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Mabus
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Lab tips & tricks
While the Improvisation page is good for offering advices on various lab items and jerry-rigs, as are the cleaning, handling and disposal articles, I think a page for other lab tips is needed, like say, lab space, organization (space and time), less known properties of lab
items or reagents, ventilation, cleaning, lab item storage, how to do a proper setup or a more effective one, shortcuts, maintenance, etc. you get the
picture.
The article is here, there is still plenty to modify and improve, and if you can't edit, write your ideas in this thread. More is better.
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Sulaiman
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"Place the reagent storage shelves/closet close to your bench, but away from the kitchen sink"
to
"Always keep chemicals and chemistry separate from food and cooking"
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Eyewash Station ... really ?
How many of us have an eyewash station ?
Is it a prerequisite for hobby chemistry?
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"Keep the glassware in drawers, separated by types (beakers in a drawer, condensers in another, etc.)"
Why can't I use my stackable transparent plastic containers ?
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"Never keep your glassware and fragile objects on a shelf nailed to the wall, as there's always the risk of falling and breaking your lab items,
always keep them "grounded""
My shelves never fall down and being attached to the wall makes them stable.
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"Place all of your small metal items (keck clip, scoopula, spatula, wire gauze) in one drawer, while larger items (clamps, jacks, tripods) in separate
locations"
I prefer to group my stuff by function rather than material.
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How many here use a lab coat ?
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"When doing a reflux reaction that needs distilling afterwards, use a Liebig condenser as a fractionating column in a distillation setup, then connect
the output of the distillation condenser to the bottom of the Liebig to reflux."
... fractionating column ? ... needs clarifying.
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"If you're distilling compounds that attack the rubber seals of on ordinary thermometer adapter, instead of getting fancy ground glass thermometers or
a teflon adapter, wrap one layer of teflon tape wrapped around the thermometer, then just poke it down into the adapter and thread the cap on top,
sealing the teflon against the glass"
A) you could have your thermometer smash into your flask below like that
B) do you trust that to seal against e.g. HCl, Cl2, vacuum etc.?
I don't think I would.
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more if required.
you have been too specific, not generally applicable in my opinion.
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CAUTION : Hobby Chemist, not Professional or even Amateur
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j_sum1
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Hkparker (or was it mystYt32) did a nice little video on this topic.
My contribution: masking tape. The rolls can act as stands for RBFs.The tape is good for labelling.
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Ubya
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Don't keep oxidizers and organic solvents in the same place,
5kg of potassium nitrate near a few liters of acetone, toluene, ethanol and petroleum ether seems a wonderful idea (yes i kept all of these in the
same cabinet until i thought it wasn't a great idea at all)
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feel free to correct my grammar, or any mistakes i make
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Mabus
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@Sulaiman I mostly added stuff from both SM threads and other chemistry sites most from professional chemists. I'll alter some of that text to fit
better with out line of work.
EDIT:
| Quote: |
"When doing a reflux reaction that needs distilling afterwards, use a Liebig condenser as a fractionating column in a distillation setup, then connect
the output of the distillation condenser to the bottom of the Liebig to reflux." ... fractionating column ? ... needs clarifying.
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OK, upon seeing the original text, I too admit I didn't quite understand what the person meant, so I'll just replace it with something else
| Quote: |
"If you're distilling compounds that attack the rubber seals of on ordinary thermometer adapter, instead of getting fancy ground glass thermometers or
a teflon adapter, wrap one layer of teflon tape wrapped around the thermometer, then just poke it down into the adapter and thread the cap on top,
sealing the teflon against the glass"
A) you could have your thermometer smash into your flask below like that
B) do you trust that to seal against e.g. HCl, Cl2, vacuum etc.?
I don't think I would. |
The idea is that that you replace the silicone rubber ring with one or more layers of PTFE tape, and while the guy said one layer should be enough,
more might be needed depending on the diameter of the thermometer or the inner bushing adapter. Not seeing why it won't hold, PTFE tape is very soft
and deforms easily, it should hold.
While it's true that thermometer adapters (or bushing adapters with screw cap) are unsuitable for vacuum work (and finding a thermometer with a ground
glass is a pain in the ass these days), I don't see why this method couldn't work when distilling stuff that contains HCl, Cl2, Br2, NO2, as in the
past I've used PTFE tape successfully to seal bottles containing fuming nitric acid and iodine for long periods of time, and was pretty effective.
[Edited on 7-4-2018 by Mabus]
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Sulaiman
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short answer
I do not think that you should pass on tips that you have not tried personally.
