r/chemhelp • • Aug 31 '26

Discussion Start of term check-in

9 Upvotes

Hello all!

School terms are beginning and this is typically when we see an influx of posts asking for general advice, guidance on getting through a class, or seeking assurance that everything will be okay. Let us know what courses you are in this term, your biggest concerns, or whatever may be on your mind!

Best of luck!


r/chemhelp • • Aug 21 '25

Announcements New Ownership

21 Upvotes

Hello fellow Chemists! I just wanted to introduce myself as the new head mod of this subreddit. A little about myself: I am a PhD Candidate in Chemical Biology. For me, this means that 60% of my work involves organic synthesis and the other 40% is applying my novel compounds to mammalian cells. Specifically, I am interested in early detection of diseases. In addition to my research, I have TA'd for both general and organic chemistry labs and have been tutoring students in organic chemistry for three years. Aside from my academic qualifications, I am also a moderator for another rather large subreddit. I saw that this sub needed a little bit of updating, but it did not seem like the moderators were active any longer. So, I gained ownership through r/redditrequest. I did not realize it would remove all the other moderators, but alas here we are.

Overall, I feel like this sub is fairly self-regulating. I frequently see good discussions and people generally are following the already existing rules. With that said, there are some changes I was considering, and would love input:

  1. New rule prohibiting commenters from solving the problem for the OP. To enforce this, the violating comment can be reported and removed by moderators. I don't see this happen often, but I have seen it occur and put an end to an otherwise good discussion thread.
  2. Mandate students include their work in their submission. Frequently, students post a picture of the question, with no work done and the caption "help please." Then in the comments you end up with people asking the OP to show their work, but from what I have seen they seldom do so. Mandating that students show work would entail removal of low effort posts by moderators. This may not be necessary since generally, commenters request more info from OP anyways, but was curious if people would like to see more enforcement on this end.
  3. What do you want to see? Those are the immediate things I was considering adding, but I would love to know if there is anything else people may want to see. I had other ideas, but I don't want to complicate a sub that I feel is already doing pretty well. Please let me know your ideas, I would love to hear them. Talk to you all soon!

Note: Please do not reach out to me about becoming a moderator. I will looking into recruiting in the near future. For now, I just wanted to get oriented.


r/chemhelp • • 3h ago

General/High School vsepr/determining if something is polar/nonpolar URGENT

2 Upvotes

hello! I'm currently taking Gen Chem 1. We've gone over how a molecule is polar if there is a net dipole moment. I put on my quiz paper than BrCl4-, ClO4-, and PCl4+ are nonpolar because the dipole moments cancel out, and he marked me wrong on all of them!! with his reasoning being because theres a plus or minus charge in the name of the formula. He tells the class that anything with a + or - charge in the name is polar. is he actually right or have i been learning chemistry wrong this whole time? HELP! I CANT DO THIS ANYMORE!!


r/chemhelp • • 2h ago

Organic OCHEM 1: These are the types of reactions we're looking at for alkenes. I plan to go to office hours, but I don't have all the time in the world to go constantly. This is a flipped classroom. What is a recommended source to look at when it comes to these types of problems?

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2 Upvotes

Learning on my own is currently a disaster. A lot of the class is struggling. I'm still scoring above average on exams somehow. (The average for the last exam was 43; it was mechanisms, IR, and NMR).

I have horrible foundational knowledge of SN1/SN2/E1/E2, which is probably why I'm struggling with this stuff.

How can I teach myself this material? What are the questions I should be asking myself?

The problems (in the pictures) on the psets are usually harder than the exams, so I tend to avoid them.


r/chemhelp • • 4m ago

Organic Help with determining reagents for alkylation reaction

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• Upvotes

Hi, doing some study for my organic exam and came across this q under the section for enol/enolate reactions, which asks for reagents for a variety of reactions. I was able to do all but this one. I know that it would require an allyl bromine group, how do you make it so that the enol doesnt form at the most acidic H in between the carbonyls? Am i right for thinking that I would need to use something like NaH to remove it first, then the other enol can form? I’m a bit confused 😭


r/chemhelp • • 7h ago

Organic BF3OEt2 + epoxide. What does this mechanism look like?

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4 Upvotes

How does the whole mechanism look like? I know that the epoxide breaks but how does the alcohol turn into a ketone


r/chemhelp • • 11h ago

Organic Mechanism query

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5 Upvotes

How do I regain the Aromaticity ?
Also tell me if any of my step is wrong !! Thank you


r/chemhelp • • 4h ago

General/High School Check for Errors in Periodic Table

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1 Upvotes

If anyone sees errors in this version of the periodic table please let me know. It was sent to me and I want to make sure I can use it with students


r/chemhelp • • 4h ago

Biochemisty [ Removed by Reddit ]

1 Upvotes

[ Removed by Reddit on account of violating the content policy. ]


r/chemhelp • • 5h ago

General/High School Chat am I cooked? Need to really get this down in 12 days ish? 3 chapters.

