CHEMISTRY COMMUNITY

Adrienne Yuh 2B

Thank you so much! That helped a lot :D

Adrienne Yuh 2B

Catalysts are seen as products/reactants but aren't really consumed or created. They are just *there* and get cancelled out in the total reaction.

Adrienne Yuh 2B

Intermediates aren't included so you have to see how it was created and find a substitution in the rate laws.

Adrienne Yuh 2B

Rate law graphs seem to be the most important, as well as heating curves!

Adrienne Yuh 2B

Is Percent Ionization/Deprotonation/Dissociation the same thing? It seems like the same way to find the answer, but I'm still a little bit confused! Thanks :)

Adrienne Yuh 2B

Hi! I just found out the correlation. The higher the solubility constant (Ksp), the more soluble the compound is. However, I don't think we really covered Ksp, so in general, when the equilibrium constant is larger, it would be more soluble. The more product (the dissolved) there is, the more solubl...

Adrienne Yuh 2B

It is only affected by temperature.

Adrienne Yuh 2B

I love Glass Animals as a whole, which Professor Lavelle incorporates into the beginning of his lectures too!

Adrienne Yuh 2B

I usually look at the oxidation numbers and see the total number of "charges" that can be balanced with electrons.

Adrienne Yuh 2B

This is just an example of a metal that you can use as an inert metal in terms of electrodes.

Adrienne Yuh 2B

I enjoyed equilibrium the most! It seemed the most straightforward and understandable.

Adrienne Yuh 2B

The final is on Sunday, 3/14 from 9:30-11 am. It will be proctored by your TA still but everyone is taking it at the same time.

Adrienne Yuh 2B

The anode is negative in galvanic cells. Meanwhile, the anode is positive in electrolytic cells.

Adrienne Yuh 2B

There is no extra credit so 50 is the max.

Adrienne Yuh 2B

I like to eat food while studying for the final! Reading over the textbook is helpful.

Adrienne Yuh 2B

Yes! The oxidizing agent is being reduced and the reducing agent is being oxidized.

Adrienne Yuh 2B

Work on system is +, work done by system is -.

Adrienne Yuh 2B

I think a 50% is needed to pass the class, but 28 points are the max you can miss to get an A.

Adrienne Yuh 2B

ice cream omg :D

Adrienne Yuh 2B

Week 7-8 Homework is due next sunday, 2/28!

Adrienne Yuh 2B

Adiabatic means no heat transfer so q=0.

Adrienne Yuh 2B

Kelvin is always positive so temperature shohld not have an effect on the positive or negative nature of G.

Adrienne Yuh 2B

The equation sheets have the units so make sure to check the units of given information.

Adrienne Yuh 2B

Looking at units and given information helps us determine which one to use.

Adrienne Yuh 2B

I’m super nervous about this midterm because there is just so much to remmeber! The equations and applications are still extremely confusing to me.

Adrienne Yuh 2B

Make sure you’re converting C to K and to look at the units. kJ and J makes a huge difference in answers

Adrienne Yuh 2B

Definitely read the textbook and take notes! I think it gave a lot of simple concepts to remember and supplement it with the sapling problems. You got this good lucK!

Adrienne Yuh 2B

We don't need to memorize these as they should be given on the test.

Adrienne Yuh 2B

I think for The Staff it means that they haven't determined a professor for this class.

Adrienne Yuh 2B

I think for The Staff it means that they haven't determined a professor for this class.

Adrienne Yuh 2B

I think tests are never curved, but he will look at the distribution of grades at the end of the quarter.

Adrienne Yuh 2B

Thank you to Dr. Lavelle for making this quarter fun and exciting!

Adrienne Yuh 2B

I'm pretty sure that it's going to update as you post for this week!

Adrienne Yuh 2B

The textbook uses Celsius but just make sure to know how to convert between depending on the problem.

Adrienne Yuh 2B

They will be provided, but remember that bond enthalpies are the most inaccurate way to calculate!

Adrienne Yuh 2B

Professor Lavelle's questions are always clear and simple, so they should be included.

Adrienne Yuh 2B

I was also wondering this, but the relative ratios of change (delta) creates the 2:1:2 pattern.

Adrienne Yuh 2B

The anti-log is really important in converting between pK vs K, pH, etc. Just put the value to the negative pwoer of 10. ex) 10^-x

Adrienne Yuh 2B

Hi! It's definitely hard to see how they add together but looking for key elements in your desired equation helps!

Adrienne Yuh 2B

Yes! Your equation is right. Make sure to be using equilibrium/ICE tables to calculate the values needed.

Adrienne Yuh 2B

They are both the same thing!

