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Questions tagged [equipment]

Questions regarding the equipment used in labs (such as flasks, tubes etc.), their operation and maintenance.

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40 votes
5 answers
76k views

Choosing the right condenser

What are the advantages and disadvantages of the various types of condensers commonly found in the laboratory? Obviously more intricate pieces of glassware are more costly but assuming they are all ...
Radu's user avatar
  • 1,062
27 votes
3 answers
4k views

What benefits do higher-rated NMR tubes provide?

You can buy NMR tubes in a huge variety of qualities, with an equally huge difference in price between the cheapest and the most expensive NMR tubes. They are usually rated for a specific spectrometer ...
Mad Scientist's user avatar
24 votes
11 answers
3k views

Help me identify this glassware!

I'm a freshly graduated physics and math teacher moved into a small school from the late 1920s. The equipment here is old and confusing, at the very least. I have found many things which I have ...
Jesuspowder's user avatar
23 votes
4 answers
54k views

what kind of suspension liquid should be used with ferrofluid (so it does not stain the glass)

Please take a look at the following video: I am working on a new project, and I need to find whats the best liquid to hold ferrofluid inside the glass (or maybe even plastic) container, so that ...
Damjan Stankovic's user avatar
22 votes
1 answer
2k views

Does anyone know what this piece of glassware is?

I recently found this piece of lab glass with a jacket and spout. It says eubilicmeter but I cannot find any information about it online and I do not know what it is supposed to do. It is hollow in ...
Chad's user avatar
  • 221
22 votes
2 answers
5k views

pH probe bulb - what is happening within the glass?

I am trying to understand how the glass bulb of a pH electrode of a pH meter works - the glass bulb itself. Not the reference electrode or the rest of the electrode (HCl, Ag/AgCl wire, etc...), the ...
uhoh's user avatar
  • 5,788
18 votes
2 answers
6k views

What is the "blue spirit" (or "red spirit") in mercury-free thermometers?

I surmise it's some kind of alcohol, but is there a standard chemical used for these? One of them just exploded in my students' lab! It was the kind with blue fluid in it.
khaverim's user avatar
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18 votes
1 answer
721 views

Unknown glassware

I recently found a piece of older glassware in our lab and nobody seems to know what it is. It appears to be some sort of condenser; however, it does not have both the in and out little notches on it. ...
skennedy's user avatar
  • 181
17 votes
5 answers
5k views

Why isn't pressure filtration popular compared to vacuum filtration?

I want to build a DIY vacuum filtration apparatus with a bike pump but it's very difficult to find one the could be easily converted into a vacuum pump. This prompted an idea to simply build a reverse ...
Francis L.'s user avatar
  • 1,480
17 votes
1 answer
2k views

What's the purpose of this vintage glassware?

I found this glassware in a phytochemistry lab abandoned in the 1990ies. The piece itself was shelved in the storage room, thus probably already obsolete back then. The device, entirely glass, is a ...
I_O 's user avatar
  • 281
17 votes
1 answer
2k views

Conventional heating compared to microwave heating of chemical reactions

In order to try to increase yield of my cross-metathesis, it was suggested to carry out the reaction in the microwave (a lab microwave, not a kitchen microwave). The rationale for this was that ...
James Dealon's user avatar
17 votes
2 answers
2k views

Safety in handling of concentrated ammonium fluoride

I recently saw a protocol for extracting organic materials that are bound in the silica matrix formed by diatoms. The extraction protocol used 10 molar ammonium fluoride ($\ce{NH4F}$). I briefly ...
Curt F.'s user avatar
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16 votes
1 answer
2k views

What's this glassware?

Can anybody tell me what this glassware with a stem, bulb and long tube is?
Alexander's user avatar
  • 171
15 votes
2 answers
2k views

Why does KCl come in amber coloured bottles?

I remember from school that photosensitive chemicals are kept in amber coloured bottles. Is KCl photosensitive? I read up the impurities list on the bottle and it says that it may have bromides too? ...
Polisetty's user avatar
  • 422
15 votes
2 answers
1k views

What is this Lab equipment?

I want to know the name of this equipment with a sealed graduated tube and the purpose it's being used. I went through all the results of Google, but I was unable to find this exact equipment. I ...
Nimeshka Srimal's user avatar
15 votes
2 answers
2k views

Are PTFE stir bars resistant to all lab solvents?

It seems like glass-coated stir bars are a specialty item. Standard stir bars are coated in PTFE. Is PTFE resistant to all typical lab solvents? Or is there a reference to check to ensure it is ...
feetwet's user avatar
  • 3,300
14 votes
5 answers
21k views

How to stop goggles from fogging?

