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JJay
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Quote: Originally posted by ave369  | Today, in a break between playing Fallout 4, I decided to test my brand spanking new distillation setup. When I ran it on water, it all did
handy-dandy. But then I've run it on Glauber's nitric acid synthesis, and totally forgot about that rubber bung sitting on the top of my Wurtz
flask...
Poor, poor bung. It weeps some black liquid into the flask...
[Edited on 1-12-2015 by ave369] |
I know not everything in my lab is not exactly state of the art [yet], but I am glad I don't have to use such primitive equipment!
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aga
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Rubber is one of the most advanced materials we have !
In Engineering terms, imagine your Car Tyre.
Temperatures from -40 to +50 and it works fine.
Immense pressure changes, high speed rotation etc etc.
Rubber is an Outstanding material.
Just that HNO3 is nasty to it.
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JJay
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I don't like using rubber anything... I'd use ground glass test tubes and Erlenmeyers if I could afford them.
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ave369
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By the way, the bung is basically okay. It merely has some bubble-like deformations in the bottom. But the flask, the flask! Now I need a 125g of
perhydrol to make piranha and remove that black carbony stains it wept!
Smells like ammonia....
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ave369
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That's basically where I got equipment not so long ago. Now I have an additional source: discount deprecated glassware from China.
Smells like ammonia....
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The Volatile Chemist
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What do you mean by 'bung'? Are you referring to a rubber 'stopper'? I guess my terminology isn't up to date...
I've ran a few HCl distillations with a rubber stopper, and was thinking about doing an acetone one. Glad I happened to ruin another stopper prior to
doing that one...
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phlogiston
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3 liter erlenmeyer on a hot plate. 68% nitric acid + excess of lead. Reaction proceeded nicely at first, but slowed down after a while despite heating
almost to boiling. When I realized the lead nitrate precipitate was inhibiting the reaction I added distilled water.
Good idea, but way too much at once.
The reaction suddenly became extremely vigorous and the gas evolution was enough to launch nearly half the contents of boiling hot nitric acid
saturated with lead nitrate out of the erlenmeyer. Fortunately, it was contained well because I had a basin placed underneath the hot plate and the
fume hood caught the little splashes that escaped it. But it was a toxic mess to clean up nevertheless.
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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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aga
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Bung is a more ancient word for a Stopper.
Being English, i'd say 'rubber bung' or simply 'cork' if it was made of cork.
Probably a Nautical term in origin.
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aga
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Ouch !
Could have been a Nasty accident phlogiston.
Great idea to have some sort of Containment system for liquids in case of accidents.
My own is simply that the bottom of the fume hood is a glass tray made from glass pieces and silicone sealant.
Saved liquid escaping the area a couple of times (accidents do happen !)
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phlogiston
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Yes, it is definitely a good idea to have a little raised edge on the fume hood bottom to contain liquid.
During a practical course a fellow student once had a large round bottom flask break that was filled with a large quantity (liters) of an
acetone/ether mixture that was boiling under vacuum.
The quantity of the mixture was so much and it was released to suddenly that it a lot of it splashed out of the fume hood all over his trousers and
shoes.
Amusingly, his pants and shoes both quickly dissolved which left him barefoot with just his underwear for the rest of the day, when a friend fetched
him a new pair from home.
He was very fortunate that it didn't catch fire. The students in the adjoining fume hood were using a burning bunsen burner.
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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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aga
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Hmm.
Better to do Chemistry in a group or alone ?
Pros and cons both ways.
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ave369
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Generally, being on the meds makes me a total klutz. Casualties in my lab yesterday: funnel, drip tube, small Erlenmeyer flask, measuring cylinder,
balance (I spilled conc sulfuric on it, and it ate some of the electronics inside), and once again an already glued Buchner funnel.
Addendum: I'm losing Erlenmeyers one after another! Just found out that the other one, the favourite 100 ml Erlenmeyer cracked!
[Edited on 4-12-2015 by ave369]
Smells like ammonia....
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eanardi
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[rquote=428227&tid=63645&author=Jars are for storage, NOT heating. 
[ Thats true, and I learned it when I was cleaning up the jar I used to carry out exotermic solutions (in this case I had used it to react calcium
carbide with water). Fortunately the calcium hydroxide that sticked to my coat didn't even react with it! /rquote]
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The Volatile Chemist
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Alone, or with a lab partner of the opposite gender (kidding...).
I talked to my uncle, once a member of the US Navy, who was an electrician and rubber and plastics technician. Bung is a term used for rubber plugs,
even those not like a so-called 'stopper'. Probably nautical.
Not really an accident, but today I tried to make copper(II) borate from basic copper(II) carbonate and boric acid. After much heating, a total
waste...