Adrienne Yuh 2B

They are essentially the same, but amphoteric is acting as both an acid or base while amphiprotic is can accept/donate protons.

Adrienne Yuh 2B

This only happens between two amphiprotic molecules!

Adrienne Yuh 2B

Hi! When you calculate pKb/pKa, you have to remember if its releasing OH- or H+. That way, the reactants and products are different depending on if it's an acid or base. Using the equilibrium equation, you can see that depending on the solution, the numerator for Kb [conj acid][OH-]/[base], with the...

Adrienne Yuh 2B

According to Professor Lavelle, 1 bar = 1 atm so don't worry about it too much!

Adrienne Yuh 2B

Q is basically the equilibrium coefficient but at a certain moment/concentration/pressure of the reactants/products. Comparing this to K can give us a lot of insight, especially in terms of Le Chatelier.

Adrienne Yuh 2B

I want to be more organized and driven this year! I've found it really easy to slack off and use the pandemic as an excuse, but I'm hoping that I can actually succeed this year.

Adrienne Yuh 2B

Equilibrium can still favor it depending on the size of K. Large values of K favor products and small values favor reactants

Adrienne Yuh 2B

Same with Margaret, I think having Google Calendar is really helpful in keeping a schedule! Make sure not to be too hard on yourself and definitely give yourself breaks.

Adrienne Yuh 2B

Yes, they all mean the same thing. Basically, going towards the products of the equations.

Adrienne Yuh 2B

Lectures are always recorded and uploaded to CCLE, but there are office hours that are optional.

Adrienne Yuh 2B

Solids and liquids in general aren't included in equilibrium.

Adrienne Yuh 2B

Calculation wise, both use the same steps except Kc is using concentration and Kp is pressure.

Adrienne Yuh 2B

You have a lot of time before it's first due, since Professor wanted to give us time to settle in. Use the 14 day free trial first!

Adrienne Yuh 2B

Kelvin! Make sure you know how to convert F, C, and K.

Adrienne Yuh 2B

Hi! A quick correction: you said "a shorter, weaker bond corresponds to a stronger acid." A LONGER bond would create a weaker bond and therefore a stronger acid, since it can dissociate easily. For binary acids, a weaker bond comes from the size of the atom (A in the acid). The larger the ...

Adrienne Yuh 2B

Yep! The positive charge of H+ ions are what are deemed "protons." We rarely see an acid donate another element as a proton.

Adrienne Yuh 2B

Another way I use to see if something is amphoteric is seeing if it's a metalloid since nonmetals are usually acidic and metals are basic. This method isn't completely accurate, though.

Adrienne Yuh 2B

I think other than memorizing the strong acids and bases, determining if something is a salt is also very important (the other box). Make sure you're double checking if the weak bases are in the right box, too since it's easy to confuse with strong bases.

Adrienne Yuh 2B

I'm not very sure how much we need to know either, but my TA said to not worry about it as much since there won't be many questions on this. I would probably just be familiar with most of the names. I hope Dr. Lavelle can provide more insight on this!

Adrienne Yuh 2B

Yes! I think polydentate also includes bidentate. In the textbook it says, "Some ligands are polydentate (“many toothed”) and can occupy more than one binding site simultaneously. For example, each end of the bidentate (that is, two-toothed) ethylenediamine molecule, NH2CH2CH2NH2 (8), has a nit...

Adrienne Yuh 2B

alebenavides wrote:does anyone know how to input Roman numerals into the first question of week 9 sapling homework?

Hi! I think you can just type (III) or whatever Roman numeral it is with the letter I (capitalized i).

Adrienne Yuh 2B

I like to draw out the figure and arrows pointing in the dipole directions. Memorizing what cancels what is really helpful.

Adrienne Yuh 2B

Don't worry! There's plenty of homework and chem community opportunities left as well as a final. Since we only need a 50% to pass, I'm sure you'll do fine and work hard on the final!

Adrienne Yuh 2B

Like everyone said, you just count the regions around the atom. I like to count how many orbitals there are to make sure I'm doing it right. Ex) 2 lone pairs, 3 bonding atoms ==> sp3d (1 s, 3p, 1d has a total of 5)

Adrienne Yuh 2B

It is 30 questions, 6 points each for 1 hour and 30 minutes.

Adrienne Yuh 2B

I'm pretty sure we have to memorize it. I don't see a VSEPR chart on his website and we had to remember all of them in high school.

Adrienne Yuh 2B

He is probably going to finish with the material a while before the final. That way, we have more time to study and ask questions.

Adrienne Yuh 2B

I'm assuming it will follow normal UCLA grading, with 93-100 being an A. Aside from that, we need 50% of the poitns to pass the class.

