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Author: Subject: Bad days in the lab or with glassware?
aonomus
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[*] posted on 3-1-2010 at 19:03
Bad days in the lab or with glassware?


So I'm sure that while accidents aren't funny, I'm sure we have some minor things that aren't major accidents, or involve breakage of glassware. I thought I'd share my bad day in the hopes that others have had similar experiences. Perhaps there is something to learn?

So today started out fine enough, and I was in the process of recovering a nice CuSO4 crystal that I slowly grew over a few days in a desiccator. Once I had it out, I managed to drop it from about 4ft off the ground, having it shatter. I was dejected, but kept on working and recovered the bits of the crystal.

Later on, a housemate drops a can of pepsi from about waist height onto my big toe while I was taking a short break from cleaning glassware.

Limping over to the lab I finish rinsing my glassware, and set down a 29/42 to 24/40 adapter on a plastic tray to dry. It rolled about 1 inch and hit another piece of glassware, taking a big chip out of the adapter....

Notice how the adapter instantly makes a sad face :(







So instead, I decided to make fun of the broken adapter, and personified it.



[Edited on 4-1-2010 by aonomus]
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[*] posted on 3-1-2010 at 19:10


Aww, Mr. Adapter is sad. He should rub himself against his wrists in angst.

Tim




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[*] posted on 3-1-2010 at 22:02


I once knocked a cheap 250ml beaker off my desk, had it bounce and roll. No problems. Wiped forehead and continued.

Half an hour later I was washing a much more expensive, durable boiling tube with a soft cloth and had it shatter in my hands. That was fun, picking out the pieces from my hand! Typical.




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anotheronebitesthedust
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[*] posted on 3-1-2010 at 22:27


How about getting excited about a new shipment of glassware that you spent $500 on only to find that 2 of the flasks have air bubbles in them, and the other flask and the condensers are shattered.
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[*] posted on 4-1-2010 at 01:20


I once made some bromine (distilling from NaBr+KBrO3+H2SO4 all in water). I had 10 ml of bromine in a little flask. I decided to dry this with 10 ml of H2SO4 which works great. Next I went outside and wanted to separate the H2SO4 and bromine. I went outside because of the bromine vapors. I poured the mix of Br2 and H2SO4 in a separating funnel, only to discover that the liquids simply run through :o. I had forgotten to close the funnel at the bottom and all liquid (and a lot of work and time) was gone. Fortunately no personal accident happened and the mess was outside. I cleaned the mess with dilute ammonia (giving dense white smoke of NH4Br).



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[*] posted on 4-1-2010 at 03:12


the first time i made a sodium solution in ammonia the rb flask cracked in the alcohol bath without my knowing allowing very wet alcohol to seep in, i discovered it a few minutes later when i went to photograph the glorious blue to find it had all gone white. I calmly removed the flask and placed it with a bucket within a bucket. there was only ~1g of sodium in it so i guess not really that much could have happened.
Undeterred i managed several lovely attempts crystallizing the sodium out of the evaporating ammonia solution, forming intricate sodium dendrites up the walls of the flask, glistening with sodiums metallic luster. So fragile both mechanically and chemically it is special to witness.




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[*] posted on 4-1-2010 at 04:05


Ow yes i remember a couple of bad days.

This one is not my fault and could have been fatal.

In my second year of education (chemistry) I was in the lab with a girl next to me.
She was doing a filtration using a ceramic filter and a thick walled erlenmeyer.
It was almost time for a coffee break and i went to the other side of the lab to get my coat and cigarettes.
The girl that was next to me left the lab right before me.
Suddenly a very loud explosion occurred.
Pieces of glass smacked against the wall just inches away from where i stood.

Well what had happened...
The girl had left the vacuum open, the filter clotted and the vacuum got so deep that the flask was not capable of holding it.
It imploded and if course exploded directly afterwards.

