CHEMISTRY COMMUNITY

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All three reactions will be linear. For zero and first, k is negative (negative slope). For second-order, k is positive (positive slope).

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It honestly depends on the time and also how you're managing recorded/online lectures right now. For me, if it's a morning class I definitely prefer online but if it's during the day in-person classes are awesome! And etc for discussions.

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What are some of your best study spots/relaxing places on campus? I'll start, mine is probably the front of Saxon--I could probably spend hours out there on a good day!

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The units would be M-1s-1! For zero, it's Ms-1, for first, it's s-1, and as a result, for second-order, it would be M-1s-1.

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Every graph should show a linear graph, it's the axis that are different.

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The boltzmann constant relates the absolute temperature and the average kinetic energy in each molecule of an ideal gas with units of J/K. It is also the ideal gas constant per molecule. So by multiplying by Avogadro's number (Na), we get the gas constant (J/K*mol). Thanks, this helps a lot! I was ...

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Hi! Could someone explain why a reactant has basically no effect on the initial rate if they are large in concentration/in large excess? Thank you!

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Have two reactants stay at the same concentration, and notice when the other reactant changes concentration, and how that affects the initial rate. If the initial rate stays the same, the exponent is 0. If it increases by the same fold as the change in concentration of the reactant, it’s exponent is...

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There shouldn’t be any negative values, so it should be 2/3! Flipping the sign doesn’t pertain to molar ratios.

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The half life equation is t(1/2) = 1/k[A]0, where k is the rate constant and [A]0 is the initial concentration!

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Gibbs free energy, or the energy available to do work, is equal to deltaH - TdeltaS! If Gibbs is negative, the reaction is spontaneous, if Gibbs is positive, the reaction is non spontaneous.

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If the Gibbs free energy is negative, the reaction is spontaneous. If S(total) is positive, the reaction is also spontaneous!

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I love it too, especially when you make the table all neat, it’s so aesthetic and satisfying!

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My friends and I have been so obsessed with this green grape candy from Hmart in Ktown!

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It depends on the substance or the question! If the question is given in minutes, you should probably calculate it in minutes but generally I think seconds is more common in our textbook problems.

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If you’re given a plot, there should always be a straight linear line shown. It’s the axis that show a difference between 0 order reaction, 1st order, etc. For a 0th order, it would be t plotted against concentration.

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The half life equation is t(1/2) = [A]0/2k, where k is the rate constant and [A]0 is the initial concentration!

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The rate law is never negative but a the formula asking for a rate can have a negative sign in front of it, as when reactants are spent they’re decreasing, therefore leading to a negative sign in front of the equation. However, overall the result should still be positive!

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Hi! The context will most likely tell you the difference between the ks, but generally an uppercase K stands for “Kelvin,” and a lower case k is either the equilibrium constant or the rate constant. The rate constant you’ll see in questions pertaining to kinetics, and the equilibrium constant in the...

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I believe that it's the balanced number of electrons that we look for when we plug in the n value! It should be same for both reactions in the redox reactions!

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A spontaneous reaction would occur with no energy input. As a result, in usual cases you should look for energy that is being released, or exothermic reactions, and a negative delta G value.

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The first equation is for irreversible reactions, and the second equation is for reversible equations!

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When a reaction is at equilibrium, there is essentially no change in free energy as the rates of the forward and reverse reactions are the same. As a result, Delta G is 0.

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Elysee in Westwood is a great place to study at! The pastries are super delicious :)

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Reduction potentials are intensive because the amount of substance doesn't affect the value. As a result, when calculating the potentials, you don't multiply by the number of moles if you alter the chemical reaction.

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Yeah, I believe so!

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Oxidation is when something loses electrons, and reduction is when something gains electrons. I think it's a little counter-intuitive, but I like to think of reduction, as the charges (values) are reduced, for example from 3+ to 2+. This occurs when electrons, a negative value is gained.

