CHEMISTRY COMMUNITY

Joanne Kang 3I

Paige Lee 1D wrote:For #1c on mini marshmallow, how do you know to choose NH4+ and not NO3- for the net ionic equation? Since they're both weak acids and bases

NO3- is the conjugate base of a STRONG acid, so NO3- is very stable/does not affect the pH.
The only thing affecting pH then would be NH4+ producing H3O+

Joanne Kang 3I

For mini marshmallows 2b, why is the coordination number 4?

Joanne Kang 3I

Ashley Osorio wrote:How would one phrase number 36C?? Also, 36B is both Amphoteric and amphiprotic, right?

Yes.

Joanne Kang 3I

min marshmallows 1c... why isn't it neutral?

Joanne Kang 3I

The two strands of the nucleic acid DNA are held together by hydrogen bonding between four organic bases. The structure of one of these bases, thymine, is shown below. (a) How many protons can this base accept? Why can't the Oxygen molecules be proton acceptors as well? They have lone pairs https://...

Joanne Kang 3I

Why is KF basic while KBr neutral even though both anions are in the same group?

Joanne Kang 3I

Suggest an explanation for the different strengths of (b) acetic acid and formic acid.
Can someone please explain the answer to this? Thank u!

Joanne Kang 3I

3d. Use the information in Table 9C.1 to write the formula for each of the following coordination compounds:
d. sodium bisoxalato(diaqua)ferrate(III)
I left my solutions manual at ucla.. What is the answer to this question? Thanku!

Joanne Kang 3I

Finals are coming...
but my last brain cells argon...
My gpa and social life argonna be gone soon too..

Joanne Kang 3I

Joanne Kang 3I

State whether the following oxides are acidic, basic, or amphoteric:
b. SO3
Can someone please explain why this molecule is basic??

Joanne Kang 3I

1. The molar concentration of HCl in hydrochloric acid is reduced to 12% of its initial value by dilution. What is the difference in the pH values of the two solutions?
Can someone please explain the solution for this question?

Joanne Kang 3I

When someone posts a really obvious question on Chem Community...
Everyone:

Joanne Kang 3I

Do hydrogen bonding sites include the lone pairs of the hydrogen bond within the molecule? Ex. H2O

Joanne Kang 3I

Joanne Kang 3I

Like the person above said, when the s character increases because there is a decrease in the p character. This means that there are less lone pairs and bonds contributing to the hybridization number. So if there are less lone pairs and bond overall, the bond angle between atoms in the molecule incr...

Joanne Kang 3I

Identify the hybrid orbitals used by the atom in boldface red type in each of the following species:
d. SeF3+

Why is the answer sp3?
Thanks

Joanne Kang 3I

What is the difference between molecular shape and electron geometry with regards to VESPR?

Joanne Kang 3I

Not sure. If you look up the VESPR theory chart, it can give you all the possibilities of VESPR shapes.

Joanne Kang 3I

To make sure, you should draw the compound's lewis structure. When you draw it, you may notice that the bonds within it are polar, meaning one atom is more delta negative or positive than the other.

Joanne Kang 3I

I think lone pairs affect bond lengths because lone pairs cause repulsion. Structures without lone pairs have no extra repulsion except from the atoms in the molecule. Minimal e- repulsion causes the max distance between atoms.

Joanne Kang 3I

Does anyone remember what Dr. Lavelle was saying about Xenon during lecture? Thanks

Joanne Kang 3I

For the first question we just have to use Wavelength = Speed of light / Frequency. It's given us the frequency, just in the wrong units, MHz not Hz. Remembering SI stuff, M = mega = 1,000,000 = 10^6. Now we have 8.01 x 10^7 Hz Wavelength = 3 x 10^8 / 8.01 x 10^7 = 3.74272732 meters Wait but I thou...

