CHEMISTRY COMMUNITY

Emma Goellner 2I

II would recommend looking at the document Dr. Lavelle sent out with all of the information on the final! There is a breakdown of the topics and how many weeks we spent on them.

Emma Goellner 2I

Morgan Micallef 1A wrote:Phoebe Bridgers, Jhene Aiko, Lucy Dacus, Daniel Caeser, and Dominic Fike are some of my favorites

Oh my gosh. You have an immaculate taste in music.

Emma Goellner 2I

Kayla Ziebell 1H wrote:I love the song "space song" by beach house when I study

That song makes me cry haha! It's so good though, Beach House is one of my favorite bands ever.

Emma Goellner 2I

Violet Mbela 2B wrote:
Emma Goellner 2I wrote:The Marias, Men I Trust, and Phoebe Bridgers are really nice to work or study to

I love the Marias!

They're so amazing! I love finding people with similar music taste haha :)

Emma Goellner 2I

Termolecular reactions are less common because all three reactants must simultaneously collide with each other, with sufficient energy and correct orientation, to produce a reaction.

Emma Goellner 2I

It should be a linear graph for a second order reaction!

Emma Goellner 2I

Online has worked just fine for me! I've gone in person once, but only since I had an early morning class nearby. I'd suggest to do whichever works best with your schedule and preferences!

Emma Goellner 2I

In the equation you reference, "n" stands for moles.

Emma Goellner 2I

Sharetea is really good for boba. There's also a Starbucks, movie theater, Urban Outfitters, and some nice coffee shops to explore around Westwood.

Emma Goellner 2I

Zero order reactions are less common because for the majority of reactions (especially the ones we study), their rate is dependent on the concentrations of one or more of the reactants.

Emma Goellner 2I

Yes. We are not going to be asked to derive any of the formulas we derive in class on an exam.

Emma Goellner 2I

Do all of the textbook problems! It is unbelievably helpful to prepare for the exams and to practice the content learned in lectures. That is definitely my number one recommendation, but continue to keep up good homework and study habits along with it.

Emma Goellner 2I

I love the ICE BOX. It is an incredible invention. Whoever decided to put the numbers in a nice little box slayed tremendously. It helps my brain interpret the information, overall a very good time.

Emma Goellner 2I

I usually see Ea used to represent activation energy, but I'm sure if you see EA in a problem it probably means the same thing. However, as other people mentioned, it could stand for electron affinity.

Emma Goellner 2I

I think they are less common. They often occur when a catalyst or enzyme is required. The catalyst or enzyme is saturated and increasing the concentration of reactants does not increase the reaction rate; the reaction rate is limited by the rate constant, k.

Emma Goellner 2I

w=-P∆V and w=-nRTln(V2/V1) are the two equations I find myself using a lot on the achieve homework and textbook problems.

Emma Goellner 2I

K is used to represent the equilibrium constant (which we've seen in ICE table problems, etc). K could also be the symbol for Kelvin (temperature). k is the rate constant which we have been using in this section on kinetics.

Emma Goellner 2I

For a first order reaction, t1/2=0.693/k
For a second order reaction, t1/2=1/k[A]o
For a zero order reaction, t1/2=[A]o/2k

Emma Goellner 2I

I wouldn't worry about it too much, since he's only mentioning it as we will be covering it later on in the course :) However, a reaction mechanism is the sequence of elementary steps by which a chemical reaction occurs. There is a lot more to reaction mechanisms and their connections to the order o...

Emma Goellner 2I

I've done a lot of examples/labs with thermodynamics involving the making of ice cream (search up ice cream calorimetry). Also, there are some articles/information about the thermodynamics of ice cream made with dry ice which I found to be really interesting! In a more general sense, heat transfer i...

Emma Goellner 2I

In a zero order reaction, the rate of the reaction is independent of the concentration of reactants. This often occurs when a catalyst or enzyme is required. The catalyst or enzyme is saturated and increasing the concentration of the reactants does not increase the reaction rate. In other words, the...

Emma Goellner 2I

It has definitely been more stressful, especially in comparison with Chemistry 14A. I am really interested in the content, however, so I've been enjoying the lectures a lot :) Hopefully I can manage my stress a bit better!

Emma Goellner 2I

The Marias, Men I Trust, and Phoebe Bridgers are really nice to work or study to

Emma Goellner 2I

Like the other comments explained, I first found the number of moles of gas using the ideal gas law. I then multiplied this value by the Cv,m value given in the problem. After, you can use this value to solve for the entropy change using the equation Delta S=Cp*ln(T2/T1). Make sure your units cancel...

