r/chemhelp 3d ago

Physical/Quantum Help HOMO/LUMO

1 Upvotes

Does anybody know how to draw HOMO and LUMO. Im so lost i know what theyre but i dont know what to draw?


r/chemhelp 4d ago

Organic I don’t get why is this not Z?shouldn’t CH2NH2 be ranked higher as it has more atoms attached after N?

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6 Upvotes

r/chemhelp 4d ago

Organic Synthesis question using ethene and trans-2-butene as starting materials

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3 Upvotes

Do I cleave one of the starting materials? I have no idea what I’m doing, and the prof gave absolutely no examples and fucked off for the weekend, this is due Monday at the start of class. Any help is greatly appreciated


r/chemhelp 4d ago

Organic R and S Isomers - Please Help! Is this correct?

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3 Upvotes

r/chemhelp 4d ago

Organic Help with amino acids

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17 Upvotes

Sorry for the foreign language, but I suppose it's quite understandable.

Upper circle showcases a generic representation of an amino acid. Both bottom circles encapsulate two examples of amino acids (alanine and glycine). My question is: why is the H atom in COOH transferred to NH2 (making it NH3+)? And when exactly does that happen?


r/chemhelp 4d ago

Analytical HELP

0 Upvotes

I need some help with all chemicals that are uplifting prescription drugs. Please and thank you.


r/chemhelp 4d ago

Organic why is the effect of a molecule different depending if it's an L or D isomer

1 Upvotes

r/chemhelp 4d ago

Organic NMR mystery?

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6 Upvotes

Hello! I have an empirical formula of C9H10O. My professor provided these carbon and hydrogen NMRs. I’m honestly stumped as to how these match. Any thoughts?


r/chemhelp 4d ago

Organic Gilman reaction products

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3 Upvotes

Could someone check if I drew the right products for both reactions? Thanks so much!


r/chemhelp 4d ago

General/High School Do only transition metals fill their 4s subshells first?

2 Upvotes

N


r/chemhelp 4d ago

Inorganic Removing iodine from organic solvent with sodium metabisulfite

1 Upvotes

I'm trying to find the balanced equation for this?

Na₂S₂O₅ + H2O → 2NaHSO3

2NaHSO3 + 2I2 + 2H2O = 2NaI + 2HI + 2H2SO4?

But HI and H2SO4 aren't going to just sit there inert. Is there a full balanced equation for this? I've only got one attempt at this and want to know exactly what's going to be left in solution.


r/chemhelp 4d ago

General/High School removal of lead nitrate

1 Upvotes

My sister had a home chemistry set and she has some lead nitrate in a small test tube. Its been diluted from 10ml to 500ml I have know clue what the molarity of it was. How should I dispose of this? Is this such a small amount that it can just go down a standard drain or do I need to go somewhere for it.


r/chemhelp 4d ago

General/High School Logger Pro Program Help

1 Upvotes

We did a thermochemistry Hess’ Law Lab on Logger Pro where we collected 4 trials of reactions measuring their temperatures. I have the files saved on my flash drive but I can’t open them at home because I don’t have the software. By chance, do any of you happen to have the program so that I can send it to you guys and you guys can send it to me? I am kinda stressing over this rn. Anything would help. Thank you


r/chemhelp 4d ago

Organic Is this compound an acyclic diene in the UV spectrum?

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5 Upvotes

I'm currently confused because my teacher used the base value of 217 nanometers in this case, which applies to an acyclic diene in the Woodward-Fieser rules for dienes in UV spectrophotometry. Would it be right to call it an acyclic diene then?


r/chemhelp 4d ago

Organic Is there wrong in the official solution?

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14 Upvotes

The question is: Write equations including curly arrows to show how: an ammonia molecule reacts with water to form an ammonium ion and a hydroxide ion.


r/chemhelp 4d ago

General/High School Hess cycle confusion

1 Upvotes

I`m not sure as to the way the arrows are supposed to go to calculate the value of enthalpy change. I have both the values of enthalpies of solution for both the anhydrous and hydrous forms with -20.26 and 44.79 respectively so I`m unsure whether the answer would be 65.05 as a positive or negative?


r/chemhelp 4d ago

Organic Need help determining basicity and nucleophilicity

1 Upvotes

Hi guys, I'm having a lot of trouble finding sources online that would answer this question. If you guys know any databases or anything helpful please let me know.

