/r/chemistry

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A community for chemists and those who love chemistry

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Past Weekly Topics

/r/chemistry

3,615,813 Subscribers

3

Someone Know where this exercise is from?

7 Comments
2025/02/01
21:59 UTC

4

Salt caused my metal pot to become rusty?

So I was cooking my pasta and like any cook pasta recipe I seasoned my pasta water with salt. But as the water was starting to boil I noticed a brownish substance forming on the side of the pot, I originally thought it was the due to the pasta sauce since I used the same spatula as I used with the sauce to mix the pasta in the water to avoid sticking. As soon as I poured the water out I noticed what seemed to be rust forming on the side of the pot. Could anyone tell me if I just cancered myself?

6 Comments
2025/02/01
21:47 UTC

3

Iron crystals by electrolysis of anhydrous FeCl₃ in non-aqueous solvent?

I got to thinking back on one of my high-school lab exercises on electrochemistry. A zinc/copper cell was set up and left for several days, which resulted in the growth of some rather pretty copper crystals. (And disappearance into solution of zinc, of course, with some black particles which I tentatively attributed to carbon contaminating the zinc.) Which led me to wonder about growing other kinds of metal crystals. Similar setups can be used to grow silver crystals, of course, and I wouldn't be surprised to learn about doing it with gold.

Other metals wouldn't be so easy because of their electrochemical potentals and competing reactions. If I tried to electrolyse iron-containing solutions in water, I'd expect to get hydrogen gas rather than iron. But perhaps in non-aqueous solution? Might it be possible to get iron crystals by electrolysis of, say, anhydrous FeCl₃ dissolved in anhydrous alcohol or acetone? "Spectrophotometric Studies of Iron(III) Chloride in Nonaqueous Solvents" (Russell S. Drago, David M. Hart, and Robert L. Carlson, JACS 87:9 1900, May 5 1965) indicates that there's dissociation of the FeCl₃ in MeOH and DMSO.

There would probably be a market for genuine "cold iron", which had never been exposed to heat at all, among purveyors of woo. :-)

0 Comments
2025/02/01
20:58 UTC

1

Previous owners lefts a bottle of nitric acid.

Is there a household use for Nitric Acid? If not, what do I do with about half a liter of it? Can I throw away?

If this isn’t the right place to ask, what subreddit can help?

7 Comments
2025/02/01
20:56 UTC

36

Does anyone else feel like hydrophobic molecules are the enemy?

Since I started learning about polar and non-polar molecules in middle school I have always felt disdain towards hydrophobic/non-polar molecules (like fatty acids, but saturated fatty acids are less evil than unsaturated). I feel like the polar head group on the phospholipid is on my side but the tails and everything else inside of the membrane are out to get me. Does anyone else feel this?

37 Comments
2025/02/01
19:40 UTC

0

Bleach and temperature

Hi there. I’m wondering how effective bleach is at sanitizing for viruses in cold temperatures? I see many things online that suggest it degrades in sunlight or temps over 70 degrees but I’m not sure about cold. For example, if I have an object in my yard I wanted to disinfect and it’s below 40 degrees outside or was even colder prior to reaching a high of 40, will applying bleach to a cold item stop the effectiveness of the disinfection and sanitization the sodium hypochlorite is designed to do?

Thoughts?

Could one test the effectiveness of bleach in cold with pH strips?

8 Comments
2025/02/01
19:31 UTC

6

This made me laugh. Lots.

This is probably a repost as something this brilliant can’t have gone unnoticed.

It starts slowly but stick with it. Superb stuff!

6 Comments
2025/02/01
19:10 UTC

0

How to catalyze conjugation of two molecules? And how this might improve alzheimer

I can get DHA and phosphatidylcholine separately, but how do I conjugate them?

For example if I eat them at the same time, will there be naturally spontanous conjugation? if so at which rate? How to catalyze it?

I want di-DHA phosphatidylcholine.

or Docosahexaenoic acid-containing lysophosphatidylcholine (DHA-LysoPC) 

In order to stabilize the DHA moiety at the sn-2 position of LysoPC, the sn-1 position was esterified by the shortest acetyl chain, creating the structural phospholipid 1-acetyl,2-docosahexaenoyl-glycerophosphocholine (AceDoPC).

How to achieve this, ELI5 please!

https://pubmed.ncbi.nlm.nih.gov/36364810/

It's explained in this patent https://patents.google.com/patent/EP2089400B1/en

But I'm not skilled enough in chemistry halp

also https://link.springer.com/article/10.1007/s11746-997-0151-8

but I just want simple conjugation

The goal is for this analysis about how to significantly slow brain aging:

While there are many experimental neuroprotectant, the most potent one is surprisingly one of the most basic, the omega 3 acid DHA of which our diet are limited.

