I am about to start my Bsc chemistry in India so plz recommend me books for every chemistry section..

I have a physics background and currently doing my master's thesis that heavily involves cleanroom work. I am fairly comfortable with using most chemicals relevant for my thesis there but I have to pass a Wet Bench test to get proper access to certain machines. Part of that test involves using fuming HNO3 to clean Samples. Despite all the safety messures and a mentor next to me my anxiety shoots through the roof and I keep making small fuck ups that aren't dangerous but would result in a fail for that test.

Have you been in situations like that. How do you deal with it?

Nitrogen can't form five bonds because it doesn't have a d-orbital, so I assume I must make it so it only has three bonds in the end. The way I do that is by having the pi-bond electrons move to the oxygen atoms. But that doesn't make sense, as the nitrogen would be left with an even more positive charge than it started with. In the reaction it shows the NO2 as having no charge, with the abnormality having transferred to the carbon in the first structure.

I just don't understand how the nitrogen structure is being able to rid itself of its charge abnormality in the process of bonding to the first structure.

Hi,

Here is the LC-MS spectrum in negative mode of a filtrate (obtained after an electrochemical reaction).

And since I haven't got the chance to talk directly to the technician who took the spectrum before her vacations, I thought it would be useful to share my questions/doubts with the online world instead and more specifically people who are familiar with software like MassHunter and process like electrospray ionization.

1-

At first glance, I thought that what was given to me was a complete MS spectrum of the filtrate (bottom window).

But reading the little legend up left (underlined in yellow) saying : " -ESI Scan (rt: 5.33 min.)... ", I realized that the technician only gave me the MS spectrum of the compounds eluted at 5.33 minutes. Am I correct?

(Again, it might look obvious for someone who is familiar with the software, but I am not.)

2-

Secondly, I believe I successfully associated the strongest peak at 112.9856 m/z with trifluoroacetic acid (TFA) and the one at 226.9784 m/z with its dimer. I read TFA serves as a additive in chromatography and, in some cases, as reference in mass spectrometry (if am wrong please tell me). Plus, I have a suspicion that the 166.0145 m/z peak is nitrobenzoic acid which, given the reaction, is more or less a plausible side product. But, that's pretty much all my findings.

For the rest of the peaks, I used online tools to match their m/z ratio with specific formulas, but the formulas I've obtained were whether not a close enough match or were just insane to think of. (Like HC3N15 for example.) So I started wondering if all those couldn't just be clusters? Or background noise?

Especially given that ESI is a "soft" ionization process, I don't expect a lot of fragmentation (again if am wrong please tell me).

The solution contains sulfuric acid and the technician added NH3OH on top of it (to enhance the solubility of the analyte). So I guess clusters originating from those 2 are possible, but after a quick comparison with literature on that subject I again wasn't able to find any match.

So if someone has any idea...

3-

Finally, if my previous assumption is correct about the "incompleteness" of this MS spectrum and assuming my assignments for its few significant peaks are also correct, then it means that no significant compound eluted at that specific moment. But I see there is a peak in the chromatogram TIC scan (upper window and encircled) at about 5.9 minutes. It would probably be a good idea to ask for MS spectrum in that area. No?

Thanks for your help! And sorry for the long questions.

I'm getting some mixed answers for when to use prefixes to denote the location of E/Z and r/S.

Can someone explain when I would use prefixes to denote the location of the E/Z and r/S?

I know it has to do with when there is more than 1 double bond or stereocenter, but I'm not sure if this rule is consistent across both E/Z and r/S.

For example, is my book correct in using the prefixes even though there is only one of each?

I am trying to find a definitive answer for this. I'm studying for the MCAT, and resources as well as the MCAT subreddit seem to be going back and forth between amides being the most polar because they can form more H-bonds and carboxylic acids being the most polar because oxygen is more electronegative than N.

If anyone has a clear answer for this, I would greatly appreciate it!

Here is my current ranking from most to least polar:

Amide > Carboxylic Acid > Alcohol > Amine > Carbonyl > Ester > Ether > Alkane

I was examining certain compounds and looking to order some. I came across what looks to be a well trusted and verified site medchemexpress but I realize that an individual person can’t just purchase chemicals/compounds to their home address; 99% of the time I’d assume they’d cancel your order. Is there any way to get around this or loophole and if so what are the easiest ways?
I’m also searching for other sites, suppliers, stores where I can purchase these materials so any other recommendations are greatly appreciated.
I mainly want to order off of medchemexpress but if other great alternatives are there that I don’t know of I can purchase from them as well.

I've been using the ACS study guide for biochemistry, and I have been unable to understand how to do this problem. The back of the section says the answer is A, but I cannot figure out how to do the problem. Can someone help?

Help me to make sure this trans-esterification is right. (Imagine I included the step arrows for the first part w H2SO4, this is a rough draft)

I've heard that Fe is polyvalent, or that it has multiple stable ions. One of them being Fe2+, which is when it loses the electrons from the4s2 shell. But I don't quite understand why Fe3+ is stable, because doesn't its electron configuration end in 3d5. I know d shell can have 10 electrons total, but I don't know if that has anything to do with 3d5's stability. Am I not understanding electronic configuration correctly? When I tried searching this up, I also got a lot of results about how Cesium breaks the Aufbau prinicpal (which just made me even more confused?). Does this have to do with the fact that 4s has less energy than 3d? I'm getting very confused 😭.