CAUTION : Hobby Chemist, not Professional or even Amateur
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JJay
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Whenever you spill sulfuric acid over valuable electronic equipment, pour dry potassium bicarbonate onto the spill.
It is suggested that you end the experiment immediately and unplug the equipment, then wipe down the area rather than simply spraying water on top of
the potassium bicarbonate and shocking yourself repeatedly.
Oh, and I use a lab coat sometimes but usually only with reagents more dangerous than concentrated sulfuric acid. Really, it's probably a good idea to
use one whenever handing reagents more dangerous than universal pH indicator.
[Edited on 7-4-2018 by JJay]
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crystal grower
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I started using lab coat after destroying sufficient amount of T-shirts  .
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Mabus
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@Sulaiman In that case I shouldn't have written the article, since more than half the info is from the forum chemists and I haven't done it myself.
What I'm trying to say is that just because you done it yourself and it worked, doesn't mean it's the ideal path. For example, I see in plenty of YT
videos chemistry professors handling alkali metals with gloves, while in other places (my former university, this forum, etc.) we're always told to
handle alkali metals without gloves and use either tweezers or spatulas. If I followed my professors advice, I'd shouldn't use gloves, but had I
worked with the other professors, I should have. So which is which? Who do I trust? That's why I wrote the article, to pool all the tips from all
kinds of chemists with different experience and compare them.
[Edited on 7-4-2018 by Mabus]
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happyfooddance
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Quote: Originally posted by Mabus  |
The idea is that that you replace the silicone rubber ring with one or more layers of PTFE tape, and while the guy said one layer should be enough,
more might be needed depending on the diameter of the thermometer or the inner bushing adapter. Not seeing why it won't hold, PTFE tape is very soft
and deforms easily, it should hold.
While it's true that thermometer adapters (or bushing adapters with screw cap) are unsuitable for vacuum work (and finding a thermometer with a ground
glass is a pain in the ass these days), I don't see why this method couldn't work when distilling stuff that contains HCl, Cl2, Br2, NO2, as in the
past I've used PTFE tape successfully to seal bottles containing fuming nitric acid and iodine for long periods of time, and was pretty effective.
|
Unless your caps are made out of an inert material, they will probably turn to dust (along with any plastic keck clips) if you try this method with
HCl, Cl2, etc. At least they did with me. These gasses are escape artists.
Also, how are screw top thermometer adapters not suitable for vacuum? I use them all the time, never have had an issue.
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Mabus
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| Quote: Originally posted by happyfooddance | | Quote: Originally posted by Mabus |
The idea is that that you replace the silicone rubber ring with one or more layers of PTFE tape, and while the guy said one layer should be enough,
more might be needed depending on the diameter of the thermometer or the inner bushing adapter. Not seeing why it won't hold, PTFE tape is very soft
and deforms easily, it should hold.
While it's true that thermometer adapters (or bushing adapters with screw cap) are unsuitable for vacuum work (and finding a thermometer with a ground
glass is a pain in the ass these days), I don't see why this method couldn't work when distilling stuff that contains HCl, Cl2, Br2, NO2, as in the
past I've used PTFE tape successfully to seal bottles containing fuming nitric acid and iodine for long periods of time, and was pretty effective.
|
Unless your caps are made out of an inert material, they will probably turn to dust (along with any plastic keck clips) if you try this method with
HCl, Cl2, etc. At least they did with me. These gasses are escape artists.
Also, how are screw top thermometer adapters not suitable for vacuum? I use them all the time, never have had an issue. |
Weird, I must have a shitty screw cap then. Couldn't get stable vacuum last time I tried that.
I've also included a small disclaimer to that tip, to avoid any confusion in the future.
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happyfooddance
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| Quote: Originally posted by Mabus |
Weird, I must have a shitty screw cap then. Couldn't get stable vacuum last time I tried that.
I've also included a small disclaimer to that tip, to avoid any confusion in the future. |
I would try it with a variety of different o-rings, having the right sized ones make all the difference. Also, test your thermometer cap alone; doing
it while you are set up to distill (with 4 or more ground glass joints in the mix) makes troubleshooting many times more difficult.
I do however, always use ptfe tape around the o-ring, like you suggest. I have distilled azeotropic HCl many times like this with no problems, but dry
HCl was totally different, every one of my caps broke into several pieces. When distilling a liquid slowly (like one should), vapor doesn't really
make it up to the thermometer cap, so that also might explain why it works okay for the 20.2%.