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Symmetric molecules are uniform structures, and as a result do not have any residual entropy as the molecules are in the same states regardless.

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Degeneracy, or W, is just the number of states that can be occupied for a certain energy state.

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Generally, if temperature increases in a system, the disorder increases as molecules move faster and bump into each other. In an exothermic reaction, heat is released from the systems, so the system's entropy decreases due to a decrease in temperature, and the surrounding's entropy increases. And vi...

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Yes! Pressure is connected to volume--if you increase the pressure, the volume decreases, and the molecules have fewer states available. As a result, the entropy decreases.

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I would try your best to post 5 times a week, but I think it also just depends on your TA. In the end the posts really stack up though, so I would definitely recommend just getting it done on schedule!

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Definitely sleeping early and going to class outside. I find that if I'm outside and not in an enclosed space I always pay attention in class better, maybe its the sunlight haha.

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I've really been loving Brent Faiyaz or BETWEEN FRIENDS!

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Wait seriously? That's actually so cool, I thought the music was from Glass Animals.

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Thrifting in Santa Monica is always a go-to! I would also recommend going to the farmers market in Westwood on Thursday.

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I love to take walks as well, and I listen to music or play my bass either by myself to practice a fun song or with my band! Academics are important but I just can't live without the activities I do outside of school.

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The baked peas are so good! Super crunchy and makes me want to work more.

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Could someone explain how you could find the entropy of vaporization of a compound at a temperature that isn't its boiling point? If the substance doesn't vaporize at that temperature, how come you can still find the entropy of vaporization at the temperature?

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When does the entropy of an isolated system increase? I understand why the change in the entropy of an isolated system stays at 0, but if there's nothing done to the isolated system, how would the entropy increase?

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A human body generates heat at the rate of about . (a) At what rate does your body heat generate entropy in your surroundings, taken to be at °C? (b) How much entropy do you generate each day? (c) Would the entropy generated be greater or less if you were in a room kept at °C? Explain your answer. F...

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Could someone please explain what the difference in the way we approach/calculate these two types of concepts/problems is? I can't really tell a difference, especially with the salt solution equilibrium.

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Hi! It really depends on the Q value, and whether the reactants or products are being used up. If you compare the Q value with K, it should explain which direction the reaction is favoring, and from which side of the reaction to subtract and add to.

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Hi! Generally choose the x value that is positive, or the (smaller) x value if both are positive, as when subtracted from the initial condition the equilibrium value cannot be negative. There most likely won't be a case where both x values are viable.

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Hi! The moles concept results when the pressure of where the reaction is taking place changes. Since the problem mentions partial pressure, especially of a product, we don't compare moles here. When the partial pressure of CO2 is increased, this results in a increase in reactants as the reaction shi...

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Hi! I know the textbook can be daunting, but it's way to understand the concepts explained in class, especially because Dr. Lavelle posts the focus topics in the outlines/syllabus.

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Hi! I believe generally the pKa values will be given especially for comparison, unless they ask for you to solve for it, or the strengths of the molecules are obvious in other ways.

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The password should’ve been provided in a email he sent earlier! If you can’t find it, it’s in the same format at the previous password just for the new year and 14B.

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Yes, it’s calculated the same way—one is just for gases (pressure) and the other aqueous solutions (concentration).

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I’m actually wondering this too because I know that 14A was all multiple choice, but I’m not sure how it’ll be formatted now that half the quarter might be in person.

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I’m actually wondering this too because I know that 14A was all multiple choice, but I’m not sure how it’ll be formatted now that half the quarter might be in person.

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I believe that all noble gases are inert, but not all inert gases are noble gases and are more context dependent. For example, Nitrogen is a inert gas but not noble.

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The differences in measurement is so small that you don’t really have to worry about it! Still just keep in mind that they are two different units.

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asheagg3I wrote:This is the group me link that I have for chem 14b:
https://groupme.com/join_group/83905907/SUP7995s

Thank you so much!!

