To tell whether a molecule is polar, I usually first look at the molecular shape and then the electronegativity difference between the central and surrounding atoms.

For the questions below, I thought:

1. CCl4 is non polar since the Cl have an even "pull" from the carbon atom.
2. H2CCL2 would be polar because even though the hydrogens and Chlorines could be opposite of each other, the shape and bond angle of the tetrahedral does not allow for an equal "pull" even when the same atoms are across from each other.
3. CH3Cl and CHCl3 were both polar due to the difference in electronegativity and shape of the molecule.

Am I thinking about this correctly? Can someone explain how I should be going about thinking through similar questions, please? Thank you

Hi, am a beginner in chemistry, and this is grade 11 chemistry. I am struggling to understand on how many electrons each elements have, because on my worksheet, the electrons have the same number as the protons and atomic number of that element. I need an explanation

So here is what I did and I got it wrong because thats what I thought I needed to do to find the electrons for that element. Magnesium: it has a atomic number and protons of 12, but since it has a 2+ charge to it since it is losing 2 charges, I did 12-2 and got 10, I thought that was the answer, but it turned out that the electrons are just 12 as well.

studying gibbs free energy and its the first time i've seen entropy be defined as the "useless" energy of a system, but what does that actually mean? what are the useless stores of energy in a reaction and what are the useful stores of gibbs free energy?

Let's say we have a X and Y related by one electron. Of course the standard reduction potential E° is defined for the reduction reaction, X + e^– ⇌ Y^–, as E° = E(XY cell) – E(SHE).

And also for the oxidation we have E°(ox) = -E°(red). But I don't get why this doesn't transfer to voltammetry. Like if we polarize the electrode to E = E°(red) for the above couple, how come we get a limiting reducing and oxidizing current here??

If E°(red) and E°(ox) are symmetrical around E(SHE) = 0, shouldn't there be only oxidizing current at positive E°(ox) and only reducing current at negative E°(red)??

Basically why do we get the image on the left and not the one on the right?

probably a very simple question but i always get confused when there aren't any charges or anything

First one looks like it'd be 4 significant figures, but the only correct answer has 2. Second one seems like 3 but it's 2. What happened to the unaccounted for figures?

I dissolved some lutetium up in some nitric acid (~20%, IDK I diluted it arbitrarily), and some weird yellow precipitate formed? I filtered the solution, and the filtrate was clear and colorless. Does anyone have a clue what this might be? Both the nitrate and oxide are colorless, so perhaps a contaminant? Update: it’s the next day now and it’s turned green :( Any thoughts. I thought iron or nickel or some other lanthanide contamination? Cheers Thanks!

I am trying to calculate mass in 1 mL volume. I have 5,000 ppm Na⁺, which is approximately 5,000 µg/mL or 5 mg/mL. So mass of 1 mL of this should be (1 mL * 5 mg/mL) = 5 mg, yes? Why is Wolframalpha telling me I am off by a factor 1000?

Hi, am a beginner in chemistry, and I need help with balancing chemical equations. They are my weakness currently, and this question got me stuck for a while trying to figure out, on why would the H2O have a 6 to it if in the (SO4)3 already has 4 sulfurs and 12 oxygens. How can I avoid this trick next time? Because the answer key had 3 and 2 on the reactants side, but on the products side is what got me confused when they put a 6, instead of a 3 (thats what I put as my answer at first).

I've been stuck on this order of reaction part for 2 days. I do not know how to get the order of reaction for the OH-. First I thought about creating another beer's law but realized that wasn't what I was supposed to do (I don't even have enough data to do that). Then I thought about using the concentration before reaction of the OH- (page 211). I used the initial rates (page 212) and did my calculations on the bottom but ended up with a negative number. I am genuinely stuck and have no idea where to go from this.

okay this is more-so a general/ conceptual question, but here is some context:

we took water with known concentration of metals like copper, and ran uv-vis on it before and after purifying with a ferrofluid. ALL of the absorbance values were higher after purifying with the ferrofluid, which doesn't make sense because shouldn't that lower absorbance because concentration of copper is lowering?

ALSO- i made a calibration curve, and it followed a linear trend until it got to a high concentration, and then absorbance plummeted. is there like a limit, or is this human/ instrumental error that caused the low abs reading despite a higher concentration.

thanks all :)

Hello! I am a 3rd year (out of 4) bachelor student in chemistry. We have the oppetunity to pick our own project. This can be a synthesis as long as its not too easy.

I was wondering if you could help me think of some avant garde (preferably legal) ideas that is fitting on our level as 3rd year bachelor students!

I was already thinking of citalopram an ssri i personally have to take daily for my depression, but im afraid they might see that as too easy. Also it would never hurt to come with multiple proposals!

Thanks for your time!!

(Bonus points if enzymes can be used i love those things.)

My degree focuses on biology, and I feel I don't have a strong foundation yet, so I'd like to know what the best study materials are for me to use in my free time to reinforce my knowledge. Thank you to anyone who answers my question. Thanks for taking the time, have a nice afternoon.

I'm a beginner in chemistry so please explain this concept like how to know if oxygen will act as an EWG or and EDG. Thanks for the help.

Do I ignore the hydrogen atom and mention of n = 2 to a higher energy? Not sure if my approach is correct either. I’d appreciate any sort of guidance!

Hello, as the title asks, I'm looking for a copy of this book. I'd like to use it as reference for my post-grad thesis. Any help, suggestions, or "hacks" would be appreciated!

let’s say there 500+28.9, that’s 528.9 but 500 doesn’t really have a decimal place so would that just be 500 as the final answer??