CHEMISTRY COMMUNITY

Aimee Alvarado 3J

It would be either 25 C or 298 K.

Aimee Alvarado 3J

I usually take notes of the lectures first and then take notes from the textbook. I feel like reading the information just cements the ideas and topics we learned in the lecture. From there, I write on note cards any information that I might need to remember and make an outline with answers and solu...

Aimee Alvarado 3J

I usually try to forget that I took an exam and remind myself that it's done and I can't change anything. With this, I begin to relax and try to move on from it by doing self-care and relaxing. Take care of yourself first before anything else.

Aimee Alvarado 3J

Hello everyone! I was just wondering if anyone had any plans for the summer/next school year. Any clubs, programs, or special classes that you're interested in? Any events (i.e. movies, tv shows, online events) that you're interested in. Being in quarantine has really made me miss being social and a...

Aimee Alvarado 3J

I agree! Usually, standard conditions will either be 25 C or 298 K. However, I believe it will be explicitly mentioned in exams what the temperature will be so there's less confusion about it.

Aimee Alvarado 3J

I don't think you can retake a class if you get a C; however, we must also remember that we are in a pandemic and it will affect us all differently. I believe that schools or programs will understand your grades if they are not what you want. Just remember to take care of yourself first!

Aimee Alvarado 3J

Kushaal Madadi 2F wrote:Yes. However, when multiplying the reaction by a factor, Eo remains the same (unlike Gibbs Free Energies and Enthalpies of Formation).

If I may, why would Eo remain the same when being multiplied? Thanks in advance!

Aimee Alvarado 3J

I agree! It would most likely be 4 points, but we can hope that it might be more!

Aimee Alvarado 3J

Yes, I agree! The Nernst equation can be used for galvanic/voltaic cells since they are also concentration cells.

Aimee Alvarado 3J

If the question says that it is a galvanic cell, then it means that Ecell must be positive. Usually, as everyone else said, the cathode will be reduced and therefore on the right while the anode will be oxidized and on the left. Sometimes though, they might only give the standard potentials, so this...

Aimee Alvarado 3J

I think so too. It might be the energy difference between the transition state and the reactants, but I am also not completely sure.

Aimee Alvarado 3J

From what I've read from the textbook, I believe it explains that electrical work is a type of non-expansion because it moves electrons without changing the volume. I also believe they are closely related, but correct me if I'm wrong.

Aimee Alvarado 3J

Oxidation means that it loses electrons and is usually the anode. Reduction means that it gains electrons and is usually the cathode. This means that in your half-reactions you have to determine which one will give you a positive value since it is a galvanic cell and has to be spontaneous. Usually, ...

Aimee Alvarado 3J

I usually go from left to right. For example, Zn -> Zn^2+ + 2e- (oxidized) and Cu^2+ + 2e- -> Cu (reduced) so the order goes from left to right or farthest to closest Zn(s) I Zn^2+ (aq) II Cu^2+ (aq) I Cu (s) So Zn will become Zn^2+ when oxidized and Cu^2+ will become Cu when reduced. I hope this he...

Aimee Alvarado 3J

Yes, I agree that the textbook provides more questions that are similar to exams. However, Sapling is a very good place to practice questions about a topic and where it can give you detailed steps or explanations. Overall, I would do the textbook first and then Sapling.

Aimee Alvarado 3J

I think if you have a large E naught then that means you must have a large K. I think it works also for very small E naughts, which would mean we have a similar small K value. Hope this helps!

Aimee Alvarado 3J

I think after the chem final I might take a quick nap before beginning to study for my other assignments. After finals, I'm hoping to completely relax by watching lots of movies and shows before school starts again.

Aimee Alvarado 3J

I'm taking Chem 14C next quarter!

Aimee Alvarado 3J

I usually try to relax and do my usual routine. I wouldn't really do problems before my exam because I feel like that would mess me up more, but I would just check my notes quickly. Also, listening to music or again doing something you would normally do in the day calms me down a lot.

Aimee Alvarado 3J

Thank you so much for all of the time that you put into teaching us chemistry, especially in a period of time where it may have been difficult to. Thank you for all of the resources and time that you gave so that we could understand all of the topics. I hope you continue to have fun teaching chemist...

