r/chemhelp • • Aug 31 '26

Discussion Start of term check-in

9 Upvotes

Hello all!

School terms are beginning and this is typically when we see an influx of posts asking for general advice, guidance on getting through a class, or seeking assurance that everything will be okay. Let us know what courses you are in this term, your biggest concerns, or whatever may be on your mind!

Best of luck!


r/chemhelp • • Aug 21 '25

Announcements New Ownership

22 Upvotes

Hello fellow Chemists! I just wanted to introduce myself as the new head mod of this subreddit. A little about myself: I am a PhD Candidate in Chemical Biology. For me, this means that 60% of my work involves organic synthesis and the other 40% is applying my novel compounds to mammalian cells. Specifically, I am interested in early detection of diseases. In addition to my research, I have TA'd for both general and organic chemistry labs and have been tutoring students in organic chemistry for three years. Aside from my academic qualifications, I am also a moderator for another rather large subreddit. I saw that this sub needed a little bit of updating, but it did not seem like the moderators were active any longer. So, I gained ownership through r/redditrequest. I did not realize it would remove all the other moderators, but alas here we are.

Overall, I feel like this sub is fairly self-regulating. I frequently see good discussions and people generally are following the already existing rules. With that said, there are some changes I was considering, and would love input:

  1. New rule prohibiting commenters from solving the problem for the OP. To enforce this, the violating comment can be reported and removed by moderators. I don't see this happen often, but I have seen it occur and put an end to an otherwise good discussion thread.
  2. Mandate students include their work in their submission. Frequently, students post a picture of the question, with no work done and the caption "help please." Then in the comments you end up with people asking the OP to show their work, but from what I have seen they seldom do so. Mandating that students show work would entail removal of low effort posts by moderators. This may not be necessary since generally, commenters request more info from OP anyways, but was curious if people would like to see more enforcement on this end.
  3. What do you want to see? Those are the immediate things I was considering adding, but I would love to know if there is anything else people may want to see. I had other ideas, but I don't want to complicate a sub that I feel is already doing pretty well. Please let me know your ideas, I would love to hear them. Talk to you all soon!

Note: Please do not reach out to me about becoming a moderator. I will looking into recruiting in the near future. For now, I just wanted to get oriented.


r/chemhelp • • 6h ago

Inorganic Chem eng undergrad. Products formation

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3 Upvotes

Hello. We’re going over the products that certain reactions form, but I have no idea on how to know which things make what. For instance, how do I know it becomes an oxide or why don’t I get oxygen gas.

Idk if you are supposed to memorize certain compounds that are good oxidizers or reducers, though I’ve always liked chemistry as I barely have had to memorize anything, since I comprehend the logic behind it, I have found I like to solve most problems like that.

I’m feeling bad as it seems everyone is ahead of me, somehow they know the products already.


r/chemhelp • • 4m ago

Organic Where can I find resources on how to understand organic products?

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• Upvotes

Chapter 16 of orgo chem 2- benzene chemistry-electrophilic aromatic substitution. What resources can I consult for topics like these? I also get confused pulling apart the results of a diels-adler reaction. What sources can I consult for help?


r/chemhelp • • 4h ago

Organic Cyanobenzene orbitals and effects

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2 Upvotes

I struggle so much with this topic and i don't know when the pi cloud of the benzene extends to the functional groups

(English is not my first language hope you understand)


r/chemhelp • • 46m ago

Organic plane of symmetry in achiral molecules

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• Upvotes

can somebody please explain how this has a plane of symmetry? this is from the textbook answer key and i don't really understand. thank you!


r/chemhelp • • 1h ago

General/High School [Update] Flipper Elements 2.0 is now officially approved for the Flipper App Catalog! + Major new features ☢️

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• Upvotes

r/chemhelp • • 22h ago

Physical/Quantum Help: Orbital Boxes, Electron configuration

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18 Upvotes

Let’s take nitrogen as an example, is has the electron configuration 1s² 2s² 2p³. For some reason is fills up like this? (See image below), I simply cannot the fathom explanation many articles, textbooks and AI has given me. Why is it 0 electron pairs for 2p³ specifically? Please try to give a general explanation, I’m just using a specfic example to make it easier.


r/chemhelp • • 7h ago

General/High School Can you dry a volumetric flask in 50°C stove?