Emma Goellner 2I

Hello! To solve this problem, we need to know three steps that involve finding the standard molar entropy of vaporization: the entropy change heating water from 59.0 °C to 100 °C, the entropy of vaporization of water at 100.0 °C, and the entropy change cooling water from 100 °C to 59 °C. To solve t...

Emma Goellner 2I

Taking walks! If I need to study, instead of just doing work in my room, I try to walk somewhere beforehand. I find that I can focus a lot better when I'm somewhere new and have just done some excersize.

Emma Goellner 2I

The rolled corn tortilla chips (TJoe's version of takis) are my favorite snack.

Emma Goellner 2I

I really like going to Kerckhoff Coffee, especially since there is both indoor and outdoor seating. Also, it's on campus, so it's convenient to get to (or stop by, if you're already going to classes).

Emma Goellner 2I

I'd have to agree with the other comment about the beach! It's pretty easy to get to Santa Monica using the busses here and the beach/pier is so nice.

Emma Goellner 2I

Sour Patch. The watermelon flavor especially is so good.

Emma Goellner 2I

Any kind of pasta has been my favorite food for a while. I love the pasta at Epicuria.

Emma Goellner 2I

My current favorite shows are ATLA, Fleabag, Community, and Parks And Rec.

Emma Goellner 2I

Happy (late) Valentine's Day!

Emma Goellner 2I

Oxidation involves loss of electrons, while reduction involves gain of electrons. Since the electrons are flowing from the anode to the cathode, oxidation occurs at the anode and reduction occurs at the cathode.

Emma Goellner 2I

Q is the reaction quotient when the system is not at equilibrium. K is the equilibrium constant, so it uses the concentrations of reactants and products at equilibrium.

Emma Goellner 2I

The actual value of R will stay the same, as it is a constant. However, the units of R are very important, so it's necessary to ensure the right cancellations can be made.

Emma Goellner 2I

The pathway does not matter for state functions, just the initial and final states. This makes calculations very straightforward. Some examples of state functions are enthalpy, entropy, and Gibbs free energy.

Emma Goellner 2I

It's definitely still possible using moles, but it usually is clearer/easier to use units of molarity. This is because ice tables are intended to organize the initial, change, and equilibrium concentrations of the reactants and the products.

Emma Goellner 2I

Yes, you should reach out to your TA if you want to review your midterm 1 answers. Dr. Lavelle also sent out an email about this.

Emma Goellner 2I

Yes, you do.

Emma Goellner 2I

I believe we are expected to post 5 times a week. I haven't been told how it's graded for this quarter in 14B, but in 14A, we were allowed to make up posts.

Emma Goellner 2I

When delta G is negative, the reaction is spontaneous.

Emma Goellner 2I

Dr. Lavelle sent out an email about the future for classes.

Emma Goellner 2I

It is helpful to remember that for an exothermic reaction, the products have lower energy than the reactants, creating a negative delta H value. This means that heat is released. On the other hand, for an endothermic reaction, the products have higher energy than the reactants, creating a positive d...

Emma Goellner 2I

I also ended up with that answer!

Emma Goellner 2I

An open system is a system where matter and energy can exchange with the surroundings. An example of this is a beaker of water, where the water is able to evaporate and the beaker does not insulate. In contrast, a closed system can exchange energy with the surroundings, and an isolated system can't ...

Emma Goellner 2I

It states that for a closed system, internal energy changes as a function of heat and work.

Emma Goellner 2I

Mathematically, it is that the limit as T approaches 0K of S is equal to 0 (for a perfectly ordered material).

Emma Goellner 2I

Take breaks! Don't push yourself harder than you are capable of withstanding. It is always important to exercise your mind and body (as Dr. Lavelle often mentions at the end of lecture). Talk to some friends, take a walk, or maybe listen to some music that makes you happy.

Emma Goellner 2I

I completely understand how you feel, since I've also felt overwhelmed at times. I've found it really helpful to identify what specific topics I'm struggling with. Based on that, I can get a better sense of how many review sessions I want to attend. If you're intimidated by the amount of resources, ...

Emma Goellner 2I

The reactants are being used up in the forward reaction to create the products. Thus, the concentration of the reactants will decrease from the initial value, and the concentration of the products will increase from the initial value. The final values of the ICE Box are the equilibrium concentrations.

Emma Goellner 2I

Allow yourself the space to take a break and really allow yourself to relax. Take a shower, listen to some music, talk to your friends, and maybe watch a show that makes you laugh.