Aimee Alvarado 3J

Since Professor Lavelle won't be teaching Chem 14C, what will happen with our posts? Will they forever remain on this website and can we access it whenever we'd like? I know that there are some posts that are from years ago, so I was wondering how this would all work out. Thanks in advance!

Aimee Alvarado 3J

Just to make sure I'm doing this correctly and efficiently, I will note down the steps that I take to solve these problems. Please let me know if something is wrong or missing and give me tips if you'd like to: Acidic Solutions: Recognize them because one reactant will have oxygen and the products w...

Aimee Alvarado 3J

I usually make a schedule for the week and decide which day or days I would use to relax and not do a lot of homework or studying. It has really helped me not burn out or lose my motivation for days when I do need to work. I always recommend doing self-care days because your health will always matte...

Aimee Alvarado 3J

I hope that all of you are doing well! I have a question about organizations and clubs. How many clubs are you involved in and how involved are you? I feel like quarantine is making it especially difficult to actually be a part of something.

Aimee Alvarado 3J

In Brooke's final review worksheet (3/8), there was a problem (#2) where it asks what would increase the pH of a buffer solution. What could we add/remove that would increase or decrease the pH of a solution in general? Thanks in advance!

Aimee Alvarado 3J

I really enjoyed doing chemical equilibrium and thermochemistry. I guess thermochemistry just made me realize how many things are related to it and how it all works. I still find it kind of hard to understand, but I really enjoy it!

Aimee Alvarado 3J

I'm a little confused about what the answer would be for problems that are Galvanic cells and those that are not. If a problem states that it is Galvanic, would E cell always be positive? If it does not state that, would E cell always be negative? Thanks in advance!

Aimee Alvarado 3J

Exothermic means that the delta G is going to be negative while endothermic means that the delta G will be positive. However, without any values to determine this, is the general rule that if a reaction is forming a product then it is exothermic (i.e. 3H2 + N2 -> 2NH3). Is it the same for endothermi...

Aimee Alvarado 3J

Yeah, I understand how you feel. Before, I would spend every single day either studying for an upcoming exam or just catching up on assignments and homework without actually taking a break. This led to me burning out a lot more as the days went by until I started setting up a schedule to at least ha...

Aimee Alvarado 3J

On Brooke's final review worksheet (3/8), we had to calculate E naught. On the worksheet, it didn't mention which was a cathode or anode, so how would you determine which was which to solve the problem. Thanks in advance!

Aimee Alvarado 3J

oh man i want to move into dorms in the fall! but does anyone know if it'll be only single dorms or if there's a chance to have doubles? (i'm pretty sure a single dorm would be a hefty cost for me but i think i might still try? not too sure lol) Yeah, I also want to move in, and I'm hoping that the...

Aimee Alvarado 3J

I always found ceviche to be an interesting dish! It's essentially letting raw shrimp marinate in an acidic base (oxymoron haha) mainly composed of lemon or lime juice. The citric acid causes the proteins in the shrimp to go through denaturation, changing its physical and chemical properties so tha...

Aimee Alvarado 3J

I'm a sophomore, and I miss the people in my residential house. It was nice to know everyone and have people to rely on for a lot of things. I guess it also adds to how I miss talking to people and the scenery on campus. I also really miss the events that would take place there.

Aimee Alvarado 3J

I've been craving fast food these past few weeks!

Aimee Alvarado 3J

At the moment, I am in PATHS!

Aimee Alvarado 3J

I've been rewatching all of the seasons for Avatar. It's kind of nice because I remember watching this as a kid and there are moments where I'm once again surprised. It's like watching it for the first time again.

Aimee Alvarado 3J

Now that the winter quarter is almost ending, how have y'all been doing in terms of everyday feelings and motivation? It feels like every day in quarantine is the same, so what do you do to make every day the best?

Aimee Alvarado 3J

"Neutralization reactions occurring when acids and bases are mixed can be very exothermic. Suppose you are investigating how the heat released in various neutralization reactions is related to the structures of certain acids. A constant-volume calorimeter was calibrated by carrying out a reacti...

Aimee Alvarado 3J

Will we need to identify systems for the midterm? How will it affect the problem in the way we solve it? Do you have any examples or keywords necessary to identify/remember which system is which?