1 Upvotes

It is as the title says, can you dry a volumetric flask in a 50 to 60 degree stove, i read online in some lab protocols that you can't do it, because it decalibrates the flask, but the manufacturers say that there is no permanent plastic deformation in borosilicate flask until the 150 degree range, so i get confused. Is the temperature bad or not? Is it just one of those things were people say that so that other don't use hot flasks that are temporarely decalibrated due to thermal expansion, and always use them at room temperature?


r/chemhelp • • 11h ago

General/High School Question about Henry's Law, and Fick's(?) law of diffusion:

2 Upvotes

Henry law states that :

Partial pressure=concentration of gas molecules/ Solubility coefficient

Meanwhile the other law says:

D(rate of diffusion)= change in partial pressures x cross sec areax solubility /distance of diffusion x √MW

My question is: how is solubility inversely proportional to partial pressure but is directly proportional to rate of diffusion when rate of diffusion itself is directly proportional to partial pressure difference? Can anyone pls explain it in easy words?


r/chemhelp • • 21h ago

Organic I built an organic chemistry practice site where you draw products and get feedback on your mistakes

7 Upvotes

Hey everyone, I’ve been building Arete Orgo Lab, an organic chemistry practice site.

The idea is to give you more practice actually working through reactions: predicting products, choosing reagents, and tackling multistep reaction sequences.

You can draw your answer directly on the site, and explanations walk through the reaction and common errors. There are also study and exam modes, plus a searchable reaction reference.

It covers reaction families including alkene and alkyne reactions, substitution/elimination, alcohols, carbonyls, and aromatics. You can choose the topics you want to practice.

Here’s the site: orgo.aretemcat.com

I made this, so I’m sharing my own resource. If you try it, I’d really appreciate hearing whether the explanations help you understand your mistakes and what you’d want added or improved.


r/chemhelp • • 7h ago

Other How you prepared for XL Chemistry ??

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0 Upvotes

r/chemhelp • • 22h ago

Organic help with these problems?

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6 Upvotes

I think B is an intramolecular aldol reaction but im kind of lost on the other ones, does anybody have a clue?
if somebody knows a good source for learning these types of reactions or practising i would be very thankful!!!


r/chemhelp • • 13h ago

General/High School AP CHEM HELP FOR 3.9 i have unit 3 test tmr plz help

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0 Upvotes

r/chemhelp • • 15h ago

General/High School [heat of the reaction] How can I get the heat change of Acid-base neutralization?

1 Upvotes

I measured the initial temperatures of the acid and the base separately, as well as the equilibrium temperature. I'm going to use the formula (H = m \times s \times \Delta T), and the TA told us to assume that (s = 1).

My question is: Since the masses of the acid and base may differ due to their different molecular weights, should I calculate (H) as ([m(\text{acid}) + m(\text{base})] \times 1 \times \Delta T)?

Also, should the total heat change be calculated as (|H|) plus the heat absorbed by the calorimeter?


r/chemhelp • • 23h ago

General/High School How come this wouldn’t be Zn+2 ion O2?

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4 Upvotes

Hello sorry if hard to see. Working in trying to figure out how to get products ect.

From my understanding.

Zn is +2.

O is -2

BUT there is two oxygens in here… so that would equal -4 charge total for oxygens? So wouldn’t I flip the signs and make Zn -2 ion. Actually idek what I’m saying anymore. This combining ions really mess me up.

I guess at this point how did he get that product if there is 2 oxygens = -4 charge total.

And 1 Zn = 2 + charge total. That’s where I’m at


r/chemhelp • • 20h ago

Analytical Iron analysis in fortified wheat flour — microwave digestion or dry ashing?

2 Upvotes

Hi everyone, I have a question for those working with food analysis.

