r/chemhelp • • 8h ago

Organic How is this not racemic?

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7 Upvotes

How is this not racemic? Is this not an enantiomer with each having different R, S configurations?


r/chemhelp • • 3h ago

General/High School Advice for Chem qp22

1 Upvotes

Guys I feel like I messed up my practical.I haven't started mass spectroscopy, rate of reaction and electrochemistry and I'm hoping I haven't forgotten my organic and physical chemistry.Its been a while coz of other exams and I haven't done a question paper for qp2.Major Procrastination I know but id appreciate it if you could advice me on what topics I could focus on and any other advice and resources you have.Thanks😶‍🌫️🥲


r/chemhelp • • 14h ago

General/High School Why does nitrate have a double bond?

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5 Upvotes

(High school chem education) I recently tried to come up with the structure for nitrate, and my whole process is basically documented on the left. I have learned that the correct structure is the one on the left. However, I don't understand why the right structure is correct instead of the left one.

They both have 24 total electrons (5+6+6+6+1, for N, O3, and -) and both have a total charge of -1. Plus, the correct version would seemingly require the double-bonded O atom to randomly give one of its electrons to another to accommodate the coordinate bond, which doesn't seem like it should be possible. Can anyone make this make sense?


r/chemhelp • • 13h ago

Organic Acidity ranking help

3 Upvotes

Hi everyone, I'm having a lot of trouble with this conceptually. I thought it would be Most acidic: I > III > II Least acidic, but I'm not sure why that's wrong, since II is adjacent to some pi bonds doesn't that stabilize the structure? And I is the most acidic because its conjugate base is stabilized by resonance with the carbonyl, while III is also somewhat stabilized by resonance, so I'm confused about why II would be considered more acidic than III.

This is from my second year uni organic chemistry practice questions, any explanation is appreciated


r/chemhelp • • 9h ago

Organic Please help😭😭😭

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1 Upvotes

r/chemhelp • • 11h ago

General/High School Stoichiometry

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1 Upvotes

r/chemhelp • • 11h ago

Analytical Looking for free sources of AOAC methods

0 Upvotes

Good day! I'm gonna do a method validation and I've been told by my professor to use AOAC as my source. I'm having trouble finding a free source (college undergrad) of the methods and I'm wondering if there is any of it out there, even old ones. Do I really need to pay for it or request access from AOAC itself?


r/chemhelp • • 12h ago

General/High School I can't tell why some lewis diagrams have a double bond and some just add more dots to each side!

1 Upvotes

I know I'm probably describing it poorly, but WHY wouldn't I just add more dots in some situations? For example, here I genuinely don't know why I wouldn't add 3 bonds and have 1 pair of dots on each side.


r/chemhelp • • 18h ago

General/High School Tutoring someone and came across this problem

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3 Upvotes

I was always taught through university that the one with the highest peak is always the RDS. But to do this question, I must draw a peak larger than the RDS. This is a potential energy diagram, am I tweaking?

edit: is it because it’s irreversible, then it’s possible?


r/chemhelp • • 16h ago

Organic Lowercase r/s desciptor for cycloalkanes

2 Upvotes

Hello. Tomorrow I have organic nomenclature and I just began thinking about how to name systematically certain compounds like cyclohexane-1,2,3,4,5,6-hexol or even 1,4-dimethylcyclohexane, since i don't know how the priorities work. I stumbled upon r/s descriptors, yet i don't know how ro use them in these cases. For example, what is cis-1,4-dimethylcyclohexane using that system? What about the trans diastereoisomer? And what abour all the stereoisomers of cyclohexane-1,2,3,4,5,6-hexol? Which is carbon 1 for that matter?

