CHEMISTRY COMMUNITY

Isaias Gomez D3A

Yes, you can disregard. Another way is to work through and compare the concentrations at the end to check how close the % concentrations are.

Isaias Gomez D3A

memorize the list of those listed, that way you could classify all others as not.

Isaias Gomez D3A

depends on the initial concentrations given and whether it is a product or reactant. The products get +x and reactants get -x.

Isaias Gomez D3A

Pretty much :) just a change in its state of matter: gas, liquid, or solid.

Isaias Gomez D3A

Yes! since its asking for the weak base :)

Isaias Gomez D3A

k won't change unless temperature changes

Isaias Gomez D3A

After a while it will be easier to notice which is correct. If there is a negative, then we can rule that one out, but if not then it can get easier to tell by looking at how high or low the values are. Number 10 on sapling is a good example, since both possible values of x were positive, but it was...

Isaias Gomez D3A

honestly I think just studying them over and over is the only way, I had the same question at first :/

Isaias Gomez D3A

I found that its definitely a lot easier to make them as so, otherwise conversions might have to be done after.

Isaias Gomez D3A

the ice table helps a lot, when setting up the ice table just make sure to add 1.0 to the initial for 2NO2

Isaias Gomez D3A

Pressure and volume are inversely proportional.

Isaias Gomez D3A

The coefficient of 2 in front of S03 must be accounted for by being multiplied.

Isaias Gomez D3A

Quotient starts with Q. Thats what Q is, while K is the constant

Isaias Gomez D3A

When a reaction is reversed, K -> 1/K

just the inverse :)

Isaias Gomez D3A

Conceptually, are concentration and pressure basically the same thing, just for different states? Pressure is just used for gas, but they are the same when calculating?

Isaias Gomez D3A

It requires some thinking about the different parts. In different cases it will be able to both donate and receive, you just have to picture different combos.

Isaias Gomez D3A

A Strong Acid + a Strong Base = a neutral salt

A Strong Acid + a Weak Base = a acidic salt

A Strong Base + a Weak Acid = a basic salt

Isaias Gomez D3A

the overall charge minus any known charges should give you oxidation number.

Isaias Gomez D3A

correct, from my understanding :) and very useful, thank you!

Isaias Gomez D3A

yes, it is by the strength of the acids and bases, the stronger the base, the higher the ph.

Isaias Gomez D3A

How does one determine the common geometries for a certain coordination number? We can obviously rule out which geometries are impossible based on the coordination number, but how can we figure out which are most common out of those possible?

Isaias Gomez D3A

I really hope not, but I would assume things like that would be given to us.

Isaias Gomez D3A

Honestly, for some common ones seen often it might be helpful to use some flashcards to memorize them.

Isaias Gomez D3A

Well we know that Chlorine has a charge of -1 and there are 3 of them, giving us a charge of -3 from the Chlorines. We also know that NH3 is neutral meaning it has a charge of 0. If the whole compound has a neutral charge overall, that means Co must have a charge of +3 to cancel out the -3 from the ...

Isaias Gomez D3A

It helps if your first step is to disregard any known neutral parts of the compound.

Isaias Gomez D3A

Here is a link to one: https://web.gccaz.edu/~chriy68124/VSEPR%20handout.pdf :)

Isaias Gomez D3A

When I think of a delocalized pi bond, I think of pi bonds that could move around depending on which resonance structure is used. In a situation where a double bond can be placed in three different spots, there is a possible delocalized pi bond, since there are different possible locations for the b...

Isaias Gomez D3A

A single bond consists of one sigma bond, a double bond consists of one sigma and one pi bond, and a triple bond consists of one sigma bond and two pi bonds.

Isaias Gomez D3A

Honestly, for me it was just attempting different formations and checking to see if it worked. I just moved around the bonds till I found three possible ones that worked.

Isaias Gomez D3A

yes, simply add up the atoms and lone pairs attached to find hybridization. This YouTube video helped me: https://youtu.be/4xl0BD-tMeA

Isaias Gomez D3A

The more negative, the more repulsion. The way I think of it is by picturing the VSEPR model. The pole that repels the most is the most negative.

Isaias Gomez D3A

A bond between two identical atoms would be non polar

Isaias Gomez D3A

How does one determine the bond angles present, if the VSEPR model only provides qualitative distortions?

Isaias Gomez D3A

Does the presence of lone pairs play a part in the molecular shape, or can they be ignored when asked for the shape of a molecule?

Isaias Gomez D3A

For clarification, the presence of double and triple bonds instead of single bonds will not affect the molecular shape of the molecule?

Isaias Gomez D3A

Once you draw the Lewis Structure, determine the electron groups to figure out whether they are linear (2 groups), trigonal (3), tetrahedral (4), trigonal-bipyramidal (5), octahedral (6).

Isaias Gomez D3A

You can look at the differences in electronegativity. Lavelle showed us a periodic table with numbers to compare as a helpful tool during one of his lectures, although I can not remember which one.

Isaias Gomez D3A

With delocalized pi bonds, the electrons are able to move over the nuclei.

Isaias Gomez D3A

That is correct, and it should also be the only possible way to be drawn/structured?

Isaias Gomez D3A

It indeed means there can be more than four bonds. It all depends on the element and the bonding element.

Isaias Gomez D3A

To have some covalent character would mean partial sharing of electrons between atoms of an ionic bond.

