Organic Chemistry Lab: Recrystallization

[Diogocc2]

What was the substance used in the video ?pliz

[tiptopluongo]

LOL for my recrystallization lab, started out with .46g, ended up with 0.04g. Worst part was I needed it for the next lab xD. I cannot express my hatred for ochem lol

[porterwake]

Vacuum drying in a steam bath is the best way to crash out solids. Especially in a sibata.

[gogo7822]

Thank you it was really useful

[MScEMRS]

I think you have something wrong at the end of the video. You have written "(...) the solvent may recrystallize (...)", but it is not the solvent that recrystallizes.

Kind regards,

E.

[xsnappyjx]

Your videos are the most helpful I've found, thank you!!

[cobrastriking]

0:19 - ARHHH THE THE THE LOOL



[eurestim87]

Omg this was sooo helpful. Thank u so much! =D

[Riza8599]

Thank you so much! I feel ready for lab today.

[ServingBongs]

With video's like this, poeple don;t even have to go to school, the future is here.

[seecherub]

thanks so much!i watched this video twice and FINALLY fully understand what crystallisation is! thank you(:

[jadiyy]

sups helpful! im taking chemistry online & would be sooo lost without youtube videos like these! thanks

[ob2be]

I wish you included your vacum filtration step in the video too, but great video!

[TSNam]

crystallization is black magic

[HamNediaj]

im on my way to clandestine chemistry , fuck going to university ! the internet is truly a remarkable tool ,

[TheWholefoodfarmacy]

Great vidio

[criticsable]

thank you!



[gradu813]

@vahedah Indeed!

[gradu813]

I love this video! Very helpful

[gradu813]

Love this video! extremely helpful :)

[xamorxamorx]

Great video! This is my first semester of Ochem lab, so I'm really nervous... I have a teacher with a reputation of being obscenely strict, so I'm trying to get ahead so that I can be competent when the time comes ... Thanks for the video, It's very clear cut and easy to understand!

[ntnhoa2011]

I'm getting into this. Thanks

[faradoidflask]

you shoud do a reflux video

[dbgb1234]

You speak without confidence, and even though the volume is really loud I feel like I can't understand what you're saying at all and it's not your English nor is it my comprehension. If you speak like you're doubting yourself, others will doubt you too. Have confidence man...

[mannendobos]

@dbgb1234

A relatively smart human beeing should understand that actually this is a realy good video for amatures. He speaks so that everyone understands and explaining the things in a good way.. And it dosnt matter if he is a little shaky in hes voice. This is a instruction video and it dosnt need to have a act in It. As long as it is educational. And FYI this man is probably more confidence with chemistry then u r :).. have a nice day

[dbgb1234]

@mannendobos "And FYI this man is probably more confidence with chemistry then u r"

That sentence makes your first sentence ironic; especially if you consider yourself a "relatively smart human beeing."

And if he didn't have more confidence than me in chemistry, he fails, because he is an assistant professor, he is expected to be good at chemistry. I wasn't insulting his knowledge of Chemistry, I was just telling him to have more confidence in himself when he speaks. That's universal advice.

[1Project1Haiduc1]

Did I just hear the Erlenmeyer flask crack at 4:30?

[austin777136]

@1Project1Haiduc1 it sounded more like the bottom was wet when it hit the hot surface

[nick11927]

did this and made aspirin

[muhkuh77]

I prefer reflux condenser and recrystallisation over night in the oil bath.

[kayenta33]

very helpful, wish i'd seen this before i fucked up in labs the other day by adding way too much solvent!

[Chuichupachichi]

This video shows you how to do it the long, complicated, unnecessary way. All you have to do is remove the lighter from underneath and you get recrystallization. It's that easy. "Hands on" is always the best way to learn anything

[UbeefHooked]

7:22 Bling

[kuvOyojOhmoob]

Thanks this was really helpful.

[hockeyrules186]

amazing! this is exactly what i was looking for. i'm doing a recrystalization lab in my organic chem lab tomorrow!

[mobilescene]

many thanks

your tips where too useful

thanx

[AlectrickPK]

thanks for this

[Hafdany]

wouldn't transfer of the powder to the flask cause your calculations to be skewed due to residual powder on the weighing paper and funnel? Or is the residual powder irrelevant in your calculations?

[cjk100000]

@Hafdany

In real life applications, it is impractical at times to worry about that.

An analytical chemist on the other hand though...

[fredstarwind]

@Hafdany While I agree totally with this statement (having labored over Biochemistry) every Organic Chemistry book will tell you that you will never get 100% recovery. In fact, 80% or higher is considered excellent recovery.