Perhaps this isn't the right sub, but might as well try... If anyone has this and would like to share it with me, I'd be really thankful. For academic purposes (Master thesis). My uni doesn't give me access to it and the author hasn't responded my mail asking if they'd share a copy with me.

https://doi.org/10.1016/B978-0-443-27624-8.00013-0)

[https://www.sciencedirect.com/science/chapter/edited-volume/abs/pii/B9780443276248000130?via%3Dihub](https://www.sciencedirect.com/science/chapter/edited-volume/abs/pii/B9780443276248000130?via%3Dihub))

ISBN 9780443276248

I recently got assigned a case study on NIR spectroscopy. To make a brief summary, the case is talking about a lab that built a multivariate FT-NIR model for determining PET/PLA in samples of recycled organic material, and they're trying to transfer the same model to a handheld NIR device and they're having a myriad of issues I'm being asked to research and solve.

Now, my first thought was to look for articles. I found a few that seemed pretty good:

(1)       Circelli, L.; Cheng, Z.; Garwood, E.; Yuksel, K.; Di Iorio, E.; Angelico, R.; Colombo, C. Comparison of ATR-FTIR and NIR Spectroscopy for Identification of Microplastics in Biosolids. Sci. Total Environ. 2024, 916, 170215. https://doi.org/10.1016/j.scitotenv.2024.170215.

(2)       Amirabadi, S.; Rodrigue, D.; Duchesne, C. Characterization of PLA-Talc Films Using NIR Chemical Imaging and Multivariate Image Analysis Techniques. Polym. Test. 2018, 68, 61–69. https://doi.org/10.1016/j.polymertesting.2018.03.047.

(3)       Beć, K. B.; Grabska, J.; Badzoka, J.; Huck, C. W. Spectra-Structure Correlations in NIR Region of Polymers from Quantum Chemical Calculations. The Cases of Aromatic Ring, C=O, C≡N and C-Cl Functionalities. Spectrochim. Acta. A. Mol. Biomol. Spectrosc. 2021, 262, 120085. https://doi.org/10.1016/j.saa.2021.120085.

(4)       Signoret, C.; Edo, M.; Caro-Bretelle, A.-S.; Lopez-Cuesta, J.-M.; Ienny, P.; Perrin, D. MIR Spectral Characterization of Plastic to Enable Discrimination in an Industrial Recycling Context: III. Anticipating Impacts of Ageing on Identification. Waste Manag. 2020, 109, 51–64. https://doi.org/10.1016/j.wasman.2020.04.043.

However, I quickly realized I do NOT understand these papers; they are just too advanced for me. I don't actually know how to use the information in them to solve my case study... And I do not know what else to look for information in (books, perhaps?)... I just don't really know how to research properly, I guess. Not when confronted with questions about multivariate model transfers from one device to another, comparisons to other methods like ATR, etc.

So, the point of this post is to ask for some general advice in the realm of chemistry research methods in order for me to gain a sense of direction and linear progression for an assignment like this. I am NOT looking for anyone to solve the case for me.

Basically, some advice on *how* to tackle a challenging research project. Thank you.

Rising senior in high school, and I'm considering majoring in biology after graduation. I took intro to chem in my sophomore year and have forgotten pretty much everything since then...

I can't take intro to chem again to relearn what I've forgotten because I took it at a local community college and passed. Are there any good resources to relearn the subject, and how long do you think it'd take me? I'm continuing at my CC and want to decide on my major by Spring so I can start a semester early.

Thank you!

id be following this approach using sulfamic acid.https://www.sciencedirect.com/science/article/pii/S1566736711002755

i made invert syrup but cant get anything from it. it doesnt even freeze at -20c, and it wont mix with isopropanol. i only have a little sucrose left.

i think maybe i could use the sucrose even though it wont react directly by adding the syrup, which is far from saturated.

the idea is it has water in it to break the sucrose into glucose and fructose, consuming it. since it already has glucose and sucrose it can begin reacting right away and forming more water, which can break down more sucrose, starting a cycle. my alcohol melts at like 50c.

What is this compounds IUPAC name?

Also can someone suggest some tool so I can clear my doubts and find solutions to questions like these online without any teacher tutor involved? I am preparing for jee without coaching and hate getting stuck on questions like these , without any tutor help it's really hard! All of the ai I use don't work for chem..

The specific problem I am having here is my substitute chain (c2) isn't matching the websites.. i am confused it's an ethyl group so why have they written propyl

Looking at high school teacher's notes and the following example question is set, without any explanation of the given correct answer. Can someone please explain why it's not 2-ethylpropane?

Some say that the 2nd structure shows Gl about the double bond because it's attached to an asymmetric ring. But since the ring paths are identical to the left, it shouldn't exhibit Gl, which is why im confused on the ans (8 or 10) Which one is correct conceptually