CHEMISTRY COMMUNITY

TYun_1C

How do you determine if a coordination compound is a chelate when you're only given the chemical formula, like in mini marshmallow #2?

TYun_1C

Recall that hydrogen bonds can form when a hydrogen that is bonded to a Nitrogen, Oxygen, or Fluorine is strongly attracted to a Nitrogen, Oxygen, or Fluorine with a lone pair. In problems where it asks you to find how many hydrogen bonding sites there are, you should look for the hydrogens bonded ...

TYun_1C

How do you determine the number of hydrogen bonding sites? Like the last question on test 2 or 41.d of the marshmallow practice test?

TYun_1C

How exactly do you determine what dentate a ligand is?

TYun_1C

it is given for a weak acid because we assume that strong acids are 100% dissociable

TYun_1C

ion-dipole is stronger than hydrogen bonding but hydrogen bonding is the strongest of the covalent intermolecular forces

TYun_1C

Sigma bonds are stronger because they overlap to a larger extent than a pi bond.

TYun_1C

Will we be getting the sheet for the ligand names and their charges on the exam? I cannot remember if Dr. Lavelle mentioned it. Thank you!

TYun_1C

The transition metal and all its ligands are contained in the coordination sphere and should be put in brackets.

TYun_1C

Sigma bonds are bonded to a greater extent because the orbitals are overlapping each other. This increased surface area of the bond makes it stronger than the side to side pi bonds.

TYun_1C

No, I believe Dr.Lavelle does not bruincast his lectures.

TYun_1C

Same!! I owe you my life. My email is tinayun0505@gmail.com

TYun_1C

Non polar molecules have dipole moments which are the same magnitude but different directions. Looking at the molecular shapes for non polar molecules, it seems that all of them are symmetrical.

TYun_1C

Bronsted acids and bases deal with the donation and acceptance of a hydrogen ion. Lewis acids and bases deal with the donation and acceptance of an electron. I'm not completely sure about Arrhenius acids and bases but I think it has something to do with hydroxide ions.

TYun_1C

Thank you everyone for the clarifications!!

TYun_1C

Michael Jackson be like....
atomic #2, atomic #2
(He He)

TYun_1C

In an acid base reaction, the bronsted acid will donate the H+ to the bronsted base.

TYun_1C

The coordination sphere consists of the ligands attached to the central ion.

TYun_1C

Also, is dipole induced- dipole induced the weakest intermolecular force?

TYun_1C

Can somebody please give me an example of a dipole induced- dipole induced force? Is it always between two non polar molecules? I wrote in my notes that it is present in all molecules.
Thank you!

TYun_1C

There are many different structures that contain lone pairs. They are not only a bent shape-- this is the shape for a molecule with 2 bonds and one lone pair. It is a good idea to think that lone pairs will generally push the bonded atom away from it due to the fact that it takes up space but also b...

TYun_1C

Yes, out of the intermolecular forces for molecules, hydrogen bonding is the strongest.

TYun_1C

Dr. Lavelle uses the terms dipole-dipole, LDF, and van der waals forces interchangeably. In high school I was taught the difference between these forces and was responsible for naming the most prominent kind of intermolecular force in a certain molecule. In this class, do we just consider them inter...

TYun_1C

Another things that helps is knowing that carbon is “happy” with 4 bonds, nitrogen with 3, oxygen with 2 and fluorine with 1. Meaning that when these elements have these number of bonds, they have a formal charge of zero.

TYun_1C

I think the key of the question is that after you have to remember that the hydrocarbon you are solving for has oxygen. In other words, after solving for the moles of all other elements, you must convert these into grams, add the grams up, and subtract from the total grams to find the grams of oxyge...

TYun_1C

In hydrogen bonding there is a hydrogen bonded to either N,O,F. These are some of the most electronegative elements in the periodic table and therefore have great polarizing powers, making their bond with hydrogen very strong.

TYun_1C

Chemistry majors be like I got a chemistry community due this Friday

TYun_1C

And a half filled shell is more stable than one that is half filled with an extra electron (regarding ionization energy etc.).

TYun_1C

I believe for anything to do with electrons and electron emission I think he wants us to use this one En = - h R/n^2 . This is what is on the constants and equations sheet. Yes use this equation and do energy of the final minus energy of the initial to solve for the amount of energy emitted/ absorb...

TYun_1C

nicole-4d wrote:A neutron walks into a bar. He asks the bartender, "How much for a beer?"
The bartender gives him a smile and says, "For you, no charge"

hahahhaha this one made me chuckle

TYun_1C

I don't think we would be responsible for the exact cut offs for the types of radiation but I would just make sure to know the wavelength region for visible light (400-700) and the regions for infrared and UV radiation.