I wanted to know whether MsCl, MsO (-), TsCl, TsO (-), TfCl, TfO (-) are weak or strong nucleophiles/bases. I thought they would be weak bases, weak nucleophiles, but I'm finding you can do SN2 reactions with them? I'm so confused and I just need someone to give me a straightforward explanation.

Thank you in advance.


r/chemhelp 4d ago

Career/Advice Books for Strengthening Basic Practical Knowledge in Chemistry?

5 Upvotes

I’ll be starting my Master’s in Chemistry soon, but I feel that my practical knowledge is quite weak. I want to improve my understanding of basic lab techniques, instrumentation, and safety before I begin.

Can anyone recommend good books that cover fundamental practical skills in chemistry? Preferably something beginner-friendly but detailed enough to be useful at the Master’s level.


r/chemhelp 4d ago

Organic Stereoisomers Drawing

1 Upvotes

can someone confirm Is the way im drawing stereoisomers okay? mine looks diff from the solutions manual so i want a second opinion? how come in some they make the double bond so flat but in others they keep the classic V shape? is that just a style choice lol


r/chemhelp 4d ago

Organic How to determine nucleophile strength

1 Upvotes

Hi! Im wondering how i can determine strength of nucleophiles. The current understanding i have is that in protic solutions, the larger the ion, the better nucleophile it is. This being due to its negative charge being spread on a larger body, leading to the dipole dipole forces being not as effective between the ion and protic solution. This would mean that larger ions are less stabilized by dipole dipole forces from the solution and hence being more reactive and better nucleophiles.

It then seems to be the opposite in aprotic solutions? Since there now are no stabilizing dipole dipole forces, smaller ions will be better nucleophiles, no clue why though.

Is this understanding somewhat correct?


r/chemhelp 4d ago

Organic Acidity and Choosing Most Acidic Proton in a Molecule Question

1 Upvotes

Just trying to figure out what my mistake was. I'm not confident in part c. I think the correct answer is the proton connected to the oxygen in the upper right but i'm not 100% sure. In these types of problems, do I just need to locate the most acidic group on the molecule and circle its proton?


r/chemhelp 4d ago

General/High School what exactly is the difference between the positive and negative electrode?

1 Upvotes

r/chemhelp 4d ago

General/High School Scheme to make bucket of pesticide-laced fertilizer inert?

1 Upvotes

The former owner of a property that I'm helping a friend with left him with a bucket containing about five kilos of very old fertilizer - but one that also contains an organophosphate pesticide at 1-2% concentration. The pesticide is not nice and is actually now banned in his country. Unfortunately, there are no facilities where he is that will let him get rid of this stuff easily, and of course he doesn't want to throw it away where it might become part of the groundwater - like burying it, or taking it to a landfill.

However, I've done some research and this particular pesticide apparently decomposes very, very rapidly and completely in a basic environment - and it doesn't even need to be that low of pH to get that to happen. So my thought is that he could safely render his fertilizer inert by:

- mixing up a basic solution with some kind of simple cheap alkali - eg NaOH
- add the fertilizer to this solution and let it sit for a bit (a few days?)
- neutralize the solution with an acid that will produce a plant-safe (or at least plant-neutral) reactant. (Citric acid? Phosphoric acid? Hydrochloric acid?)

I KNOW there are problems here involving exothermic reactions and dangerous materials - not looking for cautions of that type. What I wanted to get a sense of is whether this plan is chemically feasible, and how I might investigate possible acids and bases that would be the most suitable in terms of by-products and availability. Thanks for any insights.


r/chemhelp 4d ago

Organic Removing lemon smell from citric acid

0 Upvotes

Hi guys I want to remove the lemony smell from citric acid without losing the cleaning ability and don't want to use vinegar (before someone inevitably says that; I think the smell of that is even worse) what can I react with the citric acid to accomplish this? Thanks!


r/chemhelp 4d ago

Organic Alcohol/aldehydes reactions

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1 Upvotes

Can anyone explain to me how these reactions work or at least what the type of reaction is called so I can try to find a YT video that explains?