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1 Upvotes

These are all the topics. I feel MOSTLY confident in chapter 4. Need to fix up my oxidation skills. Was going to use most of this week to get chapter 5 down. Then work on chapter 5 late this weekend into next week. I have a feeling chapter 6 is going to be the hardest does that seem true?


r/chemhelp • • 9h ago

General/High School Please help me with the lewis' structure of saccharose

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2 Upvotes

I want the lewis' structure of saccharose, but I can't find the chain structure (I think), like the structure of image, to convert into lewis' structure, (I don't finished teach English, sorry if my English is bad)


r/chemhelp • • 12h ago

Organic Reaction product not crystallising, need advice

3 Upvotes

The r/chemistry rules regarding posting led me here, as I believe this is a lab question.

Partial S(Ar) bromination (2 and 3/4 possible spots) of my 2, 2' biphenyl 1, 1', 3, 3'-tetrametoxi compound is not crystallising and is in an oily state. Excess bromine was neutralised with ascorbic acid (thiosulfate messes up the next reaction, even in miniscule amounts) and removed everything water soluble from the mixture with a water/DCM extraction. The DCM solution was dried on MgSO4, and the excess solvent evapourated.

So far I have tried antisolvents of ethanol, methanol, toluene, water, diethyl ether and hexane, with one phase mixtures being the result of everything but ethanol and water, scrubbing any of them with a spatula did not initiate any crystallisation. I have tried freezing the oil, but without access to liquid nitrogen or dry ice, the best I could do was -14 °C. I also left the mixture for the last weekend to evapourate, but with no success.

Any guesses as to what could work to get this to crystallise?

Thank you in advance!


r/chemhelp • • 6h ago

General/High School How to know where hydrogens connect on an alkenes?

1 Upvotes

I’m sure this is a really obvious question that I just can’t find the words to elaborate on but I just started organic chemistry in class, I’ve scoured the internet and there’s no answer as if it’s something that doesn’t need explaining. Alkanes are always saturated but with alkenes the carbon atoms can have 1, 2 or 3 Hydrogen atoms attached with no clear pattern (the same goes for the double bond).


r/chemhelp • • 8h ago

General/High School Chemical Engineers: Do You Understand the Equations Behind Aspen HYSYS and Aspen Plus?

0 Upvotes

Hello, fellow chemical engineers!

I am conducting a study to explore how well chemical engineers understand the scientific principles, mathematical equations, and computational methods used by specialized chemical engineering software, such as Aspen HYSYS and Aspen Plus, to solve engineering problems and simulate processes. I would greatly appreciate it if you could share your experiences and perspectives.

My main question is:

When you use software such as Aspen HYSYS or Aspen Plus to solve a chemical engineering problem or simulate an industrial process, how well do you understand the specific equations, mathematical relationships, and scientific principles the software uses to perform its calculations and obtain the results?

For example, suppose you use HYSYS to simulate a distillation column or a separator. The software provides you with information such as:

  • The flow rates and compositions of outlet streams;
  • The mole fractions of individual components in the liquid and vapor phases;
  • Stream temperatures and pressures;
  • The energy consumed or released by equipment;
  • And other parameters required to analyze process performance.

Do you know which equations and computational methods the software uses to calculate these results?

For instance, are you familiar with mass and energy balance equations, vapor–liquid equilibrium (VLE) relationships, thermodynamic models, the equilibrium-stage equations used in distillation columns, and the numerical methods employed to solve these equations?

Can you explain how these relationships are interconnected and how the software uses them to obtain the final results?

My more important question is:

If you were given the same problem or project that you had previously solved using HYSYS or Aspen Plus and were asked to solve it without using either of these software tools, would you be able to independently explain the solution methodology and carry out the necessary calculations?

I do not necessarily mean that you should be able to perform every complex, repetitive calculation manually or reproduce the results to the last decimal place.

What I really want to know is whether you understand which scientific principles, equations, and relationships are needed to solve the problem, what assumptions must be made, which material and energy balances must be formulated, and what steps must be followed to obtain the desired results.

In other words, can you understand the underlying logic of the software's calculations and, if necessary, explain how the problem could be solved without relying on the software itself?