TYun_1C

The half filled shell is more stable because with 4 electrons, there is electron to electron repulsion in the first orbital, making the electron easier to remove.

TYun_1C

The 3d orbital is not used by these atoms normally, but remains open to be used when bonding. After the 3s and 3p orbitals fill up, the 3D can be used to hold extra electrons during bonding.

TYun_1C

Brackets are used when citing the electron configuration in the shorthand. You only list the outer orbitals after the last noble gas. You start with the next s orbital after that noble gas.

TYun_1C

Thank you everyone for the clarification!!

TYun_1C

Since noble gases already have filled octets, they are extremely stable and do not want it gain another electron, which would make it much more unstable. Therefore, there is almost zero energy released (electron affinity) when an electron is added to a ground state noble gas,

TYun_1C

I don't think you have to be super meticulous about the angels of the atoms, just the general area would be sufficient. Just remember to place atoms in the way that they are attracted to each other, like the anion next to the cation and not the cation next to the cation or the anion next tot he anio...

TYun_1C

That you for the clarification, it helped a lot! If anyone could explain the zero density stuff, it'd be very helpful. Thank you!

TYun_1C

I'm not sure as to why they would place the electrons like that, but I would guess that it is in the ground state. Since theres still 4 electrons total, the atom would have a neutral +0 charge since the nucleus is +4 and the electrons are -4. Because of the neutral charge, I would assume it to be in...

TYun_1C

Though I'm not sure about the derivation of this equation/inequality, the essence of what it is trying to convey is that the more we know about momentum, the less we know about position and vice versa. In other words, we must sacrifice one or the other to obtain accuracy in one. Hope this helps!

TYun_1C

Whenever a electron goes from a higher energy state to a lower one the electron's energy has decreased and the energy is released as electromagnetic radiation, so we use the negative sign to describe the change in energy. This can be calculated through E=-hR/n^2 and delta E= Ef-Ei. Hope this helps!!

TYun_1C

I'm having some trouble with some of the topics discussed today in lecture. What does Professor Lavelle mean when he says that p- and d- orbitals have nodal planes and therefore have zero e- density and non-symmetric e- distributions? He also mentioned that s- orbitals have no nodal planes so they h...

TYun_1C

You should use the M initial * v initial = M final * v final. However, that question seems kinda weird because we are solving for initial volume and have the initial molarity and final molarity but no final volume. They need to specify what the final volume of the solution is, so we can properly sol...

TYun_1C

Diffraction patterns prove wavelike properties because it shows that the particles are moving around instead of shooting straight forward. Therefore, this example proves that neutrons have wavelike properties.

TYun_1C

Looking at the speed of light equation, as the wavelength increases, the frequency increases. Seeing that higher frequency light can eject electrons while higher intensity light cannot, this proves the photon properties of light.

TYun_1C

I dont't personally draw out the energy levels, but it might help to do so to figure out which is the inital energy level and which the final. This way you don't get confused when you subtract the energies. Hope this helps!

TYun_1C

Yes, if the masses are the same, you would get 1 when you divide the two masses; therefore, the empirical formula or the lowest whole number ratio is the molecular formula.

TYun_1C

Theoretically, you could multiply the percent by the molecular weight since every element would still be in the same ratio, but it would just add an extra step to the calculation. It's usually easier to just assume that the sample is 100 grams since the percentages are portioned out of 100. Even if ...

TYun_1C

I'm also pretty rusty on nomenclature right now! Though I don't think we will be held responsible for naming on upcoming tests, I would recommend reviewing the common polyatomic ions and their charges as well as the charges for the transition metals (ferric vs ferrous etc.). Also, the common rule is...

TYun_1C

Just assume that the sample is 100 grams and turn all the percents into grams. From there you can convert the grams of elements into moles then divide all the moles by the smallest number of moles. This will give you a relative ratio of each element within the compound. Since the empirical formula i...

TYun_1C

It would be impossible to have an actual yield greater than the theoretical yield if you used the current amount of reactants. Due to the law of conservation of mass, the amount of products made should be equal to the amount of reactants. However, this is an extremely idealized situation and in a re...

TYun_1C

Remember that Na2Co3 will dissociate in a ratio of two Na+ ions to one CO3 polyatomic ion. That way, you know that in a certain molarity sodium carbonate solution, the concentration of pure Na+ ions is doubled. Use the M initial x V initial = M final x V final equation of find the volume needed of o...

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