CHEMISTRY COMMUNITY

Rohan Kubba Dis 4B

Are all pi bonds in the p-orbital, and if so why?

Rohan Kubba Dis 4B

Yeah, in addition to above I’ll use the example from the Marshmallow Review: 1. Atomic Size Basically, the atom with a larger atomic radius makes it a stronger acid: HF v HCl Because F has a smaller atomic radius than Cl, HCl is comparatively more acidic 2. Stability Basically the most stable molecu...

Rohan Kubba Dis 4B

Yes there are metals that extend beyond 4, although I’m pretty sure we won’t have metals that go beyond 4.

Rohan Kubba Dis 4B

I don’t necessarily know if we have to know the names of certain molecules, but on one of the TAs said that usually it will be given to us and it won’t really be cryptic. I think our best bet is to memorize some of the basic ones though.

Rohan Kubba Dis 4B

Yeah, mostly what I have seen shows that molecules with dipoles are usually polar, however, XeF4, which has lone pairs is actually non polar. So I would just recognize that usually it is heavily dependent on shape and structure. But more on your question, usually if there’s a lone pair, there’s prob...

Rohan Kubba Dis 4B

Is there a quick formula or trick that can give me the oxidation state of a metal in a a coordination compound?

Rohan Kubba Dis 4B

Why is the pH scale the standard, or more used scale? Is it just traditional, or are there more problems that arise from using the pOH scale?

Rohan Kubba Dis 4B

Yeah I had a similar story too. I didn’t feel like I did well even after going through a bunch of problems and going to a couple sessions. I think the best thing is to ask your TA question-specific questions. Also, just watching OrganicChemistryTutor on YouTube really started to help me. So in addit...

Rohan Kubba Dis 4B

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=imgres&cd=&ved=2ahUKEwiUscKRxpDmAhUmIDQIHbCoACcQjRx6BAgBEAQ&url=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FGeneral_Chemistry%2FMap%253A_General_Chemistry_(Petrucci_et_al.)%2F18%253A_Solubility_and_Complex-Ion_E...

Rohan Kubba Dis 4B

I understand that pH is a concentration, mostly of Hydronium ions (sometimes Hydroxide), however, it goes from 1 to 14. I know that the 14 is equal to 1.0 x 10^-14M (basic), however, can the basic scale extend beyond 14?

Rohan Kubba Dis 4B

Are there any exceptions to the naming rules other than the fact that if a coordinate compound is negatively charged we add and -ate? If so, what are they?

Rohan Kubba Dis 4B

Can someone differentiate between the Lewis base/acid, the Bronsted/Lowry base/acid, and Arrhenius base/acid definitions?

Rohan Kubba Dis 4B

I know that Lavelle talked about how negatively charged coordinate compounds need to have an -ate at the end of their name, however, what about if there is a positively charged coordinate compound? Is this possible and if so, what would be an example?

Rohan Kubba Dis 4B

Basically, if molecule has more than one bonding site (ie usually 3 atoms or a lone pair), hybridization will occur. If you think about it, hybridization is directly related to the number of bonding sites as well: eg. 3 bonding sites= sp2, 4 bonding sites=sp3 and so on and so forth.

Rohan Kubba Dis 4B

Essentially, if both have LDF as their chiefs intermolecular force, the one that is larger or more polarizable will have a stronger LDF. Another way to push this is to say that the one with a larger molar mass will have stronger London Dispersion Forces. This means that as you go down in group, it w...

Rohan Kubba Dis 4B

Basically, a good example to look up is 2E30. (Yes I know it is an even question, but it is a good example). If you look at it there are three forms of essentially the same element. In the second and third versions, these are the trans and cis versions of the molecules respectively. Essentially in t...

Rohan Kubba Dis 4B

Essentially this is when there are 4 bonds to a central atom and a lone pair. (AX4E). This can also be called sawhorse though.

Rohan Kubba Dis 4B

If you are referring to substances with the same electronic configuration, this is because the lone pairs of a substance affect the molecular geometry of substance more than atoms. In other words, if you look at rule 4 in the book, it explains that lone pairs repel the other atoms more than atoms an...