If you know your solids funnel is clean, then you can try adding your warm solvent through the funnel first ti pick up any leftovers, but you risk catching impurities from the funnel and skewing your data more than if you had just let it be.

[rosemovieXD]

OMG thanks sooooo much, my freaking teacher doesnt freaken tell you how to do anything thanks so much, finaly someone who understands, thank god for you, what would all us youtubers in chermistry do without you seriously

[xXB3AST47Xx]

i completely understand where you are coming from. Id be so lost. and my ta never explains ANYTHING.

[brian38383838]

I don't know why you guys do these videos, but thank you. It helps A LOT to see these experiments performed BEFORE lab.

[MsGrammarnazi]

Damn! I wish I would have watched this BEFORE I went to lab!

I had no idea what the hell was going on.

Great video

[aaarchvile]

Very nice videos!

[TaniaGeoluhread]

He said "you can remove this wooden thing if you`d like" .. well.. of course. do you want your crystals to form on it? heard of boiling chips?

why didn`t he filter when the solution was hot? shouldn`t he be getting rid of impurities? crystals may form on them, right?

[otleybey]

He goes to all the trouble of recrystallizing it...but he sticks a lump of wood in there! We done use bumping sticks, the last thing you want is wood fiber in your crystals.

[drrklepper]

The amount of solvent to use really is not a judgement call as you can determine a very close measurement simply by looking at solubilities.

[HaloGears360innit]

Sorry I didnt mean vacuum filter while the solution is still hot. I meant just filter (without vacuum)

[HaloGears360innit]

Why vacum filtrate after it recrystallizes then you still have all the dirt. Vacum filter when it still hot and then let it cool. Makes more sense to me :-)

[adomth3rice]

If you vacuum filter while the solution is still hot, some of your product is going to pass right through the filter (it's still dissolved).

Yield is often something that is graded in a chemistry lab.

Also, there should be any dirt. If you were referring to impurities, a good recrystallization would have few.

[jessica507]

Thank you so much!!

[mufdver8]

thanks clarified alot of questions

[Memoriesofnobody09]

ah i see ok ^^

[Memoriesofnobody09]

dude,where is your lab gown?

[scivislab]

Believe me, we did try a lab coat, but the studio lights were so intense that our instructor shone like a fluorescent bulb, ruining the whole frame. We tried *three* different shirts until we decided to go with this very unprofessional-looking shirt, which worked the best with the lights.

[havabighed]

@scivislab thats because of the black background you are using. Its all about quantum wave mechanics bro... its all about quantum wave mechanics.

[rg62191]

@aokka

Those aren't chemists. A chemist knows the reasoning behind the steps he uses. He doesn't merely play "monkey see monkey do" for quick monetary gain.

[krutmin]

I'm not familiar with vacum filtration, is there an easier way to remove the crystals?

[Ribosome21]

it goes WAY faster if you add your compound to a minimal amount of solvent and then heat gun it until it disolves.

[sujeeta2007]

i prefer re-cryst by dissolving in minimum solvent that the compd is soluble and adding drop by drop anti-solvent.

[mavadd88]

its good you got points deducted...I forgot to use one, and when i added a tiny bit more water it shot out of the erlenmeyer flask, thats when i finally knew what bumping meant...my recovery was horrible by the way and got even more points taken off

[ahcali08]

Hahaha, I remember during first semester's o-chem lab final I got points deducted for not using a boiling stick! I hated o-chem labs so much!

[TL6547]

Could you do that to yourself?

[drgergens2]

I can't tell, did you cap and cool the mixture like you are supposed to do ? SO HAPPY to see you are not recrystallizing in beaker like some knuckhead instructors do.

[brianng999]

Wouldn't it be easier to retrieve the crystals from a beaker than a conical flask?

[rebirthatthefountain]

thanks a lot, i did a recrystallization of adipic acid using your advice and my IR turned out perfectly! : ) thanks a lot

[kaoishii]

I thought the best way to obtain pure crystals was by letting it sit at room temperature?

[Forlo12345]

It is, the purpose of putting it into the ice bath is just to get more precipitate. Usually it isn't such a good idea, depending on the solvent and what compounds you have in solution. It was okay in this experiment because he probably formed the compound with nitric acid and sulfuric acid (hence, nitrated benzoic acid). In which case, nitric acid and sulfuric acid are completely soluble in water, so they will remain in solution regardless, but precipitate the crystals.

[OKGeoStudent]

Show us vacuum filtration!

[Delta9son]

:) that would be nice...

[greenapplemania]

i like how i found this out right after my ochem lab final.....:T

[urbantribes]

cool stuff