Would it been a minute earlier i could have been perforated with thick pieces of glass.
I was lucky, very lucky.

guess one could call this a bad day :)






What a fine day for chemistry this is.
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aonomus
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[*] posted on 4-1-2010 at 05:14


Quote: Originally posted by User  
Well what had happened...
The girl had left the vacuum open, the filter clotted and the vacuum got so deep that the flask was not capable of holding it.
It imploded and if course exploded directly afterwards.


Wow, the house vac at your undergrad lab was that good? Usually during the lab hours, the vacuum pressure drops significantly, to the point where water aspirators do a better job. I suppose its all a matter of scale, but when you have 100+ students vacuum filtering with the same vacuum system in the building, plus a bunch of rotovaps humming away, things get to the point where even if you left the vac open, you wouldn't get too strong a vacuum.

Good to see that no one has hurt themselves here, but it goes to show how Murphy shows his face from time to time with all of us...
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[*] posted on 4-1-2010 at 05:37


It was at the end of the day.
Could well be that she was the only one using the system.

She wasnt really one of the smartest persons in the class ;)


Working with some people made me feel more insecure than the most dangerous and maybe even irresponsible experiments that I performed.
I also remember some dude that wiped a complete distillation set-up filled with hot solvent off the table.
Ouch..

I barely broke glass in the last couple of years.
A short while ago i did something stupid.
I had a 2 litre erlemeyer with a ground joint.
An adapter had frozen in the joint :S
I applied some force , not that much.
I broke the whole damn top off the flask.
Guess it was already weak.
Still those damn things are expensive.

[Edited on 4-1-2010 by User]




What a fine day for chemistry this is.
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mr.crow
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[*] posted on 4-1-2010 at 07:07


I guess glass breaks when it wants to :(

Does anyone think the adapter is still usable or is it filled with internal stress and could shatter at any moment?

woelen: Holy cow thats the worst time to have an open sep funnel :o
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[*] posted on 4-1-2010 at 07:11


Wandering a little offtopic, but... should the strength of the vacuum even be all that relevant? I would think that a flask designed for vacuum would have some safety margin, and the difference between a hard vacuum and a relatively poor one wouldn't be all that much in terms of forces exerted on the flask.
Kind of curious since I have a heavy-walled 2l Erlenmeyer which is supposedly designed for vacuum, and I would prefer not to have to be overcautious in terms of how hard a vacuum I subject it to... I'd hope that an implosion would be a result of cracked or flawed glassware.
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[*] posted on 5-1-2010 at 02:40


In some instances, where a breakage is not in a critical part of a piece of glassware, and it is not likely to be subjected to high temperatures or mechanical stresses, e.g. a piece broken from the foot of a measuring cylinder, it may be possible to glue it back together with a two-pack epoxy glue (Araldite etc.).
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[*] posted on 7-1-2010 at 06:19


ya I remember (may be 1 year back), I had a bad experience with methylene chloride filled glass jar. I kept methylene chloride in normal glass vessel without any space (full). It was summer and after few hours there was big sound BuMMMM. To my surprise, there was methylene chloride all over the floor and I saw the glass vessel was broken (due to pressure exerted by methylene chloride vapor). Since then, I started leaving some space for solvent vapors to play freely...GOOD LESSON;)



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aonomus
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[*] posted on 7-1-2010 at 06:32


Yikes, DCM is one of those solvents I'd rather not have spill all over a lab floor....
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Jor
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[*] posted on 7-1-2010 at 06:42


Some DCM on the floor is no problem at all. DCM is alo in paint stripper, and i guess many people use it in great quantities without high quality ventilation. It quickly evaporates, leaving no residue. What is much worse is spilling non-volatile toxins. I have twice kicked over a beaker by accident. One time it contained a conc. copper sulfate solution and once it contained a Cr(III)-solution. These are quite nasty experiences, having to clean it all up. When I spill solvents I just let it evaporate.
Also I once had a wet precitipate of PbI2, wich i was heating with my burner, as i was impatient to use the hotplate, wich i normally use (at bout 90C). I heated to fast, and some water boiled splattering small amounts of PbI2 crystals all in the hood, staining the bench. it was a total of 200mg i think. This is also very annoying to clean up.

