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Gasses Sink/Float: Molar Mass or Density? by Shitting Beblingsutch - Sat, 11 Apr 2015 01:39:44 EST ID:vFjYr6dk No.76360 Ignore Report Reply Quick Reply
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If I want to know if one gas sinks below another, do I look at molar mass or density?
Cyril Brettingchodge - Sat, 11 Apr 2015 11:57:09 EST ID:72wOh3Tw No.76361 Ignore Report Quick Reply
Nicholas Guttingdock - Sat, 11 Apr 2015 12:09:46 EST ID:nJ2oIuZB No.76362 Ignore Report Quick Reply
This, commonly used haloalkane solvents like DCM are dense and usually form the bottom layer in a separation funnel.
Nicholas Guttingdock - Sat, 11 Apr 2015 12:21:17 EST ID:nJ2oIuZB No.76363 Ignore Report Quick Reply
Oh jolly african-american, I misread your post OP. Dun Goof'd. Still is useful I guess.
Bombastus !!HToBa9dh - Sat, 11 Apr 2015 19:31:53 EST ID:ElYFdcKO No.76364 Ignore Report Quick Reply
Density. Ether is commonly used to describe just this. It hugs the floor and is hard to suck up by fume hoods this way. It's also immiscible with atmospheric nitrogen and oxygen.

When it burns, it burns up, and rises. This is why it is so dangerous as it will (literally) scan your body with flames as it rises and gets hotter. Fun times.

non traceable poisons by Nigger Birrychock - Sun, 29 Mar 2015 15:35:45 EST ID:/UUEsarU No.76315 Ignore Report Reply Quick Reply
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I am studying chemistry and work on my toxology certificate.
Are there educational materials for such things?
Eliza Firrynit - Tue, 31 Mar 2015 12:26:35 EST ID:mEgh7QsF No.76316 Ignore Report Quick Reply

your classes?
Graham Tootshit - Wed, 01 Apr 2015 10:19:27 EST ID:+0Ci6TLP No.76317 Ignore Report Quick Reply
Look into choking agents and blood agents. Pretty much everything is detectable in some way.
Sorry, you're not going to be some sort of evil mastermind.
Priscilla Blatherbury - Thu, 02 Apr 2015 03:45:20 EST ID:FNUHoZhY No.76322 Ignore Report Quick Reply
there are plenty of non traceable ways to kill someone with substances. i dont get your point. do you want to specialize on them or something?
Beatrice Greenshaw - Thu, 02 Apr 2015 09:17:43 EST ID:9rpu1XKo No.76323 Ignore Report Quick Reply
poison is bad, mmkay?

don't do poison.
Nigger Clovingkack - Sun, 12 Apr 2015 01:38:28 EST ID:T3+BR5r7 No.76372 Ignore Report Quick Reply

I don't know why this doesn't work out by Hannah Nottinghit - Fri, 27 Mar 2015 08:02:42 EST ID:a+ez4ZPu No.76311 Ignore Report Reply Quick Reply
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Okay, I need some help understanding this. I thought I understood it but now it's driving me mad. The question is this:

>>An emu accelerates at 2.5 m/s2 from an initial unknown speed for 3.1 s, and covers a distance of 25.97 m. What was it's initial speed?

From the information given I have;
Acceleration = 2.5 m/s
Time = 3.1
Distance = 25.97 m

I found out the final velocity because v = d/t so;
25.97/3.1 = 8.38 m/s

Now that I know this I can use the equation; u = v - at
to get an answer of 0.627 m/s
Comment too long. Click here to view the full text.
Martin Clayham - Fri, 27 Mar 2015 20:46:50 EST ID:+0Ci6TLP No.76313 Ignore Report Quick Reply
>I found out the final velocity because v = d/t so;
25.97/3.1 = 8.38 m/s

That's not the final velocity, that's the average velocity.

