CHEMISTRY COMMUNITY

Nare Arakelian Dis 3E

Someone said this Friday at 5 but I am not sure how accurate that it

Nare Arakelian Dis 3E

and also how to switch majors

Nare Arakelian Dis 3E

Does anyone know when we will get our scores back

Nare Arakelian Dis 3E

I have been wondering this too. All I know is 250/500 is considered a C- and then I think he is just gonna wait to see how the final average comes out and figure out the curve then

Nare Arakelian Dis 3E

for pH, the number of digits after the decimal point equates to the total number of sig figs for the concentration

Nare Arakelian Dis 3E

This is amazing

Nare Arakelian Dis 3E

the stoichiometric point is when the moles of acid equals the moles of base, and knowing the volume and moles this can be used to calculate teh concentration and then the pH

Nare Arakelian Dis 3E

Thank you for explaining , I was confused on this topic as well

Nare Arakelian Dis 3E

The oxidation number comes after the metal atom in parenthesis

Nare Arakelian Dis 3E

Does it involve ligands that are polydentates? and is cisplatin a chelate?

Nare Arakelian Dis 3E

I think just a general sense of what it means in relation to bond strength and strength. So a bond order of 3, or a triple bond, is shorter and stronger than a bond order of 2, or a double bond

Nare Arakelian Dis 3E

You use brackets to indicate what is inside the coordination sphere, or what is directly touching the central metal atom

Nare Arakelian Dis 3E

I was confused on this too, thank you!

Nare Arakelian Dis 3E

Ion- ion forces > ion-dipole forces > dipole-dipole > dipole - induced dipole > induced dipole -induced dipole. And then hydrogen bonds are basically just really strong dipole-dipole forces

Nare Arakelian Dis 3E

A double bond has a bond order of 2, a triple bond has a bond order of 3, etc...

Nare Arakelian Dis 3E

a ligand is an electron dense molecule

Nare Arakelian Dis 3E

A sigma bond is a single bond and a double bond has one sigma and one pi bond

Nare Arakelian Dis 3E

Why is knowing the number of regions of electron density necessary when naming a molecule? The number of regions of electron density affect the shape of the molecule, but the naming of the molecule comes from only the bonded atoms, not the lone pairs. So if a molecule has 4 regions of electron dens...

Nare Arakelian Dis 3E

Thank you so much!

Nare Arakelian Dis 3E

Lauren Sanchez 3D wrote:So if there are only two areas of electron density, that is when they are opposite of each other due to the strong repulsion?

Yes, I believe so because this minimizes the repulsions by putting the lone pairs farthest away from each other

Nare Arakelian Dis 3E

Does anyone have any tips or tricks for remembering the angles for each shape?

Nare Arakelian Dis 3E

If a molecule, like NH3 for example, has a hydrogen bonded to an electronegative element does this mean there is hydrogen bonding? or does this hydrogen then have to be bonded to another electronegative atom in order for it to be a hydrogen bond?

Nare Arakelian Dis 3E

do we need to know this for the test?

Nare Arakelian Dis 3E

EvanWang wrote:Covalent bonds occur between two nonmentals, while ionic bonds occur between a metal and a nonmetal.

does this infer that polar and ionic are interchangeable? You have me a little confused.

Nare Arakelian Dis 3E

It's a bond where both electrons come from one atom, completing the octet of an atom existing in a compound with an incomplete one. The example provided in class and in the textbook was that of boron trifluoride BF3, and boron has only six valence electrons. Its octet is completed when it forms a c...

Nare Arakelian Dis 3E

Thank you guys for answering! This cleared up a lot for me!

Nare Arakelian Dis 3E

It's never been explicitly expressed, so I'm assuming that sig figs won't have any effect on grading on the test, but maybe I just missed when they said that. Are sig figs taken into account with points when grading?

Nare Arakelian Dis 3E

aww that's a bummer... we just gotta grind hard boys

Nare Arakelian Dis 3E

Polarizability is the ability of an atom to have a distorted electron cloud. These are usually anions, and the larger they are the more likely it is for their electrons to be on one side at a moment in time. Polarizing power is the ability of an atom to induce this dipole moment and distort the elec...

Nare Arakelian Dis 3E

Shorter bond lengths are stronger because the distance between the atoms is smaller so they are pulling more tightly on each other, leading to a stronger bond. The longer the bond length and greater the distance between the two atoms, the weaker the nuclear force is holding these atoms together and ...

Nare Arakelian Dis 3E

Radicals occur when there is an odd number of valence electrons, so there will be one unpaired electron. CH3 for example has 7 valence electrons so in the lewis structure there will only be one lone electron on the carbon. I think we just have to know what they are and how to identify them. Just bec...

Nare Arakelian Dis 3E

I think just with an arrow pointing towards the molecule with the partial negative charge

Nare Arakelian Dis 3E

Do the halogens like fluorine and chlorine never form double bonds in lewis structures?

