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/r/chemhelp
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can someone help me with my homework
can anyone solve for all the boxes on number 4. i tried to solve it on my own but the percent yield always turns out to exceed a hundred which is an error. the balanced chemical equation is 2CuS04 + 2H202 ----> 2H2504 + 2CuO + 02. thanks!!
13:28 UTC
Alkylation of 2, 4-diphenyl-2-butanol
Was stuck on this question for a while. I know the formation of carbocation by removing the -OH (H2O), with a positive charge on the 2nd position of butanol. Then I'm not sure how to proceed the electrophilic aromatic substitution.
11:31 UTC
Electron withdrawing group and Electron donating group
Is there any way to remember the EDG and EWG s and also their comparative strength like which one is stronger than the other?
11:11 UTC
Wolf Kishner vs Clemenson Reduction
i know the reagent , i both of them reduce ketone to alkane , so whats the difference between their roles , when to use wolf kishner when to use clemenson?? what organic compounds can wolf kishner reduce but not clemenson and vice versa?? which one of them can reduce aromatic ketone??
10:54 UTC
Dilution problem
Good day Chemists out there! I just have a question about this, my classmates and I battle for whose correct answer is really the correct answer. How should we properly account for the dilution?
The question goes:
A 10.00 mL of a city drinking water was diluted to 100.0 mL. A 10.00 mL aliquot was treated with a small amount of an NH3-NH4Cl buffer to bring the pH to 10. After the addition of Calmagite indicator, the solution required 10.39 mL of 2.672 × 10-3 M EDTA. Calculate the water hardness in terms of ppm CaCO (MM: 100.087).
Our answers vary from: 27.79, 277.9, 27 789
Help!
09:52 UTC
Can someone help with the mechanism?
English is not my first language so excuse me if my wording is improper, but the H kation will attack the double bond and will bond with the primary carbocation and then the OH group will bond with the secondary carbocation? Because that seems to me like a very vague structure.
08:42 UTC
Is this mechanism correct?
04:16 UTC
Methoxide vs Methanethiolate, what is the stronger base?
Hi all! Had a quiz question pop up recently for which the image I've included below. Essentially asking whether methanethiolate or methoxide is a stronger base. My rationale was that methoxide is the weaker base because it is more electronegative and holds on to its electrons stronger, making methanethiolate the stronger base. However, upon answering the quiz, it states methoxide is the stronger base without giving a reason as to why.
Can anyone please let me know why methoxide is a stronger base than methanethiolate? Any help is appreciated!
04:02 UTC
Is the carbon attached to the isopropyl group a chiral center? I would say no because two of the groups form around the ring and to the hydroxyl groups - making them the same?
03:27 UTC
epoxidation of alkenes: why is mCPBA still present for cis?
taken from wade organic chemistry 9th ed.:
The book doesn't provide an explanation for why mCPBA is still present for the cis molecule but not the trans one, albeit in decreasing concentrations (if I'm interpreting that arrow correctly?). Could someone explain why such is the case?
Thank you!
02:56 UTC
My labcoat is a mess please help me!!!!
I have washed my lab coat multiples times and the stains are not going at all.Its also a brand new lab coat so i cant buy another one.So Please help me!!!!
02:50 UTC
Mechanism problem help (Orgo 2)
Got stuck on the third part of the question and now I’m unsure about what I have written down already. For the first part I’m pretty sure it’s just an SN2, but I couldn’t really come up with a good mechanism for the second part besides what I drew in the picture. My thought process was that the cyanide as a base (albeit weak) could maybe deprotonate the alpha hydrogen of the ketone, since I know HCN has a pka of 9 and the alpha hydrogen of a regular ketone has a pka of like 20 and the bromine next to it would lower the pka by inductive effect, and then the carbon could be protonated again creating the enantiomer of the A molecule half the time, which could then undergo SN2 like in the first part. I was also trying to consider if anything could happen with the cyanide reacting with the carbonyl carbon (like top left drawing) since it’s a strong nucleophile but weak base but I can’t think of anything besides it just popping back out. However, I’m now stuck on the third part. I felt like it had something to do with the slow SN2 at a second degree carbon, but I didn’t know how to connect that to the reason why C forms mostly (R) D, since if the mechanism I had in the second part was right, shouldn’t there be equal amounts of both enantiomers at most as the proton would be added back randomly? So now I’m not sure if the second mechanism I drew is right, but I also can’t think of anything that wouldn’t just add randomly. Sorry for the lengthy post, and thank you!
