CHEMISTRY COMMUNITY

Khushboo_3D

I think knowing the concepts behind bronzed acids and bases as well as lewis acids and bases is also important.

Khushboo_3D

It basically asks you the coordination number that is the number of points at which ligands are attached to the central metal atom. For instance, the coordination number for part a would be 4 and so on

Khushboo_3D

What helped me the most was going to the workshop sessions which go over specific concepts in detail and also assign problems.

Khushboo_3D

All the ligands that are directly attached to the central metal atom are part of the coordination sphere.

Khushboo_3D

They will go over the solutions of the final on Friday from 7:30-10pm!

Khushboo_3D

I think he said conjugate bases of weak acids affect the ph of a solution.

Khushboo_3D

If you were given a Hydrogen concentration of [H+]=0.1M, for example, and asked to find the pH, you would plug the concentration into the formula pH=-log[H+]; pH=-log[0.1M], and just plug it into your calculator. So would our answer just be 1? Also, would this be interpreted as our pH being 1? This...

Khushboo_3D

The second bond formed as a result of an unhybridized orbital would be a pi- bond.

Khushboo_3D

Another important rule to remember is that, If the ligand name already contains prefixes such as di-, tri-, etc. (as in ethylene diamine) or if it is a polydentate then the prefixes bis-, tris-, tetrakis-, pentakis- are used.

Khushboo_3D

EDTA is an important example for a chelating ligand.

Khushboo_3D

EDTA- Ethylene Diamine Tetra Acetate is an example of a chelating ligand.

Khushboo_3D

The presence of a lone pair is what makes it polar.

Khushboo_3D

The main reason is because sigma bonds are formed when orbitals overlap end-to-end and pi bonds are formed when orbitals overlap side- by -side. This therefore, makes it difficult for pi bonds to rotate since they would break if rotated.

Khushboo_3D

In addition to the previous answer, the bond angle for linear would be 180 degrees and for tetrahedral will be 109.5 degrees

Khushboo_3D

H2O will have the highest boiling point due to hydrogen bonding. For the remaining 3 compounds we consider London forces, which depends on the size of the atom. In this case, atoms grow bigger as we go down a group and so Te will be bigger than Se which will be bigger than S. Therefore of the remain...

Khushboo_3D

Yes, it is better to know both since they were both covered in lecture.

Khushboo_3D

Not really, the example that Doctor Lavelle gave in class of dichloro-ethane. In this case, the cis-dichloroethane will be polar since the dipole moments do not cancel. However, in case of trans-dichloroethane- it is non-polar since the dipole moments cancel each other.

Khushboo_3D

According to the VSEPR theory, lone pairs of electrons repel each other and therefore should be placed as far apart from each other as possible, thus impacting shape of the molecule. The textbook also states it precisely as, "Lone pairs distort the shape of a molecule so as to reduce lone pair–...

Khushboo_3D

This is because of the increase in number of electrons shared. Precisely, the textbook defines the reason as, "A multiple bond is almost always stronger than a single bond because more electrons bind the multiply bonded atoms."
Hope that helps

Khushboo_3D

In the textbook it states that, "When a small, highly charged cation is close to a large anion, the electron cloud of the anion is distorted in the process we call polarization." This implies that the anion is polarizable while the cation should have the polarizing power. Smaller atoms wit...

Khushboo_3D

I think we have studied only about two types of chemical bonds that is covalent and ionic. Ionic bonds results from the transfer of electrons between two atoms while covalent bonds result from the sharing of electrons between two atoms. I do not know about the third kind of bonds.

Khushboo_3D

According to my understanding of it, the Lewis structure tells us about the electronic structure of an atom, it tells us about about bond lengths, bond strengths etc.
The VSEPR model tells us about the molecular geometry- that is the shape of the molecule.

Khushboo_3D

I also think this might appear when Dr Lavelle begins to discuss the shape of molecules and structures in class.

Khushboo_3D

Atoms like Boron and Aluminum are also exceptions, since they can accommodate only 6 electrons in their valence shell.

Khushboo_3D

He has also posted a similar sheet on his website under "Constants and Equations" in case you need to use it for practice problems!

Khushboo_3D

An example of this can be oxygen I think, because it has 2 unpaired electrons in its valence shell. The textbook also defines radicals as any species having unpaired spins.

Khushboo_3D

I think he said there would be 8 questions on the midterm.

Khushboo_3D

It covers upto and including focus 2D in chemical bonds.

Khushboo_3D

I think Dr Lavelle sent out an email about Sapling learning which is an online resource, and he has created multiple assignments and objectives on those. I hope that helps!

Khushboo_3D

One of the UA's at yesterday's workshop said that it would be till whatever he covers this week, but he would definitely let us know in class sometime during this week.