Nare Arakelian Dis 3E

Why are Phosphorus, Chlorine, and Sulfur exceptions to the octet rule when their electron configurations do not have a 3d orbital? Is it just because they are in the third energy level?

Nare Arakelian Dis 3E

Do we want to make it so that the central atom has a formal charge of zero?

Nare Arakelian Dis 3E

Sulfur, phosphorous, and chlorine are examples of an expanded octet because starting in this row, these atoms have a d orbital which can hold extra electrons. In the normal state, they are not usually all filled so when it comes time to share electrons they are able to store more in the d orbital. H...

Nare Arakelian Dis 3E

They are different concepts I believe. Shielding occurs when the inner electrons block the outer electrons from the nuclear positive charge, which makes the outer electrons easier to remove. I would use this as a justification for ionization energy, but not atomic radius. Electron electron repulsion...

Nare Arakelian Dis 3E

I think chemical bonds

Nare Arakelian Dis 3E

Double bond lengths are shorter than single bond lengths because double bonds are stronger, which means the force between the two atoms is going to increase, pulling them closer to each other. It would require more energy to break a double bond for this reason, because the atoms are closer together ...

Nare Arakelian Dis 3E

So if an atom's electron configuration breaks one of the rules, like Hund's rule or Pauli exclusion principle, that means it is not in ground state but in excited state

Nare Arakelian Dis 3E

Why is 3d at a lower energy level than 4s?

Nare Arakelian Dis 3E

yess! my email is narkeli17@gmail.com

Nare Arakelian Dis 3E

Is the work function the same as the ionization energy then?

Nare Arakelian Dis 3E

For p-orbitals, for example, it is unlikely to be near the nucleus because they have a nodal plane at the nucleus which means there is zero probability of finding an electron there. Due to the fact that p-orbitals, unlike s-orbitals, have angular momentum which pushes the electron away from the nucl...

Nare Arakelian Dis 3E

So would it be correct to say that there are 3 p subshells in each shell or energy level?

Nare Arakelian Dis 3E

Why do electron-electron repulsions lead to 3d having higher energy?

Nare Arakelian Dis 3E

The problem could just be asking to compare the ionization energies of two elements and state which is larger. The energy of a photon = ionization energy plus the kinetic energy so the value of the ionization energy could also be used here for a photoelectric effect problem.

Nare Arakelian Dis 3E

Are they only the same when the kinetic energy is zero? Or does this not matter

Nare Arakelian Dis 3E

I think I'm still struggling with grasping the difference between diffraction and interference. Can someone please explain?

Nare Arakelian Dis 3E

When waves encounter a barrier, like a wall, with small slits or openings, the waves will spread out past the openings and create these patterns as they interfere with one another. This is my understanding, I hope it helped!

Nare Arakelian Dis 3E

Arianna Perea 3H wrote:Are diffractions only analyzed through the peaks of waves?

I think so because in order to analyze the interference patterns, you can look at the peaks of the waves to see if they are getting narrower, larger, etc.

Nare Arakelian Dis 3E

I am still kind of confused on why the kinetic energy does not change if the light intensity increases. Can someone please explain? Thanks!

Nare Arakelian Dis 3E

To prepare a fertilizer solution, a florist dilutes 1.0 L of 0.20 m NH4NO3(aq) by adding 3.0 L of water. The florist then adds 100. mL of the diluted solution to each plant. How many moles of nitrogen atoms will each plant receive? Solve this exercise without using a calculator. I used M1V1=M2V2 to ...

Nare Arakelian Dis 3E

For E21a) in particular, you're converting 0.0981 moles of Al2O3 into molecules because Al2O3 is a molecular compound. If you were dealing with an element, however, like Al, you would be converting into atoms. In both cases though, you would use Avogadro's number to convert. I was a bit confused on...

Nare Arakelian Dis 3E

So with adding and subtracting is the rule that the answer should have the same number of decimal places as the number with the least decimal places or should have the same number of sig figs overall as the number with the least number of decimal places?

Nare Arakelian Dis 3E

I think everything is right up until the point where you convert 0.0406 moles O2 to grams of P4010. To get 5.77 grams, I multiplied 0.0406 moles O2 ( 1 mole P4O10 / 2 moles O2) (283.89 g / 1 mole). I think you just multiplied by 2 moles of O2 instead of dividing. Hope this helps!

Nare Arakelian Dis 3E

And the same applies for rounding down, right? For example, if after dividing I get 2.067 I can safely round down to 2

Nare Arakelian Dis 3E

Thank you so much for sharing your experience! I know getting letters of recommendation is a part of the application process, and I was wondering if you had any advice on how to get close and comfortable enough with professors to ask for a letter? I am also not 100% sure I want to follow this path a...

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