All Questions
Tagged with equipment experimental-chemistry
60 questions
2
votes
1
answer
121
views
Is it safe to use borosilicate lab glass as an autoclave?
I'm attempting to do a one-pot synthesis that requires autoclaving the chemical mixture. I thought this process would be greatly simplified by using the lab glass itself as the autoclave in situ ...
- 149
5
votes
2
answers
646
views
What does the blue square on a volumetric flask mean?
What does this blue square on my volumetric flask mean? I see such squares/rectangles on a numerous other flask brands as well. What is its purpose?
user146152
-2
votes
1
answer
117
views
Why potassium carbonate breaks glass when heated? [closed]
I have been studying about desiccants for a while and testing some inorganic salts, including calcium chloride, sodium sulfate and potassium carbonate. When they get enough moisture from air, I ...
3
votes
1
answer
407
views
How can I read an Anschütz/Bennert manometer and how can I make sense of it?
Recently I have come across a mercury-filled manometer for vacuum distillation that somewhat resembles a U-tube shaped manometer, but with one arm sealed and completely filled with mercury. Searching ...
- 392
1
vote
0
answers
482
views
Can I use a mechanical pipette to transfer strong acid?
I am an undergraduate student majoring in physics. I am looking for the best method to accurately measure the volume of strong acids like hydrobromic $(w(\ce{HBr(aq)}) = 48\,\%)$ and hydroiodic $(w(\...
- 27
0
votes
1
answer
485
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Experimental setup
I would like to know your opinion regarding the setup of a system for oxygen purging with nitrogen. Before ordering the necessary materials, I'd like to be sure if this setup is feasible or if it can ...
- 11
4
votes
1
answer
3k
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How should you report measurements and uncertainty for a measuring cylinder with 0.5 mL graduations?
I understand that a common convention is to report the uncertainty of an analogue instrument as plus or minus half of the smallest scale division.
By this logic, a measuring cylinder with $\pu{0.5 mL}$...
- 135
6
votes
2
answers
4k
views
Which is a more accurate scale for a chemistry high school lab - a triple beam balance or a digital balance and why?
I would like to ask the experts of this chemistry community their opinions on which balance is more accurate and effective to use in a high school chemistry lab- a triple beam balance or a digital ...
- 805
0
votes
0
answers
762
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What is the product of ammonia reacting with silicone?
I used a soft silicone hose to carry ammonia at ~70 °C. I was surprised to later find the hose had hardened.
A quick materials compatibility search for silicone had given me a lot of info but an "...
- 1,107
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 ...
- 1,162
11
votes
1
answer
3k
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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 ...
- 639
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 ...
- 1,480
1
vote
1
answer
201
views
Can I safely use a separatory funnel to extract the precipitate from a solution?
Can a separatory funnel be used to collect a precipitate, or would that risk clogging the stopcock on it?
I'd like to recoup the precipitate for filtering without passing the entire solution through ...
- 471
4
votes
0
answers
84
views
An unknown glassware piece from our cupboard
We have multiple of these. It is a small glass funnel with splits into 3 spouts from it. Now, we are thinking it might be similar to a cow receiver, however, I have never seen one this small or ...
- 99
4
votes
0
answers
46
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Unknown possibly handmade glassware- description in information below
Okay, Another random item from the cupboard (unknown users or discipline of life sciences unknown) could be anything up to 40 years old....
This appears to be a 2 neck quickfit adapter (B19 and B14) ...
- 99
0
votes
0
answers
64
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Unknown glassware please help, vshaped with a small bulb on one side, hollow but narrow to both sides!
Looking to try an identify some glassware we have found in a cupboard. This is just the start of it...
1 item here, v-shaped, small bulb but hollow, narrow entrance and exit...
- 99
16
votes
1
answer
2k
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What's this glassware?
Can anybody tell me what this glassware with a stem, bulb and long tube is?
- 171
4
votes
1
answer
256
views
Pipette pumps durability
According to your experience, in terms of durability and longevity of the tools, which one of these types of pipette pumps is better and why?
Tri-valve pipette bulb
Syringe pipette pump
Electronic ...
- 41
4
votes
1
answer
2k
views
When to disconnect tubing in vacuum filtration?
The UCLA site says in step 6 to disconnect the vacuum tubing before turning off the vacuum and the second link from Leeds says in step 11 to turn off the vacuum source first and then disconnect the ...
user9974
-1
votes
1
answer
5k
views
Determining the depression in freezing point experimentally
I was reading about Beckmann's method for determining the depression in freezing point:
First, the solvent is placed inside the cooling chamber directly and the approximate freezing point is ...
-2
votes
2
answers
677
views
Magnesium oxide lab question [closed]
For my magnesium oxide lab, one of the question asks why I need to include the cover of the crucible when weighing it with the magnesium before the reaction, then again after with magnesium oxide, and ...
- 21
1
vote
1
answer
68
views
Viscosity of liquid interrupts accuracy of micropipette?
Does viscosity of liquid interrupt accuracy of micropipette?
I would like to dilute 85% $\ce{H3PO4}$ acid to $\pu{1.194 mol/dm3}$ so I had to pipette 366 microliter into 4.634 mL of water. Then, I ...
- 453
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 ...
- 38.5k
17
votes
1
answer
2k
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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 ...
- 326
2
votes
2
answers
130
views
Choice of equipment for distilling
I need to distill some reagents, and the book Purification of laboratory chemicals suggests first refluxing over $\ce{P2O5}$ for several hours before distilling across.