You should just use x - x0 = v0t + 1/2at2
those x0 and v0 mean "initial point" and "initial velocity". You can set x0 as 0. The x-x0 portion is used to calculate distance traveled, which we already know is 25.97.

v0=??? (initial velocity! the thing you're trying to figure out!)

slap it all together for 25.97= v0*3.1 + 0.5*2.5*9.61
Comment too long. Click here to view the full text.
Martin Bicklenitch - Sat, 28 Mar 2015 08:09:25 EST ID:FN5/PnRw No.76314 Ignore Report Quick Reply
OP here. Thanks a lot for clearing that up. It makes A LOT more sense now. Man I sure felt silly mistaking average velocity for final velocity.

A/B extractions by Shitting Murdson - Sat, 21 Mar 2015 04:37:58 EST ID:QTA7XiiV No.76297 Ignore Report Reply Quick Reply
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Lets say for example someone was looking to do A/B extractions of spice containing plant material, or clean up HBWR seeds and choose a solvent.

Typical teks ask for naphtha, usually in the form of camping gas fuel or premium blends of white spirits/thinners. I guess this is because they are easiest to obtain.

In this case though, the easiest things on hand are toluene and acetone, plenty of lab grade around. Any dangers/things to be aware of? Obviously someone could easily go and get a bottle or two of lighter fuel or premium white spirit (heavy naphtha) but if what is already on hand is a superior solvent for the purpose what would be the point?
trypto - Sat, 21 Mar 2015 10:08:33 EST ID:MX8ylq9S No.76298 Ignore Report Quick Reply
They're flammable and require a lot of ventilation. Toluene is a neurotoxin.
Clara Lightworth - Sun, 22 Mar 2015 18:25:36 EST ID:40Q00fz0 No.76300 Ignore Report Quick Reply
They use naptha for a number of very good reasons.
Acetone is polar, no good for defatting.
Ebenezer Pummerwater - Thu, 26 Mar 2015 16:30:03 EST ID:D/LtHvOX No.76310 Ignore Report Quick Reply
I really hate when I'm taking a shit and the tip of my boner touches the water
Fucking Sidgemere - Fri, 27 Mar 2015 19:26:56 EST ID:W9ZvC6sa No.76312 Ignore Report Quick Reply
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Lithium carbonate by Wesley Gindlefield - Tue, 17 Mar 2015 19:54:32 EST ID:sVHDOd8A No.76284 Ignore Report Reply Quick Reply
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Can lithium carbonate pills be used in the production of meth? If not, is it possible to decompose the lithium carbonate into elemental lithium? I'm not knowledgeable about chemistry at all, so I'm not going to try making meth regardless, I'm just curious
trypto - Tue, 17 Mar 2015 20:58:34 EST ID:MX8ylq9S No.76286 Ignore Report Quick Reply
>Can lithium carbonate pills be used in the production of meth?
No. That lithium is in an ionic form. I think it would need to be oxidized before it could be used as a reducing agent.
> If not, is it possible to decompose the lithium carbonate into elemental lithium?
Probably. I'm not sure how. You'd need to oxidize it in a non-aqueous environment, which I'm not sure how they do that.
trypto - Tue, 17 Mar 2015 21:00:07 EST ID:MX8ylq9S No.76287 Ignore Report Quick Reply
>That lithium is in an ionic form.
Actually, so is LAH. I have no idea, disregard post, etc..
John Pimmlestock - Wed, 18 Mar 2015 00:50:57 EST ID:nP+ABieG No.76288 Ignore Report Quick Reply
Metallic Lithium (0 oxidation state) is used in the reaction that you're referring to. It's known as the Birch Reduction, look it up. Anyway lithium carbonate is in a higher oxidation state so if you were to attempt to use it you would have to reduce it first. I'm sure it's possible somehow, but whether or not it's practical is the real question. Just use batteries man
Thomas Tillingdale - Sun, 22 Mar 2015 17:34:07 EST ID:WLI2JfZi No.76299 Ignore Report Quick Reply
use the lithium from batteries

Hypothetical drug question by Phyllis Fombleneg - Fri, 20 Mar 2015 18:28:24 EST ID:RythmNZp No.76293 Ignore Report Reply Quick Reply
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This is a purely hypothetical question, first off. I want to get that out there because I have no intention of committing any illegal acts whatsoever.

