CHEMISTRY COMMUNITY

Joshua Eidam 2A

I am super confused on this problem because even after setting up my ice box, and calculating for x in multiple ways, I keep getting the same answer (0.0375). Subtracting this from 0.900 gets me 0.8625. I have tried changing the sig figs and everything but it is still telling me I am wrong. Am I doi...

Joshua Eidam 2A

Just adding on, and I am not entirely certain if this is what the original question is asking for, but in the context of bonds, the boiling and melting points are heavily affected by the strength of the bond. Specifically, the stronger the bond length is, the higher both the melting and boiling poin...

Joshua Eidam 2A

What exactly is a ligand in the context of chemistry? Sorry if this is a simple question I just have the biological definition of a ligand stuck in my head and it's confusing me. They're somewhat similar right?

Joshua Eidam 2A

Yes, as previously stated when you are being asked for the charge of a transition metal, it should almost be within the context of the TM in a compound, otherwise it is hard to determine since their charges can vary. Use any element in the compound that you know the given charge of, as well as the o...

Joshua Eidam 2A

Also I think it is important to notice that other electrons contribute to the shielding effect with the negative repulsion. I found this on a website and I thought it was helpful: "In hydrogen-like atoms, which have just one electron, the net force on the electron is as large as the electric at...

Joshua Eidam 2A

Hi I also found this snippet from this website: "There are four nodes total (5-1=4) and there are two angular nodes (d orbital has a quantum number ℓ=2) on the xz and zy planes. This means there must be two radial nodes. The number of radial and angular nodes can only be calculated if the princ...

Joshua Eidam 2A

Could someone clarify for me what a buffer exactly? I am confused as to both what they are and what their intended purpose is? Also, how do you identify them?
Thanks

Joshua Eidam 2A

Yes I believe stability is the main factor for why hybridization takes place. Without hybridization taking place, I believe the overall energy level would be higher and the likelihood of there being instability increases.

Joshua Eidam 2A

Adding on to this, since O is very electronegative does that mean it shouldn't be the central atom in lewis structures? Neha, the least electronegative atom is in the middle, and since nitrogen is less electronegative, it is the center atom. This is not to say though that oxygen can't be the centra...

Joshua Eidam 2A

Hi, I am a little confused as to where exactly the cutoff is for elements that are able to have more than 8 electrons in their valence shell. Also, I am confused about how to calculate what the central atoms expanded octet is when given a lewis structure or just a formula?

Joshua Eidam 2A

Kelly Singh wrote:KA measures the strength of an acid whereas pKA is the negative log of that value. It's just an easier and more convenient way to refer to the KA value as far as I know. =)

Does a higher Ka value represent a stronger acid or is it not that simple?

Joshua Eidam 2A

I thought the same thing but as previously mentioned, the COOH gives it away to be a weak acid. It dissociates partially into H+ and COO−. Here is a link that explains more about the carboxyl group: http://www.phschool.com/science/biology_place/biocoach/biokit/carboxyl.html#:~:text=Carboxyl%20groups...

Joshua Eidam 2A

I am still a little confused as to what causes delocalization in an atom or molecule? What could change an unstable molecule with uneven electron distribution into a stable one?

Joshua Eidam 2A

So what is the exact equation for Ka? Also if only aqueous samples are used in calculating the Ka, then are any samples in different forms (solid, liquid, gas) just disregarded?

Joshua Eidam 2A

Sukhkiran_Kaur_3F wrote:If there is more than one H in front, it'll be polyprotic.

Is it specifically just in front or is it in general? I am a little confused as to whether or not all the H contribute to it being polyprotic?

Joshua Eidam 2A

For this question, I am confused as to how I am supposed to determine the pH of "the predominant species present at pH 2.70". How do I know what the predominant species is and how do I know what its pH is? How does the given pH and pKa help with that? Please help. Thank you.

Joshua Eidam 2A

I remember hearing about the term amphiprotic. What is the difference between amphiprotic and polyprotic? polyprotic is the ability of an acid to donate multiple protons (H+) while amphiprotic means a substance can act as an acid and a base. Yes, but not to confuse amphiprotic with amphoteric, whic...

Joshua Eidam 2A

What characteristics make a salt acidic or basic or neutral? Is it similar to normal acids and bases or is it different?

Joshua Eidam 2A

I am confused as to how I can identify an amphoteric substance from a list of substances. I know that it means it the substance can act both as a Bronsted Acid or Base but how can I identify that just from looking at a list of substances?

Joshua Eidam 2A

I am confused as to why something that is more electronegative would result in the formation of a weaker acid. Would the H+ not be more attracted to Cl- if it is so electronegative, thus making it harder to break away and therefore an overall weaker acid?