Emma Goellner 2I

Hi - it depends on how the pressure is changed. If the pressure is changed by changing the volume of the system, this will affect the value of K, and the reaction will adjust by shifting to the left or right accordingly (to minimize the effect of the change, as explained by Le Chatelier's Principle)...

Emma Goellner 2I

Yes, it does :) You just have to make sure that the ratios are correct and take that into account when setting up your ICE Box.

Emma Goellner 2I

The ICE Box acts as an extremely helpful organizational tool, although technically you could solve an equilibrium problem without it. It just makes it very easy to identify your known and unknown values.

Emma Goellner 2I

We won't have to deal with cubic problems with a large K in this course, fortunately. When K is very small we can just use the small x approximation to make the calculations doable.

Emma Goellner 2I

When there is a separation of charge in a molecule, there is a dipole moment. If the dipole moments cancel out, then there is no net dipole moment. If the dipole moments are additive, then there is a net dipole moment, and the molecule is considered polar.

Emma Goellner 2I

It stands for valence shell electron pair repulsion theory. VSEPR helps describe the shape of a molecule in a way that Lewis Structures cannot, since it takes into account repulsion from lone pairs and the number of bonds that a molecule has.

Emma Goellner 2I

Yes, I agree with what someone already said, which is to look up a picture or chart of the different wavelengths and which series they correspond with :)

Emma Goellner 2I

Yes, as already mentioned, part of what we learned was how to name coordination compounds.

Emma Goellner 2I

Very funny thank you for sharing :)

Emma Goellner 2I

Emma Goellner 2I

I had to make a bad chemistry joke here because all of the good ones Argon :(

Emma Goellner 2I

The closer the electrons are being pulled in towards the positively charged nucleus, the harder they are to remove, and thus there is a higher ionization energy. The electrons have a stronger pull when the radius is smaller, because they are closer to the nucleus. When the radius is larger, the ioni...

Emma Goellner 2I

If there is simply a single bond, it is a sigma bond. When you have double and triple bonds, you have both sigma and pi bonds. Double bonds will contain one sigma and one pi bond. On the other hand, triple bonds will contain one sigma and two pi bonds.

Emma Goellner 2I

Lewis acids can accept electrons, while lewis bases can donate electrons.

Bronsted acids can donate protons, while bronsted bases can accept protons.

Emma Goellner 2I

AsCl5 is a nonpolar molecule because there is no net dipole moment. The electron density is being pulled towards each Cl, which is more electronegative than As. Since all 5 elements bonded to the central atom are the same, and it is trigonal bipyramidal, there is no net dipole, and the molecule is n...

Emma Goellner 2I

As we went through some examples of calculating pH in lectures, I think it would be good to be familiar with it. Also understanding the meaning of and how to find KA and pKA is probably a good idea.

Emma Goellner 2I

Water is left out when calculating KA because it doesn't change in concentration. Dr. Lavelle mentioned in lecture that you could technically include it, but it would just cancel out on the numerator and denominator, because the concentration stays the same. The concentration of water is constant.

Emma Goellner 2I

When NaCl is added into H2O, it dissociates into sodium and chloride ions. Neither of these ions react with water molecules, so it won't affect the pH (only the volume of solution). However, a salt can affect the pH of water if it reacts with water molecules, thus affecting the concentrations of hyd...

Emma Goellner 2I

Bronsted acids donate protons, while Bronsted bases accept protons. An example of an amphoteric compound is water, since it has the potential to act both as an acid or a base depending on the circumstances.

Emma Goellner 2I

Why do chemists enjoy working with ammonia so much?

Because it's pretty basic stuff

;)

Emma Goellner 2I

Lewis acids are acceptors of electrons, while lewis bases are donators of electrons. Drawing out the lewis structure can be helpful to see which molecules might have an electron pair that could be donated, or which molecules might be good candidates for accepting electrons in a reaction.

Emma Goellner 2I

I think this is a really good idea, and would also like to be involved if anything is still happening!

Emma Goellner 2I

Thank you haha his songs are really one of the highlights of the class I love it.

Emma Goellner 2I

When looking at the boiling or melting point of a compound, you would want to look at the intermolecular forces present. The stronger the intermolecular forces, the more energy needed to boil or melt the substance. This is because energy is required to break bonds. Some examples of IMFs that could c...

Emma Goellner 2I

To stay motivated, it helps me a lot to work and study with others, make a plan, and get enough sleep every night. Being in a good mood from socializing, eating enough, drinking water, and sleeping enough. Taking care of yourself should always come first, since it can be hard to feel motivated if yo...