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Sigmatropic
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Screw top thermometer adaptors are not suitable with vacuum because the thermometer can be sucked into the apparatus. In my case the thermometer was
intact but the vigreux column not so much  .
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LearnedAmateur
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Oh yeah, I use a roll of Gaffer tape for resting my 250mL RBF and smaller flasks sit quite quite comfortably inside without spilling. Thought I was
the only one to be honest. Barring that, if you’ve got >100mL beakers not in use, they can serve the same purpose.
[Edited on 8-4-2018 by LearnedAmateur]
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
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Sulaiman
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So far I have not used more than two or three RBFs at a time,
so I use 'spare' retort clamps to hold them if required.
The one time that I used many flasks at once I used Florence/Florentine flasks.
(from an eBay bulk buy of surplus/used glassware)
Retort clamps are also very useful for holding washed glassware up-side-down for draining/drying.
CAUTION : Hobby Chemist, not Professional or even Amateur
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DavidJR
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| Quote: Originally posted by LearnedAmateur |
Oh yeah, I use a roll of Gaffer tape for resting my 250mL RBF and smaller flasks sit quite quite comfortably inside without spilling. Thought I was
the only one to be honest. Barring that, if you’ve got >100mL beakers not in use, they can serve the same purpose.
[Edited on 8-4-2018 by LearnedAmateur] |
Often when I've used a spare beaker as a flask stand the flask tips over. Glass on glass just isn't a lot of friction. Rolls of tape work better.
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Plunkett
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I use an aquarium air pump and vinyl tubing to force air through wet flasks and condensers to make them dry quicker; a slightly less effective method
is to prop the glassware upside down over a floor vent. In either case, the glassware dries significantly faster than just leaving it to air dry.
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Sulaiman
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Mabus
The O-ring size is important,
I have a screw-top thermometer adapter and a screw-top still head adapter,
as supplied with my cheap distillation kit.
I cannot use the thermometer supplied with the kit (c5.5mm dia.) as it will slip,
but my 'normal' thermometers (c6.5mm dia.) fit very well.
CAUTION : Hobby Chemist, not Professional or even Amateur
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LearnedAmateur
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| Quote: Originally posted by DavidJR |
Often when I've used a spare beaker as a flask stand the flask tips over. Glass on glass just isn't a lot of friction. Rolls of tape work better.
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I only use 50mL beakers as a stand for 100mL flasks when they’re empty, I meant placing them inside a beaker with a larger diameter than the flask
so that the joint/mouth rests against the rim. 250mL beakers should house 100mL RB and pear flasks quite snugly, I would test to make sure but I
don’t actually have any, the one I did have shattered and went in the bin months ago.
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
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Mabus
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| Quote: Originally posted by Sigmatropic | | Screw top thermometer adaptors are not suitable with vacuum because the thermometer can be sucked into the apparatus. In my case the thermometer was
intact but the vigreux column not so much . |
I never got to that part since I couldn't get a vacuum
@Sulaiman I purchased my thermometer adapter separate from the thermometer exactly for that reason (I could have bought a distillation kit, but I
didn't want to get some unexpected surprise).
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JJay
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I've used screw top thermometers with vacuum dozens of times without issue... it is essential to make sure that the thermometer is secure before and
preferably also after applying a vacuum.
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Tsjerk
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Always wear a lab coat and goggles, you will be happy when it saves you that one time when the accident came out of nowhere. I have been lucky to be
wearing them that one time I needed them. It came out of nowhere while working with stuff less dangerous than pH indicator
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Texium
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Mabus, Dr. Bob should still have some 10/18 GG thermometers if you're looking for one. I bought one from him recently, as I've had 10/18 jointed still
heads for years but never a thermometer to go with them. Up until now I just stuck a normal thermometer in there and held it in place with a rubber
anti-roll ring and copious PTFE tape.
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fusso
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Filtration tip your professors probably won't tell you/ Filtration tip for purity OCD(mysophobia)
Think about which part of the rxn mixture you want before taking a piece of filter paper out of its box:
If you want the filtrate: fold the 'up' (dustier) side inwards and immediately put it in a freshly cleaned funnel to prevent dust being washed into
the filtrate.
If you want the solids, remember which side is down. Leave the 'down' side facing down. Only flip it up side down immediately before
filtration and use the cleaner 'originally down' side to catch the solids. Best to also cover the whole filtration setup with air-permeable
material like paper, cloth.
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VSEPR_VOID
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Same...I am up two two shirts and a pair of pants.
Within cells interlinked
Within cells interlinked
Within cells interlinked
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