Joshua Eidam 2A

So basically to find the conjugate acid of a molecule, we add a hydrogen to it and give it a positive charge, and to find the conjugate base of a molecule, we take a hydrogen away from the molecule and make it a negative charge? Yes that is one way of looking at it for sure. I think focusing on how...

Joshua Eidam 2A

Does anyone know if we need to understand more than just how acid rain is formed? Or will we have to know more about the biological applications as well like how it negatively affects the environment etc.?

Joshua Eidam 2A

Amphoteric substances can act as either acids or bases, I think lavelle also said that the amphoteric substances often align with the diagonal band of metalloids, but that it doesn't match up perfectly. Can you clarify more on the "aligning with the diagonal band of metalloids"? Was he su...

Joshua Eidam 2A

Also, when trying to find the concentration of the H+ or OH- from a pH or pOH, how do you do the reverse of -log[ ]?

Joshua Eidam 2A

lwong Dis1L wrote:What is the difference between pH=-log[H3O+] and pH=-log[H+]?

They are the same thing. The H3O+ just represents the H+ bonded with an H2O but the concentration of either of them can be used to find the pH.

Joshua Eidam 2A

Just to clarify, when using the concentration of OH to find the pH, you simply subtract -log[OH-] from 14 and that will equal the pH?

Joshua Eidam 2A

In regards to what the Chem Mod wrote about conjugate bases and acids, when an acid or base dissociates, is the portion that is not the H+ or the OH- the conjugate base and acid respectively? For example, ClO4- is the conjugate base but in the case of NaOH dissociating in H2O, the water is the conju...

Joshua Eidam 2A

What exactly makes an acid or a base a Bronsted acid and base? Are there unique characteristics to them compared to other types of acids and bases?

Joshua Eidam 2A

Does anyone know what the format of the test is going to be like as well as how long the test is going to be?

Joshua Eidam 2A

Just to clarify, the roman numerals only apply to transition metal cations and anions? Also, the way you determine their charge is by looking at the charges of the other elements in the compound, as well as the total charge of the entire compound? Someone please correct me if I am wrong.

Joshua Eidam 2A

I was wondering what are some helpful ways of remembering how to recognize which is a Lewis Acid and Lewis Base when presented with an equation for a reaction. For whatever reason I find it challenging to identify them when I look at an equation. Let me know!

Joshua Eidam 2A

Like the person above mentions, there are a lot of really great graphics that display all the different shapes based on lone pairs and such. Here is a link to a website with a graphic that I find quite helpful: https://courses.lumenlearning.com/boundless-chemistry/chapter/molecular-geometry/ Hope th...

Joshua Eidam 2A

Another question that I am confused about is how LDFs are affected by the molecule's surface area? If I am not mistaken, I believe that greater surface area means strong LDFs but why would that be the case?

Joshua Eidam 2A

I understand that if there are multiple polar bonds present, and their dipole moments are not canceling out, then the molecule is polar. But what exactly makes a certain molecule more polar than another? Does it have to do solely with the strength of the polar bonds or are there other factors that c...

Joshua Eidam 2A

I agree with the previously mentioned equation using dots and lines. By counting each dot and line as 1, there is less confusion (at least for me) in terms of what value do I subtract from the valence electrons.

Joshua Eidam 2A

Is there a specific benefit for hybridization? Why does it occur in the first place?

Joshua Eidam 2A

In a triple bond, is there a way of knowing which specific bond is a sigma or a pi bond? Do we even need to know how to do this?

Joshua Eidam 2A

I believe that overlapping waves will alter one another no matter where each wave is in its respective cycle. The obvious effects can be seen clearly at the peaks and troughs of the waves (when overlapped with other peaks and troughs), but I am sure that different effects can be noted at any point a...

Joshua Eidam 2A

I believe "ejected" electrons are ones that have been removed from the atom due to the high frequency of the light being shone on it. "Excited" electrons are ones that are raised to higher levels of energy in the atom but do not leave. They eventually return to their original ene...

Joshua Eidam 2A

I ordered the textbooks required for Chem 14A from the UCLA bookstore but they are insanely back ordered I think because I still have not been contacted to get them. Does anyone know of another way to access the textbook? I know we are going to be needing it more and more as the quarter continues. T...

Joshua Eidam 2A

Has anyone else ordered a textbook from the campus bookstore and it still hasn't arrived? I am not really sure what to do about it because I already spent the money on it but we are going to be needing the textbooks more and more. Does anyone know of a place online where I can find it? Thanks.

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