CHEMISTRY COMMUNITY

brennayoung

How are we supposed to know that Boric acid B(OH)3 is a lewis acid? I woulve thought it would be a weak base b/c it has an OH in it. Also in terms of writing equations how do lewis acids/bases and bronsted acids/bases differ?

brennayoung

Does anyone know if we need to be able to identify buffer solutions for the final?

brennayoung

I think the book is using the calculations that Lavelle told us we would learn in 14B. He went over a few examples of those briefly today in lecture.

brennayoung

Fluorine is too small to accommodate the negative charge. Don't think of strength of acids based on electronegativity but based on electronegativity AND size.

brennayoung

Why doesn't the conjugate base of a strong acid affect pH? The conjugate base of a strong acid is a stable compound that is also a weak base. As it is a stable compound, it does not have much charge and will not prompt further electron or proton transfer, therefore not affecting the pH So if this w...

brennayoung

Amphiprotic means that a substance can both accept and donate a proton or H+. Amphoteric means that a substance can act as both an acid and a base. All amphoteric substances are amphiprotic because if a molecule can either donate or accept a proton, that means it can act as both an acid or a base. ...

brennayoung

Not entirely sure how the anion portion of this affects it but what I learned was that the more stable the base, means it is a weak base, and will produce a strong acid.

brennayoung

Nawal Dandachi 3G wrote:lewis acid is an electron-pair acceptor while a lewis base is an electron-pair donor.

Is the donor/receptor just based off of electropositivity and electronegativity respectively?

brennayoung

Can't the same metal have different oxidation states, though? Like Fe can be +2 or +3 Yes, but to figure out which oxidation state the metal has, we use the ligands to figure out the charge that we must balance out. As such, memorizing the ligands essentially works towards knowing the oxidation sta...

brennayoung

One of the UA's said we don't need to know the Ice tables.

brennayoung

if a paramagnetic electron means it is unpaired, then does that mean the molecule is radical? okay I thought about this more and I am going to answer my own question, I realized that a paramagnetic electron from one atom could bond with a paramagnetic electron from another atom so it is not always ...

brennayoung

We learned bond order if by bond order you mean strength but im not sure about the molecular orbital theory or what that entails. I would go off the Lavelles practice problem sheets he lists the key concepts of that unit down below and I would assume all of them would be on the exam or could be on t...

brennayoung

You draw d orbitals similar to how you would draw a pi bond i think, however i dont think we will be asked to draw any of them or be asked about d orbitals to begin with, in terms of hybridization

brennayoung

Hybridization applies to atoms not to bonds or lone pairs, this might be some source of the confusion not entirely sure though.

brennayoung

Does anyone know if this will be on the final?

brennayoung

I dont think we went over it so it shouldn't be on the final

brennayoung

Why does P4 have the hybridization of sp3 and not sp2?

brennayoung

when can you say if there should be a coeficient greater than 1 in front of a hybridization like 2sp3 or something like that as opposed to just sp3?

brennayoung

As far as I know resonance structures at this level shouldn't affect the number of sigma and pi bonds as the creation or reduction of sigma and pi bonds via the manipulation of lone pair electrons would change the formal charge and I think we only need to worry about the resonance structures where t...

brennayoung

The lewis or VSPER structure is the only way to find it

brennayoung

I like to think of sigma bonds as a long cylinder and pi bonds as like a bubble encasing the sigma bond thats connected on either side. ___pi____ | ________ | C |--sigma |C |____pi____| so for my attempt here, imagine that the dashed line and solid line above it comprise of a cylinder like shape whi...

brennayoung

Does anyone know how promotion figures into electron configuration and the bonding? Like is promotion different than just regular hybridization?

brennayoung

In a normal sigma bond say something that has the orientation of 2sp2 2p2, all 3 of the p orbitals will go into the hybridization even though only 2 possess electrons. However in the case of pi bonds they occupy empty p orbitals which allow for rotation whereas sigma bonds do not. If the same electr...