Aimee Alvarado 3J

In the textbook, it mentions that when external pressure is zero, then work is also zero because it is expanding into a vacuum. Are there any examples of this occurring?

Aimee Alvarado 3J

In one of Lavelle's recent lectures, he mentions that our bodies give off heat because of our body's wasteful biological processes. Despite it being wasteful, is it more beneficial for us? Are there any consequences towards this?

Aimee Alvarado 3J

Which molecules' standard states are we supposed to memorize for the midterm? It's H2(g), I2(s), Br2(l), C(s), Fe(s), but are there more that we're supposed to know?

Aimee Alvarado 3J

I understand that when calculating x, we can sometimes approximate if K is larger than 1.0 x 10^3 or smaller than 1.0 x 10 ^-3, but do we only approximate if it's a large number (i.e. 1.0 x 10^-15 and 1.0 x 10^15)? Or can we still approximate if it is 1.0 x 10^4 / 1.0 x 10^-4?

Aimee Alvarado 3J

How do you recognize when something is a strong acid/base or is neutral? Is there a list that we can use to memorize them and where can I find it?

Aimee Alvarado 3J

The problem asks to determine the value of K using other chemical equations. Looking at the solutions book, I can see how it would work and where we would get the answer, but I'm still a little confused. Can someone please explain how they understood and got the answer to the problem? Thank you!

Aimee Alvarado 3J

The question is asking for the equilibrium constants after adding 1.00 moles NO2. One of the questions asked about the equilibrium concentrations of N2O4 and NO2, and I had problems setting up the quadratic equation to solve for x. Can someone tell me the steps they took to solve it? Thank you in ad...

Aimee Alvarado 3J

My comfort movie is Spirit: Stallion of the Cimarron. As a child, I loved watching this movie, and it's a miracle it isn't broken from the number of times I've watched this movie. It's a kid's movie, and it has an amazing soundtrack to listen to.

Aimee Alvarado 3J

In most cases, K will be raised to a very large power (for example 2.0 x 10^-37). Because it is such a small number it won't necessarily make a big change when calculating for equilibrium or anything related. Without approximation, we would have to do difficult calculations. If K is greater than 10^...

Aimee Alvarado 3J

Hi everyone! I have certain problems with ICE tables. I understand how to use them and what I need to put in each part of the table, but there are moments where I mess up in small things. Any tips or advice on what to do on these occasions or what you always do to solve a problem?

Aimee Alvarado 3J

Hi everyone! I had trouble with the problem that had multiple given equations to solve for K. I was able to solve the problem, but it took me a lot of tries and a lot of time. Can someone explain how they worked through the problem with the steps and what worked best for you in terms of how you solv...

Aimee Alvarado 3J

I plan to relax by watching shows, hanging out with my family, and starting up my self-care routine. Lately, I have not been doing it, and I think I'm definitely going to feel better after I start again.

Aimee Alvarado 3J

How did you all stay motivated this quarter and what did you do to keep it up? I feel like this quarter just zapped my energy and motivation slowly as the quarter went on, and I want to be prepared for the next quarter.

Aimee Alvarado 3J

I would recommend Mindhunter. It's so good but sadly the third season is going to take a long time to come out. It left off on a huge cliffhanger the second season, so beware!

Aimee Alvarado 3J

For those who did very well on the 14A final, what were your study habits? What did you do to understand the topics, and how did you work through topics that were very difficult?

Aimee Alvarado 3J

That's so amazing! I miss traveling and seeing new places. For winter break, I'm most likely going to stay home and start my self-care routine again. Hope you have fun and stay safe!

Aimee Alvarado 3J

Can someone explain to me the difference between the theories regarding acids and bases (i.e. Bronsted-Lowry, Lewis, etc.)?

Aimee Alvarado 3J

In the lecture, professor Lavelle explained a strong acid is very electronegative. However, the textbook mentions that the greater the atomic radius is the stronger the acid will be (HF < HCl < HBr < HI). How is this possible if the bigger the atomic radius the less electronegative it will be. What ...

Aimee Alvarado 3J

What is the difference between amphoteric and amphiprotic?

Aimee Alvarado 3J

Is there an easier way to name coordination complexes? Any tips or advice on learning the list?

