Questions tagged [safety]

Questions regarding chemical and lab safety. This includes questions about proper lab procedure, safe chemical handling, and such.

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90
votes
7answers
227k views

Is it actually possible to dispose of a body with hydrofluoric acid?

In the TV show "Breaking Bad", Walter White frequently gets rid of people who get in his way by submerging them in a plastic container full of hydrofluoric acid. This, at least in the TV show, ...
74
votes
6answers
20k views

Do all salts taste salty?

Recently, I am learning the production of soluble and insoluble salts. My friend and I have done this experiment at the school lab. We wanted to taste them to see whether they are salty are not. The ...
68
votes
5answers
16k views

How do people know HCN smells like almonds?

I was told by my chemistry teacher that $\ce{HCN}$ smells like almonds. She then went on to tell a story about how some of her students tried to play a prank on her by pouring almond extract down the ...
55
votes
4answers
198k views

Why add water first then acid?

From school, I remember a very important rule: first you need to pour the water and then the acid (when you need to mix them) not vice-versa. This is because otherwise the aсid becomes very hot and ...
50
votes
2answers
4k views

How does chloroform degrade nitrile gloves?

Many of us have experienced the failure of nitrile gloves when exposed to chloroform. What's going on at a mechanistic level when this occurs? I would guess that the chloroform dissolves some of the ...
40
votes
5answers
35k views

Is there any substance that's a 4-4-4 on the NFPA diamond?

A lot of the organometallics are rather... interesting compounds to work with. The most famous (among those who care, anyway) is tert-butyllithium or t-BuLi. It is the textbook example of a pyrophoric ...
32
votes
1answer
1k views

Flammability (NFPA) - how is it defined?

I was reading up on a wonderful little chemical compound known as chlorine trifluoride ($\ce{ClF3}$). For a primer, check out Dr. Derek Lowe's blog post here: Sand Won't Save You This Time. The title ...
31
votes
9answers
8k views

Realistic chemical spill accident in high school chemistry class

In a story I'm writing, a teenager spills chemicals on herself in a high school chemistry class, causing her to be put under the safety shower. The spill destroys her clothes and causes minor burns. I ...
28
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5answers
58k views

Acid Accident Treatment

What are the general ways to treat an accident involving highly concentrated or similarly dangerous acids? I have a lab instructor who recently debated with our group about treating an acid spill on ...
27
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2answers
3k views

How to properly store acids at home?

I bought different kinds of acid for experiments and home usage that I stored in secured containers into an IKEA cabinet. I just realized that despite the fact that all the containers are properly ...
22
votes
1answer
2k views

How can I safely handle a concentrated (fuming) nitric acid spill?

I will shortly be using $90~\%$ or higher concentration nitric acid in a home environment for the purpose of decapping ICs. I understand the corrosive dangers of nitric acid, and most of the important ...
21
votes
1answer
11k views

Brown stains on skin after working with Tollens' reagent

I was working in the lab preparing Tollens’ reagent. When I came back home, I observed that my fingertips were brown, and I tried to wash it with soap several times but it didn't work. It has been a ...
21
votes
4answers
22k views

How can I clean my lab coat?

Over the course of my studies, my lab coat has absorbed a non-negligible amount of different chemicals, some of them nasty organic polymers, some are more insoluble inorganic compounds like $\ce{Cr2O3}...
20
votes
3answers
12k views

Please explain why dioxygen difluoride is so dangerous

I just read this article that mentioned that dioxygen difluoride is very dangerous. The terms it uses are "awful", "violently hideous" and "deeply alarming". But I couldn't get a handle on exactly ...
18
votes
1answer
2k views

Can I eat the lemons after I have used them as a battery?