I wear corrective eyeglasses, and because of this, I frequently experience problems with fogging when I wear safety goggles. How can I prevent or reduce fogging? The safety goggles I use are the ...
AJMansfield's user avatar
14 votes
1 answer
605 views

Why do Büchner funnels have no glaze on the top rim?

I have a question about Büchner funnels (just out of pure curiosity). The funnels I have seen have no glaze on the top rim. Actually, the question is why the top end is not glazed. Does it have any ...
Istrel's user avatar
  • 251
13 votes
3 answers
2k views

What are the plastic connectors called (for glassware)?

I can't remember for the life of me, and google isn't making it easy. e.g. the things labeled 24/40 etc., as in this picture:
khaverim's user avatar
  • 3,610
13 votes
3 answers
19k views

Cleaning a round-bottom flask, especially after distillation

I was wondering, how can I clean my RBF after doing a distillation? Cleaning it with a simple pipe-cleaner or similar cleaner is a headache, due to the roundness of the flask. Is there a more ...
Fiire's user avatar
  • 466
13 votes
4 answers
18k views

How to remove a stuck stopper from a flask?

How do I remove a stopper that has been stuck in the neck of a 100 mL round bottom flask since I forgot to wipe the neck of the flask. A salt was formed in the 100 mL flask and the stopper ...
user avatar
13 votes
3 answers
12k views

Why is the outermost part of the Bunsen burner flame not the hottest region?

Why is the blue flame the hottest on a Bunsen burner? I thought the outermost part of the flame must be the hottest region because of complete combustion of gases taking place there. Where am I ...
Piyush Raut's user avatar
12 votes
1 answer
1k views

How is polarization of light measured?

Chiral molecules are classified as dextrorotatory (+) or levorotatory (-) depending on whether they rotate plane-polarized light (ppl) to the right or left. My question is, how is such a measurement ...
Steven's user avatar
  • 149
12 votes
1 answer
167 views

High temperature bath chemicals

I have an electric mantle that I want to bathe reaction vessels at temperatures up to $\mathrm{750^{\circ}C}$. Obviously that rules out oils. What substances are used as bath media at such ...
feetwet's user avatar
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12 votes
1 answer
2k views

What is the fabric in heating mantles made of?

An ordinary lab heating mantle often has a white fabric coating for the flask compartment, which looks like an inorganic fiber: Image source I'm pretty sure that for some time in the past ...
andselisk's user avatar
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11 votes
3 answers
3k views

Sintered vs perforated plate Büchner funnels

I just bought a sintered-glass style Büchner funnel for some vacuum filtration tasks. There's two issues I'm having with it: Filter material, especially activated charcoal, ends up stuck in the glass ...
Jason C's user avatar
  • 1,172
11 votes
1 answer
3k views

What is the scientific term to describe the operation of a bong?

What is the scientific term for the separation of dust particles from air by suction through a specialized flask in a way similar to the operation of a bong? The thing that led me to this was a ...
soundslikefiziks's user avatar
10 votes
3 answers
5k views

Is it better to use a smaller, more accurate measuring cylinder several times or a larger, less accurate one for the same volume?

I need to measure out 70 ml of liquid. I have a 10 ml measuring cylinder with a maximum uncertainty of 0.1 ml and a 100 ml measuring cylinder with a maximum uncertainty of 1 ml. I've calculated that ...
John Johnson's user avatar
10 votes
1 answer
6k views

How is aqua regia stored?

How is aqua regia stored as it dissolves all metals?
user57139's user avatar
  • 117
10 votes
3 answers
676 views

MacGyvering a sealed tube

Is it possible (advisable?) to make a sealed tube by melting and twisting the end of a borosilicate test tube? One issue that I can think of is that the pressure might be too high if I then proceed to ...
Radu's user avatar
  • 1,062
10 votes
3 answers
56k views

Water flow in condenser

How should the water flow in your condenser? From the flask to the top of the condenser, or from the top of the condenser back to the flask? I could imagine both: flask to top will fill the entire ...
Jori's user avatar
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10 votes
3 answers
3k views

What angle limits should apply to Graham condensers?

I have seen Graham condensers set at an angle (perhaps as low as 30 degrees from horizontal). I guessed this wouldn't be a problem because siphoning would clear the condensate. But I recently saw an ...
feetwet's user avatar
  • 3,300
9 votes
2 answers
8k views

What is the accuracy of medical syringes?

I am interested in both low and high volume syringes.
Euphorbium's user avatar
9 votes
2 answers
770 views

400–430 degrees Celsius heated bath

I want to perform a reaction which needs the temperature to be maintained between 400–430 °C. Since it's the only practical solution, I opted for a heated bath. I'm looking for a hydrocarbon fraction/...
Francis L.'s user avatar
  • 1,480
9 votes
1 answer
435 views

Why is there a bulge at the top of my volumetric flask?