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I hope everyone did great on their finals!

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Honestly I was thinking about switching majors too, but it's a totally natural thing to do so don't stress about it! I know so many people who have already switched majors/are thinking of switching majors, and as long as you have you ges and plan out well I'm sure you'll be fine!

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Taylor K 2D wrote:These are memes I made when I took chem in high school lol.

oh [censored] these are too good

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I don't think there's a check in but make sure to do your covid monitoring as always and just arrive a couple minutes earlier!
Good luck on the exam :)!!

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Good luck!! I hope everyone gets plenty of rest and you will all do great. <3

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I'm pretty stressed because all of my finals are very close together, but I'm excited to finish this quarter and enjoy my winter break :,). Good luck to everyone!

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Ligands are ions or neutral molecules that bond to a central metal atom or ion. Ligands act as Lewis bases (electron pair donors), and the central atom acts as a Lewis acid (electron pair acceptor). Ligands have at least one donor atom with an electron pair used to form covalent bonds with the cent...

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I would definitely have an understanding of the specific biological importance--there is a chance that we'll be tested on it, so just review just in case.

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I'm still really confused as to how to identify if a molecule is a ligand, and how many attachments it can form. If anyone could do a quick clarification, that would be really great!

Thank you!

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Hey! A pretty easy way of understanding hybridization is to look at the shape, as as each shape corresponds to a specific hybridized orbital as mentioned before hand. A really good practice problem to work on that attacks this in depth would be 2.45 in the textbook--it's a pretty hard problem, but w...

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Hi!

The way I'm identifying if the sol'n of a salt is acidic, basic, or neutral is to compare the conjugate bases and acids. I saw a section in the textbook talking about the role of cations and anions in salt solutions though--does it play a role in the pH of the solution as well?

Thank you!

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Hi there! 6.21a) The two nitrogens in the molecule both have lone pairs, so they can each accept one proton. Therefore, this base can accept two protons. 6.21b) Amphiprotic means that the molecule can either donate or accept a proton. If either NH gains a proton, they become NH2. NH2 is amphiprotic...

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Maybe not memorize, but definitely understand the concept behind why the trend occurs and have basic understanding of what lies where!

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Lindsay Beckwith 3C wrote:Can we miss a few posts one week and make up with extras the following week?

Yup! I believe so, at least the people who I talked to say that it'll be counted up at the end of the quarter.

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Hi,

I was just wondering what we need to know about acidic and basic oxides. What practice problems should I focus on?

Thank you!

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Hi!

Could someone explain problem 6.21, c from the textbook? How do you decide if a compound shows amphiprotic character?

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Hey, I'm not online but I would love to join a study group as well, would be totally down to have an in person study session.

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This is late, but congratulations!

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I think we can expect topics we spent more time on (like quantum) to have higher weight. But we should also expect a good amount of questions on acids and bases since we haven't been tested on it. I agree with this, I think there's gonna be a good amount of untested material on the final since it m...

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My best study tip is to skim over the textbook and definitely practice, practice, practice! The textbook personally helps me understand the concepts we learn in more depth, and practice helps with the more repetition based solving problems we come across.

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Just a warning to all! I'm not sure if I'm the only one but be careful with how heavily you rely on outside material. It can be useful to get another explanation that might make more sense to you but remember that these sources aren't in direct relation to the course. Personally, I think your best ...

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Samurai's Garden by Gail Tsukiyama and any other Japanese literature just hits different for me. The tone, the setting, and the way characters are portrayed just feels so humane and real. Definitely recommend!

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Ratatouille. Hands down one of my favorite movies of all time, I've loved it since a kid so it holds really fond memories in my heart. I watch the movie every time I get unsure about the future or just need a day of rest.

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This is so relatable. Honestly I just take it day by day, plan my day out and have a set of goals that I want to accomplish by then. I try to split my studying up so that I don't get overwhelmed or burnt out too.