My question is, would it be possible to accidentally synthesize methamphetamine while trying to synthesize dextroamphetamine?
Syllogism - Fri, 20 Mar 2015 19:18:11 EST ID:stqlrmZK No.76295 Ignore Report Quick Reply
They can be made from the same precursor but the conditions for affording one vs. the other are drastically different.
Emma Gobberridge - Thu, 26 Mar 2015 02:31:37 EST ID:T3+BR5r7 No.76309 Ignore Report Quick Reply
I doubt it unless you have no clue what your synthesizing.

Polyurethane glue by Cedric Brebblesat - Thu, 19 Mar 2015 13:50:01 EST ID:r2jX1VWD No.76289 Ignore Report Reply Quick Reply
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Safe to use on a vape? I broke a glass neck on my buddies vape, the piece which would connect to either the ballon or the whip, and used gorilla glue to fix it. Gorilla glue is a Polyurethane glue, and i haven't found much on the internet concerning how it reacts to heat. I usually set my vape between 350 and 400 degrees F, getting the internal weed temp to about 200 degrees, meaning the glue must withstand in or just below that temp w/o releasing vapors or melting. What do yall think /chem/? Is it safe or am i giving myself cancer?
Cedric Brebblesat - Thu, 19 Mar 2015 14:01:41 EST ID:r2jX1VWD No.76290 Ignore Report Quick Reply
Correction, the brand i have is gorilla SUPER glue, which is a cyanoacrylate adhesive, and can withstand tempuratures around 200 - 220 F, according to the website,

nb for double post
David Dongercocke - Thu, 19 Mar 2015 19:33:52 EST ID:W9ZvC6sa No.76291 Ignore Report Quick Reply

it isn't safe.

dem polymerz by Fuck Saddleridge - Mon, 16 Mar 2015 19:09:11 EST ID:9FLQiANc No.76278 Ignore Report Reply Quick Reply
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sup /chem/ I am trying to remold a polymer object because it broke, how would you go about filling in gaps/holes in a polymer object? I'm not really looking for how to fill the gaps, that part is obvious, just what I should use is the problem. Should I just melt some plastic in a crucible and pour it in? And how do I make it bind/what can I use to stop up areas I don't want the stuff to flow into that won't bind to the liquid?

Should I just go buy something? i'd rather not, I prefer learning how to make stuff like this to just buying something and missing out on knowledge.

So what can you tell me /chem/?

BTW this is my first post here. Please be gentle.
trypto - Mon, 16 Mar 2015 23:26:33 EST ID:MX8ylq9S No.76279 Ignore Report Quick Reply
If it's just for filling cracks/holes, then silicone sealant works great and is easy to work with. It's relatively soft, and isn't great at joining two pieces.

If you want a harder filling, or if you need to join pieces that would be under stress, epoxy is the way to go. This is comes in packages of two liquids that you mix to get thick fluid. This cures in 5-15 minutes into a very hard plastic.

If you're reattaching small pieces of plastic, superglue works well for most plastics. This is also gives the closest bond, since it's much less viscous than epoxy or silicone. but it needs a decent sized surface area for the joint to be any good. Unlike Epoxy and silicone, this doesn't solidify into a substantial chunk of plastic.

>And how do I make it bind/what can I use to stop up areas I don't want the stuff to flow into that won't bind to the liquid?
With superglue, just be careful and wipe off excess. With silicone, you can easily cut off the excess shit when it dries. With epoxy, it's a matter of cleaning up while it's still wet (best to have a scraper).
Hannah Wammercocke - Tue, 17 Mar 2015 12:58:55 EST ID:9FLQiANc No.76282 Ignore Report Quick Reply

Okay thanks matey, I was hoping for something about melting down broken pieces of plastic garbage but I do have some epoxy so fuck it why overcomplicate
Cyril Bleblingnat - Tue, 17 Mar 2015 19:23:14 EST ID:MX8ylq9S No.76283 Ignore Report Quick Reply
I think by the time most plastics freely flow, they're very near their burning point. So it's not usually practical.