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aga
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Heigh Ho.
Shit happens
Things (good or bad) only Happen when people have the Will to actually Do things, and then actually Do things.
Your Experience quotient just went Up TVC.
As a post-experimental dissection, what did you expect the product to be ?
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The Volatile Chemist
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Haha, Copper(II) borate. ...Are metal borates even reasonably possible from boric acid? (My practical knowledge is very low...)
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chemrox
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| Quote: Originally posted by aga | jsum_1 made an incredibly good point today : what Can go wrong is rarely documented, just the Successes are publicised.
I suggest we share the knowledge of what actually happens when chemistry is done wrong/badly.
For starters: forget to add boiling chips to the boiling pot when distilling Phenol under vacuum.
What happens is that it boils nicely for a while, then the liquid goes still for a few seconds, then explodes up the column and pukes all over the
place before boiling nicely again for a few seconds, then goes silent again etc.
Edit:
We should learn by our mistakes, and that means sharing them.
[Edited on 15-9-2015 by aga] |
Boiling chips don't serve in vacuum. What you need is very fine bubble inlet. Or use a vigeraux to minimize the bumping consequences.
Having made the rant; I think publishing errors is not too bad an idea. Most of us do that by raising questions. The latter approach makes us research
the issue prior to posting. Otherwise the risk is getting a lot of random posting with no real chemistry.
[Edited on 13-12-2015 by chemrox]
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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The Volatile Chemist
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Indeed, they're useful. Perhaps our SM Wiki should include more of such.
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KesterDraconis
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I spilled quite a bit of acid all over a glove the other day. It ruined the glove, but I am fine. I had placed it on wrong/insecurely, and it came off
in an unexpected manner.
Just a friendly reminder to respect the chemicals (even when is seems safe, like in a bottle) and wear your protective equipment, it will save you
from a lot of pain!
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The Volatile Chemist
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Today at school, we did gel electrophoresis in my AP Bio class. I was the only one who wanted to fill the gels (the holes are tiny, of course). We ran
them in boxes that fit two, and my group of four was the second to fill ours (we filled them after they were in the fluid). I filled the first one,
and in filling the second one, my hand started shaking a bit, and got pretty shaky by the end of filling. One of the guys in the group said I looked
like I had Parkinson's, and that I was more shaky than his grandpa...well...
At least I got samples of the DNA we were using, Lambda Phage DNA. 
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tommy claisen
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Another unfortunate event occurred while extracting the product of an ester hydrolysis. 30l of aqueous were being dropped from the wash tank in the
walk-in hood. The MTBE fumes from what was dissolved in the water layer ignited, causing a brief but rather startling fire. It's a miracle that the
organic layer in the tank was not ignited by this event. The product was then stripped of solvent and vacuum distilled as normal.
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chemrox
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Rubber belongs on when chem goes wrong
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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JJay
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I was just boiling some copper (II) chloride solution to dryness in a dish in a small oven, and after the solution became saturated, it started
bumping badly, splashing concentrated copper (II) chloride solution all over the inside of the oven. Fortunately, the oven is mostly stainless steel.
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The Volatile Chemist
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| Quote: Originally posted by JJay | | I was just boiling some copper (II) chloride solution to dryness in a dish in a small oven, and after the solution became saturated, it started
bumping badly, splashing concentrated copper (II) chloride solution all over the inside of the oven. Fortunately, the oven is mostly stainless steel.
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This has happened to me, too. I think it's a given for making the dry salt.
I accidentally forgot to read the graduated cylinder before titrating today at home... Wasted 2g KH - Phthalate...
Also got ~0.25mL ~2M NaOH on my pointer finger and thumb, found out how that felt...
But at least I found a method of producing Copper(II) Phthalate (If this compound doesn't exist, please tell me, otherwise I'm fairly sure I've
produced it).
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Heavy Walter
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Hi
Here are my old bad experiences:
-When working at the university, I needed to protect some carbides from ambient humidity, so I picked up a large 5 lt vacuum desiccator on heavy
glass, looked for a cover with stopcock and started evacuating the desiccator, which after some minutes, I left on a table.
After walking out ONE step outside the lab a large explosion brought me back into: the lab was full of small glass pieces...
That way I learned that covers and desiccators are matched, grinded and polished to couple exactly. Using a different one subjected the cover to
excessive stresses by deformation.
-When needed to cool a trap with liquid nitrogen, I employed a home plastic food flask. After using it, at pouring the excess into a large industrial
dewar the flask suffered stresses so extreme that the flask exploded, ejecting liquid nitrogen, plastic and glass by its bottom.
Here are my two cents...
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