My most nasty spill ever, was about 200mg of HgO (long time ago) on the bench. It also stained my bench, so i had to pour acid on the bench to dissolve the stains, and absorb into paper. Now I always work over containment when working with things like Hg, Pb and Cr(VI), unless test-tube scale.
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[*] posted on 7-1-2010 at 07:57


Quote: Originally posted by Jor  
Some DCM on the floor is no problem at all. DCM is alo in paint stripper, and i guess many people use it in great quantities without high quality ventilation. It quickly evaporates, leaving no residue. What is much worse is spilling non-volatile toxins. I have twice kicked over a beaker by accident. One time it contained a conc. copper sulfate solution and once it contained a Cr(III)-solution. These are quite nasty experiences, having to clean it all up. When I spill solvents I just let it evaporate.
Also I once had a wet precitipate of PbI2, wich i was heating with my burner, as i was impatient to use the hotplate, wich i normally use (at bout 90C). I heated to fast, and some water boiled splattering small amounts of PbI2 crystals all in the hood, staining the bench. it was a total of 200mg i think. This is also very annoying to clean up.

My most nasty spill ever, was about 200mg of HgO (long time ago) on the bench. It also stained my bench, so i had to pour acid on the bench to dissolve the stains, and absorb into paper. Now I always work over containment when working with things like Hg, Pb and Cr(VI), unless test-tube scale.


Ya its volatile and easily evaporates. Even then we can't risk to its exposure as it has been classified as carcinogen (though many compounds fall in this category). Yes, you are rite it is used in paint but due to its toxicity (though mild) people are trying to ban or lessen the concentration. Pls check out the link below.

http://www.europarl.europa.eu/news/expert/infopress_page/064...

There was no problem cleaning methylene chloride but it was quite boring to collect glass pieces. It might be dangerous if someone was present there during the breakage. :D




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aonomus
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[*] posted on 7-1-2010 at 08:19


I fear for the undergraduate chem labs at my uni who have a lab of 24 students work with DCM at the bench for the first time ever, packing and running microscale columns.

I remember walking by and nearly keeling over from the fumes in the hall, I don't know how they survive in that lab. One spark and the whole place would go off.
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[*] posted on 7-1-2010 at 08:50


For practical purposes DCM is non-flammable in the typical undergraduate laboratory setting. I believe that is why it has replaced ether as a solvent whenever possible. For a truly hazardous situation go back to the 1960's when the lab could be filled with the smell of ether. :o

24 students in one organic lab seems like too many. But then maybe I've been spoiled.




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[*] posted on 7-1-2010 at 09:13


Well, at our uni laboratory, we use ether in organic synthesis instead of dichloromethane.
I don't understand it, as I consider dichloromethane one of the safest solvents, due to its non-flammability, relatively low toxicity (if you handle it in a well ventilated area at least).
But they say it's dangerous as it's a carcinogen... I mean, common, if you use this stuff in a fume hood it is EXTREMELY safe, outside a hood but with good ventilation it is still one of the safest solvents as long as you don't use it daily.

But they are pretty paranoid here. Chloroform and toluene may not even be used by 1st year undergraduates (although in second year it is used as a starting point for synthesis). Well finally I convinced them I could use some toluene after a lot of arguing. Also for one synthesis I needed 400mg of sodium, but this was not allowed... I just needed to dissolve it in benzyl alcohol, I mean what is dangerous about that, you even need to heat to dissolve it.
Mercury compounds are completely banned AFAIK on our uni... (that's just insane, banning an element from a research institute).
But it's ironic that they let us weight out p-toluidine and p-nitrotoluene just in the open, no hood. Especially the former is quite nasty, especially compared to toluene....
Well not really a problem for me :) I have most things at hand at home anyways, so I can use these materials when I want :)

