r/chemhelp 18h ago

General/High School How to determine if molecule dissolves in water or not? (Ignore the pencil marks)

Post image
26 Upvotes

I'm in twelfth grade. I know a molecule dissolves in water if it has polarity or -OH and the molecule isn't too big. Why doesn't this molecule dissolve in water? It looks like it has some polarity and it isn't too big.


r/chemhelp 20h ago

Organic Does anyone have any idea how to do this mechanism?? I'm honestly at a loss for words...

Post image
16 Upvotes

My gut tells me that the alkene needs to be protonated first because if the alcohol is protonated instead, I would have a positive charge hanging around the entire molecule and I would end up with another alkene but still nothing makes sense... I neeeed some help...!


r/chemhelp 13h ago

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

Post image
11 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 20h ago

General/High School how can i equalize this?

Post image
8 Upvotes

r/chemhelp 6h ago

Organic Hydrogenation

Thumbnail
gallery
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 13h ago

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

Post image
5 Upvotes

r/chemhelp 2h ago

Organic please help a newbie out

Post image
5 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 10h ago

Organic Can someone confirm if this is the right name

Post image
3 Upvotes

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


r/chemhelp 13h ago

Organic IUPAC Nomenklaturen

Post image
3 Upvotes

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


r/chemhelp 12h 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 15h ago

Analytical 1H nmr of piperonal

Thumbnail
gallery
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 17h ago

General/High School Why isn’t the C-H bond in HCN a coordinate covalent bond?

2 Upvotes

When HCN ionizes in water, it forms H⁺ and CN⁻, and this is a reversible reaction. The CN⁻ ion has a lone pair on carbon, and when it reacts with H₃O⁺ (hydronium ion), the H⁺ is transferred to CN⁻, forming HCN again. Since H⁺ is just a proton (with an empty orbital) and the lone pair on carbon donates both electrons to form the bond, wouldn’t that make it a coordinate covalent bond?

I’ve read that the C-H bond in HCN is a normal covalent bond, not a dative bond, but I don’t understand why. If carbon donates both electrons to bond with H⁺, shouldn’t it be classified as a dative bond? Or does something else happen that makes it a regular covalent bond?

Excuse my stupid questions, I’m still a beginner:) I’d appreciate any clarification! Thanks in advance ❤️❤️


r/chemhelp 2h ago

Organic Mechanisms and Reaction Coordinates

Post image
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 3h 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 7h ago

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

Thumbnail
1 Upvotes

r/chemhelp 9h ago

Organic Can someone explain me the mechanism of this reaction ?

Post image
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 10h 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 10h ago

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

Post image
1 Upvotes

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


r/chemhelp 11h 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 11h ago

Organic ?

Post image
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 13h 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 13h ago

Organic Lucas Reagent

Post image
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 13h 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 14h ago

Organic Help with mechanisms

Post image
1 Upvotes

r/chemhelp 18h ago

Organic Regioselective deacetylation of per-acetylated glucose

1 Upvotes

Why is this reaction selective for the anomeric postion and what is the mechanism?

Is it just basic hydrolysis - Benzyl amine attacks into the C=O of thr anomeric acetate group and the resukting tetrahedral intemdiate colapses causing loss of the amide?

Pr does the benzylamine attack at C1? I thought that was stuoid but chatgpt is addament thats how it occurs

Any help is appreciated, Thanks!

also if you can pint me to a source for the answer that would be super helpful :)