Adrienne Yuh 2B

The unstable nature of unfilled orbitals allow silver to "borrow" an electron from the s orbital to the d, to make it complete.

Adrienne Yuh 2B

Metallic character is greatest at the lower left corner! This is where they usually lose their electrons easier.

Adrienne Yuh 2B

They are both affected in the same way by intermolecular bond strengths, but are defined differently as shown above.

Adrienne Yuh 2B

They have similar chemical properties and are usually grouped near each other.

Adrienne Yuh 2B

I think doing the textbook problems again and going to TA/UA hours would be extremely helpful. There's probably going to be a lot on the final, so starting now would be very beneficial.

Adrienne Yuh 2B

Lewis acids ACCEPT electrons, meaning they usually have a positive charge or full shells while bases donate since they have lone pair electrons and a negative charge.

Adrienne Yuh 2B

Like said above, you had the electron configuration wrong. Otherwise, you would be taking electrons off of the valence ones first (s and p).

Adrienne Yuh 2B

Dipole dipole interactions happen between fixed partial charges while a dipole-induced interaction happens during an interaction between a polar molecule and a non-polar molecule.

Adrienne Yuh 2B

Electrons always fill 4s before 3d because 3d has more energy, so they are harder to remove.

Adrienne Yuh 2B

Yes :) Refer to Professor Lavelle's email to find out which ones are happening specifically.

Adrienne Yuh 2B

Hi! I think Professor Lavelle mentioned that there are going to be more questions with less points each for this midterm.

Adrienne Yuh 2B

I like reviewing textbook problems and reading through the lessons to find things I have trouble with. TA/UA sessions are pretty helpful too!

Adrienne Yuh 2B

I think a helpful tip is to read through all the problems first, without spending too much time on hard ones. This allows you to think about it or get hints from later questions, without wasting your effort or time. Pausing for a bit and forcing yourself to relax is a good way to calm your nerves, t...

Adrienne Yuh 2B

Yes! I think all of the Group 13 Elements don't require an octet.

Adrienne Yuh 2B

Me too! Professor Lavelle said we could look at similar problems in homework/textbook but I don't really remember what questions I had trouble with.

Adrienne Yuh 2B

I don't think he mentions anything on this, but he does say 50% or higher is required to pass with a C- or higher.

Adrienne Yuh 2B

I think a lot of the major problems (ones worth 12 points) were probably broken down into partial credit!

Adrienne Yuh 2B

The h-bar symbol represents 2pi! I would ultimately just follow the formula sheet to keep it a familiar representation of the equation.

Adrienne Yuh 2B

I like doing arts and crafts, whether it's drawing or watching videos on it! Playing games with your friends is a fun way to relax, too.

Adrienne Yuh 2B

I think the best way to do molar mass, and to be as accurate as possible, is to first take all the numbers without rounding and then do the calculations. At the end, you can round to get the most exact answer.

Adrienne Yuh 2B

Like many people said, it depends on if it's an emission or absorption problem. I think you'll mostly see it used in emission though!

Adrienne Yuh 2B

In most problems like these, there will usually be unit conversions given since miles aren't metric!

Adrienne Yuh 2B

I think he said he would release it after he has everyone take it and can look over any errors! Probably after Friday :)

Adrienne Yuh 2B

The sapling questions are randomized, which Professor Lavelle emailed Sapling about. I think the textbook questions are probably more helpful in determining the content for the midterm.

Adrienne Yuh 2B

This is an error in the textbook. The real answer uses 10, which you're right about! You can find the corrections on the solution errors page on his website.

Adrienne Yuh 2B

Yea! I asked the professor about this and he said he uses the one with frequency since it's easier for a lot of the problems we have. It's just a difference between whether the equation is wavelength or frequency, but it's better to stick with one and convert after solving.

Adrienne Yuh 2B

Working with others, teaching people (just to solidify concepts), and watching review videos are all really good ways to study! Make sure to sleep well so you can retain information better :)

Adrienne Yuh 2B

I think there are constants and equations sheets on Professor Lavelle's website, if you want to see what the given sheets will possibly look like during the midterm! I think it's a great way to be familiar with where and how the individual constants and equations are displayed.

Adrienne Yuh 2B

There are different variations of R online and in the textbook, but the one the professor gave us is relative to frequency, R=3.29*10^15.

Adrienne Yuh 2B

Hi! Spectral lines show the emissions/absorptions of energy by electrons.

Adrienne Yuh 2B

Thank you so much for the responses! For the wavelength questions, I think we are supposed to use the Rydberg equation.

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