brennayoung

Why is carbon's hybridization 2sp3 if there are only 2 electrons present in the 2p orbital? I know carbon has 4 valance electrons, 2 from the filled up 2s2 orbital and then the remaining 2 from the 2p level as to give it the 1s2 2s2 2p2 configuration so why then is its hybridization listed as 2sp^3?...

brennayoung

For the final do we need to have the different wavelength series memorized for the energy required to raise it one energy level like quantum state =1, n=2 etc?

brennayoung

Is there something the Rydberg equation should NOT be used for? I remember my TA saying something about if we used the Rydberg equation in a problem on midterm 1 we would receive no credit but I don't remember which problem it is.

brennayoung

Is there any way to know for sure if the substance is magnetic other than prior knowledge like is there a formula we need to know?

brennayoung

How would u represent sigma bonds being end to end or side by side in the case of pi bonds in terms of drawing it?

brennayoung

Do we know up to what topic in the book will be tested on for the final?

brennayoung

do coordination numbers also depends on the size of the coordination compound?

brennayoung

As far as I know its basically because Coordination Compounds take into account the size of the atoms specifically the metals and ions

brennayoung

would a single sigma bond be stronger than say 2 pi bonds though?

brennayoung

the bent shape is the only one that can have 1 or 2 pairs of lone electron pairs

brennayoung

Do yall think the final will take the full 3 hours or if the 3 hours will be more than needed like extra time

brennayoung

So we have to have all of the angles and possible lone pair induced angles memorized for test 2?

brennayoung

How would the induced O2 dipole occur in the first place?

brennayoung

Is there any practical application to viscosity like do yall know if there are any formulas that factor in viscosity or is it more just a property of certain substances to be aware of in general knowledge?

brennayoung

Does anyone know if we need to have all of the bond angles of each shape memorized for Test 2? Also on that note if we do, do we need to know by how many degrees a lone pair would affect the angle or just that it would make it smaller due to electron repulsion pushing down the other atoms. Thanks!

brennayoung

When drawing the Lewis structures do we have to use the dashed lines and filled in lines to demonstrate which plane the atoms are on? Or is that like a separate thing from Lewis Structures?

brennayoung

Can someone explain how hydrogen bonding works in reference to polarity? Thanks

brennayoung

How can you tell that it is n=7 based off of the numbers? I found a couple diagrams online that show 410.2 as n=6.

brennayoung

How do we find the frequency once we've found the Energy using E = phi + 1/2mv^2 ? because the ones that have frequency we aren't supposed to use if there is mass involved i thought

brennayoung

First, calculate the molar mass of KMnO4 (158.09g/mol). Next, concert 5g KMnO4 to moles and 150mL to L and use the formula M=mol/L to calculate the molarity of the first solution. Lastly, use the equation M1V1=M2V2 equation to calculate the concentration of the second flask by using the value you p...

brennayoung

In the initial question, wouldn't you need to convert the velocity of the electron 3.6x10^3km.s^-1 into m.s^-1 so it would be 3.6m.s^-1 to be in SI units or am I mistaken?

brennayoung

If you want tutoring there are the different learning sessions- but does anyone know the functional difference between the step up and workshop? Like will they provide problems to do if you don't have any specific questions?

brennayoung

This equation can be used for other atoms than hydrogen right?

brennayoung

I know he said 720 to 400 but 700 was acceptable but wouldn't that change the calculations?

brennayoung

In my discussion we dont really use dimensional analysis per say so I would think as long as you display some work it would be fine.

brennayoung

This was very interesting, thank you for sharing!

brennayoung

For my final answer I got down to (2.12x10^5) / (6.022x10^23) = 3.52x10^-17 % but does this mean that there is no money left since its a negative exponent or just that its a very small amount? And if its a very small amount how would one know like it in whole numbers as opposed to as a percentage of...

brennayoung

I don't fully understand why they did their unit conversions as such, or how we knew to convert it to atoms at all. Thanks!

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