Aimee Alvarado 3J

In the textbook, it explains how the valence bond theory calculates the probability of finding an electron in a certain location, but I don't understand how it would do that. Can someone explain what is connected to this theory and what it means?

Aimee Alvarado 3J

In the textbook, it mentioned that there are some bond angles that are "fixed," which means that we will always know what they are if we know the shapes, but it also mentioned experimental bond angles. Will we have to know how to find these for the final? If so, how would we find it or kno...

Aimee Alvarado 3J

I'm a little confused about what hybrid orbitals are and how to determine them. Can someone explain them to me?

Aimee Alvarado 3J

There were some problems in Sapling where we had to make Lewis structures, but I am confused about some of the feedback I got on them. It mentioned that I needed to do ring or cyclic structures, but I'm not sure what they are. Can someone explain all the structures we need to know in order to do the...

Aimee Alvarado 3J

What are all of the things that we need to take into account before determining which resonance structure is stable or not?

Aimee Alvarado 3J

Is there a difference between London Dispersion Forces and van der Waals forces? If there isn't, would all interactions between molecules have LDF or does it only pertain to van der Waal forces?

Aimee Alvarado 3J

Would having more bonded atoms make LDF interactions stronger? Why would that make it stronger?

Aimee Alvarado 3J

I usually know if a molecule is polar or nonpolar depending on if there is an unequal or equal sharing of electrons, but would I need to do more to make sure?

Aimee Alvarado 3J

There was a problem on Sapling that asked if all three structures were resonance structures. Why are they not considered this?

Aimee Alvarado 3J

In sapling, there was a question in regards to a delocalized pi bond. What is that, and how would you recognize it in an example?

Aimee Alvarado 3J

In Sapling, they gave a question about how many sigma and pi bonds there were in a molecule? Would we have to count each time the number of sigma bonds in each bond and then move on towards counting the pi bonds?

Aimee Alvarado 3J

What are the differences between sigma and pi bonds and how can you recognize them in examples or pictures?

Aimee Alvarado 3J

On Sapling, there were some questions about hybridization, and it gave a chart that said bonds and lone pairs determined the level. Is there a simpler way to do this, or can someone clear it up a little for me? Thank you in advance!

Aimee Alvarado 3J

In the textbook, it explains that a lone pair that is equatorial has the lowest energy. What makes it have the lowest energy compared to an axial lone pair?

Aimee Alvarado 3J

First, are there any tips on how to memorize the shape names? Second, will we need to memorize the degrees of the angles in the shapes for the midterms, and are there any tips on how to memorize them?

Aimee Alvarado 3J

In the lecture, Lavelle explained what delocalized means, but could someone explain to me the importance of double bonds being delocalized? Also, why does is it important to draw the delocalized double bonds in multiple structures rather than only using one structure?

Aimee Alvarado 3J

In the lecture (11/02), Professor Lavelle discusses how to do Lewis structures and how they should look like (double bonds and formal charges). What are all the steps needed to complete the Lewis structure? By this, I mean, would it not be enough to make sure all valence electrons are bonded or that...

Aimee Alvarado 3J

In the lecture, Professor Lavelle explained the Pauli exclusion principle and Hund's rule, but I am still a little confused about it. Can someone please explain it to me?

Aimee Alvarado 3J

In Lavelle's lecture about ionic and covalent bonds, he discussed how one side of the periodic table forms cations and the other forms anions. Why does this occur?

Aimee Alvarado 3J

I was wondering if anyone can share tips on how to memorize the trends in the periodic table (i.e. atomic and ionic radii, etc). Thank you in advance!

Aimee Alvarado 3J

In sapling, there are some problems where they give you the equation 3.29 x 10^15(1/n1^2 - 1/n2^2) and another identical one except they use 1.0974 as rydberg's constant. How would you know which one to use and what are the differences in both of these?

Aimee Alvarado 3J

You would use the de Broglie equation. Because it is asking for the velocity of the particles, you would need to change it from lambda = h/(mv) to v = h/(m/lambda) to solve the problem.

Aimee Alvarado 3J

The quantum numbers n,l, and m describe the energy, size, shape, and orientation of wave functions, and I understand how to use them to find the ground state and everything else involved. However, I still have trouble remembering what the rules are for each rule for the quantum number. For example, ...

