Chemistry

Questions tagged [equipment]

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

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12
votes
3answers
8k 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 ...
17
votes
2answers
1k 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 ...
2
votes
1answer
467 views

What is this glassware for a distillation apparatus called?

I'm messing around with building a solar distillation apparatus, and one of the parts I think I need looks kind of like the following, except I have no idea what it is called (and thus can't look it ...
0
votes
1answer
696 views

Is the condenser for a Soxhlet extraction left open on top

My question is about the condenser used in a Soxhlet extractions. It's unusual looking compared to the rest of condensers, used in distillation for example, I've noticed it has a thin and short tube ...
9
votes
1answer
717 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, ...
3
votes
1answer
384 views

Devitrification vs glass transition temperature

This graph comes from a so-called "differential thermal analysis". It is studying the effects of temperature on glass. I don't understand what the difference between "glass transition" and "...
2
votes
1answer
109 views

Does someone know the name of this equipment?

I think it is used to measure force or something like that. I broke it and have to buy a new one.
0
votes
1answer
1k views

Estimating magnitude of percentage and absolute error

Can someone at least give me a hint to push me in the right direction of how to estimate the magnitude of the absolute and percentage errors when using a smaller amount in mL of a substance for a lab ...
1
vote
3answers
5k views

How can I clean solid sulfur and its oxides from test tube?

I was experimenting with sulfur few years ago. The test tube I used for that purpose has still sulfur stuck onto it. I was searching for a way to dissolve it. I found an idea to try warm acetone. ...
10
votes
3answers
36k 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 ...
4
votes
3answers
820 views

Refluxing with tilted condenser

Can you reflux without any problems/dangers with a tilted condenser (e.g. because you don't have enough space in your fumehood)? I would say there isn't a problem, because both the surface area of the ...
2
votes
1answer
1k views

How do I make a simple home distillation device?

Like this: I have two medium sized glass flasks. I understand I need a T-shaped adapter from the first flask that will connect the thermometer and the condenser. So, I also need the condenser and a L-...
3
votes
1answer
738 views

How do you dry a Graham condenser?

I have a Graham condenser and tested it out by distilling water from salt water then I washed it and now I can't get either the coils or the jacket completely dry. Any advice? If there isn't a ...
2
votes
1answer
1k views

Vacuum-jacketed distilling column

I was looking for some distillation equipment on Sigma Aldrich because I wanted to perform some vacuum distillation, when I came across a vacuum-jacketed distilling column. Now as far as I understood ...
6
votes
2answers
7k 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?
4
votes
4answers
7k views

Why are we not supposed to heat Erlenmyer flasks?

Chemistry says that we are are we supposed to heat boiling flasks, and not Erlenmeyer flasks. However, I can't find any information about this on Google. Is there a particular reason for this? Is ...
1
vote
1answer
70 views

Is there any way to use syringe pumpe in pumping flow

I want to use syringe pump to pump water at 0.82 ml/min for 30 min ? Is that possible ( I read some paper use that but don't know how ?)
10
votes
2answers
3k 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 ...
3
votes
1answer
786 views

Parts of a manometer

There is a poor quality photo in the diagram of a manometer below: The picture is too poor for me to understand what they mean by "glass pointer marks calibrated volume". I would be interested if ...
2
votes
0answers
290 views

Glassware Test Instruments CAD blocks library

I am designing a fairly simple distillation for dichloromethane. Being an engineer I feel more comfortable working with precise dimensions of both the separate glass vessels (condensers, evaporators, ...
4
votes
2answers
218 views

Will borosilicate glass absorb 808nm laser light?

Will borosilicate glass absorb 808nm laser light? If it instead refracts, then what is the refractive index? Also, will borosilicate reflect lower frequencies of light like those used in non contact ...
5
votes
1answer
2k views

Stir bar size and volume to stir

I'm looking for a table showing which size of bar to use for a given volume to stir. Or a formula if there is one.
12
votes
3answers
14k 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 ...
9
votes
3answers
614 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 ...
38
votes
5answers
47k 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 ...
22
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4answers
42k 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 ...
27
votes
3answers
2k 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 ...

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