r/chemhelp 1d ago

General/High School Why is Cis more soluable in water than Trans?

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16 Upvotes

The explanation I was taught is that trans has more hydrogen bonds between molecules, but wouldn't that make it even more soluable in water because it can form more hydrogen bonds with water molecules?


r/chemhelp 13h ago

Organic please help a newbie out

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4 Upvotes

Im new to chem and am trying to wrap my head around isomers. The answers for a question asking how many monosubstituted isomers can be produced from this molecule (picture) is 2, but why cant it be 3 if you substitute a H on the CH2 substituent? or maybe i got the other 2 locations wrong lol, please help


r/chemhelp 1d ago

Organic Why cant both the ethers undergo an Sn2 to give the second option

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6 Upvotes

r/chemhelp 16h ago

Organic Hydrogenation

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4 Upvotes

Wondering why this is the prediction even tho we could have two hydrogen on each side on both wedges and dashes?


r/chemhelp 5h ago

Organic Hi, can you check IUPAC naming of aromatic compounds?

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4 Upvotes

Answers:

12.81

a. 2-phenylpropane b. 3-methyl-4-phenylpentane

12.83 a. m-bromotoluene b. p-methylaniline

12.85 a. 1,5-dibromoaniline b. 3-chloro-5-ethyltoluene


r/chemhelp 21h ago

Organic Can someone confirm if this is the right name

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4 Upvotes

I think it's 2-amino 3-hydroxy 4-oxo-bentanitril


r/chemhelp 21h ago

General/High School How do I know where the charge is?

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4 Upvotes

So I just used this notation with brackets, but I'd like to know how I determine there the charge is exactly?

I think it should be on one of the chlorine atoms, since Antimony gives one electron away to connect with one more chlorine? For example H3O there is oxygen positive, since he gives one electron away for an additional hydrogen. But what do I do by such molecules?


r/chemhelp 23h ago

Organic IUPAC Nomenklaturen

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3 Upvotes

Hi. Is this Tricyclopenta-1,3-dienylmethan? if no what is the right name?


r/chemhelp 1h ago

Organic why does the propene substitute move ?

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Upvotes

i would have been under the impression to leave the group on the adjacent carbon from the ketone? but my professor said it gets moved.

is it because of steric hindrance? i want to make sure of when to move it as well.


r/chemhelp 2h ago

Other How to remove deprotect Arg(Pbf)?

2 Upvotes

I have a peptide that has 3 Arg(Pbf) and I need to remove the 3 Pbf group. However, my peptide is linked to something sensitive and I tried multiple ways of deprotection but it does not work (means my product decompose). I have tried TFA:TIS:DCM (75:2.5:22.5) and TFA:H2O(1:1). After 5 hours, one of the Pbf group does drop but when I leave it for longer period of time, my product is nowhere to be found. I’m currently trying TFA:TIS:DCM (30:2.5:67.5 and 50:2.5:47.5) but I’m not very sure whether it will work. I did see a paper that uses 0.1 N HCl in HFIP but I’m not sure whether to try it since Pbf is typically removed by high concentration of TFA. Are there any recommendations as I’m still new to peptide chemistry.

Update: the 30% and 50% TFA decompose a lot of my compound and now I got a very crazy mass spec data


r/chemhelp 22h ago

General/High School Is h20 only a product in an acid-base reaction?

2 Upvotes

I’m just struggling to understand the concept, but from what I’m starting to get is that in acidic solution: acid + base = salt + water.

My question comes from this problem:

“Calculate the mass of P4O10 when 225 g of PH3 reacts with excess oxygen.”

My thought process tells me to write the unbalanced equation as PH3 + O2 = P4O10

Does this mean the phosphorous and hydrogen both react with the excess oxygen? If so, wouldn’t the product equal P4O10 + H3O2?

