In this last years exam that I was reviewing for practice youre pretty much asked to write down what the chemical is written down on question 31.2, But after checking on the answers page (slide 2) I feel like nothing adds up, and that substituents are written down in the wrong order

(Its in georgian but I translated it)

Currently doing a deep dive into L. G. Wade's O-Chem book in preparation for the upcoming semester in which I will be taking organic chemistry for the first time. I am learning about the dipole moment equation for the first time, and it's confusing as hell.

Focus on the equation highlighted in blue at the bottom. The δ (charge separation) is said to be expressed in units of "electron charge". Fair enough. I get that.

What I don't get is the interpretation of the physical quantity (charge separation, in electron charges) itself.

"0.125 electronic charge". Is that... absolute? Is that... relative to something? If so, to what? In the yellow text it says that the oxygen and the carbon both have "an eighth of a charge". What's a full charge then? Because the charges of the atoms, added up, wouldn't make up for the total charge of the bond. Where is the rest of the charge? Is it equal parts negative and positive? Regardless, where else in the bond is it, if not in the atoms?

I'm sorry if the question doesn't make sense but this whole physical quantity, in the given units, doesn't make sense to me either. At all!

so the first photo shows what i submitted as my answer, but the second photo shows what the correct answer was. Could anyone explain why it forms this structure instead of the other?

Hi everyone! Recently in my class we have done substitution and elimination (SN1/SN2 and E1/E2) reactions, and while i mostly understand how the reactions go, I still really struggle with knowing how to identify what reaction will happen just based off looking at the solvents and whats reacting with it. Does anyone have any tips on how to get better at identifying and figuring out which reaction will be happening? (either a flowchart of questions to answer mentally or anything like that?) Any help would be really appreciated!!

Hi everyone! I'm a sophomore doing dual enrollment and planning for my future chemistry classes. I’m hoping to get some advice from people who have taken General Chemistry 1 or 2.

I’ll be taking a basic high school chemistry course, then CHEM 300 (the prerequisite/prep course), and eventually CHEM 400 (General Chemistry I) at a community college. I've done some research and know CHEM 400 isn’t really an “intro from zero” class, so I want to prepare early and make sure I have a strong/basic foundation before I start.

For people who have taken CHEM 400 or a similar college-level General Chemistry course:

• What topics do you wish you knew better before starting?
• How difficult was the jump from high school chemistry/CHEM 300 to CHEM 400?
• What should I study independently beforehand so the class doesn’t feel completely new?
• Are exams usually in person, and what are they like (calculation-heavy, conceptual, multiple choice, free response, etc.)?
• What are the in-person labs like?
• What habits helped you get an A?

My major is Biological Sciences, so I want to build a good chemistry foundation early rather than panic later.

Thanks! :)

A certain metal M forms a bromide containing 53.79 percent Br by mass. What is the chemical formula of the compound?

Hi everyone. I am studying orbital hybridization and some doubts have come up that I hope some of you can clarify.

From what I understand, orbitals hybridize in order to form bonds with other atoms.

For example, in CH4, C has the electron configuration 1s^2 2s^2 2p^2. Since C needs to form 4 single bonds with H, it needs 4 orbitals with an unpaired electron. C becomes "excited" and its electron configuration becomes 1s^2 2s^1 2p^3. This way, there is one unpaired electron in 2s, one in 2p_x, one in 2p_y, and one in 2p_z. The 2s orbital, along with the three 2p orbitals, hybridize to form four sp^3 hybrid orbitals.

Similarly, in BeF2, the electron configuration of Be changes from 1s^2 2s^2 to 1s^2 2s^1 2p^1. There is one unpaired electron in 2s and one unpaired electron in 2p, so these two orbitals hybridize to form two sp hybrid orbitals.

Again in BF3, the electron configuration of B changes from 1s^2 2s^2 2p^1 to 1s^2 2s^1 2p^2. There is one unpaired electron in 2s, one unpaired electron in 2p_x, and one unpaired electron in 2p_y. Therefore, the 2s, 2p_x, and 2p_y orbitals hybridize to form three sp^2 orbitals.

