CHEMISTRY COMMUNITY

harperlacroix1a

Can someone explain to me what an oxoacid is, and how it differs from a normal acid?

harperlacroix1a

The trends are the same. They increase up a group and across a period. It usually helps me to draw a diagonal line up and across the periodic table to remind myself of this trend during tests!

harperlacroix1a

Sigma bonds are allowed to rotate because the electron distribution does not change and bond strength stays the same due to the fact that electron density in sigma bonds are along the axis

harperlacroix1a

How do you know which prefix to use? Bi vs Bis, Tri vs Tris, Tetra vs Tetrakis

harperlacroix1a

the coordination number is the number of atoms/ions that surround the central atom and you find it by calculating the charge

harperlacroix1a

Dipole Dipole is molecules having a concentration of charge in a certain area due to polarity, which allows for greater attraction with another molecule that has its charges concentrated in certain areas. Hydrogen bonding is just super strong Dipole Dipole because of the Hydrogen with very electron...

harperlacroix1a

How does hydrogen bonding, LDF forces, and dipole dipole interactions affect the melting and boiling points of molecules? does it have to do with the electronegativity or strong/weakness of the force?

harperlacroix1a

Yes, these will be on the test

harperlacroix1a

Can someone explain the isolobal principle/analogy to me? In problem 3.101 of the 6th edition, they replace bonds of C-H in the benzene structure with nitrogen but I'm confused as to why this is possible or why it happens.

harperlacroix1a

Since oxygen is more electronegative, it pull on the molecule making it polar

harperlacroix1a

It covers all of chapter 4 and the end of chapter three as outlined on his website

harperlacroix1a

It exists because hybridized orbitals are lower in energy which results in a more stable compound

harperlacroix1a

Degeneracy is basically the levels of orbitals with the same energy, signified by the principle quantum number

harperlacroix1a

A radical has an unpaired valence electron on an atom

harperlacroix1a

The central atom is usually the one with the lowest ionization energy

harperlacroix1a

When determining molecular structures, is having the formal charge be 0 or having a complete octet more important?

harperlacroix1a

What is the difference between trigonal planar and trigonal pyramidal? why are the bond angles in trigonal planar 120 degrees but the angles in trigonal pyramidal differ?

harperlacroix1a

For problem 4.1 in the 6th edition, it asks whether there can be lone pairs on the central atom of the ball and stick models of the atom. part (a) models three atoms with an angle of 120 degrees and the second is a linear model with an angle of 180 degrees. how does the degree decide how many lone p...

harperlacroix1a

Yes, the way he spoke about it in lecture today was that since it is 3d, the tetrahedral molecules have bond angles of 109.5 degrees

harperlacroix1a

In today's lecture (11/9) we went over linear, trigonal planar, and tetrahedral.

harperlacroix1a

It would be 3d

harperlacroix1a

This asks to draw the lewis and appropiate resonance structures for a hydrogen sulfite ion. Why does the hydrogen bond to one of the oxygens, instead of just attaching to the sulfer?

harperlacroix1a

Why can some elements have expanded octects? for example, problem 3.57 in the 6th edition asks for lewis structure of a sulfite ion (SO3)2- and in the expanded octet, sulfur has 10 electrons attached to it. why can this happen and when do i know that a compound has an expanded octet?

harperlacroix1a

You would first need to find the mass percentage of the element, and then assume that the mass percent is equal to grams and that you have 100 g of the substance.

harperlacroix1a

Do we need to know how to calculate the exact ionization energies for the midterm? If so, how do we do it?

harperlacroix1a

Should the formal charge for a Lewis structure ever not be equal to zero? Is something for sure wrong with the structure if the formal charge not equal to zero?

harperlacroix1a

I believe you put them on both the cation and anion to show how they are charged. []- and []+

harperlacroix1a

in problem 33 in the 6th edition, it asks for the lewis structure of NOF. the solutions manual shows a double bond between O and N, with N having a lone pair, O having 2 lone pairs, and F having 3 lone pairs and a bond with N. Why couldn't you have two double bonds between N and O/F with O and F hav...

harperlacroix1a

I doubt we will be expected to know exact values. I think just knowing the trends and which radii is larger is sufficient

harperlacroix1a

Thank you!

harperlacroix1a

test 2 only covers material up to last friday's lecture, so it includes nothing about periodic table trends

harperlacroix1a

Basically electrons in both atoms and molecules can be excited to higher energy states (n=1,2 etc) so when they emit electromagnetic radiation, it gives detail to the spectroscopy

harperlacroix1a

My TA mentioned that it would 40 points. It is going to be less questions apparently, but more in depth

harperlacroix1a

Our first test had a formula sheet on the front. I assume that is the same sheet we will be given all quarter

harperlacroix1a

Can someone explain what the Balmer and Lyman series are? I know that the Lyman series corresponds to UV light and the Balmer series corresponds to visible light, but where is this relevant and what does this mean?

harperlacroix1a

C represents the speed of light

harperlacroix1a

Homework due this week is chapter's 1 and 2 I believe. We definitely have not started a new chapter since Friday, so homework should be from 2 especially, and 1 if you need practice. Every TA is different, but if you are doing current material, they should not mind.

harperlacroix1a

These problems should always add up to 100%. If not, it might be a trick question or you are mis calculating.

harperlacroix1a

There is a formula sheet uploaded onto Lavelle's website, however, it doesn't have much to help with the fundamentals section. He will probably still give it to us, but not sure how useful it will be. The only thing to memorize for this test would probably be the SI unit conversions.

harperlacroix1a

Will homework always be due on Friday during the lecture? Or will we switch to turning in HW to the TA during our discussion period? Just wondering because what if we have to turn in homework that wasn't covered yet (in case our lecture is after our discussion period). Homework will be due, startin...

harperlacroix1a

I think that balancing by jumping back and forth is the best way to do it. I always like to leave oxygen last because sometimes things get weird with the oxygen (and theres usually a lot of oxygen in complicated equations), but other than that, I can't think of any good 'tricks'

harperlacroix1a

In the 6th Edition, questions E21 asks for the amount (in moles) of molecules and formula units. What is the difference between these when calculating?

harperlacroix1a

I began this problem by multiplying 1.00 mol of Ag by Avogadro's number to get 6.022x10^23 atoms of Ag. Then I multiplied that by 2(144 pm)--144 pm is the radius of the atom, so to get the total length of the atom you have to double it. The end result was 1.73x10^26 pm, which is equal to 1.73x10^11...

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