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I'll start! Mine was great, got to meet up with a bunch of hometown friends and had a really relaxing couple of days. I missed my cats so much and being able to cuddle with them was the highlight of my trip.

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Reading through the textbook might seem daunting, but it really is a good resource to tackle the more conceptual questions on the exam. Sometimes these questions pop up and having that "aha!" moment from reading the textbook is really nice. Best of luck!

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I agree with everyone who has posted before! It varies from person to person, but this seems like a really homework and study focused course load that could be overwhelming at times. If fall quarter wasn't too bad, and you think you can handle more then go for it, but honestly I would take less for ...

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I like to plan out my day beforehand so I have some kind of outline to follow throughout my day! It's totally ok to not be focused sometimes, but placing your devices in a different space will definitely help as well.

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Even though this would take some time, I would also REALLY recommend skimming through the textbook--it provides so much more information than you need to know, but it helps with the more conceptual questions on the exams.

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I wasn't able to enroll in the lab for next quarter 14B, how much of a disadvantage is that when taking the chem 14 series and do people usually drop during the quarter? Thank you!

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I died laughing at this. It's been a while since the midterm but I still really needed the pick me up, thank you!

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I would usually take a walk, or make sure to get plenty of sleep! Hype music also always makes me feel a ton better, as well as talking to my close friends and properly expressing my feelings of stress to others.

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Hey! I was wondering if you guys had any music that would be perfect to destress with that isn't too sad. I personally love Strawberry Swing by Coldplay.

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Angela Denvir 1A wrote:Hi!

Even though the formal charge of radicals is zero, the electron shells will still have single, unpaired electrons, making it very unstable. This is more significant and thereby, kind of overrules the formal charge being zero. Hope this helps!

Ok thank you so much, that makes a lot more sense!

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Could anyone help me out with problem 3 from section 2C? Draw the Lewis structure, including typical contributions to the resonance structure (where appropriate, allow for the possibility of octet expansion, including double bonds in different positions), for (a) periodate ion; (b) hydrogen phosphat...

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Hi! I was just wondering why radicals are so reactive if the elements have a formal charge of 0. Shouldn't this mean that they are more stable and less willing to react and trade electrons?

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I love this post so much!! I write poetry that’s very personal to me but I think it’s super cool that there’s a poetry post in a chemistry forum especially with how science and humanities are separated a lot of the time.

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I generally like to listen to music without words so that I don’t have any impulses to sing along to the words. Anything from classical to something like instrumental rock is great imo!

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Ok technically it’s not Halloween anymore but me and my two friends dressed up as the powerpuff girls! Proud to say we looked very good <3

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I’m kinda stressed because I feel like I’m falling behind on classes, but I think I’ll make it through! Thanks for asking op.

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I mostly listen to music or FaceTime my close friends. I’m not an extrovert exactly, but whenever I feel stressed it’s always helpful to have someone to talk me through my thoughts! I also like to read and draw, or I take a walk without music.

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Practice, practice, practice! In my case, solving the problems should be muscle memory at a certain point, and that’s when I feel more comfortable with taking an exam. Conceptual wise, I try to connect everything together in a cohesive story so that it’s easier to remember the history and “why” behi...

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Gah, as someone who struggles from anxiety I seriously understand what you’re going through. I definitely do activities that try and take my mind off of chem so I don’t too fixated on what I have to do, that way the stress doesn’t build up. Please take care of yourselves!

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I’m hoping just to visit my family and chill with friends back home! Excited to watch a tonnn of movies.

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Definitely take it slowly and don’t try to read the textbook in one go! Since it’s such a large piece of material really take the time to split the information into sections.

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Ameen Shaheen 3K wrote:Hi Violet!
I'm in Rieber Hall on the 6th floor. While Chem may not be my strongest suit either, I would love to organize a study session for the building.

Hey! I’m Iris and I’m on rieber 6 too :D

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