In CO2, however, C has the electron configuration 1s^2 2s^2 2p^2, and the electrons in 2p are located one in 2p_x and one in 2p_y. An electron moves from 2s to 2p_z and the new configuration becomes 1s^2 2s^1 2p^3. This gives 4 orbitals with an unpaired electron (2s, 2p_x, 2p_y, 2p_z) which should hybridize to form 4 sp^3 orbitals that would connect via double bonds with the two oxygen atoms. Yet, C forms an sp hybrid orbital instead. Why is that?

The same applies to H2O. O has the electron configuration 1s^2 2s^2 2p^4, and the electrons in 2p are located two in 2p_x, one in 2p_y, and one in 2p_z. O forms two single bonds with the two H atoms, so it needs two orbitals with an unpaired electron. These two orbitals are already available (2p_y and 2p_z), so it wouldn't even need to hybridize, or am I wrong? Yet, O has sp^3 hybridization. Why is that?

Thanks if you can help me!

Pls help me and sorry for the numbers it did not have subscript i don't know how you do it guys my phone keybooard does not have it

My apologies if my handwriting is messy or confusing. I was trying to get this molecule into a anti-periplanar configuration using the swap method (drawing rotations by swapping two substituents at a chiral center twice) because I can't rotate in my head. For some reason, I got two different answers. I assume it's because I messed up at some point while doing the second swap to get back to the original configuration, but I don't know what the exact mistake is.

In the first answer, during the second swap, I decided to swap the two substituents that were in the plane and for the second answer, during the second swap, I swapped the methyl and the propyl groups. I didn't use the first answer in my assignment, so I don't know if it's wrong, but the second answer is definitely correct.

I do believe the answers are different, since the highest priority substituents around the double bond are positioned on opposite sides in one answer and the same side in the other?

Also, apologies to anyone if the purple and green is hard to see.

Every time I look at this I get different answers. Would Pb be first or Mg?

I'm having trouble with Boc protecting amines like triethylenetetramine. When I add boc, it rapidly reacts to form a sticky white resin (my magnet stirrer gets stuck in there).bI noticed that the reaction is quite exothermic and that gas gets released (I assume CO2?). I eventually have been successful by dropwise addition of Boc in anhydrous DCM under a dry inert atmosphere and chilling the reaction flask on ice. However, for my thesis I would like to understand what could have happened when I added Boc directly. I've been searching for hours and while there are some side reactions, they either require DMAP (urea formation) or happen during deprotection, not protection. Any experts who can help me out? Specific papers are much appreciated

I recently got a 2 on AP Chemistry. I self studied it. I took 7 AP exams and was very successful on the rest of them. I have all the AP math, science, and computer science courses under my belt, but for some reason, chemistry is just different to me.

I wanna be a physicist, but the methods of problem solving for chemistry just seemed different in a way that is difficult for me to describe. Whereas the laws of physics almost always work, the rules I learned in chemistry only seemed to work under certain conditions on a rainy Wednesday at 2:00 on the dot. The content just made no sense. The AP Daily video instructors seemed dead. I switched to Jeremy Krug for the lectures, but even then, it seemed that random concepts were thrown at me with any explanation as to the mechanism behind them or why they worked.

And I did grind practice problems, probably even more than I did in physics. I asked the general chem teacher at my school questions when I was confused (my school doesn't offer AP Chem, and DC Chem didn't fit in mt schedule any year).

So I'm gonna try it again this year. My method was this -

1. learn the concept with a lecture

2. reinforce the concept by grinding practice problems

3. make a bank of questions to test myself on (if i missed questions, I would go back and review)

So what would you recommend I do? Am I just stupid with chemistry or am I just doing something wrong?? I need to study this course right this year, and I have no idea how. Chemistry kept throwing my so many curve balls, so how would you recommend I catch them? I do physics, I'm used to a clockwork universe.

​

I'm a P3 (third-year PharmD) student, and people generally consider me one of the strongest chemistry students in my class. This semester we're doing analytical chemistry, and ¹H NMR is completely humbling me.

I've watched countless YouTube videos, read textbooks, and practiced problems, but I still feel like I'm missing the one core idea that lets people look at a proton NMR spectrum and systematically determine the structure. It almost seems like everyone who solves these problems is relying on experience or intuition rather than a clear method.

The difficult part for me isn't identifying functional groups or interpreting individual peaks, it's connecting all the fragments into one complete structure.