Khushboo_3D

In addition to the previous reply, after getting the frequency you need to use speed of light= frequency times wavelength to obtain the wavelength since that is what we are precisely asked for.

Khushboo_3D

I think it might refer to the number of bonds, but I'm not entirely sure.

Khushboo_3D

I am not sure if all the midterm review sessions cover the exact same materials or problems since they might be conducted by different UA's or TA's. However, the broad topics covered should be the same, only the specifics might differ.

Khushboo_3D

Put simply, there are only two types of trends we observe. Atomic radius which increases down a group and decreases across a period from left to right. The remaining three that is electronegativity, electron affinity, and ionization energy decrease down a group, and increase across a period from lef...

Khushboo_3D

For this question, to begin with you would use the equation E= h times frequency, so convert the given frequency in terms of energy. This is the change in energy, that is the amount of energy emitted when an electron jumps from a higher energy level to a lower one. This change in energy= energy fina...

Khushboo_3D

I think attending the workshops too would be helpful since they sort of summarize what has been done in lecture.

Khushboo_3D

Professor Lavelle mentioned that the quantum unit would be a couple of weeks long. And since we haven't already begun chemical bonds, I think this weeks homework should be from the quantum unit too.

Khushboo_3D

He also defined electron affinity in class as the difference between the energy of the neutral atom and energy of the cation.

Khushboo_3D

I also feel that on the midterm or final we would only be tested on s, p, and d orbitals since those are mainly what he covered in class.

Khushboo_3D

The reason for this is the difference in energies. According to Aufbau's principle, the 4s shell has a lower energy than the 3d shell and hence it gets filled first.

Khushboo_3D

In this case, I guess such an answer would be unreasonable or not possible because there is nothing that can have a speed greater than that of light.

Khushboo_3D

Even the workshops are really helpful to review the material learnt. Also, there are review sessions before the midterm so I think that would help too.
Good Luck!

Khushboo_3D

Momentum- p has units kg m/s

Khushboo_3D

The whole idea behind bringing momentum into the picture is to emphasize the fact that an uncertainty in velocity results in an uncertainty in momentum, since we know the mass of the object and it does not change. Moreover, we need the change in momentum to calculate the uncertainty because, accordi...

Khushboo_3D

Could please elaborate what you exactly mean by "energy of a particle?"

Khushboo_3D

You would have a negative sign when energy is emitted- electron moves from. higher to lower energy level- and a positive sign when energy is absorbed- electron moves from lower to higher energy level.

Khushboo_3D

On his website, it also says that the midterm will be held from 6-8pm on Wednesday, November 6th. So it will not be held during lecture I guess.

Khushboo_3D

Just as a reminder, v can also represent velocity so one should be careful while using the variable in an equation.

Khushboo_3D

I find the workshops to be most effective, since the UA's make a worksheet relating to the material taught in class which serves as a good test for the material learnt.

Khushboo_3D

To convert 400 nm to Angstroms, you would first convert it to meters by multiplying it by 10^-9. This would give you the answer in meters. Now you would convert it to angstrom. You would do this by dividing by 10^-10. This would give you the answer in Angstrom which should be 4000A.

Khushboo_3D

You would round up to 64%. This because when number ends in 5, you would round it up to the closest even number according to the rule.

Khushboo_3D

You can use De Broglie's equation to find the wavelength of anything hat has a rest mass. For example, an electron has a rest mass. However, light does not have a rest mass and so you cannot use De Broglie's equation to find its wavelength eve though the derivation we did in class involved light.

Khushboo_3D

It depends on what's given to us. Usually to find the percent yield you would need the actual yield. Through limiting reaction problems, you can usually only find the theoretical yield.

Khushboo_3D

Accuracy is its closeness of measurements to the true value. While, precision is the closeness of measurements to each other. The reason why it was mentioned is that, it is more important to be precise than be accurate with your measurements, especially in a lab.

Khushboo_3D

You have to multiply Avogadro's number with the diameter of the atoms which would be ( two times 144pm= 288pm) and also convert the diameter to meters by multiplying it by (10 to the power of negative 12). Once you multiply these three figures, you should get the answer.

Khushboo_3D

You do not proceed that way, because you can easily find the molecular formula by looking at the structure given to us. We know that dark gray corresponds to carbon, white to hydrogen, and red to oxygen hence you simply count the respective number of atoms for each from the diagram and that gives yo...

Khushboo_3D

Khan Academy seems like a good option.

Khushboo_3D

The reactant that is present in lesser quantity, that is the limiting reagent determines the quantity of the product formed. This is because, the reaction would come to a stop once once one of the reactants is completely used up, hence it is important to know which reactant is in lesser quantity bec...

Khushboo_3D

The theoretical yield is also known as the maximum yield or the best-case scenario yield.

Khushboo_3D

Next week in discussion I think

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