02:35 UTC
why use CH2Br2? carbene formation via alpha elimination
From Wade Organic Chemistry 9th ed.
I'm stuck on problem 8-28B. I've been just using CHBr3 for everything as the previous section in the book does, but I'm failing to see why we'd all of a sudden be able to use CH2Br2 and call it the same mechanism if that makes sense. I understand that we can't use CH3Br3 because that'd generate something different (I think a dibromopentane?) but I don't get why CH2Br2.
Here's the question:
Here's the solution:
and here's what I had so far (oof):
Thanks in advance!
02:30 UTC
predicting carbene addition products
Hi, I've been struggling with this reaction, and basically predicting the products for this carbene formation that is beyond the "CHX3/NaOH, H2O" reactants format. The question is Part C of 8-27 (from Wade Organic Chemistry 9th ed.):
Below is the answer:
And here's where I got stuck lol:
Evidently, I'm not quite sure what I should do with the CHBr2 that's already on the cyclohexene. If anyone could provide any guidance on this problem, that'd be greatly appreciated. Thank you!
02:18 UTC
For this mechanism, why do we deprotonate, just to protonate again in the next step?
Why do we deprotonate the OH (circled In yellow), just to add back the H in the next step (circled in green)?
01:40 UTC
Why cant A be correct?
01:36 UTC
Organic Chem Lab Results
hi, in my ochem class we did a distillation lab and we have to identify the the combination of compounds in an unknown. looking at the IR and boiling points we collected. im stuggling to figure out which combo our unknown could be given the options. any help would be appreciated.
our observed bps: were 58-60 and 77-78.
our ta did say our ir's were good for our unknown, but the bp is throwing me off.
01:30 UTC
Help with question
I dont really understand this question at all. Could someone explain why 0.07 is lower than -1.26 and why the word 'lower' is in speech marks?
Also, i cant seem to find what the difference is between electron affinity and electron gain.
22:25 UTC
Are these two SMILES strings the same compound?
Hi everyone, I'm planning to do a bit of work with an agricultural chemical called pyraclostrobin, and I want to know if these different distributors are selling slightly distinct products. I've found the two following SMILES online for the molecule (same chemical formula):
CON(C(=O)OC)c1ccccc1COc2ccn(n2)-c3ccc(Cl)cc3
COC(=O)N(C1=CC=CC=C1COC2=NN(C=C2)C3=CC=C(C=C3)Cl)OC
I know that you can have 2+ SMILES that represent the same compound, since SMILES can be written starting at different points in the molecule. However, when I visualize these two SMILES with a structure generator (e.g. https://www.cheminfo.org/Chemistry/Cheminformatics/Smiles/index.html ) the two of them spit out a different-looking structure, which, when I rotate one of them and try to account for where the compound would be able to rotate freely vs where it wouldn't be able to rotate, look different. In particular, it looks like the placement of the five-carbon ring with two nitrogens is "up" in one relative to the other half of the molecule, versus the other one. However, my organic chemistry days are far behind me, and I'm having trouble remembering whether the molecule would actually be able to rotate at the oxygen that connects the nitrogen-containing ring to the other half of the molecule.
Any help would be greatly appreciated!
22:13 UTC
Can someone help me understand how to find the cation and the anion and how to balance the compound
Ps: i've never done chemistry before i'm still really confused if you can give details and examples it would help a lot!!!
