CHEMISTRY COMMUNITY

Natalie Phan 3G

Is anyone not planning on taking 14B?

Natalie Phan 3G

Right after the test I felt alright, thinking that I managed to get a B on it. But after some reflecting and reviewing some of my notes I think I did a lot worse than I initially thought :|

Natalie Phan 3G

The 5 points are rewarded per week, but last week I accidentally forgot and wrote all 5 of my posts on Monday, the day after it was due. I still got the points so I don't think that it's super strict. The grades should be updated to say 45 points if you did all the required posts.

Natalie Phan 3G

I've been exclusively doing my homework after midnight, so hopefully without morning classes I can work on getting my sleeping schedule right and maybe next quarter I'll actually do my work in the daytime :)

Natalie Phan 3G

I don't typically listen to music when studying or doing homework, but if I do I listen to instrumental/classical music. I think that songs with lyrics throw off my concentration.

Natalie Phan 3G

I'd say to memorize the ligand names and remember the formula/order that Lavelle gave us in lecture. The prefixe, alphabetical ligand names, TM cation name, oxidation number roman numeral, and the anion if there is one.

Natalie Phan 3G

For me personally, I'm going to focus a lot on Acids and Bases because we have not had tons of practice on it like the other topics. I am also going to study a lot on early quantum (photoelectric effect, atomic spectra, etc) because it was one of the denser sections and we spent a lot of time on it.

Natalie Phan 3G

Which review sessions are you guys planning to go to/prioritizing? Which ones would you say are the most important sections to review? Thanks!

Natalie Phan 3G

How do you name anions that are on the outside of the coordination sphere? In one of the textbook problems there was a coordination compound names tetraamminediaquacobalt(3)bromide but the formula had just one Br on the outside. Wouldn't the number of atoms affect the name?

Natalie Phan 3G

How are hybridization and molecular shape related? i.e how do you determine hybridization from shape or vice versa?

Natalie Phan 3G

For the last structure, bond the carbons together in a sort of circle/triangle shape. Then bond the Hydrogens to the carbons, on the outside of the circle.

Natalie Phan 3G

What does it mean for a molecule to have a cyclic structure? This came up in my feedback for a problem on Sapling and I'm unsure on what this means.

Natalie Phan 3G

https://molview.org/?cid=962 I depend a lot on visualization and structures to understand molecules so I sometimes use this cool website. It lets you search any molecule and then displays the lewis structure and most importantly, the 3D model that you can interact with. This also helps with equator...

Natalie Phan 3G

For me, I just look at the lone pairs and bonds surrounding the atom you are determining the hybridization for. I count the number of lone pairs and bonds (double and triple bonds just count as 1 for this), and then use that number to determine the hybridization. sp is 2, sp2 is three, sp3 is four, ...

Natalie Phan 3G

How do you guys remember/study the bond degrees in a shape? I understand how to use lewis structures/VSPER to find the shape, but I can't seem to keep the different angles associated with them straight. Any tips?

Natalie Phan 3G

Multiply the week of school we are in by 5 and you should get the number of total chem community posts we need by the end of the week! We're in week 7 so we need at least 35 posts by Sunday night :)

Natalie Phan 3G

When determining which molecule has a higher boiling/melting point, do we look at the inter or intramolecular forces?

Natalie Phan 3G

Polarizability is the ability of an electron to BE distorted (by polarity). Polarizing Power is the ability to DISTORT another atom. || An atom that is highly polarizable it means it's electrons are more loosely held and susceptible to the influence of other atoms nearby. An atom that has a high po...

Natalie Phan 3G

What is the difference between polarizability and polarizing power? What periodic table trends do they follow?

Natalie Phan 3G

Here are the things we've learned so far: Left to right of the periodic table: - ionization energy increases - electronegativity increases -electron affinity increases -atomic radius decreases Top to bottom: - atomic radius increases Bottom left: - more bottom left, the more metallic it is Top righ...

Natalie Phan 3G

What are all of the period table trends we should know? I keep losing track of them and forgetting which ones are important. Thank you!

Natalie Phan 3G

Hello! Atomic radius is the distance from the nucleus to the outermost electron in an atom. It’s ionic radius is the radius of that element’s ion. An ion with a positive charge will have a smaller radius than the element’s non-ionic form and ions with a negative charge will have a greater radius th...

Natalie Phan 3G

What are the differences/similarities between ionic radius and atomic radius? I know that they both follow the same trends (decreasing across a period and increasing down a group) but I don't really know how to define either of them and I don't know how they're related. Thank you!

Natalie Phan 3G

Hi! For me it's easier to just count the number of bonds and lone pairs in a lewis structure for the atom instead of using the formula. You just need to count each electron and each line (bond) and then subtract that number from the total valence electrons for that atom.

Natalie Phan 3G

Can someone explain what the difference between intermolecular forces and intramolecular forces are? It would be super helpful if you could provide some examples as well. Thank you!

Natalie Phan 3G

Phosphorus is an atom in the third row on the periodic table and has s,p,d as its possible subshells. Why can it have a possible d-subshell when the electron configuration does not include a d-orbital? The Lewis structure of PCl shows P having 5 single bonds, for a total of 10 valence electrons. Sor...

Natalie Phan 3G

Chinmayi Mutyala 3I wrote:The 2p orbital is on the second shell which means the radius is increasing. Since there are more electrons, there is more repulsion between them so the radius increases.

This make so much sense. I guess I was just having a dumb moment, thank you!

