Not very practical, but the chemistry is interesting. Producing a strong acid from a weak acid by using precipitation as the driving force is something I don't see very often.

A bit of analytical chemistry for a change. I had never heard of a pycnometer!

Very useful video. Nitrate salts are a foundational feedstock in amateur (and professional) chemistry.

Edit: NurdRage reuploaded a slightly censored version: https://www.youtube.com/watch?v=RlonW4iJYrw

NurdRage has published a couple videos on oleum synthesis:

• Lab Notes - Making Oleum - Successful - (April 21-2024)
• Lab notes - Making Oleum - 20% yield improvement - (May 4th - 2024)

Still optimizations to be done, but cool work so far. I love that one of the OG chemistry YouTubers is still doing interesting work.

A long-time viewer of Periodic Videos grew up to study chemistry, and invented a new synthetic route for thalidomide.

Also, TIL that thalidomide still has several medical uses, as long as the recipients are not pregnant.

Cody Reeder makes thermite and has a nice "campfire".

The manual for my dishwasher says to refill salt just before running a wash cycle, because if any grains of salt spill onto the stainless steel interior it will corrode. If it runs right away, no issue because the salt is quickly dissolved, diluted, and flushed.

So then I realized when I cook pasta I heavily salt the water (following the advice that pasta water should taste as salty as the ocean). But what happens when I leave that highly salty brine in a pot, sometimes for a couple days to reuse it? Does that risk corroding the pots?

If you don't want to watch the entire video, it's a Carborane acid.

I'd love to see what the molecular orbitals look like. It's not every day that you see carbon forming six "bonds".

cross-posted from: https://lemmy.dbzer0.com/post/12359577

> There are a few youtube videos where someone suggests using sulfuric acid to clean a secondary plate-style heat exchanger (for example). Yet I’ve heard sulfuric acid is extremely corrosive to metal, so something seems off about that advice. I certainly would not want an internal leak to cause radiator fluid to enter the tap water. I saw a drop of sulfuric acid land on a galvanized steel pipe once and within minutes it was rusted on the spot. > > This guy also says sulfuric acid is an option but also says there is a safer alternative acid -- yet he did not mention what it is! Does anyone know? > > This guy says he uses an ultrasonic bath but he does not say what chemicals he uses. Would distilled white vinegar be good for this? > > Note these questions are very loosely related to this thread which describes a problem I am having, but really it’s a separate discussion. Secondary exchangers need periodic maintenance regardless of whether this is my current problem. I saved my previously clogged heat exchanger from a few years ago so I could work on cleaning it. I have a quite small ultrasonic I could try, but I cannot submerge the whole exchanger. I would have to stand it on end and only clean a few centimeters deep.

cross-posted from: https://lemmy.dbzer0.com/post/10839711

> A top-floor room that’s not currently used has mold from excessive dampness. For a month I have been running a dehumidifier as it’s too cold to open the window. > > Is this a good idea? > > My concern: I heard about running a dehumidifier long-term in a damp basement is a bad idea because making the air more dry than the wall causes moisture to continuously flow from the outside in. That flow supposedly has the effect of washing the masonry through the capillaries and causing it to break down and weaken. In my case it’s not a basement, but similar because the exterior wall is non-stop wet from the frequent rains (possibly even leaky.. i think water seeps in). > > I have the humidity set to 55%. I wonder if there is an optimum setting that would inhibit mold without overly causing water to flow through the wall (which is very old brick+mortar and rendered over on both sides, no insulation). > > BTW, the water collected in the dehumidifier looks clean. Is it good for drinking?

The manual for an ultrasonic cleaner says:

> * “Cold, clean tap water is generally best suited as cleaning fluid. The cleaning effect can be enhanced by the addition of approximately 3 drops of washing-up liquid. Do not use caustic cleaners, ammonia, bleach or heavily perfumed detergents.” (emphasis mine)

I know a professional jeweler with decades experience who cleans jewelry (mostly gold) using “Mr. Clean”¹ and ammonia, diluted, in an ultrasonic tub. The cheap ultrasonic I bought for myself is not for pros - but jewelry cleaning is the advertised purpose and it has a stainless steel tub just like the pro models have.

So the question is, what’s the purpose of the ammonia avoidance guidance, and is the pro jeweler I know making a mistake by using ammonia?

UPDATE: I also have to question why the manual says to use cold water. Pro ultrasonics have built-in heating elements. The pro jeweler waits until the solution is hot before using it.

footnote:

① out of curiosity, is there a brand-neutral name for “Mr. Clean” (aka “Mr. Propre” in French regions)?

Found this on Mastodon. A "Christmas tree" of flasks with differently colored liquids.

cross-posted from: https://infosec.pub/post/5276026

> I have a hot water dispenser, which heats the water to the temp you specify, on-the-fly. Sometimes this technology is called “insti-heat”. Instead of filling a kettle and waiting, it pumps water from a tank and heats it inline as fast as it draws it. Likely similar to how Nespresso machines work. > > This means the limescale is hidden in the internal tubes. When descaling solution is put in the tank and the descaling program runs, there are no white chips of limescale like you would get in a water kettle. Yet it seems to be working because after descaling the water flows smoothly (as opposed to coughing and sputtering which is what happens when limescale is built up). > > So it’s a mystery- where did the limescale go? Does it actually dissolve into the descaling solution? I ask because I’d rather not be wasteful.. I’d like to reuse the descaling solution, if that’s sensible.

I wish I’d grabbed a photo when I saw this but I thought it might be bad so I threw it away. Hindsight maybe that also wasn’t the best course of action but here’s my story.

Since there are a few ways to make flash cotton. I’ll give the basic ingredients I used but not the instructions. I used ammonia nitrate, sulphuric acid, and 100% cotton balls. I have nitric acid but it’s a pain in the ass to get, and expensive. So, I didn’t want to use it.

Anyway, I made this flash cotton like 3 years ago. I stuffed it all into a glass jar with a metal lid. I mean let’s face it. After you set a couple of pieces on fire, and show your 2 friends. What else can you do with it?

So, I stuffed it all into a glass jar with a metal lid, and forgot about it. Occasionally I’d see it in the kitchen drawer when I was looking for something and think yep there’s that flash cotton I made. I should burn it sometime.

Fast forward to the other day roughly 3 years from when I made it. I was looking for catfish skinning pliers when I found the jar. Only now that metal lid was half dissolved. The cotton was also gone. In its place was a yellow sludge that was growing little yellow crystals.

My initial thought was “hmmmmmmm that don’t look so good. Into the trash with you”. But now I’m curious what the hell happened? Also, maybe the trash wasn’t the best place for that?

I guess I’m just looking for insight.

Hello Chemists. I was wondering what the half-lives are for certain tear gas molecules used in tear gas used by the police. My house was tear gas due to an incident with a neighbor 5 days ago and now it still lingers.

They said that they used CN, OC and CS gas.

CN = (Orthochlorobenzalmalononitrile) OC = (Oleoresin Capsicum) CN = (Chloroacetophenone)

Thanks a lot for your help. Also, if you could note special properties of these molecules, about toxicity, etc, please let me know too :-)

Thank you!