I also forgot hot glue guns. This is actually a great option because you can also get them in a variety of colors. Hot glue is fucking great..

Salting Out IPA by Molly Sonningwill - Wed, 11 Mar 2015 21:17:11 EST ID:RLSN+6eM No.76231 Ignore Report Reply Quick Reply
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Guys I tried to get mostly pure IPA by salting it out with NaOH. So I just poured some NaOH in there, mixed for a bit, then let it settle for 20 hours. 2 layers did form, but when I did an evaporation test on the top layer I saw definite white lye residue left over.
So what am I doing wrong?
Alice Wonderford - Sat, 14 Mar 2015 22:14:52 EST ID:31mK/U3c No.76254 Ignore Report Quick Reply
>>76231 NaOH won't appreciably deprotonate IPA to salt it out; and what two layers are you talking about? can't be water/ipa
Hugh Dingerfuck - Sat, 14 Mar 2015 23:00:26 EST ID:RLSN+6eM No.76255 Ignore Report Quick Reply
It must be water/ipa. The idea is that the hygroscopic NaOH absorbs the water while being insoluble in the IPA.
I will it try it with MgSO4 next though as I've read of people using that too.
I've also read of just NaCl but that's too easy.
Alice Wonderford - Sun, 15 Mar 2015 04:19:02 EST ID:31mK/U3c No.76258 Ignore Report Quick Reply
i've never heard of that method, but just distil it from MgSO4 if you need it dry

Anhydrous MgSO4 Water Absorption by Charlotte Besslespear - Fri, 13 Mar 2015 21:08:31 EST ID:RLSN+6eM No.76244 Ignore Report Reply Quick Reply
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If MgSO4 absorbs 204.7% of its weight in water, then what will the final product be regarding the water of crystallization?
MgSO4.0H2O ---> MgSO4.xH2O

If MgSO4 molar mass = 120.37 and H2O molar mass = 18.015, then would you divide those and get (120.37 / 18.015) = 6.68?
But that does not seem right because in the notation of water of crystallization, you either have a 6H2O or a 7H2O, not in-between.
Syllogism - Sat, 14 Mar 2015 05:23:54 EST ID:stqlrmZK No.76249 Ignore Report Quick Reply
>If MgSO4 absorbs 204.7% of its weight in water
>204.7% of its weight in water

The hydrated mass is a wee bit more than just double, so rotely dividing the molar mass of the salt by the molar mass of water isn't gonna cut it here. Take this into account and you should get a more comfortable answer.
Hugh Dingerfuck - Sat, 14 Mar 2015 23:03:05 EST ID:RLSN+6eM No.76256 Ignore Report Quick Reply
Thank you; I did it!
[(120.37 * 2.047) - 120.37] ÷ 18.015 = ~7
Syllogism - Sun, 15 Mar 2015 07:24:55 EST ID:stqlrmZK No.76259 Ignore Report Quick Reply


Cleaning 2C-B by Charles Poffingpitch - Wed, 25 Feb 2015 01:07:24 EST ID:RLSN+6eM No.76152 Ignore Report Reply Quick Reply
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I read this exerpt:

"1.55g off-white 2C-B.HBr was suspended in 25ml isopropanol in a 75ml beaker with magnetic stirring, and was heated until all the salt had dissolved*, then removed from the heat, and 15ml ether added to the light amber solution. A suspension of white crystals slowly appeared, and after the solution had returned to room temperature it was put in the fridge for a few hours to ensure complete crystallization, the precipitate filtered, washed with 2x10ml ether and sucked free of solvents. After air drying overnight, the resulting fluffy white powder weighed 1.40g (90% recovery)."