Isaias Gomez D3A

The more stable the structure is, the more it contributes to the resonance hybrid, and the lower the formal charge, the more stable.

Isaias Gomez D3A

Carbon dioxide acts as a Lewis acid because the positive carbon atom center Is able to attract and accept the lone pair of electrons pairs in the oxide ion.

Isaias Gomez D3A

Basically the bases are those who give, and the acids receive the pairs of electrons.

Isaias Gomez D3A

Organic Chemistry tutor on YouTube posts some really great explanation videos! They've helped me out a lot. Just search up that channel on YouTube or you could even search up a specific topic followed by "organic chem tutor" and im sure the channel has something on it.

Isaias Gomez D3A

Hi! So, I understand that the fourth quantum number gives us the spin of the electron in the outer shell, and I understand why no two electrons in the same atom can have the same 4 quantum numbers, but what I don't understand is why the knowing the 4th quantum number is useful in any way. Is there s...

Isaias Gomez D3A

well, the energy of the photons that you calculated minus the threshold energy (work function) equals the kinetic energy of the emitted electrons. So you can find the threshold energy by simply subtracting the kinetic energy of the electrons (given) from the energy of the photons (calculated).

Isaias Gomez D3A

Basically, if the photoelectric effect is the cause of the sparks, that means that the energy per photon would have had to exceed the threshold energy (work function). Once you figure out the first part, you should then find the energy of the microwaves using its frequency or wavelength and compare ...

Isaias Gomez D3A

It really depends on the context of the problem. If its an emission, then n2 will be smaller and vice versa.

Isaias Gomez D3A

Once given the wavelength, you should be able to figure out whether it belongs to the Lyman or Balmer series. For example, if the wavelength belongs to one from the visible light spectrum, then it is the Balmer series, meaning n2 should be 2. If in Lyman's series, n2 is 1

Isaias Gomez D3A

i believe it is valid to switch the n final and n initial, because i think that term represents the difference between the two, so it should matter. I would do the higher one minus the lower one to ensure a positive answer.

Isaias Gomez D3A

I dont believe we have to have all that memorized, but just incase i suppose it might be sufficient enough to just memorize that of the first (red) and the last (violet). Definitely know that the visible light region is Balmers series, and the ultraviolet region is lymans series.

Isaias Gomez D3A

I doubt that would ever be on a test without the conversion factor, but my paranoid self memorized that one mile is about 1609 meters. So if given miles just multiply that by 1609 to get meters, then dont forget to change the hours to seconds.

Isaias Gomez D3A

I suppose the best thing to keep in mind is that the Balmer series is the visible light region, and the Lyman series is the ultraviolet region.

Isaias Gomez D3A

Did you convert the units into ev after finding the energy per photon? There are 2 possible units for energy in this problem, so that might be the problem.

Isaias Gomez D3A

I asked a similar question earlier and this response by Eva Becker helped: "Scientific notation can be used whenever you deem necessary. My past chem teachers have said that as a rule of thumb, scientific notation should be used from 10^-3 or smaller (10^-4, 10^-5, etc.) and from 10^3 or larger...

Isaias Gomez D3A

In a situation such as an ionic bond between atoms, one atom gains an electron while another loses one. In this case, the electron is transferred to the other atom and is lost.

Isaias Gomez D3A

They can display both constructive and destructive interference. In a situation where electrons come together and are in phase with each other, constructive interference will occur, while electrons that come together and are out of phase with each other will display destructive interference. It all ...

Isaias Gomez D3A

Once you have the moles of reactants, you should then figure out which is the limiting reactant by comparing mole ratios. Once you have the limiting reactant figured out, you are left with excess moles of the other reactant. At this point, you should multiple the amount of moles left over by the mol...

Isaias Gomez D3A

So I am a bit confused on why we set kinetic energy equal to 0 in some of the problems. Is this ONLY when no electrons are emitted? Also, this is only possible when the energy of the photons are equal to the work function correct?

Isaias Gomez D3A

All of your steps are correct so far, and although we don't have the same numbers, my steps match yours. Now all you have to do is find the molar mass of the product its asking for, in this case 3-methyl-3-hexanol, and multiply that molar mass by the number of moles you got in the previous step to f...

Isaias Gomez D3A

I see, that makes sense. Thank you for the help ! :)

Isaias Gomez D3A

Noted, Thank you all!

Isaias Gomez D3A

In some of the practice problems there are symbols showing ionization such as 2+ or a - sign. When calculating molarity, it doesn't seem to affect the result, but what exactly does this mean and in what context will that actually matter in terms of finding answer solutions?

Isaias Gomez D3A

I noticed that in some of the answers to practice problems, the solutions are in scientific notation, but for other solutions, the answers aren’t in scientific notation. Are there certain scenarios to when we use them, or does it not matter. For example, one answer can be listed as .055 grams and th...

Isaias Gomez D3A

As I was completing the fundamental practice problems, I noticed that the terms for "molecules" and "formula units" are used interchangeably. Are they referring to the same thing, or is there a difference in context? If so, what is that difference.

Isaias Gomez D3A

Are there any helpful tips that will help ease up conversion processes? (Such as from picometers to kilometers). As odd as it sounds, I have the most trouble doing the simplest tasks such as converting units. Also, when doing calculations, does it matter where along the process the unit conversion i...

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