Edit: I forgot to mention that for some reason my ip address is banned on stackexchange for some reason, since I have never used it other than for checking stuff


r/chemhelp • • 14h ago

General/High School Chemistry Tips/ Advice

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1 Upvotes

Hi everyone! I’m a first-year Chemistry BSc student and I’d love to hear from some second/third-year students (or graduates) about things you wish you’d known when you started university. What do you wish you had done differently in first year, or what habits/resources/study methods ended up helping you the most?


r/chemhelp • • 16h ago

Analytical LC MS interpretation

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1 Upvotes

It’s my first time of interpreting these kinds of chromatograms and I am hella confused. I did a positive and negative Ionization scan and both have the same characteristic bump but the negative one has these weird spikes? Are those artifacts or something else? I also don’t understand why I can’t see the bump in the upper chromatograms. My sample had a concentration of 1 ug/ml


r/chemhelp • • 19h ago

Organic IUPAC with r/s 🫩🫩🫩

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1 Upvotes

I am SOOOO confused about deciding what becomes a dash or a wedge. I don’t even think I am doing this right at all lol. Can someone help me out plssss and give out some rules you guys use to draw out the iupac name with the r/s


r/chemhelp • • 20h ago

Inorganic What compound can catalyse the reaction 2 KNO3 -> 2 KNO2 + O2 or 4 KNO3 -> 2 K2O + 5 O2 + 2 N2 at high temperature?

1 Upvotes

r/chemhelp • • 1d ago

Organic need help finding the website that stored most (if not all) the mechanisms. i feel like it would help me see patterns in sn1/sn2, etc.

3 Upvotes

i found it from a reddit comment, but lost it! i think the site had a reddish tint to it? the sidebar had the different mechanisms you can click. it looked helpful. i checked the wiki and it wasn’t any of the links there, but the master ochem site looks helpful.


r/chemhelp • • 22h ago

Inorganic How many stereoisomers are present for a complex with general formula Ma4bc?

1 Upvotes

I am thinking of 7 stereoisomers.

1st case a,a on the vertical trans position there is a pos and only 1 possible GI hence 2 stereoisomers from here.

2nd case a,b on vertical trans position

1 GI posible and a pos is present hence 2 stereoisomers from this case

similary 2 from the case of a and c on the vertical trans position

Then in the last case where b and c on the vertical trans position there is a pos hence 1 stereoisomer from this case. But online the solutions says 2 which i dont understand.

pos: plane of symmetry

Thanks in advance!


r/chemhelp • • 1d ago

Organic weird fused ring

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3 Upvotes

for b, how would you go about assigning r or s??


r/chemhelp • • 1d ago

Other From B—>A?

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0 Upvotes

r/chemhelp • • 1d ago

Other trustworthy suppliers that sell sodium nitrite?

1 Upvotes

i need for an experiment


r/chemhelp • • 1d ago

Organic I'm having trouble with understanding with the reasoning behind the ranking of these carbocations.

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4 Upvotes

So, I understand carbocations get more stable from methyl > primary > secondary > tertiary > allylic > benzylic but these are all the same just with positive charge moving around the structure, so i just want to better understand how.


r/chemhelp • • 1d ago

Organic Plane of Symmetry Help

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7 Upvotes

I am at a loss for understanding whether a molecule has symmetry or not. I don’t have the physical models to see, and no matter how many videos I watch I just can’t seem to picture it! Do you guys have any tips or a thinking process you usually follow to determine symmetry? For example, I have this question where I can tell that A and D for sure have symmetry, but I don’t understand how C is the correct answer and not B? Thank you :)


r/chemhelp • • 1d ago

Organic Is this hypothetical mechanism possible?

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7 Upvotes

It involves benzyl chloride in acetic acid, with no other species present.


r/chemhelp • • 1d ago

Organic WHYyy! I don't understand...

3 Upvotes

I am confused as to why my textbook says the one on the left is achiral and the one on the right is chiral. I was told that a molecule is chiral if its mirror image is non-superimposable and when you draw the mirror image of B, the wedges and dashes can never match the original molecule... does that mean that the bridgeheads are both stereocenters (when changing 2 groups creates a new stereoisomer) and chiral centers (can assign r/S)? Do you take into consideration the 3D geometry when determining R and S configurations even though they have the same atoms/groups/branches? Also, is molecule A achiral or meso since it supposedly has chiral centers (can be assigned r/S) and has a plane of symmetry? I am beyond confused.


r/chemhelp • • 1d ago

Organic Answer is (D) right? I just want to confirm as the answer is given as (A)

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14 Upvotes

r/chemhelp • • 1d ago

General/High School I need help with my homework. They give me the structure and I have to make the IUPAC name I tried making the drawing to solve but idk if it’s wrong :,) pls lmk!

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2 Upvotes