CHEMISTRY COMMUNITY

Samin Kabir

Chem_Mod wrote:I extended it to 10am Thursday for students to post for extended week 10.

Are all our grades (including the final) going to be available by Thursday or will it just be chem community points??

Samin Kabir

Hello,

So I know this is more personal and not really science related but I finished all my 50 posts and did 5 posts per week but it still says in that grade book that I didn't finish all 50 posts and only did 45. Is that going to change soon, or did I do something wrong?

Samin Kabir

For me, I watch a lot of SNL or something funny ig right before the test so I don't worry about it that much. That always calms me down.

Samin Kabir

Are these basically acids with multiple hydrogens?

Samin Kabir

Why does acid rain exist. Is it because of air pollution, and what can be down about it?

Samin Kabir

Follow up: why does Thymine have only 8 bonding sites? Shouldn't it be 12?

Samin Kabir

Why does the Heisenberg Uncertainty equation apply to only small objects and not big objects?

Samin Kabir

So in order to calculate the number of h bonding sites what do we need to do?

Samin Kabir

What would be the relationship between frequency and amplitude?

Samin Kabir

What pH range is considered neutral? What about for Acidic? Basic?

Samin Kabir

How would you determine whether a salt is an acid or a base?

Samin Kabir

How do you write the formula of a conjugate acid and a conjugate base. Like, what's the basic structure.

Samin Kabir

What are Bronsted Acids and Bases. I didn't really understand it in the lecture. Like, how would you be able to identify one?

Samin Kabir

How do you classify between strong acids and weak acids? What would be the main difference between the two?

Samin Kabir

Claire_Kim_2F wrote:Will they be proctoring through zoom again during that specific time so all the tas students will be in the zoom?

According to the Syllabus, he wants to do something like that in case we have questions about the exam while taking it.

Samin Kabir

What is the oxidation state of a metal species? Is that like oxidation number?

Samin Kabir

How do you use coordination number to determine the shape of the molecule?

Samin Kabir

Samin Kabir wrote:Will we need to be proctored by our TAs?

NEvermind I just read the syllabus... ignore this question

Samin Kabir

Will we need to be proctored by our TAs?

Samin Kabir

How do you classify coordination compounds via coordination number.

Samin Kabir

What are coordination compounds? What are the rules in terms of naming them?

Samin Kabir

How can someone determine the polarity of a molecule through the shape of it's lewis structure?

Samin Kabir

This is the question:

Draw the three possible structures of C3H4. Be sure to include all atoms.

How can one approach this problem?

Samin Kabir

What does it mean for a pi bond to be delocalized? How can one differentiate them in a lewis structure of a molecule?

Samin Kabir

Could someone please explain to me the theory behind the pi and sigma bonds? I am really confused about them and I also was wondering how can you define them?

Samin Kabir

What are axial and equatorial atoms? How can you identify one of them in an example?

Samin Kabir

Is the midterm going to be harder than the last? Also is it going to be multiple choice?

Samin Kabir

So are atoms more electronegative going from left to right because they get closer and closer to filling the octet, so the pull is stronger? What about when you go down a group what is the reasoning for why electronegativity decreases.

Samin Kabir

How can you calculate the electronegativity of an atom? For some of the textbook problems they are expecting you to know it....

Samin Kabir

What are the properties of Lewis acids and Bases, respectively?

Samin Kabir

Yea I agree with what is written above. The dipole-dipole interaction gives O a partial negative and S a partial positive charge. So because of that the interaction u see above is dipole dipole. Normally all polar molecules that are not ionic nor hydrogen bonds are dipole dipole

Samin Kabir

What about for polyatomic ions? Are we also expected to memorize it as well. If so, can someone give me a list or an easier to derive the formula for a polyatomic ion?

Samin Kabir

Thanks!

Samin Kabir

Are there any elements that tend to use the f orbital when bonded kinda like Phosphorous and the d orbital?

Samin Kabir

How do you determine polarity of a molecule. Specifically what value would be considered polar or non polar?