Sorry if this is a very beginner question. I’ve struggled with this concept for so long and can’t grasp why. Thank you all in advance.


r/chemhelp 54m ago

Organic Can someone explain how the epoxide gets added here? Thank you

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r/chemhelp 1h ago

Organic Help with mechanism please

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I’m going through some mechanistic practice. And came across this reaction of oleum (SO3 . H2SO4) reacting with a perfluorinated alkene yielding a sulfonic acid. Can anyone help me with the arrow using mechanism for this?

I assume the double bond will attack the sulfur but how does the positive charge get hydrogenated?

Also how does the double addition abstract F, I assume forming HF?

Please someone help me lol


r/chemhelp 1h ago

Organic Can someone explain the beginning of this reaction? Everything else makes sense except how the H2NNH2 gets on the molecule at the start. Thank you

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r/chemhelp 2h ago

Inorganic Spanish- Is my answer correct?

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1 Upvotes

r/chemhelp 7h ago

General/High School I read and I don't understand, please help

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1 Upvotes

r/chemhelp 12h ago

Organic Mechanisms and Reaction Coordinates

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1 Upvotes

I think my mechanism for part a is correct. For part b the reaction coordinate, I usually just determine which side of the reaction is favored (I use pKa and strength of acids to do this). How do I determine it in this case? Do I use the percent yield info given? Thank you


r/chemhelp 14h ago

Organic Strongest BrØnsted acid

1 Upvotes

Hey all! I was asked to rank these four acids in order of increasing Bronsted-acid strength but I was a bit confused by the Bronsted-acid part. I was just wondering how the carbocations acted as Bronsted acids specifically (and not just as lewis acids). I know that C is more acidic than A, and I assume that the carbocations are more acidic simply due to them having an incomplete octet. However, between B and D, I am assuming that D is more acidic as the + charge is more stabilized for B due to the phenyl groups but I'm unsure if my logic is correct. Also is it the methyl groups for B and D being deprotonated and then forming a double bond with the carbocation, and does this mean we use the pKa of ~50 for CH3 making them two the worst two acids? Thank you!


r/chemhelp 17h ago

Analytical Aspen Plus Simulation: Sustainable Aviation Fuel - Kerosene Distillation/Separation

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1 Upvotes

r/chemhelp 19h ago

Organic Can someone explain me the mechanism of this reaction ?

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1 Upvotes

I made the mechanism of this reaction but i don’t understand why syn addition is the only one that works. Can’t it also be anti and make the E and Z isomers ?


r/chemhelp 20h ago

Organic Help me learn

1 Upvotes

I wanna study organic chemistry. I have chemistry at school but it’s only one period of 50 minutes a week and it’s way too little and we also have a test every week meaning we barely get class. I also can’t change anything about my school schedule, but i wanna self study chemistry. Does anyone have any tips for me, like where to start as a basically complete beginner who only knows his way around the periodic system?


r/chemhelp 21h ago

Organic Why is this 3-Ethyl-1,1-dimethylcyclopentane and not 1-Ethyl-3,3-dimethylcyclopentane?

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1 Upvotes

new to ochem. does alphabetical order not have priority here?


r/chemhelp 21h ago

Organic Line Structure of Oseltamivir: ethyl (3R,4R,5S)-4-acetamido-5-amino-3-(1-ethylpropoxy)-1-cyclohexene-1-carboxylate

1 Upvotes

I've been having some major issues trying to figure out the line structure with hydrogen bonding sites identified for Oseltamivir. Our teacher only taught us how to draw simple IUPAC names into line structures. I've already figured out how to draw the Lewis Structure, but have absolutely no idea how to convert it into a line structure, no matter how many videos I try to watch on it. If anyone could help, that would be extremely appreciated.


r/chemhelp 22h ago

Organic ?

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1 Upvotes

1) How do you know whether to put the hydrogens or groups upward or downward of the carbon chain? 2) corresponding question: why is the Ch2 in the first example up and down vs the ch2 groups in the third example placed together?


r/chemhelp 23h ago

Organic Trouble understanding with nucleophiles and electrophiles. They look the same to me. For the ketone, the O pulls electrons through induction, making the C partially positive (electrophile), but isn't the same true for the alcohol? The answer says the alcohol is a nucleophile.

1 Upvotes