Joanne Kang 3I

Can someone please give me the solutions to these questions? They are from the Week 3 Worksheets. 2. The CHEM radio station broadcasts at 80.1 MHz. Calculate the wavelength of the corresponding radio waves and tune in to the station one day. 4. Can an electron from the hydrogen atom be confined to i...

Joanne Kang 3I

Does anyone have the solutions for Lyndon's workshop sheets for "week 1 chem 14A learning session: High School Chem"??
If so, can you please put the answers to questions 6 and 8 below?

Joanne Kang 3I

Can someone please explain the significance of this equation and why we need to know it?

Joanne Kang 3I

Yes. Work functions should always be in Joules and then you most likely also convert the moles to atoms as well(with Avogadro's num).

Joanne Kang 3I

I believe Dr. Lavelle said that he would not include the last slide he went over in lecture, which was "Interactions Between Ions & Molecules". Other than that I think everything else can possibly be on the test.

Joanne Kang 3I

Will bond lengths and energies be on the midterm? What will not be on the midterm?

Joanne Kang 3I

Draw the complete Lewis structure for each of the following compounds:
c. glycine, H 2 C(NH 2 )COOH, the simplest of the amino acids, the building blocks of proteins.

How do you know how to write the Lewis structure for a complex atom like this?

Joanne Kang 3I

Is Coulomb's law more greatly affected by the charges or by the distance?

Joanne Kang 3I

Thank you so much for the advice!

Joanne Kang 3I

Can someone please explain what de-localized means?

Joanne Kang 3I

What are the principal and orbital angular momentum quantum numbers for each of the following orbitals: (a) 6p; (b) 3d; (c) 2p; (d) 5f?

Can someone please explain how to solve this

Joanne Kang 3I

Is the right equation △p△m ≥(h/4π) or △p△m ≥(1/2)h???
Lavelle and the solutions manual say different things...

Joanne Kang 3I

For 1B.27, the solutions manual is wrong. The answer should be 6.7x10^-34 m. This may clear things up for you

Joanne Kang 3I

Lavelle actually said that after the 4s state/orbital is occupied and the electron enters the 3rd orbital, then the 3d state is lower in energy than 4s

Joanne Kang 3I

It basically means that electrons fill orbitals in the lowest energies levels first before taking up higher energies. This is because atoms always want to be in the lowest energy state as possible.

Joanne Kang 3I

Can someone reiterate Hund's rule and summarize its main point/why it's important please?

Joanne Kang 3I

What is main point of Heisenberg's equation?

Joanne Kang 3I

In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series or Lyman series, as shown in Fig. 1A.10). What is common to the lines within a series that makes grouping them together logical? Can someone please explain the ans...

Joanne Kang 3I

Since amplitude is not included in the equations that were taught to us, I don't think we should worry about it. Like you said, the most important concept is that as wavelength goes down, frequency goes up and vice versa.

Joanne Kang 3I

What are the best sessions to go to for getting extra practice outside of the textbook problems?

Joanne Kang 3I

Is there a course reader for Lavelle’s class? If so, where can I get it?

Joanne Kang 3I

When we write out a chemical equation, do we have to write their physical states like (l), (g), (aq) next to the molecules??

Joanne Kang 3I

Are there practice problems for the fundamentals section? If so, where is it?

Joanne Kang 3I

Which SI units should we memorize for the test?

Joanne Kang 3I

0.00431 would be considered 3 sig figs, meaning the three zeros in front are insignificant.
For 4 and 5
ex. 50.00 and 5.000 x 10 has 4 sig figs
0.00501 and 5.01x10^2 has 3 sig figs

Joanne Kang 3I

The question: The field of nanotechnology offers some intriguing possibilities, such as the creation of fibers one atom wide. Suppose you were able to string together 1.00 mol Ag atoms, each of radius 144 pm, into one of these fibers by encapsulating them in carbon nanotubes (see Chapter 7). How lon...

Joanne Kang 3I

Yes. This is a trick question, so doing the stoichiometry for each molecule should reveal that they both convert to 1.22x10^4 moles.

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