It's remarkable how safely you learn to work at home, if you experiment a lot. At home you are responsible, and you experiment a lot more (at least I do) than do students, and you work very carefully. My supervisors (3rd or 4th years students) were quite stupid on safety point of view, I saw them doing things wich I would never do. And they don't even know what's gonna happen. For example, for analytic project, we had to dissolve brass in nitric. Well the supervisor (a woman), thought it was too dangerous using the conc. acid (as she thought the reaction might be somewhat explosive :D), so she thought let's dilute the acid to 2M. The dissolving took a LONG time.
Also they stress us here to add acid to water instead of reverse. I was diluting 4M HCl in the reverse order and they freaked out :o . I mean an experienced chemists should know that on a small scale this rule only applies (of the standard acids) to conc. H2SO4, and to some extent to 37% HCl. All these people only get to learn safety theory, but no practise.

[Edited on 7-1-2010 by Jor]
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[*] posted on 7-1-2010 at 09:38


Whilst diluting 4M HCl your way may indeed be fine, I beleive its more about the principle. They don't know you wouldnt change the order if it was conc. sulfuric, and its good lab practice to ALWAYS add acid to water, regardless of the concentration.
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[*] posted on 7-1-2010 at 12:12


I agree with Jor. You have to know what you are mixing, otherwise you should not be mixing anything at all. With conc. H2SO4 I always pour acid in water, but with 4M (appr. 12% HCl) I just do what is most practical and convenient and do not care about the order of adding. The same is true for 30% HCl or 65% HNO3. Adding water to 90% HNO3 is stupid, but mixing such a concentrated form of HNO3 with water is stupid anyway, for that purpose we have the much easier to obtain 65% or 53% grades of HNO3.



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[*] posted on 7-1-2010 at 13:56


The more conservative rules and heuristics are designed to protect those who don't know as much about the properties of the chemicals they're dealing with. For example, standard safety procedures for chemical spills at my company are fairly agnostic about *what* medical/therapeutic agent is spilled, so that in theory at least a broken beaker that results in a puddle of potassium chloride solution is going to be treated much the same way as a spill of some quite toxic chemotherapy agent. Whether the lab techs actually use their knowledge of chemistry to downgrade the level of protection when it's not needed, I don't know - but they aren't supposed to.
As that pertains to home chemistry though I would quote William Blake: 'One law for lion and ox is oppression'.
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[*] posted on 7-1-2010 at 15:24


I have broken a number of pieces of glassware but the most frustrating is breaking beakers or Erlenmeyer flasks because I purchsed them as a set from 50ml to 1L and I can't get individual beakers or flasks of the same make without purchasing the whole set again. :mad:



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[*] posted on 8-1-2010 at 02:27


Rules, laws, guidelines etc are written so the stupidiest person covered by them will not hurt themselves/get into trouble. Try pointing this out to a policemen when you are explaining to him that because you know why the law was written and that this 'spirit of the law' was not intended to be applied in such a circumstance. Policemen do not enjoy being asked questions they cannot answer.
Jor i feel your pain, throughout undergrad i had constant disagreements with the demonstration staff (usually 3rd or 4th years) regarding 'modifications' to the procedures i employed to expedite the tedium of our prac lessons. When asked why the procedure was written as such they usually had no idea, they were just dogmatically following some code they didn't understand.
That said it gets very dangerous when you start being so arrogant as to believe you understand the motivations ffor all such guidelines and i have made many mistakes thus.




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[*] posted on 8-1-2010 at 05:55


To provide counterpoint, in one of the 3rd/4th year teaching lab courses, the professor does use current syntheses from the literature alongside older syntheses, however sometimes modifications are made, possibly to the students detriment. Additionally, it seems short notice is always given, so the lab tech and I are always scrambling to make up new solutions and switch things around.

Fortunately though, in the teaching labs there is quite a bit of sanity regarding spills and glassware breakage - ie: if you know what was in the glassware, you can grade the threat/hazard accordingly. No worries for clean empty beakers, minor slip hazard for water baths, NaCl sol'ns, etc. like mentioned above.
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