The obvious choice is a ...
- 381
1
vote
0
answers
286
views
What is substance that has high melting point in its powder form?
In laminated glass bending process 2 glass sheet will be superposed in a furnance.The seperation powder will be interposed between layer for avoid 2 glass sheet being bound together.
I'm trying to ...
- 19
7
votes
1
answer
11k
views
How many decimal places should a volume measurement in a beaker include?
I have a beaker which goes up in $0.5~\mathrm{mL}$ increments and my teacher told me that my measurement $(15.50~\mathrm{mL})$ was incorrect, and instead the answer was $15.5~\mathrm{mL}$. I don't ...
- 71
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 ...
- 435
1
vote
1
answer
68
views
Washing glasswares [closed]
What do most labs use to wash their glasswares? I usually use plain clothes detergent. But, I'm starting to suspect that there are residual detergent even though I've brushed the glassware; rinsed it ...
- 302
4
votes
1
answer
514
views
What is this device? (Constant level device?)
Found this in my lab on a random shelf (water quality lab). It is old enough that nobody knows where it came from. I think it's a constant level device. It has in- and out-flow connections, as well as ...
- 101
9
votes
2
answers
631
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 ...
- 863
0
votes
3
answers
15k
views
How to judge accuracy and precision of measurement devices?
I am unsure about the accuracy and/or precision of measuring instruments.
For example, if we have a graduated cylinder, a pipette and a beaker, how and why can we assert them that they can be used ...
- 11
1
vote
0
answers
54
views
Automated chemistry test machines? What is currently done, and what is research leaning towards?
There are small and large chips and machines to effect admixtures,blends, fusions of different chemicals into a variety of test samples, and there are machines to measure many vials of all kinds of ...
- 573
2
votes
2
answers
141
views
Is there a way to counteract the problems with weighing hot objects?
I am currently performing an experiment in which it would be greatly beneficial to be able to accurately measure the mass of a hot object without waiting for it to cool. The current plan is simply to ...
5
votes
2
answers
2k
views
Preparing an inert atmosphere reaction vessel with only an input?
One time, the graduate student that I work with was showing me how to prepare an inert atmosphere in a double necked round bottom flask. After drying it in the oven, she used a torch to drive out all ...
- 24.1k
12
votes
1
answer
177
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 ...
- 3,352
4
votes
2
answers
3k
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Choosing a vacuum pump for fractional distillation
I have a fractional distillation setup. I would like to purify a small mixture ($\pu{\approx 100-150 mL}$) of high boiling point compounds (between $200$ and $\pu{300^\circ C}$). The one that ...
- 71
1
vote
0
answers
156
views
How to test acid-base reactions under pressure?
I am trying to test chemical reactions, more specifically reactions between an acid and a base, at different levels of pressure.
I would like to know if there is some kind of equipment I can get that ...
- 111
4
votes
1
answer
69
views
Refrigeration for Cryochemistry −35 °C
I need to cool a tube containing liquid to −35 °C for a cold chemical experiment that will last about a week. The glass vessel I need cooled is 500 mL in volume and will be giving off $\ce{H2S}$ gas. ...
- 2,682
10
votes
2
answers
8k
views
6
votes
1
answer
258
views
Types of argon gas regulator? [closed]
I have a high pressure bottle of argon gas (99.98 %) that I need to use in an experiment. The problem is that the regulator I have is a generic type that is seemingly optimized for high flow rates (...
- 1,836
4
votes
2
answers
419
views
Name of round piece of glassware with thin neck?
Found in the lab, it looks like a round bottom flask with an extremely thin neck. Effectively a glass sphere about 60 mm in diameter with what looks like a capillary tube as the neck. Not sure whether ...
- 1,836
3
votes
2
answers
1k
views
What equipment to use to make liquid oxygen?
I'd like to do some experiments with liquid oxygen but as a first step I'll have to make some. Unfortunately I don't have any experience designing cryogenic experiments. I'm thinking I'll cool gaseous ...
- 31
2
votes
1
answer
1k
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How to get meniscus down to the calibration mark with a volumetric pipette
I am having trouble taking aliquots using the 10 ml volumetric pipette.
After rinsing, I draw the solution up past the calibration mark and stopper the pipette with my index finger. Then I slowly ...
- 637
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 ...
- 3,352
1
vote
0
answers
347
views
Why molten lithium burns through the glass but sodium not?
It's well-known in laboratory practice that one shouldn't melt lithium in a glass equipment and there isn't such rule about other alkali metals.
You may damage the glass with sodium but lithium will ...
- 11
3
votes
1
answer
153
views
NO2 gas was detected in FTIR
We have a laser chamber full of $\ce{F2}$ gas (no air should be in the chamber) and several parts including steel, wires, ceramics, zinc.... This is for laser generation so the temperature is pretty ...
- 31
15
votes
2
answers
3k
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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 ...
- 3,352
5
votes
1
answer
747
views
Can I get an accurate temperature reading from a flask with a built-in thermometer well?
I recently purchased a flask with a built in thermometer well, but I have discovered that simply setting a rod thermometer in the well does not produce a very accurate reading. I was wondering if ...
- 171
0
votes
1
answer
1k
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How to attach a liebig condenser to a flask for reflux heating?
I know it's probably a stupid question, but I can not figure this out. I have a liebig condenser that I usually use for distillation with a Kjeldahl bulb, which makes it easy to attach to a flask ...
- 171