20:42 UTC
How to keep your head up and improve when you keep falling short? Organic 1
Hi. I really loved gen chem 2 and I kept learning more about chemistry and started loving it. I switched my major to chemistry and am hoping to go into industry. But imposter syndrome goes crazy. Have a 17-20 question quiz every week and it’s just been rough. I’ll get 1-3 wrong each time but each question is worth roughly 4-8% so it knocks it down quickly. I got a 68% on the quiz yesterday it was on SN2, E2, E1, and SN1. I’m upset I missed 3/17 questions and it did some damage. I’m sitting at an 84% in the class and I keep trying to pull it up. Got a 94% on the last quiz though. And a 74% the week before. I just need tips for one shaking it off and organic 1 tips in general. My current studying methods aren’t working and I can’t figure out what will help. We have 3-4 chapters left and I really want to pull my grade up. I’ve not gotten a B before in chemistry so I’m upset but I don’t deserve an A based on my performances this semester. I also every week in lab fuck it up. Fucked up my KD lab with separating, i fucked up my recrystallization. Beautiful crystals I made I fucked it up when drying it. I really want to go into industry but I fear I suck at it and it’s a sign it’s not my calling. I love learning about it and organic is very cool it’s just I fail a test and then it’s hard for me to keep going, I doubt myself change my answers, and harm my grades. I know it’s a struggle everyone goes through and that’s the privilege of higher education and learning these complex concepts that are so cool. I just want to do better.
20:08 UTC
How would I find (NOT calculate) the mass of the excess reagent? I have outlined my experiment below
My experiment topic is: How does concentration of sodium chloride affect the solubility of caffeine
However, one issue would be finding the mass of the excess caffeine when dissolving caffeine within the solution. Is there a way to do this that is simple and not time consuming? I am aiming to keep each trail under 15 minutes.
The simplest way I can come up with would just be to put in small amounts of caffeine at a time, and once I can visibly see that it stops dissolving, I can directly get the total mass dissolved, however there are a lot of systematic errors when doing it this way.
Thanks in advance.
19:53 UTC
How to draw [Fe(CN)4(CO)2]^2- Lewis Structure?
This is wrong and I apparently got 56 total electrons so far but I don't know what to do after. Should I add the 2 more electrons because it's a 2- charge or should I leave it at 56 since the Fe is +2 so it kinda cancels out. I've never had to draw a lewis structure this complex before.
17:54 UTC
In a glavanic cell, what triggers the electrons to move from the anode to the cathode? Is the trigger: the anode metal, like zinc, dissolving in the solution, or is it the natural pull of an oxidizing agent element, like copper, in the cathode (so a regular redox reaction)?
Is it A - due to the zinc dissolving in the solution, which leaves electrons in the anode causing an excess negative charge to build up resulting in a difference in electric potential between the anode and the cathode. This ,potential/electric potential difference, is what drives the electrons across the external wire to the cathode.
Or B - The cathode, copper/copper cations, is more electronegative with a lower potential energy acts as an oxidizing agent pulling electrons from the higher potential energy element, zinc, in the anode via the external wire. This results in zinc losing electrons forming zinc cations, which then dissolve in the solution, so its a regular redox reaction that happens to be connnected via an external wire.
is dissolving of the anode material the trigger for the redox reaction (A), or is dissolving of the anode material a result of the redox reaction (B)?
Because i've read conflicting info, some websites say its A and some B.
17:03 UTC
Using sodium hydride as the limiting reagent, how?
Hi guys. There were two -OH groups in my molecule and I wanted to deprotonate only one using NaH (60% in mineral oil). The first time I did the reaction, I put NaH in THF and then added it to the reaction mixture using a syringe. Then I realised that NaH didn’t dissolve in THF as it is ionic and I was probably adding mainly mineral oil to my reaction. It was not surprising that I got only 10% yield. The next time I added NaH solid to the reaction portionwise and I got like 70% yield. But the thing is that I also deprotonated two hydroxyls in the same molecule to some extent and I didn’t feel safe adding it this way. I had my NaH in an open flask and added it to the reaction mixture (in a two-neck flask, one end was open and one end had an argon balloon) with a metal spatula. What should I do instead in terms of being safe and getting good deprotonation? Maybe if I add NaH more slowly it’ll be okay? Any advice would be appreciated!
16:32 UTC
Retrosynthetic help
Having difficulties adding the final cyclohexane group to synthesise the target compound… any tips?
15:40 UTC
Alkenes comparison
Which of the two is more stable? Cyclohexene or Trans-2-butene
On one hand, an alkene within a stable ring (6 carbons) should be more stable. On the other hand, 2-butene is a trans double bond, which is more stable than the cis double bond in the cyclohexene.
it was a part of ochem test question in which i had to rank 4 alkenes by their stability : a. styrene b. allylbenzene c. cyclohexene d. trans-2-butene. My ranking was a>d>c>b
13:18 UTC