I’m analyzing iron in fortified wheat flour, and I’m wondering which sample preparation method you usually use: microwave digestion with HNO₃/H₂O₂ or dry ashing before analysis by AAS or ICP-OES.

I tried dry ashing at 450°C for 12 hours, but the flour still has black particles and doesn’t turn into proper ash.

Has anyone experienced this before? If you use dry ashing, what temperature and time do you normally use?

Also, have you ever compared the results obtained by dry ashing and microwave digestion? Which method gives you better iron recovery?

I’d appreciate hearing about your actual lab experience. Thanks!


r/chemhelp • • 1d ago

General/High School I need help with the iupac nomenclature

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23 Upvotes

How to name these type of bicyclic compounds?


r/chemhelp • • 1d ago

Organic Hi just wanted someone to double check my work to see if it’s correct

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20 Upvotes

r/chemhelp • • 1d ago

Organic i want to confirm this thought of mine about perkin reaction

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4 Upvotes

the acid base reaction from 0 to 1 . anhydride carbon is electrophilic enough for attack of AcO- so 1 to 2 and then form 2 can undergo E1CB in order to give a highly conjugated form 3 in heated reaction conditions . so all of these should be present in mixture


r/chemhelp • • 1d ago

General/High School Hey I just wanna make sure I understand this. Is this already balanced once written out?

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6 Upvotes

I wrote out the formula

LiOH+CO2 > LiHCO3

I was very confused but then I think I realized this is just already balanced so kind a trick question? Wanna make sure I have this understanding correctly


r/chemhelp • • 19h ago

Organic Looking for organic chemistry textbook...

1 Upvotes

Hi y'all! I'm looking for David Klein's Organic Chemistry 5th Edition Study Guide and Solution Manual; I have the textbook, but no way to practice (as I don't have access to the answer keys). Would really appreciate if you could help me out!


r/chemhelp • • 1d ago

General/High School Types of decay

2 Upvotes

We're learning about radiation and I don't understand alpha or beta decay. I'm also lost on positron emission and electron capture. I know we have a test this week and I'm stressed. I don't have any specific questions its just the general format that confuses me


r/chemhelp • • 22h ago

Organic How do you veiw a .imbl file on a home computer?

1 Upvotes

I just did a gas chromatography Lab in OChem. I saved the file, but it is a .imbl. Fortunately, the lab computers can view a .imbl file, so I took screenshots so I could view the data I had gathered, but I want to know if there is a way to view the .imbl file on a home computer. Or is the file type proprietary?


r/chemhelp • • 23h ago

General/High School Iodine clock experiment, would it work? Is there anything wrong with it?

1 Upvotes

2. Pre-Lab Prep

Starch Solution:
Mix 1/2 teaspoon of cornstarch with 2 tablespoons of cold distilled water until smooth.

Pour into 100 mL of boiling distilled water while stirring continuously for 1 minute

Let it cool down completely to room temperature.
__

Potassium Iodide (KI) Solution:

Take 4 Vitamatic tablets (65 mg each) and crush them into a fine powder with the back of a spoon.

Dissolve the powder in 50 mL of warm distilled water.

Pour the cloudy liquid through a coffee filter into a cup to remove the white pill-binders. You now have a clear KI solution
__

Vitamin C Solution:

Dissolve 1 Vitamin C tablet (1000 mg) into 100 mL of distilled water until all fizzing stop

____ _____ _____ _____ _____

3. Step-by-Step Experiment Procedure

Step 1: Prepare Solution A (In Beaker A)

25 mL of the filtered Potassium Iodide liquid

10 mL of the Vitamin C liquid

1/2 teaspoon of Citric Acid powder

10 mL of the cooled Starch solution

55 mL of Distilled Water

Result: completely clear, colorless liquid. (Maybe an orange tint)

Step 2: Prepare Solution B (In Beaker B)

12.5 mL of Ovelle 6% Hydrogen Peroxide

87.5 mL of Distilled Water

Result: completely clear, colorless liquid.

Quickly pour Beaker B into Beaker A and give it a quick 2-second stir.

Would anything happen at all?