After completing the lemon battery experiment, can I eat the lemons when I'm done? More broadly, what will happen to the lemons? What are the chemical reactions, what chemicals might be present/...
17
votes
3answers
4k views

How to dispose of pure potassium

I have about 2g of 99.5% Potassium. I want to get rid of it, right now it's in a glass jar sealed. What is the proper protocol? I was going to combust it in water and wash it down the drain but ...
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 ...
16
votes
1answer
3k views

Neutralizing a sulfuric acid spill

From my AP Chem Prep Book: What should you do if you spill sulfuric acid on the countertop? A) Neutralize the acid with vinegar. B) Sprinkle solid NaOH on the spill. C) Neutralize the acid ...
16
votes
2answers
2k views

Emergency shower for nitric acid spills

Disclaimer: I'm asking this because I am curious. Not because I'm actually handling nitric acid. In another answer I was reading, the poster mentioned that if you spill nitric acid, you shouldn't ...
16
votes
3answers
5k views

Why did the salt on the skin of my turkey react with the aluminum foil it was touching?

I sprinkled salt on my turkey skin and left it to dry out over night. It was covered with aluminum foil. The next morning the aluminum foil had holes ‘burnt’ in it and the turkey skin turned silver at ...
16
votes
2answers
18k views

How to properly dispose of sodium…or store it properly

While performing an inventory of my school's chemical storage closet today, my fellow teacher and I found some sodium tucked away in the back corner of our flammables cabinet. One container appears ...
16
votes
2answers
3k views

Why is use of calcium carbide as an artificial fruit ripening agent banned?

Fruits like mangoes can be ripened using agents like ethylene, acetylene or calcium carbide. Of these, the latter is dangerous and is banned in most countries. Wikipedia says it is because calcium ...
15
votes
4answers
23k views

Are modern newspaper inks a health risk?

It's very common in India to see newspapers being used to absorb oils from oily snacks, or simply for temporary food packaging. Some articles say that covering food items in newspaper is a health risk....
14
votes
6answers
50k views

Handling and storing sodium hydroxide, hydrochloric acid, hydrogen peroxide and isopropyl alcohol

I'm an electrical engineering and I hope you can give me some advice as I'm not much into chemistry. I'm trying to start making my PCB (Printed Circuit Board) at home but I'd like to have some advice ...
14
votes
3answers
14k views

What is the effect on humans of using dry ice and liquid nitrogen as food additives?

I have seen on a TV show that some guy uses dry ice (solid $\ce{CO2}$) to make ice cream and on an another TV show, liquid nitrogen ($\ce{N2}$) is used with tequila. Both are edible. I know that ...
14
votes
4answers
28k views

How explosive is hydrogen gas?

I want to electrolyze water to get oxygen and hydrogen. I want to mix them in a regular balloon and ignite it. How much hydrogen would you need in a 2:1 ratio with air for it to be dangerous? Is this ...
14
votes
1answer
3k views

What is the meaning of the '2' on some Compressed Gas Hazard signs in the lab?

The main chemistry prep room at my institution (and also at the ambulance station) is labelled with the standard green compressed gas sign. However, there is a small '2' included within the diamond. ...
14
votes
3answers
4k views

Practical safety of storing potassium

Potassium ($\ce{K}$) seems to be the transitional alkali metal in terms of safety. Lighter than $\ce{K}$ and we can store under oil with no worries. Heavier than $\ce{K}$ and only ampules will work. $\...
13
votes
2answers
6k views

Does latex protect against acids?

I heard somewhere that some plastics are pretty good at resisting decently strong acids. To what degree is this true? Does latex protect against corrosives? Are plastics good at "resisting" bases or ...
12
votes
3answers
8k views

Calcium carbonate toxicity

I can't make heads or tails of the information on the net — although there seems to be plenty of it, it seems contradictory. Supposedly, calcium carbonate is used in antacids—yet there are warnings ...
12
votes
2answers
1k views

How does heptafluoropropane suppress fire?

How does heptafluoropropane suppress fire? It says here that it does so by "inhibiting the chain reaction." What does that mean specifically? Does $\ce{O2}$ attach itself to the heptafluoropropane?...
12
votes
5answers
17k 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 ...
12
votes
2answers
1k views

Polypropylene 55 gallon drum

Can a polypropylene 55 gallon drum previously filled with chemicals used in the chrome plating process (possibly Nickel Sulfate) ever really be "cleaned out" for re-use? Can polypropylene ever absorb ...
12
votes
3answers
35k views

Does milk drinking prevent long-term chemical poisoning?