DHA in longitudinal studies shows a 50% reduction in the occurence of dementia. Which could be interpreted as rhoughly halving brain aging. People that are not responders are apo-e allele carrier which is the biggest driver of alzheimer and indeed the main mechanism behind the mutation is reduced ability for DHA to cross the blood brain barrier.

As such, one has to ask:

  1. can the effect of DHA supplementation be made even more potent in healthy humans?
  2. can improving DHA blood barrier crossing in apo-e alzheimer risk patients significantly improve their prognosis.

Another piece of evidence comes from modern precision medicine proteomics that shows that among the hundreds of defence proteins that are upregulated as a pathological response to alzheimer, the one the most significantly upregulated is a protein that plays a role in improving BBB import of DHA. Despite this homeostatic response, it appears such upregulation is ineffective because of the apo-e defect.

Hence while it is often underappreciated that DHA, as is, is the most potent longitudinal neuroprotectant, its actual potency, if we improved the pharmacokinetics could potentially transcend current DHA supplementation efficacy and be a medical breakthrough!

Because even if most people are deficient in the diet and that supplementation long term usually fix the level in erythrocytes, there is empirical evidence that apo-e carriers are functionally deficient of DHA selectivelly in the brain because of reduced BBB crossing/import.

Even in healthy humans, BBB import of DHA is very limited, and is crucially dependent on the form of DHA.

There are two main form of DHA sold, the base form and the re-triglyceridated (rTG) form. While rTG has 4 time better bioavailability at increasing levels in red blood cells (which might be beneficial for cardiovascular health) it is a fundamental misconception that this would be a reliable proxy for brain levels.

Indeed this has been specifically studied both in mouse (in vivo) and in BBB human cell cultures (ex-vivo/in vitro)

https://pmc.ncbi.nlm.nih.gov/articles/PMC6885117/

They find that the triglyceride form does not increase DHA levels in the brain.

Unclear if they have tested the base form but they says it is not effective too (or weak).

On the contrary they make the major breakthrough discovery, that DHA conjugated to lysophosphatidylcholine very significantly increase brain levels.

they show that di-DHA phosphatidylcholine cross it too though less effectivelly than DHA-LPC.

As you probably know phosphatidylcholine is a popular neuroprotectant (for myelin and cholinergy) and is enriched in eggs, or in supplements such as CDP choline.

But here the lyso form is more effective which is usually not supplemented (although partially synthetized ? from the base form). I'm not sure but maybe lecithin contains the https://en.wikipedia.org/wiki/Lecithin lyso form? it should be easy to produce otherwise.

https://en.wikipedia.org/wiki/Lysophosphatidylcholine

LPC in principle does not sounds too desirable (as lpc increase phagocytosis of cells, and of myelin..) but such revolutionnary DHA incorporation might be well worth it. Otherwise as stated di-DHA non lyso is devoid of this issue.

> LPCs occur in many foods naturally. According to the third edition of Starch: Chemistry and Technology, lysophosphatidylcholine makes up about 70% of the lipids in oat starch (p.592).^([11])

Anyway I have an extremely basic question in chemistry, how do we make molecule conjugates?

I can get DHA and phosphatidylcholine separately, but how do I conjugate them?

For example if I eat them at the same time, will there be naturally spontanous conjugation? if so at which rate? How to catalyze it?

0 Comments
2025/02/01
18:26 UTC

0

I have a question can you use a carbon anode in an electrochemical ethane production cell

2 Comments
2025/02/01
18:08 UTC

0

Nail polish remover vs white plastic, what happened chemically?

I just discovered that our thermometer for measuring body temperature in ear seems to be melting on its side right next to the temperature display. I noticed that a bottle of nail polish remover right next to it had leaked some of its content.

The ingredient list of the bottle reads: propylene carbonate, parfum, isopentyldiol, benzyl alcohol, citronellol, garaniol. The thermometer is made of white plastic.

What happened here chemically? May there be any toxic chemicals on the thermometer now because of the reaction? The part for measuring temperature is not damaged and it works just fine, but still it doesn't smell very healthy where it melted. I tried to remove the soft almost fluid plastic with tissue paper but that doesnt work as it's rather sticky as well.

3 Comments
2025/02/01
17:06 UTC

0

OMG it's coming for my job. I asked it to list all stable isomers of C3H6O and determine which ones are chiral.

18 Comments
2025/02/01
16:19 UTC

399

My roommate let dishes soak in bleach for 3 days… what happened to my plate?

This plate didn’t look like this before. It was sitting at the bottom of the sink completely submerged with silverware and more pots stacked on top. I’m curious as to what and how and why? Also am I good to eat off these in the future?

90 Comments
2025/02/01
15:45 UTC

4

Are two of the same elements chemicaly combined considered a compound?