Rohan Kubba Dis 4B

An example of a van der waal force would be that of a sample of Helium. Essentially, it has a full valence shell and it would have a momentary dipole (one side of atom is positive and the other side is negative), therefore another helium atom could interact with its positive portion to the negative ...

Rohan Kubba Dis 4B

A refers to the central atom, X refers to the number of bonds and E represents lone pairs. However, just remember when you have a radical, you treat that lone electron like a loan pair. So, essentially, E usually represents lone pairs of electrons, however it is important to note that radicals are t...

Rohan Kubba Dis 4B

Also, my TA I taught us a really easy way: Valence electrons of element-(number of bonds(lines) + the number of lone electrons(not pairs)). This seemed to work for me and it was fast too. Another trick I learned was that when finding the formal charge for oxygen, if it was double bonded and had two ...

Rohan Kubba Dis 4B

This is the main deviation of the periodic trend of ionization energy increasing to the right and up (fluorine). In this case, nitrogen has a a higher ionization energy than oxygen. The reason is because if you look at the 2p shells of each element, you will see that oxygen has 4 total electrons in ...

Rohan Kubba Dis 4B

There are many octet exceptions. First, H only needs one electron to complete its shell, and this extends to He and a couple of other elements. Next, we have expanded octets which can be any element in the third period which includes P, S, and Cl. Moreover, then we have radicals and biradicals. Alth...

Rohan Kubba Dis 4B

When would dipoles cancel out. For instance, CH4 (methane) has two different elements yet all the dipoles “cancel out”; when would I know when other elements have dipoles the cancel out? Would I just have to draw them and evaluate?

Rohan Kubba Dis 4B

Do elements that are diatomic like O2 or Br2 have dipoles or is it only between molecules?

Rohan Kubba Dis 4B

Obviously Copper and Chromium have special electron configurations to maintain stability (3d10 4s1 and 3d5 4s1), however, does this trend continue to the corresponding elements in each group (Molybdenum for Chromium and Silver for Copper)?

Rohan Kubba Dis 4B

I understand that some elements like S and P can have more than 8 valence electrons, however, is their a way to determine what other elements have the same condition? How would you derive the amount of valence electrons for an element like these? Do we just memorize these exceptions in the table and...

Rohan Kubba Dis 4B

In the review session, the UAs mentioned three ions that were isoelectronic, meaning they were equal in valence electrons, however, in this case they explained that ionic radius still increases as you move down a group and increases as you go down a period. I’m just confused as to why this is the ca...

Rohan Kubba Dis 4B

I know at the review session, the UAs explained that oxygen has a lower ionization energy than nitrogen because nitrogen has a symmetrical arrangement while oxygen does not. Are there any other cases that differ from the general trend of ionization energy increasing to the right and up the table lik...

Rohan Kubba Dis 4B

I understand that sometimes we are going to be given a molecule and we may not have enough electrons to fill up all the shells. In these cases, with an odd number of electrons, where do we give that extra electron to? In other words, which element gets the extra electron? Does it have to do with ele...

Rohan Kubba Dis 4B

Is there a general rule for the d-block elements for the expanded octet, or is it completely variable from element to element? Also, how are we able to derive the expanded octet numbers from these elements?

Rohan Kubba Dis 4B

Essentially, you are right, each atom wants to be fully stable, and while there are other factors, such as electrostatic attraction, that ultimately impact bonding, the idea is that each atom wants to fill its outer electron shells to achieve the highest energy level it can. Of course, Hydrogen just...

Rohan Kubba Dis 4B

Also, higher polarizable atoms are typically atoms with electrons that are far away from the nucleus, (many shells), and because the electrons are further away, the electron cloud is large and highly polarizable as denoted by the textbook. Also, cations are generally not highly polarizable because t...

