Questions tagged [equipment]

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

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16
votes
2answers
2k 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 ...
22
votes
4answers
41k 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 ...
12
votes
3answers
7k 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 ...
7
votes
1answer
961 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 ...
2
votes
2answers
1k views

Using sigfigs when measuring with an instrument with marks other than powers of ten?

If an instrument does have markings that are powers of ten, then finding the precision of the instrument is easy. For example, if a graduated cylinder had markings for every 0.1mL, or every mL, or ...
38
votes
5answers
44k 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 ...
12
votes
3answers
13k 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 ...
15
votes
2answers
1k 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 ...
10
votes
3answers
1k 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 ...
9
votes
3answers
6k views

Bunsen burner and 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 ...
1
vote
1answer
73 views

Order of internal pressure resistance to expect from laboratory glassware?

I have a need to use more pressure differential than can be afforded by vacuum vs atmospheric pressure alone, and so I've come to consider using pressurised laboratory glassware for part of my setup. ...
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 ...
8
votes
1answer
4k views

How is aqua regia stored?

How is aqua regia stored as it dissolves all metals?
2
votes
0answers
276 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, ...
1
vote
1answer
874 views

Stirring the reaction between hydrochloric acid and a powdered substance

For an experiment, I'm adding several substances (as powders) to hydrochloric acid, and measuring the temperature changes to calculate enthalpy. However when adding the powders, the mixture requires ...
1
vote
0answers
309 views

Possible Method for Testing Ammonia (and Nitrite/Nitrate) Concentration in Water

I am designing an automated system testing device for my high school's aquaponics club. We need to test for a number of ion concentrations, including ammonia and nitrite/nitrate. In my research, the ...
0
votes
1answer
216 views

Why laboratory glassware shatter in big pieces?

What are laboratory glassware made up of? This question came up in mind because once I accidentally dropped a test tube and it shattered into big pieces. I observed that it didn't broke into pieces on ...
0
votes
0answers
31 views

Highly concentrated NaOH solution at high temperature vs borosilicate glassware and cellulose?

I've read here on stack-exchange that NaOH will react with glass through the following reaction: 4 NaOH + SiO2 ⤑ Na4SiO4 + 2 H2O I would like to briefly heat a highly concentrated NaOH solution to ...