I have heard some rumors that drinking milk prevents chemical poisoning. I have done a bit research and some sources confirm that. Corrosive Poisons The best first aid is to dilute the poison ...
12
votes
3answers
9k 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 ...
12
votes
3answers
320 views

Why do most explosives have symmetrical chemical structures?

I was just turning the pages of my chemistry dictionary, when I found the structure of TNT (Trinitrotoluene): ...there after I got interested in its symmetry as an explosive, and started looking for ...
12
votes
1answer
7k views

Why would sulfuric acid turn gray/black?

About 2 years ago I purchased 2 liters of 98% concentrated sulfuric acid. It's in a standard poly bottle with leakproof lids, and originally was clear. Recently I noticed the acids have turned a dark ...
12
votes
2answers
212 views

Why do seemingly reliable sources give NFPA 704 Health ratings ranging from 1-4 for elemental mercury?

Recently a user posted the question Do Mercury have a NFPA 704 classification?. Why the present question is not a duplicate: Although there is no accepted answer to the above question, I think it's ...
12
votes
1answer
1k views

What would be an appropriate way to clean up equipment contaminated with ethidium bromide?

I want to clean up some old equipment that was used to visualize nucleic acids with ethidium bromide. It's a UV table, built from glass and metal (stainless steel, I assume). Ethidium bromide is ...
11
votes
3answers
13k views

How are N95 masks different from dust masks?

There is a fire raging through my hometown right now. People in the area are advised to be wearing N95 masks to filter out smoke and particulates; and there is misinformation being spread that these ...
11
votes
5answers
7k views

Why does oxygen not condense onto open dewers of liquid nitrogen?

I had a discussion with my supervisor today after I was a touch careless pumping down a flask with a liquid nitrogen cold trap attached. I checked, and there are reports of explosions after running ...
11
votes
2answers
11k views

At what amount is digesting soap unhealthy?

Several of my friends, when they do the dishes manually, do not rinse the dishes after cleaning but merely dip them in the dishwater and then dry them (using a towel or a dish rack). I myself on the ...
11
votes
1answer
5k views

Should β-mercaptoethanol and anything that touches it be handled only under fume hoods for safety aspects?

Background: I recently started in a lab that regularly uses β-mercaptoethanol (βME) for protein purification. I know that the chemical is an irritant for the lungs if inhaled (mucus ...
11
votes
2answers
25k views

What type(s) of gloves are effective against DCM and acetone?

I know that standard latex and nitrile gloves don't stop common organic solvents such as DCM and acetone. However, I was reading a Reddit thread and there were comments that if you are coming into ...
11
votes
2answers
6k views

Proper use of vacuum pump during vacuum distillation

I am preparing to do a vacuum distillation and am unsure exactly how to manage the vacuum. The vacuum pump I have is a two-stage rotary vane pump which is capable of 250 microns or lower. It has a ...
11
votes
2answers
13k views

How to store methanol

We will be buying methanol by a about 200 liters at a time, I was wondering what I should consider when storing it. So far I know that it should be in the shade earthed with a copper stake in a ...
11
votes
1answer
312 views

What would happen if someone consumed a Silica Gel Packet? [closed]

Most packaged goods have the tiny Silica Gel Packets packed along with a clear warning on every single packet. My question is: What hazards of desiccant silica gel are they concerned about that it is ...
11
votes
2answers
28k views

What makes Kleenex Cool Touch tissues cool to the touch, and is it safe?

I love Kleenex Cool Touch tissues. I'm just wondering what makes them actually feel cool. For some reason it makes me think of refrigerant but I'm sure that's not in them. Is it the combination ...
10
votes
4answers
2k views

Would the concentration of oxygen around fire increase as we get close to the fire (from the outside)

Since fire require oxygen, wouldn't a fire, like those in the American forest along west coast, constantly draws in oxygen from around? And if that is so, would the concentration of oxygen around the ...
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 ...

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