Rohan Kubba Dis 4B

I understand that there are not truly any definite values that dictate whether a bond is covalent or ionic. However, in the book it says that a good rule of thumb is that an electronegativity difference of two means that the bond has so much ionic character, it is best regarded as ionic. Are there a...

Rohan Kubba Dis 4B

A good rule of thumb when dealing with electronegativity is that as you are going across a period, generally, that has more impact than variance within a group. In other words, that electronegativity is usually closer across a period. With that in mind, even though Chlorine is in the same group as f...

Rohan Kubba Dis 4B

I understand that the P orbital has an x, y, and z portion to it depending on the element; however, is the ordering of the orbitals arbitrary? In other words, are we defining the axes first and then deciding that they are x, y or z? Because from different perspectives, the x-axis can be the y-axis a...

Rohan Kubba Dis 4B

Why is it that when we are dealing with energy levels, as the energy levels increase, they get closer together? Does this also affect our calculations with the Bohr frequency condition or the E=-hR/n^2 formula in any way?

Rohan Kubba Dis 4B

Can someone please describe Hund’s Rule and the Pauli Exclusion Principle, and its direct correlation to how it helps us write e- configurations? I am confused on when each one is applicable and not.

Rohan Kubba Dis 4B

Can someone please explain the exceptions to the multi-electron atoms? If someone could use some examples and explanations to describe these special cases, it would be much appreciated.

Rohan Kubba Dis 4B

I understand that the orbital is a probability field of the highest likelihood of the atoms position, however, is the probability uniform throughout the orbital or is it more likely to be near the nucleus and why?

Rohan Kubba Dis 4B

I understand that electrons have a duality of having particle-like properties as well as wave-like properties, however, what are the exact examples or properties or that make each side valid? (Atomic Spectra, Photoelectric effect, etc.)

Rohan Kubba Dis 4B

Unless we are not in a vacuum, the speed of light will stay constant at 3.0 x 10^8 m/s.

Rohan Kubba Dis 4B

Diffraction, in our context, refers to the patterns of high and blow intensities generated by an object in the path of a ray of light. Basically, it is referring to the idea of constructive and destructive interference that shows the wave-like properties of electromagnetic rays.

Rohan Kubba Dis 4B

Another important aspect to remember is that each photon interacts with only one electron, and furthermore, if you increase the intensity of the light and if you have enough energy per photon, then more electrons would be emitted.

Rohan Kubba Dis 4B

Another way to think of constructive v destructive waves is that when two waves are in phase, meaning they are both peaks or both troughs at the same moment, you add them. These are constructive waves. Moreover, when two waves are out of phase, meaning one is a trough and the other is a peak at the ...

Rohan Kubba Dis 4B

The general idea for sig figs is that you are trying to be precise because your calculation is only as accurate as your least accurate measurement. For example for the hypothetical problem find moles of F- in 25.2kg of UF6, it is important to round your answer to three sig figs at the end. The reaso...

Rohan Kubba Dis 4B

In the periodic table, there are elements (mainly from groups 3-12) that have variable amounts of electrons present. In this case the difference between Iron (II) (ferrous) and Iron (III) (ferric) is that in iron (II), the iron atom has lost two electrons to form Iron (II) and in iron (III) the iron...

Rohan Kubba Dis 4B

Basically, on that question you count the figures of each type of element. You then have your molecular formula, which would be C4H6Cl2. That would be your molecular formula. Then, you would divide by the greatest common factor. In essence, divide by 2 and you would get C2H3C6, which would be your e...

Rohan Kubba Dis 4B

I understand that the molarity equation is M1V1=M2V2, however the molarity equation is = to M=n/V. So, basically, I am asking about the idea that shouldn’t the volume cancel out in the M1V1=M2V2. I know my thinking is wrong but I just need a plausible explanation for it.

Rohan Kubba Dis 4B

A key component to remember how to solve for the moles of F- ions in 25.2 kg of UF6 is to understand the idea of the molar ratio. That means that for ever one atom of U there are 6 atoms of F, so your conversion factor is 1 to 6. So, that means you could solve this by first solving for the moles for...

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