Sometimes volumetric flasks are designed with a bulge in the neck right below the stopper opening. What is the design intent of that bulge?
Brett Baker's user avatar
9 votes
2 answers
6k views

How to quickly cool a test tube without cracking it?

Is there a way to safely cool a heated test tube quickly without cracking it due to sudden thermal stress in the glass? One thing that I tried was blowing on it, cooling it in slightly lukewarm water ...
user80551's user avatar
  • 400
9 votes
1 answer
2k views

Why are Erlenmeyer flasks shaped the way they are?

The title says it all. We could conceive a good number of other possibilities. Why did Erlenmeyer arrive at this design?
docscience's user avatar
  • 2,773
9 votes
2 answers
623 views

Use of pipette during experiments for determination of oxygen by Winkler's method

We were performing estimation of $\ce{O2}$ by Winkler's method and we were told by the instructor that while adding $\ce{MnSO4}$ and $\ce{NaOH}$ / $\ce{KI}$ the pipette tip should be well below the ...
Tyto alba's user avatar
  • 863
9 votes
1 answer
2k views

Gold Plating on Glass?

I am considering labware options to handle NaOH solutions at ~150 °C. One appealing idea would be to coat my current glassware with gold. I've read different sources mentioning the possibility without ...
Hans's user avatar
  • 1,097
9 votes
1 answer
1k views

Why does a glass tube show white bands after being heated with a torch?

When I use a torch to split a glass tube, there's always a hazy white band which appears. Does anyone know what the cause of this is? It was a hydrogen-oxygen torch. The glass is fused quartz glass, ...
user1704042's user avatar
9 votes
4 answers
1k views

How much does the quality of glassware matter, really?

Discussing about the pros and cons of glassware from different manufacturers for chemistry experiments easily becomes a heated debate. Well, that's how it seems if you read the chemistry related blogs,...
per's user avatar
  • 91
8 votes
1 answer
716 views

What is this piece of glassware called?

Here's an image: The left side is designed to be fitted into a beaker, and it captures gas evolved during a reaction. The right side can be filled with a liquid to then react with that gas. We use ...
realityChemist's user avatar
8 votes
1 answer
973 views

What kind of filter can remove zeolite dust from ethanol?

I only really have high school level knowledge of chemistry, and also I don't really own any lab equipment. I'm using 3A zeolite molecular sieves to dry ethanol (and sometimes isopropanol) and they ...
Jason C's user avatar
  • 1,172
8 votes
1 answer
2k views

Vacuum distillation apparatus selection and configuration

I want to assemble a "hobbyist-level" vacuum distillation apparatus for extracting small volumes of "typical" solvents (e.g., water, alcohols, ketones, diols). I already have standard lab glassware ...
feetwet's user avatar
  • 3,300
8 votes
1 answer
92 views

Identifying Name/Purpose of piece of ellipsoid glassware with internal tube?

I recently went to a market in Southern France and found this little piece of equipment for sale along with a whole bunch of other chemistry things. the guy had no idea what it was for or where he'd ...
Robert Gregson's user avatar
8 votes
0 answers
2k views

What drives the cost of Raman spectroscopy? [closed]

Raman spectroscopy setups are quite expensive- \$10-\$30k seems pretty common. The spectrometer, the probe/fiber cable, and the laser are typically each $3k+. The spectrometer could potentially be ...
ericksonla's user avatar
  • 1,700
7 votes
2 answers
9k views

Why is a volumetric flask shaped the way it is?

A volumetric flask does not look like an Erlenmeyer flask, but has more of a pear shape. Is it just to distinguish more easily between them while they are on the shelf?
user2132672's user avatar
7 votes
3 answers
3k views

Why did my glass pot explode when I boiled sugar in it and added cold milk?

I decided to try some cooking with sugar and put a glass bowl on the flame with half a cup of sugar in it and some water. After bubbles appeared I stirred the sugar for about a minute and then I ...
soundslikefiziks's user avatar
7 votes
2 answers
10k views

How to identify a blow-out pipette?

Is my pipette a blow-out pipette? I suspect that it is a blow-out pipette, though the double lines aren't rings. My guess is it is a TC blow-out pipette. It's a big 50 mL pipette, longer than my arm. ...
user1095108's user avatar
7 votes
1 answer
795 views

What are these upside-down glass egg-shaped containers for?

I took this picture from a chemical vendor, but I've seen these things many times already. How are they called and why are they upside-down?
waterlemon's user avatar
  • 1,641

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