August and we had are starting chapter 4 in solomon's book on mon. (next lecture).

 

[Anastasis]

88 but it will be 93 since one question was messed up.

we started the last week of August and we had are starting chapter 4 in solomon's book on mon. (next lecture).

Okay so apparently we are going REALLY slow.

 

[Truman Stanford]

To everyone using Solomon's book - what chapter are you on? We're still on Ch 1 - 3rd week of lectures. Apparently we're only doing the first 6 chapters in the first semester. Is that normal? It seems REALLY slow. Am I going to get thru all the stuff I need for the MCAT by April?

That seems about right...but I don't know the book you're using. Wade anybody? We're almost to ch 4 in the 3rd week, but we flew through 1 and 2 and are going swiftly through 3, who knows. My prof likes to use the analogy of Lance Armstrong going through the flat lands the first two tests, then reaching the 40 degree incline at Elp Due' (i don't know the spelling of the big mountain along the tour de france). Then flattens out a test 4 again.

 

[dbhvt]

That seems about right...but I don't know the book you're using. Wade anybody? We're almost to ch 4 in the 3rd week, but we flew through 1 and 2 and are going swiftly through 3, who knows. My prof likes to use the analogy of Lance Armstrong going through the flat lands the first two tests, then reaching the 40 degree incline at Elp Due' (i don't know the spelling of the big mountain along the tour de france). Then flattens out a test 4 again.

Alp d'Huez.

Wade is a weiner, by the way. I didn't like his attitude. I supplemented with Solomon, which really helped. Gotta love those orgo memories.

 

[Dave_D]

To everyone using Solomon's book - what chapter are you on? We're still on Ch 1 - 3rd week of lectures. Apparently we're only doing the first 6 chapters in the first semester. Is that normal? It seems REALLY slow. Am I going to get thru all the stuff I need for the MCAT by April?

When I took it first semester was the first 10 chapters. Anyway stopping at 6? Geez, you're not even going to get to the reactions, lucky you Seriously though the massive memorizations part of the book starts with chapters 7 and 8.(6 is Sn1, Sn2, E1, and E2 reactions which are more general.)

Oh, before anyone asks Zaitsev's rule is ******ed and so is the explaination of what a nucleophile is

 

[DrBowtie]

We are going to ~10 as well.

 

[DrBowtie]

Today I had another lab. This one was simple and fractional distillation. It was easy. I just set up the apparatus and heated. The only downfall was the time it takes for the distillations (4 hours). Overall, I had a much better lab experience and I'm not as frustrated with it.

 

[beastly115]

.

 

[DoctaJay]

This website is for an older book, but it did WONDERS for me. It has powerpoints on all the infromation you'll possibly cover and it has practice quizzes, etc. Check it out:

http://www.brookscole.com/cgi-wadsw...uct_isbn_issn=0534166962&discipline_number=12

 

[Anastasis]

Today I had another lab. This one was simple and fractional distillation. It was easy. I just set up the apparatus and heated. The only downfall was the time it takes for the distillations (4 hours). Overall, I had a much better lab experience and I'm not as frustrated with it.

I found that lab pretty easy just very time consuming. Has anyone done distilling clove oil from cloves yet? You stink for the rest of the day. When I got home my dad asked me what smelled like pumpkin pie.

 

[Anastasis]

Good luck on your test, Megboo!

 

[PhotoMD]

I used Carey and thought it was really excellent, but that's me.

 

[Jaykms]

Anyone use Loudon? It's pretty good. We're up to 6.

 

[Dave_D]

True, the distillation lab wasn't bad for us last year either.(Well, the only part that was even slightly difficult was figuring out that theoretical plate stuff since it wasn't explained very well in our manual. Well that and the fact someone in my lab asked for help but couldn't even draw a graph properly. Yes, I'm serious and no I have no idea how this student got into the class in the first place.)

 

[aunaturel]

our distillation lab didn't work out at all. no one in my lab got good results. we did separation of an acid and base this week though and that was pretty easy. took about 2 hours overall.

 

[Dave_D]

So we were supposed to have exam 1 today -

The professor started passing out the exams and realized he was 40 short. So he made us turn them all back in and we're going to have the exam on Monday. Since I sit in the front row, I got a good, long look at it, and I would have ROCKED it. Now we're getting a re-written exam .

Hopefully the questions are similar!

Oh well, on the plus side since he has so much less time to do it he'll probably lean more heavily on older tests and homework problems Oh well, good luck.

 

[Truman Stanford]

Are there any supplimentary books that anyone recommends I use. The book we use is okay, but not nearly enough. We are just on the first few chapters. My impression was that the first 2 weeks or so would be a piece of cake, but it's not that easy.
Any books that could help?

The first two weeks ARE very easy, however they are very critical to understanding the rest of the course. The way and the specificity to which the material is presented is different for each professor. For instance, primary, secondary, tertiary etc. carbons is a very easy concept to understand but when a professor gives you a very large molecule to depict these from could make it tougher. This is just a for instance. Small mistakes in the problems cause big point deductions, at least in my class. If your book doesn't contain a lot of practice problems, get one that does. Lack of writing down things is the main cause of bad grades in organic. I think getting problems wrong in practice is very important. How many things do you remember that you got right?...not very many probably. However, you can probably remember the things you screwed up on and won't make those mistakes again.

 

[beastly115]

.

 

[Dave_D]

We actually went through with our 1st exam today! I finished in 20 minutes (I hope that's a good sign), but probably because I got to skim through the first test before it was recalled. I know I missed one because of stupid bubbling - I bubbled the wrong answer for one of the problems. I it when I went back over the test before I handed it in, and it still didn't register until I walked away from the building .

Hopefully the rest will go better!

Well if you really skimmed the first time and had a leg up(Kind of hard not to do so if you've seen some of it already) then I could see that. Actually it's kind of hard to tell if it's a good sign or bad at this point. However with me generally speaking when I did well I had a 30/20 thing going. Basically the first time through would be just about 30 minutes. I would then go through the test a second time double checking everything and that would take 15-20 minutes.(Usually catching a bunch of stupid mistakes.) Occasionally I had enough time for a 3rd check. Basically what I'm saying is if you have a lot of time left over just go over it carefully and really think about your answers.(Actually answer it again and then look at what you wrote and see if you figured out anything new.) Good test taking strategy means that you use as much of the time they'll let you use. (Generally speaking I never left more than 5 minutes early regardless of how fast I blew through the first time.)