Say is ozone (3 atoms of oxygen)considered a compound,what about diamond.google doesnt give a clear answer.

9 Comments
2025/02/01
14:14 UTC

1

Help in finding question papers for ccho (chinese national chemistry olympiad)

Hi, I'm a student in india pursuing an exam called JEE(Joint Entrance exam) , I love solving chemistry problems recently I had checked out some icho past papers (Spoiler Alert:- They were hard asf) I heard somewhere on the internet that ccho prelims is harder than icho itself but couldn't find ccho papers other than 2 translated and released by MIT.edu website of ccho 2016 and 2012 then I found a website called dcho.us ( decoding of chemistry olympiad) there I found links to ccho prelims papers released by chinese Chem society by they were in chinese and it was warned to not reproduce the paper on internet ,So if anyone can help me with this ,It would be much appreciated.

0 Comments
2025/02/01
11:44 UTC

1

Can you dehydrate using a microwave?

Say that you have a caffeine hydrate and you want the anhydrous form. Is using a microwave a suitable alternative to a drying oven?

I assume it would go something like this: Use low power [to avoid degradation] and do bursts of x seconds, pause and stir x times [to vent and heat evenly].

5 Comments
2025/02/01
10:29 UTC

18

What is the best chemistry textbook you've ever read? Why?

At any level high school, university and from any country

23 Comments
2025/02/01
09:53 UTC

11

If you had to summarize all of Chemistry how would you do it?

If you had to summarize all of Chemistry upto let's say a high school senior's level how would you do it? And if you wanted to make any changes on how chemistry or science is taught in schools what changes changes you make

36 Comments
2025/02/01
06:31 UTC

7

Ranch Emulsion

This is what ranch looks like after it has been soaked in water for a day. It’s surprisingly beautiful and I want to learn more about emulsions. Does anyone have recommendations for a textbook that covers topics like emulsions, colloid chemistry, interfacial rheology, surfactants, or any other topics relevant to these types of interactions? TIA

6 Comments
2025/02/01
04:50 UTC

63

How does iodine leach through glass? A sealed vial clearly is oozing out onto the paper towel, how does that happen?

38 Comments
2025/02/01
04:07 UTC

1

FTIR microscope Ge crystal question

I run a ftir microscope currently. My coworker thinks our Ge crystal is too damaged but I am not so sure. Any advice on how to know if the Ge crystal is too damaged to get good data. Any help is welcome. Thanks!

5 Comments
2025/02/01
03:08 UTC

441

The Chemistry Bible, how relevant is this edition?

Bought it for $3 at McKay’s

36 Comments
2025/02/01
03:01 UTC

1

Sonogashira coupling in presence of hydroxyl groups

Hi, I'm currently trying a sonogashira coupling in a derivate of bromohydroquinone. It's important to protect the hydroxyl groups when you are doing it? I was using dhp and the purification of the compound is being really difficult. Any more protecting groups that survive under really basic conditions?

1 Comment
2025/02/01
02:35 UTC

0

Help with hair bleach

Hey everyone,

My partner is a hairstylist. We’ve been having a quiet night watching a movie and her product rep just emailed advising that the hair bleach powder she uses is increasing in price by ~8 dollars a tub. The tubs are relatively small.

I just googled the chemical composition of this stuff. It’s Ca(CIO)2. For further reference, the brand she buys is L’Oréal.

Now, I’m not a chemist like the people here, but I’m kinda handy around the house. Can someone help me with instructions on how to get to a point where I can present her with a barrel of powder possessing essentially identical properties?

NB, because I feel like the crowd here might be like, hey everyone, look at this non-chemist asking chem q’s! you’ve already heard about my handiness, which is formidable. If that’s not enough, my dad and my brother are engineers, so I’d appreciate it if you would please extend what I assume is some fraternal order of science kinship to friends and family, and take a sec to help out.

Thanks!

12 Comments
2025/02/01
01:34 UTC

139

What is this flask?

a friend found this in a back stockroom earlier. Any idea what kind of flask it is and what it’s used for?

42 Comments
2025/01/31
23:32 UTC

0

Question

I’m trying to determine the PPM of toxic fumes in a space containing bleach at 95 degrees Fahrenheit. The solution is a percentage of NaOCl which chemically reacts to give off chlorine gas. I’ve got most of what I need but cannot determine how to calculate the rate at which the chlorine gas is being produced to use that volume to calculate the ppm.

The Arrhenius equation seems to be what I need but the pre exponential factor and activation energy seem to both be obtained via experiments , which I cannot conduct. I’ve found assumed rates to be about 10^11 to 10^13 for pre exponential factor and anywhere from 50 to 100 KJ/mol for the activation energy .

Does this seem correct, anyone have any input?

8 Comments
2025/01/31
22:32 UTC

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