For example, if you were given the results of a distillation column simulation, would you be able to explain which equations and algorithms were used to obtain those results? Could you identify the fundamental equations governing the process and explain how the software solves them simultaneously to arrive at the final solution?

Or do you generally rely on the software's results without having a detailed understanding of the calculations and methods behind them?

I would be particularly interested in hearing about your actual experiences, whether in academia or industry, and the types of projects you have worked on using these software tools.

Thank you very much for taking the time to respond to my question. Your answers and insights would be extremely valuable to my research, and I sincerely appreciate your willingness to share your experiences and knowledge.


r/chemhelp • • 8h ago

Career/Advice in need of an old version of MOE to graduate

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1 Upvotes

r/chemhelp • • 8h ago

General/High School What is the Schotten-Baumann method? Why is this method extremely useful for the acylation of poorly reactive amines or easily hydrolyzable structures? help me pls

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1 Upvotes

r/chemhelp • • 5h ago

Inorganic What concentration of ammonia is used in ammonium nitrate

0 Upvotes

Hello, im trying to synthesize ammonium nitrate by mixing nitric acid and ammonia to form this reaction

HNO3 + NH3 → NH4NO3

What should the concentration of the ammonia be and in what ratio should it be mixed with the nitric acid. The concentration for the nitric acid is 55%. Any help will be appreciated, thanks!


r/chemhelp • • 7h ago

Organic Would this be correct?

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0 Upvotes

I know radical halogenation is Anti-Markovnikov, but I don't know how this excess alkane changes this reaction.


r/chemhelp • • 1d ago

Other So the person I have some sort of bond sent me this, any help? Im sorry but im kinda dumb for this kind of thing

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91 Upvotes

Sorry if its not fitting to the sub but I have no idea where to ask, I do not trust Google ai overview


r/chemhelp • • 19h ago

General/High School How can I maximize elephant toothpaste to get the largest explosion possible in terms of height and physical volume?

1 Upvotes

I am working on a volcano model project for a science fair and want to scale up the elephant toothpaste experiment to get the absolute maximum height and width

I’m working with a 1/4 illustration board with no height limit


r/chemhelp • • 1d ago

General/High School Would this be a valid isomer of HBrO3?

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3 Upvotes

Normally Bromic acid has a single bond with one of the oxygens, which then the hydrogen bonds to that oxygen. But i was wondering if theoretically an isomer could exist where the bromine is double bonded to all three oxygens, and then single bonded to the hydrogen. it’ll probably be less stable than the normal isomer which is why it doesnt exist naturally or by normal production methods. The vsepr diagram is probably off too


r/chemhelp • • 20h ago

General/High School Precipitate image

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0 Upvotes

r/chemhelp • • 1d ago

General/High School how to study for chemistry

3 Upvotes

I wouldn't say I'm struggling with chemistry nearly as much as I am with math, especially because I'm starting to understand the concepts a lot better now. However, I'm worried that I might eventually come across another unit that I really struggle with.

For example, our first unit was thermodynamics, and I spent a lot of time studying and preparing for the unit test. I genuinely felt confident going into the test and even felt pretty good about it afterward. But when I got my mark back, I found out I had only scored 51%, which was really disappointing considering how much effort I had put into preparing.

Right now, we're learning about redox reactions and electrochemistry, and things have been going pretty well. I'm actually enjoying this unit, and I feel like I'm understanding the concepts much better than I did in thermodynamics. My marks have also started improving, which is encouraging.

However, I don't want to wait until I encounter another difficult unit before realizing that my study methods aren't working as well as I thought.

What I really want to know is how I can study chemistry more effectively and efficiently in general. I'm someone who learns best by understanding the logic behind concepts rather than simply memorizing formulas or procedures. I also find visual explanations and worked examples more helpful than just reading a textbook.

I'd love to hear what study methods have worked for other chemistry students, especially when it comes to understanding difficult concepts, remembering what you've learned, and applying that knowledge correctly on tests.

My goal isn't just to improve my grades in the unit I'm currently taking, but to develop a study method that will help me succeed in future chemistry units as well.


r/chemhelp • • 1d ago

Organic Why is this molecule a meso compound?

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6 Upvotes

Hey all!
I’m doing some OChem practice before an exam and I got this question wrong. RealOChem says the compound IS a meso compound but I don’t see the line of symmetry.
Any help is appreciated!


r/chemhelp • • 20h ago

Organic Sn1, Sn2, E1 and E2 reactions

0 Upvotes

Hi Sorry my exam is tomorrow. I'm super clueless on the difference between these, especially retrosynthesis reagents catalysts used for each reaction. I can't get my head wrapped around this. Any pointers? 🥹 First year organic chem student at University btw ^^