Emma Goellner 2I

Yes, we will. In order to determine the shape of a molecule, you will need to know the Lewis Structure (to find out how many bonding and non-bonding pairs are on the centralized atom).

Emma Goellner 2I

It helps me a lot to feel prepared and organized before any test, and especially for the final. Also, studying with a group of other people can be less stressful, more fun, and more effective. Take deep breaths, remind yourself to be present, and be kind to yourself.

Emma Goellner 2I

Hi -
I don't remember exactly how it works, but there is a Youtube video with a nemonic device (BLTS) that you can watch just by searching it up. I haven't used it since high school, but I remember it helped me.

Emma Goellner 2I

I always remind myself that the results of my exam do not necessarily reflect the effort (or even the amount of knowledge) I had when taking it. If possible, try not to compare your results with others or open your results around others. Stay kind and compassionate to yourself!

Emma Goellner 2I

Staying organized helps me to stay focused. Plan out what material you are going to work on and/or study beforehand. It can also help to set a time you are going to work to help keep yourself accountable.

Emma Goellner 2I

It helps me to first highlight/circle all pieces of information and values you are given in the problem. Then, I identify what I need to find or what the question is asking. I look at the equation sheet provided by Dr. Lavelle to see what possible equations I could use to find the answer given the i...

Emma Goellner 2I

Thank you so much! This is really helpful.

Emma Goellner 2I

It is always important to be compassionate towards yourself, even when you feel unproductive. If you are having a hard day, it is okay to make space for yourself. When I am feeling particularly stressed out, I like to take a shower, drink some tea, listen to some music, and recharge. In order to get...

Emma Goellner 2I

I find that when I prepare myself ahead to study and work, I am more likely to actually get work done. Setting specific times and days to work on specific assignments helps me to feel organized. If I don't have a clear idea of what I need to do, it can be really hard to be productive. Also, instead ...

Emma Goellner 2I

I am thinking of taking Chem 14B, Math 31B, and a GE (thinking of taking a film class, possibly). If anyone has any GE suggestions I am still unsure of what I want to take.

Emma Goellner 2I

I love listening to classical and jazz music while studying. Also, any of the study music playlists on Youtube are great. I also like to put rain noises in the background of the music, as it helps me relax.

Emma Goellner 2I

To relax, I like to take walks, talk to friends, eat some comfort food, take a shower, and listen to music.

Emma Goellner 2I

I agree with most people that studying on the day of the exam is not a great idea. It is best to prepare yourself before. Wake up early, get ready, eat breakfast, etc. Make sure you have everything you need for the final (materials, papers, etc). It helps me a lot to talk to a friend beforehand. You...

Emma Goellner 2I

Happy (late) birthday!

Emma Goellner 2I

The very end of the information covered right before Midterm 1 will be on Midterm 2 (periodicity, etc). Aside from that, I believe everything we've covered so far. I think Dr. Lavelle will specify the cut off for topics next week.

Emma Goellner 2I

Recently, I have started watching the Netflix show You, and I definitely recommend it. My other favorites are Bojack Horseman, Community, Grey's Anatomy, and the Midnight Gospel. I'm always looking for new show recommendations.

Emma Goellner 2I

Hank Green is my favorite chemistry Youtube channel. He explains things in a way that makes them really interesting, and its clear he genuinely is passionate about chemistry. His videos have helpful animations and examples as well. Overall, Hank Green's videos are best if you want a good overview of...

Emma Goellner 2I

Yes, you should use those equations (E=hv, wavelength=c/v) to get the equation E=hc/wavelength. You can use this to calculate the solution to the problem.

Emma Goellner 2I

Most of the content in the Quantum Unit will be on the test. From what I heard, there may be some content in the homework assigned on Achieve that will not be included in this midterm, but if this is the case, it will be on the next midterm. Also, it wasn't clear what specific topics might not be on...

Emma Goellner 2I

You should bring a hard copy of the given periodic table and equations sheet provided by Dr. Lavelle (found on website).

Emma Goellner 2I

Yes, you should bring hard copies of the given periodic table and equations sheet provided by Dr. Lavelle. You won't need to memorize any specific chemical equations - the information you need should be provided on the exam.

Emma Goellner 2I

The work function represents the minimum amount of energy needed to eject an electron from the given metal. In this sense, the work function can also be thought of as the ejection energy. Different metals will have differing values for the work function depending on how easy it is for an electron to...

Emma Goellner 2I

I like to do art, whether that be painting, drawing, or sewing. I also enjoy reading to take my mind off of things, watching Netflix, eating good food, and drinking tea. Listening to comforting music can really help me unwind after a hard day as well, so I always have my airpods with me.

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