Samin Kabir

Are we going to be given a Vsepr chart for our midterms and final? Or are we expected to just memorize it

Samin Kabir

Is there a discord or a group me for Chem 14A

Samin Kabir

What is a formal definition of this? And what would be the ground state electron of an ion and how would it be different compared the neutral state of an atom

Samin Kabir

What is bond character and how do you determine whether it is ample or overwhelming?

Samin Kabir

Also another question, why is it that the more delocalized the electrons are, the more stable? Is this for all lewis structures or just the ones with resonance

Samin Kabir

What does it mean for electrons to be delocalized? Are certain lewis structures resonance structures because of these delocalized electrons? Im also having a hard time visually understanding this concept.

Samin Kabir

Thanks this means a lot!

Samin Kabir

Thanks everyone this means a lot!

Samin Kabir

Not the best thing in the world but here ya go
Q: What did the scientist say when he found 2 isotopes of helium?
A: HeHe

Samin Kabir

When do we get the midterms back?

Samin Kabir

Happy Halloween!

Samin Kabir

Yea because you were expected to have already learned most of the strong bases, strong acids and the polyatomic ions. I personally think that if you know those your golden for the midterm (although I haven't really taken it yet)....I could be wrong about this.

Samin Kabir

Why do we have to include the delta sign above the arrow on only combustion rxns?

Samin Kabir

Hello,
When we have to balance chem equations do we have to include the states of matter in all components. Additionally how do we know what state of matter a reactant/product is in?

Samin Kabir

I also had a question... IS it gonna be curved?

Samin Kabir

When are these chem community questions due? Is it at the end of every week (on Saturday) ?

Samin Kabir

They also said that it would be reasonable enough to answer within the 50 minute discussion section we have. I was also told that they would also mirror a lot of the questions from the textbook and the homework.

Samin Kabir

@Neel Sharma 1G Yea thanks that does help and I just saw the lecture!

Samin Kabir

Can someone help me with this: 1B.4 From the following list of observations, select the one that best supports the idea that particles have wave properties. Explain your reasoning. (a) Scattering of α particles by gold foil. (b) Electron diffraction. (c) Cathode rays. (d) The photoelectric effect. T...

Samin Kabir

I know that light can act as a particle because of the photoelectric effect, but what are some examples where it acts as a wave?

Samin Kabir

Hi,
Do electrons ever skip energy levels. For example, can an electron go from n =1 to n=5 all in one step or does it have to go to n=2, n=3, n=4 before getting on the n=5 and also when the electron comes back down does it have also go down serially. Is this also how you would find spectral lines?

Samin Kabir

Did he cover how to find spectral lines yet? If so, how would you calculate number of spectral lines? Would it be n-1 or something like that?

Samin Kabir

Hi,
Is the sapling homework that was originally due next Sunday(week 3) now moved to week 4? Because he said something about adding more questions to cover weeks 2,3 and 4.
Thanks

Samin Kabir

For exams, do we just do all calculations as it is without rounding and then round our final answer to the nearest sigfig?

Samin Kabir

Is there an easier way to solve this problem than how it is solved on the solutions manual: Polychlorinated biphenyls (PCBs) were once widely used industrial chemicals but were found to pose a risk to health and the environment. PCBs contain only carbon, hydrogen, and chlorine. Aroclor 1254 is the t...

Samin Kabir

Can someone explain step by step how to do this problem:M.19 A stimulant in coffee and tea is caffeine, a substance of molar mass 194g/mol. When 0.376 g of caffeine was burned, 0.682 g of carbon dioxide, 0.174 g of water, and 0.110 g of nitrogen were formed. Determine the empirical and molecular for...

Samin Kabir

Also in today's lecture the professor also mentioned something about how molecule shape depends on its electron density. Can someone explain how it is dependent on electron density?

Samin Kabir

So in the beginning of the professor's lecture he talk about some examples of how excited electrons can emit light using the fireworks and the sun example. When he was talking about how they display a specific color (like green, red, orange, etc), I got a bit confused. How do they get the color they...

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