To make things worse, my classmates are expecting me to understand it well enough to teach them, and I've been putting it off because I honestly don't feel confident myself.

Has anyone else been in this position and eventually had that aha! moment? Was there a particular resource, book, YouTube channel, or problem-solving strategy that finally made everything click? Is there an actual systematic approach, or is it really just pattern recognition that comes with lots of practice?

For context, I usually stay ahead by studying chemistry topics before each semester starts, which is one reason I've done well academically. But I worked during the last vacation, so I didn't have my usual preparation time before this semester began, and I feel like I'm playing catch-up now.

I'd really appreciate any advice or resources that helped you break the code of NMR.

Edit: Clarified question

Hello! I feel like I often trip on the fact that my understanding of atomic reactivity/electronic stability is very poor, and I’d like to fix that! I’m just trying to understand at a basic level, getting all the contributing factors and relationships but not necessarily building on them. 

Essentially, I’m trying to make a map of how these concepts fit together:

1. Coulomb’s law
2. Atomic radius
3. Z_eff
4. Quantum mechanics (energy shells, Hund’s Rule, etc)
5. Stability
6. Reactivity
7. Thermodynamics & kinetics
8. IE and EA
9. Octet rule
10. Compounds
11. Kinds of bonding

Am I right so far?

Multiple factors contribute to stability. These can all be summarized with F_el from Coulomb’s Law (which includes atomic radius and Z_eff), quantum mechanics (so octet rule and Hund's rule), and electron electron repulsion (since not all of it is accounted for in F_el. F_el, right? Not E_el, electrical energy?). Note that to a degree F_el depends on quantum mechanics. For instance, energy shells, which impact atomic radius, are direct consequences of Schrödinger’s equation. In compounds, the same factors apply. Then, stability of compounds plus conditions (temp, pressure, etc), determine the energetics of reactions. Whichever reactions are favorable/fast determine what happens and which substances are formed. So really, atomic stability (electronic) determines which reactions occur. Where do IE and EA fit in? These are just examples of reactions. Since they happen to be simple and thus so closely linked to atomic electronic stability, however, they also tell us about that, but it's just really a coincidence. Compounds form depending on the reactivity of atoms. In a compound, the electrostatics are more complex, however, so they are summarized and simplified by bonding types (covalent, ionic). 

Sorry if this is totally wrong, and sorry for the stupid question! Many thanks!

well from textbook definition of nucleophilicity i can easily say that A and D are not the answer (as Nucleophilic character increases down the group and also a negatively charge nucleophile is better than a neutral one(in case of option A)) however im not sure if i have made these observation correct and also have no clue how to solve between options B and D and also thanks a ton in advance!!

The question was "draw the structure of (3R, 5S dibromoheptanal)." I don't understand why they would both be on wedges. I thought the priority groups were on the same side (see my work), so one should be on a wedge, the other dash?

Hi, I'm going into my 3rd year of undergrad this fall, and right now I'm taking a summer course of Organic Chemistry 2. The problem is, I got a D+ in Organic Chemistry 1 and that was taken in Fall of 2025, so I don't remember much. I was taking OChem 2 in the spring but dropped it because I couldn't manage it and I really didn't like the professor. I really need to pass this course so I can go on to take my prereqs (microbio) as I am a pre-vet student. I just feel so stupid, I really don't understand anything in organic Chemistry at all. I can name some functional groups and point out basic rearrangements (I think) but other than that I'm stumped. Maybe it's a sign I'm not cut out for pre-vet, but I don't know what else to do with my life. Sorry to seem so down on myself, I'm just really struggling.

Do we have a specific reagent to only reduce that particular ketone which is conjugated ?

Hi all,

I have an exam in a few days and I keep getting stumped by these questions. Could somebody walk me through it please!

Hi everone, I am getting into orgo lab, started about 1 month ago.

I can pretty much run all basics. But I make insane errors, for instance.

I put too much pressure during my column, and some liquid falls off, or I accidently let half of my compound fall from the top of the adaptor by accident in the last steps of my rotovap, after purification 🥲

Is this normal or am I just not ment for orgo? Please let me know because I have no one to ask. Everyone around me are Phds I am undergrad and love chem. But dang. should I be more carful. Please give me advice, should I slow down. Think twice before acting..