Natalie Phan 3G

Hi! It's because P is in the 3rd row of the periodic table, so its possible subshells are the s, p, and d subshells. As a result, P can accommodate more than 8 valence electrons and since it's the central atom in this lewis structure, it can have more than 4 single bonds. For the second part of you...

Natalie Phan 3G

Why does the atom radius of an atom increase when an electron transitions from the 1s-orbital to the 2p-orbital?

Natalie Phan 3G

In Lecture 15, PCl5 was given as an example and Lavelle drew the Lewis structure with P as the center, and drew 5 single bonds to connect the Cl atoms. I was just confused why there were 5 single bonds when the other structures we saw had only 4 single bonds, making them octets? Why is PCl5 an excep...

Natalie Phan 3G

Yes they are always positive. If you do end up getting negatives, you should probably check your calculations

Natalie Phan 3G

For the energy of incoming light it's in J/photon, but be careful with your units because sometimes problems will give you kJ or ask to convert into eV. And whenever a problem is asking for moles/atoms, use Avogadro's number to convert.

Natalie Phan 3G

The energy required to remove an electron is the work function because you could have incoming light with greater energy than is required to remove the electron, which would then give you an ejected electron with kinetic energy (think about the equation E(photon)-work function= KE). The energy that...

Natalie Phan 3G

Yes for this problem the ending energy level would be n=2, in the Balmer series. What equation did you plug n and the wavelength into? If you're using Rydberg's equation, it is v = R (1/n1^2 - 1/n2^2), where n1 is the final energy level and n2 is the initial level. Convert wavelength to meters. You ...

Natalie Phan 3G

When a problem asks to find the energy required to remove an electron, is it asking for the work function or the incoming light? What about the energy that caused photoejection of an electron? I've just seen it come up a few times in homework problems so I wanted to clarify which was referring to wh...

Natalie Phan 3G

I think it's probably best just to stick with the ones assigned because they were probably assigned for a reason. Lavelle probably chose those specific ones because we're gonna be tested with problems with similar wording or similar methodology to solve them. It might be confusing to practice proble...

Natalie Phan 3G

Estimate the minimum uncertainty in the position of a marble of mass 1.0 g given that its speed is known to within ± 1.0 mm/s. In the solution for this problem 1.0 mm/s was converted to m first, then it multiplied it by 2. Why multiply by 2? I am just really confused about what to do with the ± 1.0 ...

Natalie Phan 3G

What are some keywords that give us important info for a problem? For example when a problem says that the electron is at ground-level, that means n=1. Are there anything other things similar to this that gives us important information that is not explicitly stated? I am pretty comfortable with how ...

Natalie Phan 3G

I think the best way to apply sig figs is at the very end, on your final answer. If you round too many times during the actual calculations the final answer may be way off. If you can save all your numbers on your calculator, that's great but if not, I think 4-5 decimal places should be good enough....

Natalie Phan 3G

What's a good way to remember/memorize the range of wavelengths on the electromagnetic spectrum? I know that visible light has a range of about 400-700nm, but I keep forgetting the others. Any tips/memorization devices?

Natalie Phan 3G

How do I find the wavelength of light associated with an electron energy level transition? For example what steps/formulas would I used to find the wavelength when an electron moves from n=2 to n=1?

Natalie Phan 3G

Mrudula Akkinepally wrote:Which polyatomic ions would be considered basic ones to memorize?

Based on the textbook problems, I've seen bromate (BrO3), Nitrate (NO3), Bicarbonate (HCO3), and Sulfate (SO4) pop up a lot. So I think those would be a safe bet to try and understand/memorize.

Natalie Phan 3G

Hi! In one of Dr. Lavelle's office hours I believe he said that the formulas for the polyatomic ions will be given to us on the tests (correct me if I'm wrong). But I think having a few of the basic ones memorized would be wise because he might expect us to know those! And we will be expected to kno...

Natalie Phan 3G

I think downloading zoom on your phone and pointing your camera at your workspace should be okay because LockDown browser on your computer closes all other windows anyways. But check with your TA to make sure!

Natalie Phan 3G

Can someone please explain to me what the steps are to find the kinetic energy of the ejected electron given the velocity of the ejected electron and the work function? I was confused to what formulas I should use/rearrange/plug in. Light hits a sodium metal surface and the velocity of the ejected e...

Natalie Phan 3G

The intro music is ICONIC. It actually gets me to smile before our lectures and it NEEDS to come back for the next one.

Natalie Phan 3G

Hi Natalie! I personally think that the homework problems are going to be very beneficial for studying for tests. Reviewing the lectures and textbook readings will be helpful for getting a foundation for the concepts and practicing problems is really helpful for developing the necessary problem-sol...

Natalie Phan 3G

I've noticed that the textbook problems are significantly more difficult than the examples given during the lecture and even the problems in the sapling homework. So to study for tests would it be beneficial to do more textbook problems? Or should I just review the lectures? Thank you!

Natalie Phan 3G

So far I have seen two ways to find the limiting reactant and was unsure of which method is more efficient in solving different types of limiting reactant questions. 1. Finding the moles of each reactant and using the ratio between the stoichiometric coefficients in the reactants to see which one is...

Natalie Phan 3G

From what I've heard from my TA, the exams will be multiple choice. So no need to show work! Some people prefer to write out super neat and detailed work, but it is not a necessity when it comes to grading on the tests. So whatever you want to show is fine!

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