CHEMISTRY COMMUNITY

KateCaldwell 1A

S-character is the contribution of the sigma (single) bond in hybridization. In sp^3, there is 25% s-character and 75% p-character, whereas, in sp, there is 50% s-character and 50% p-character. Therefore, the more s-character a bond has, the stronger as well as the shorter bond becomes. S-character ...

KateCaldwell 1A

I wouldn’t expect that on the final, but polar vs. nonpolar will for sure show up.

KateCaldwell 1A

I would know it just in case. Lyman is n=1, Balmer is n=2, and Paschen n=3. The other two we haven’t really discussed, so I wouldn’t worry.

KateCaldwell 1A

Part a has us solve for the volume, which I got correctly, but I keep getting the wrong pH value for part b. Can someone explain step by step how to do this? I did moles/volume the -log that value.

KateCaldwell 1A

Hybridization is the mixing of orbitals into new orbitals to accommodate electrons to form new chemical bonds of the valence-bond theory. To solve for hybridization, look at the amount of electrons/atoms bonded to the central atom. For linear, there is 2 atomic orbitals as well as two hybrid orbital...

KateCaldwell 1A

Lewis Acid: A molecule that accepts an electron Lewis Base: A molecule that donates an electron Brønsted Acid: A molecule that donates a H+ Brønsted Base: A molecule that accepts a H+ These are the main concepts to remember for the final exam as well as being able to tell apart which molecule is an ...

KateCaldwell 1A

To find the bond order, you create the Lewis structure first to see the amount of bonds in the molecule. For example, NH3, nitrogen has a bond order of 3 while hydrogen has a bond order of 1. It is just the amount of bonds created...including double and triple bonds.

KateCaldwell 1A

We won’t be asked to draw the VSEPR models, but to know their names and bond angles. In all of our homework, we weren’t asked to draw VSEPR models, but instead, a Lewis structure.

KateCaldwell 1A

I would assume so because it is a common molecule we have gone over. Lavelle has mentioned C6H6 many times and even in homework we have figured out all of its resonance structures.

KateCaldwell 1A

I believe hybridization takes into account the lone pairs of a molecule. It is further explained on this document; http://www.chem.ucla.edu/~harding/notes ... als_01.pdf

KateCaldwell 1A

A chelating ligands are ligands with two or more points of attachments to metal atoms. Some examples are ethylenediamine and acetylacetone. For more examples, this website has more descriptions and videos on chelating ligands. https://study.com/academy/lesson/chelating-ligands-definition-models-exam...

KateCaldwell 1A

It may show up as multiple choice for the final so I would study it just in case.

KateCaldwell 1A

I'm assuming we need to know both the bond names and the shape they make as well especially since past tests that I've looked at asked for small details like that.

KateCaldwell 1A

It would still be the same formula to solve for formal charge, but you can tell the atom is radical if it has an unpaired electron or odd number of electrons. For example, CH3 would be a radical since it is 4+3= 7 electrons and when you make the Lewis structure it shows a lone electron.

KateCaldwell 1A

It asked specifically for a resonance structure, so I think you have to show what the structure looks like with a charge on certain atoms. The delocalized electrons have to be show in two different Lewis structures. I'm not fully sure, but I hoped that helped.

KateCaldwell 1A

I believe the lone pairs of electrons only count when they are around the central atom. I think the lone pairs around a non central atom would form a molecular structure called a bent or a gray circle representing the lone pair.

KateCaldwell 1A

For question 3.25, "On the basis of the expected charges of the monatomic ions, give the chemical formula of each of the following compounds: (a) magnesium aresenide (b)barium arsenide...," does anyone have tips to solve for these quicker?

KateCaldwell 1A

Electrons are removed from the highest energy level because they are the furthest from the nucleus.

KateCaldwell 1A

Does anyone know how the test covers in terms of homework? Is it all of Chapter 3 or is it up to a certain problem?

KateCaldwell 1A

I believe the element in the middle (with the lowest ionization energy) would have the highest electronegativity since it has the strongest ability to attract other atoms towards it.

KateCaldwell 1A

Electron affinity increases going across (left to right) the rows and decreases go down columns. Carbon has a higher electron affinity than nitrogen due to its electron configuration. Carbon's electron configuration is 1s^2 2s^2 2p^2 and nitrogen's electron configuration is 12^2 2s^ 2p^3. Having two...

KateCaldwell 1A

Exceptions in ionization energy occurs because of the electron configuration. Taking away or adding electrons to certain atoms produces a more stable atom and creates a different ionization energy than what is expected. For example, Nitrogen's electron configuration is 1s^2 2s^2 2p^3, which is stabl...