Aimee Alvarado 3J

"The E.coli bacterium is about 2.0 μm long. Suppose you want to study it using photons of that wavelength or electrons having that de Broglie wavelength. What is the energy Ephoton of the photon? What is the energy Eelectron of the electron?" Can someone help me solve the second part of th...

Aimee Alvarado 3J

I don't believe we'll have to memorize the molecular formula or mass of certain compounds from their name alone on the midterm. Dr. Lavelle will provide most of the information we need to know, and I think that in later chemistry classes we will need to but not right now. However, I would check in w...

Aimee Alvarado 3J

Do we need to be able to find the electron density or is it something that will be given in the problems? I don't believe we'll need to know exactly the electron density or be given it. For the first midterm, we just need to conceptually understand what Schrodinger's equation is and how it relates ...

Aimee Alvarado 3J

Shrodinger's Equation deals with the probability of finding electrons in certain areas of orbitals. For example, the s-orbital is a sphere. When calculating the probability of finding an electron, there will be an equal probability of finding e- anywhere in the s-orbital sphere. However, the p-orbit...

Aimee Alvarado 3J

Amplitude is equal to the intensity and brightness of a light. It would have no effect on wavelength and frequency at all because it would only be changing the height and would not be making it smaller or longer.

Aimee Alvarado 3J

The constants and equations paper that Professor Lavelle provides for us has some of the conversions we need but are there others that we need to know? For example, we have the conversions for nanometers, picometers, kilograms to grams, and a few others, but are there some we need to know to solve o...

Aimee Alvarado 3J

Can someone explain the difference between the Balmer and Lyman series and how you would identify them? There are some problems in the textbook that have the Lyman series, but I'm not sure how you would recognize it and how you would use that information to solve the problem. Also, would the midterm...

Aimee Alvarado 3J

Jaden Haskins 2F wrote:OH this is a response to my last question and it might be silly but all electrons have the same mass correct? It doesn't differ based on the element?

All electrons share the same mass, so it will always be 9.10956 x 10^-31 kg.

Aimee Alvarado 3J

This is how I answered those questions: a) I used the equation 1/2mv^2. In this equation, m = 9.10956 x 10^-31 (the mass of an electron) and v = 6.61 x 10^5. The equation would look something like this 1/2(9.10956 x 10^-31) x (6.61 x 10^5) which equals the kinetic energy of the ejected electron. b) ...

Aimee Alvarado 3J

Because there are no parentheses around CO4, this just means that they are being counted separately. By this, I mean that C = 1 and O = 4. If it was (CO4)^2, then that would mean you would multiply each element with 2, becoming C = 2 and O = 8.

Aimee Alvarado 3J

There really isn't an order as to how to balance equations. I find it easier to separate them into a table with products on one side and reactants on the other. This just helps in figuring out which element would be the best to start with first. However, there are some times where I find that I need...

Aimee Alvarado 3J

You shouldn't have a balanced equation with mixed numbers. Usually, if you do have a mixed number (6.5), you would divide the entire equation (both products and reactants) to get rid of the mixed number. In the end, you would have whole numbers in the equation, which makes everything much easier to ...

Aimee Alvarado 3J

So this is how I solved the problem: 1. To find the grams for C, you have to use the molar mass of C (12.01 g/mol) and the mass of the compound CO2 (44.01 g). You would divide the molar mass of C by the compound mass (C/CO2). This gives you the grams for C. 2. To find the grams for H, you would do t...

Aimee Alvarado 3J

Javier Perez M 2J wrote:Was this chemical reaction balanced already or did we have to balance it? The one provided in the question

The chemical reaction that was provided was balanced already, so you did not have to balance it.

Aimee Alvarado 3J

After reading some of the replies, I'm afraid I have a silly question. People are saying to "multiply 0.325 with 590.1g" but my question is what they did to get 0.325 and why. Thank you! They got .325 from the percentage of calcium chloride (32.5%). You would move the decimal point on the...

Aimee Alvarado 3J

The formula for 2-butanone is C4H8O, and you would calculate the molar mass in order to find the moles. You would then assume from the picture that it is a 1:1 ratio and that the moles would be the same for both 2-butanone and 3-methyl-3-hexanol.

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