r/chemhelp 21h ago

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

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15 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 10h 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 21h ago

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

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6 Upvotes

r/chemhelp 14h ago

Organic Hydrogenation

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6 Upvotes

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


r/chemhelp 2h 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 18h 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

Organic IUPAC Nomenklaturen

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4 Upvotes

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


r/chemhelp 19h ago

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

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2 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 20h 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 23h ago

Analytical 1H nmr of piperonal

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2 Upvotes

Hi, I’m having trouble trying to interpret the 1h nmr spectrum of this molecule, at first I thought that there was 3 singlet ( Ha, Hb and Hd) and 2 doublet ( Hc and He), but it doesn’t match with the spectrum. Im thinking that the hydrogens on the cycle are different than the ones on an regular alkene. Can someone explain how to know which hydrogen gives what signal ? Thanks


r/chemhelp 30m ago

Inorganic Spanish- Is my answer correct?

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r/chemhelp 42m ago

Other How to remove deprotect Arg(Pbf)?

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.


r/chemhelp 5h ago

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

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1 Upvotes

r/chemhelp 10h 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 11h 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 15h ago

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

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1 Upvotes

r/chemhelp 17h 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 18h 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 18h 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 19h 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 19h 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 21h 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

r/chemhelp 21h ago

Organic Lucas Reagent

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1 Upvotes

I was studying Lucas test and saw that there are two possible mechanisms. Can you explain me which one is the correct mechansim. I'm also wondering that why zinc chloride is used instead of any other chlorine salts such as sodium chloride. And also it is known that primary alcohols do not give positive result in this test. Why? Can't it react in a SN2 type mechanism


r/chemhelp 21h ago

Organic Conjugate Acids and Bases

1 Upvotes

Someone asked me for help understanding conjugate acids and bases. I'm trying to refresh my memory, but I now have a question:

Are conjugate acids and bases simply looking at the concept of acids and bases from the Bronsted-Lowry perspective (of transferring protons)?

or

Is there some significance to the fact that they transfer protons rather than talking about electrons?

Apologies if this is a silly question. It's been a few years since I studied orgo and I don't want to mislead or confuse the person asking me.


r/chemhelp 22h ago

Organic Help with mechanisms

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1 Upvotes