KateCaldwell 1A

I believe it would be due to the larger radii in the first two rows as the electrons cannot interact with the nucleus. Exceptions usually occur when molecules have an odd number of electrons, molecules that contain atoms that have less than an octet, and molecules that contain atoms with more than a...

KateCaldwell 1A

There isn't a formula to find l number; it is just standard numbers we need to know. s=0, p=1, d=2, f=3. The only other way to solve for it is through n-1= l max.

KateCaldwell 1A

My TA told me that we have to have correct sig figs for the midterm. Is that still true?

KateCaldwell 1A

These numbers are determined by the l quantum number. The l number is the amount of orbitals an element can carry.

KateCaldwell 1A

What is a diagonal relationship? I looked it up and it said similarity in chemical properties between an element in the periodic table ande one group lying one period lower and one group to the right. I don’t remember him talking about this in class... do we need to know it for the midterm? They ex...

KateCaldwell 1A

Why is it that we can't know both position and momentum? According to the Uncertainith Principle, every particle has a wave associated with it, so it exhibits a wavelike behavior. A particle wave having a well-defined wavelength will be spread out, so the velocity will be precise but not the positi...

KateCaldwell 1A

QuincyH1G wrote:Threshold energy varies per metal correct?

Threshold does vary among different metals because the work function energy varies. The work function varies due to the position of the electrons in that metal. The shape of the metal determines where and how the electrons move off the metal.

KateCaldwell 1A

They describe the locations of electrons in a P-orbital. So instead of saying "these electron are in the front and back," we can say "their positions are on the x-axis" since they are in P-orbital, we state their location as "Px" same idea for Py and Pz The lobes are i...

KateCaldwell 1A

The only reason I can think of is since the 3d state is higher in energy than the 4s state, the 4s state would fill up faster because it would take less energy. I would have to agree with Vivian as the 4s electrons are lost first during ionization. The electrons lost first, have the highest energy ...

KateCaldwell 1A

The numerical cutoff for delta p is h/4pi.delta x. The numerical cutoff for delta v is delta p/mass.

KateCaldwell 1A

I believe a speed is reasonable if it is less than the speed of light (3.00x10^8 m.s^-1). Your answer seems to be correct then because it is much smaller than the speed of light.

KateCaldwell 1A

I'm not sure if I'm fully correct, but a Joule derives from a Newton (kg.m/s^2). Joules measures amount of work done on an object (mass) going through a distance of one meter. Which is why a Joule is a Newton times mass, so kg.m^2.s^-2.

KateCaldwell 1A

"From the following list of observations, select the one that best supports the idea that electromagnetic radiation has the properties of particles. Explain your reason." Can someone further explain the reasoning behind Einstein's theory of the photoelectric effect? Is he insisting that ph...

KateCaldwell 1A

The correct answer would be C. because according to the uncertainty principle, we cannot know both the velocity and position of an electron at the same moment. If we have definite value for the velocity of the electron, we cannot have certain answer for the position and placement of that electron. T...

KateCaldwell 1A

In the experiment, there is two plates of metal connected by wiring to create a circuit. Since the electrons are knocked off of one metal, the freed electrons moves through the circuit to the second plate. The original plate that had its electrons knocked out would become slightly positive, thus att...

KateCaldwell 1A

I believe you would have to convert the molarity of both substances into moles, then add together the two substance's moles. Add together the liters, then divide the new moles by the new amount of liters to get the new molarity.

KateCaldwell 1A

Wavelengths should be in terms of meters or nanometers. If you solve for the problem correctly, then you should be able to get meters as your units for wavelength.

KateCaldwell 1A

To solve part a you must use the equation v= R(1/n^2-1/n^2) and use the formula c=v times lambda. Then include both formulas, c= R(1/2^2-1/4^2)times lambda To solve for part b you use the value you got for part a(486 nm) and classify which series that number falls under (Balmer). To solve part c you...

KateCaldwell 1A

You cannot change a subscripts as that would change the molecule. You may be referring to a coefficient. If so, not having the coefficient as a fraction makes solving for the rest of the problem easier if we leave/make the coefficient whole numbers. If you ever have a fraction, most likely all you h...

KateCaldwell 1A

You will need to understand those concepts for future chemistry classes and even 14A. My friends who are almost done with the 14 series still use those basic concepts. Not to mention those concepts will show up on our midterm and most likely our final.

KateCaldwell 1A

I may be approaching this incorrectly, but n represents the amount of energy needed to eject the electrons or the energy levels. Each of the series is part of its own spectrum and this impacts the amount of energy needed to release those electrons. The Lyman series has a greater amount of energy due...

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