However, if I don't have access to ether, how can I clean my 2C-B? What is it soluble in and what are the possible impurities not soluble in?
5 posts and 1 images omitted. Click Reply to view.
George Creffingwad - Sat, 28 Feb 2015 00:08:32 EST ID:RLSN+6eM No.76179 Ignore Report Quick Reply
That's carcinogenic so what should I do!?
Syllogism - Sat, 28 Feb 2015 00:17:04 EST ID:stqlrmZK No.76180 Ignore Report Quick Reply

The isopropanol served as the solution for a more rigorous purification technique, a recrystallization. Washes are a last measure to remove impurities remaining on the surface of the crystal.
Charlotte Besslespear - Fri, 13 Mar 2015 22:07:35 EST ID:RLSN+6eM No.76245 Ignore Report Quick Reply
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What are some easily accessible solvents one can use to do a simple wash to remove impurities from 2C-B?
Syllogism - Sat, 14 Mar 2015 05:08:54 EST ID:stqlrmZK No.76248 Ignore Report Quick Reply

Green Fox listed a few. Go with naptha or limonene.
project2501 - Mon, 11 May 2015 16:36:32 EST ID:muMoQJT9 No.76504 Ignore Report Quick Reply
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there are alot of portfolios on common impurities as well as on the solubility of 2cb in various solvents. i think googling for 2cb h-nmr spectra should get you a pdf by some international drug task force listing qualitative solubilities

id !guess! IPA, EtOH, MeOH and water should dissolve your goal. i guess EtOAc would be too apolar, but itd make for a nice "solvent anti solvent system" with hexane

the available solvents depend on your location.
but IPA should be obtainable in perfectly fine purity. you could dissolve it in IPA, filter off solids and then let the solvent evaporate slowly. of course thatd only remove impurities insoluble in IPA

i sure hope they never prove that in humans. or atleast then id get to stop invensting in a retirement fund

Rotovaps by LEEEEEEEEEEEROY JEEEENKeeeeems - Sat, 21 Feb 2015 19:04:17 EST ID:40Q00fz0 No.76131 Ignore Report Reply Quick Reply
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Has anyone here ever built or used a homemade Rotary Evaporator?

Also, any stories or info on Rotovaps is very welcome.
10 posts and 3 images omitted. Click Reply to view.
Graham Pockville - Sat, 28 Feb 2015 14:36:14 EST ID:oDbdEczN No.76187 Ignore Report Quick Reply
Unrelated story about rotovaps,
I'm a second year chemistry major, and therefore have had to use a rotovap plenty of times. I was talking to the TA of our ochem lab and he told us that all of the non-majors taking ochem labs ( pre-meds, bio majors, and others) don't get to use rotovaps. The department apparently doesn't trust the ~1000 non-major lab students they get every year to not break all of the equipment they use. Apparently they just hold a beaker full of their solvent/product under the compressed air jet until most of the solvent evaporates. Thank god I don't have to deal with that.
Green Fox - Sat, 28 Feb 2015 23:07:20 EST ID:0YyKnwjY No.76192 Ignore Report Quick Reply

So show us your design? You need two perfectly mating surfaces which grind against one another for hundreds of hours and maintain a perfect seal.


Zuhhh? Drying glassware with compressed air is enough of a pain in the ass. Where do you go to school?

I'm a wizard with a rotovap. :) I worked in a lab with a rotovap which took 50L flasks once. Exactly the same design, just enormous everything. With hexane there would be a constant waterfall of solvent coming off the condenser during operation
Ebenezer Chizzlehuck - Sun, 01 Mar 2015 10:22:40 EST ID:iiBda9a+ No.76195 Ignore Report Quick Reply
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from a link in this thread. he later says he lubricated this with silicone faucet grease

do your research bro
Walter Surrybury - Tue, 03 Mar 2015 09:22:50 EST ID:kVxUxljq No.76198 Ignore Report Quick Reply
rotovap is ez mode equipment
lets see you boys titrate
Ian Nibbletun - Thu, 12 Mar 2015 11:00:19 EST ID:40Q00fz0 No.76237 Ignore Report Quick Reply
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I built it out of parts from Homo Depot, but no one ever contributed anything to the thread except me, so I'm just going to sell the design instead.
Only took me several tries. It even works with vacuum.

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