CHEMISTRY COMMUNITY

josephspindler2H

When a reaction's gibbs free energy is negative, then the reaction in question is spontaneous. This can be explored through the equation delta G nought = delta H nought - T * delta S nought. For example, a large positive entropy value can overcome a positive enthalpy. Remember from the kinetics sect...

josephspindler2H

I believe they will stay up, as you can search and find various old posts from years past. It's like a time capsule of sorts.

josephspindler2H

For a zero order reaction, the rate is independent of the concentration of the reactant.

josephspindler2H

Conceptually, it's helpful to remember that delta G nought is equal to work max as well as kforward/kreverse=K

josephspindler2H

I agree with Hayden, it really helps to look over practice problems and practice applying the equations so you can understand what equation goes with what concept.

josephspindler2H

Lavelle organizes review sessions throughout Week 10 so there is plenty of opportunities to review. For a study guide, the textbook problems listed on his website are a big help as well as the sections covered in the textbook.

josephspindler2H

I really miss the atmosphere. Just walking to and from class. The little things really made UCLA feel so special. Sure there were big things that made it great, too, don't get me wrong. But, the feeling of UCLA truly was something and I am excited to be back.

josephspindler2H

I've heard that some people who struggled with other parts of chemistry conceptually sometimes enjoy 14C more since its a bit different. I've heard it compared to preferring geometry or algebra. So it may appear daunting but when we get into it, you may really enjoy it. We'll find out!

josephspindler2H

These are some great suggestions. I can't wait to go back to UCLA and give some of these a try.

josephspindler2H

To help with burnout, I like to go on walks or runs. Being outside and exercising can be a great help. Also leaving wherever you work for just a little can help as well.

josephspindler2H

Like others have stated, you cannot earn more than the 50 points (5 points per week) for Chemistry Community. You just get 5 points a week x 10 weeks!

josephspindler2H

These are some solid recommendations. Breaking Bad has a little chemistry in it, but not the good chemistry we have here in the 14 series. I have to recommend the classic show Psych! It's on amazon prime video and probably hulu.

josephspindler2H

The Boltzmann constant, k, is on our equation sheet! it is equal to 1.38x10^-23 J/K. Be careful not to confuse it with K, the equilibrium constant for a reaction.

josephspindler2H

Yes, there's a question or two where you need to include the phases. It is interesting as there are some problems that have it as optional. I wonder why sapling decided to structure it this way.

josephspindler2H

E naught is a lot like G naught from thermodynamics. Its the value of E at standard conditions. At nonstandard conditions (E), we have to convert using an equation.

josephspindler2H

E depends on the path taken, so it would not be a state function. You are not able to compare the final and initial states like you would with a state function.

josephspindler2H

Definitely a good strategy is to arrange some kind of quiet time or you time before the test, so that you enter the exam with a clear mind. Test stress can hurt your focus and performance on the test, so don't over think it.

josephspindler2H

I have a friend taking 20L and it sounds fairly similar to 14BL but perhaps a little bit more rigorous and separated from the biological context found in the 14 series.

josephspindler2H

I'm going to be taking 14C and an upper div, but I am not so certain for another class since stats 13 and physics 5C filled up really quickly.

josephspindler2H

I always recommend going to the UA sessions it can help give you more advanced practice and help reinforce concepts as well as open up the opportunity to ask questions in a pseudo-in-person sort of fashion.

josephspindler2H

You are correct in assuming that you use .08206 with atm, the other value is for use with energy or work (notice it has joules in its units). Like with most concepts in this class, units are very important and can be the deciding factor for which values are used.

josephspindler2H

It will depend on the problem in question and the units that are given. Sometimes, you can get away with keeping celcius if a change in temperature is needed (since the relative difference will be the same regardless of which unit). But other times call for Kelving to be used to do a difference in u...

josephspindler2H

I would say 14BL is heavily dependent on your lab group and TA, as the workload can be very manageable with a strong group that communicates well. If you can organize well, 14Bl should be more than manageable.

josephspindler2H

As everyone is citing, the conversion is +273.15 to the C value. thats why we see 298 K so often (its 25 C or room temperature).

josephspindler2H

If there isn't a Lavelle Spotify playlist, somebody should make one! A collection of the 14 series greatest hits.

josephspindler2H

As others have stated, Lavelle factored in this week as well as the previous weeks but we have till today at midnight to get the 5 points for this week so nothing to worry about. It will be updated later on in the quarter :)

josephspindler2H

I think the lower number does not factor in multiple replies to the same post tree, while the higher number does.

josephspindler2H

My best resources have definitely been practice problems and the UA sessions. Someone posted a very useful study guide that briefly summed up each of the core concepts from each section in the textbook.

josephspindler2H

I have been reading Crime and Punishment for a long time (it's a bit boring in parts) but it's a very interesting book conceptually. Slaughterhouse Five and Fahrenheit 451 are both phenomenal books and I cannot recommend them enough--the latter of which is loosely tied to the thermodynamics of our c...

josephspindler2H

i always wondered what Lavelle decided to play in class. They sounded so familiar but I couldn't place any of the sounds.

josephspindler2H

t=Thank you for asking this question! I was wondering when we were supposed to ignore the effect of the second or third ka values.

josephspindler2H

I am taking 14BL this quarter but there is not too much overlap at the moment. I would say you could take this course next quarter or later if need be.

josephspindler2H

Thank you for this very kind post! I think it is very important to have some time to relax and focus on your own health. We're almost at the halfway point of the quarter so we should be proud of ourselves.

josephspindler2H

I plan on taking 14 C next quarter, but you bring up a good point. The content may not stick through the summer break, but I believe this may just translate to helpful review.

josephspindler2H

Based off of last quarter, I would say it takes about a week for grades to come out.

josephspindler2H

Thank you! That's really kind of you to share. Good luck studying!

josephspindler2H

I believe this would only be for gases rather than aqueous substances. Changing the pressure would only affect the moles of gas.

josephspindler2H

Although the test is not open note or open book, Dr. Lavelle has an equation sheet and periodic table on his website that we should have printed out for the midterms and final.

josephspindler2H

A phase change is when a substance changes from one state of matter to another (gas to liquid, solid to liquid, etc.). These occur at the melting point and boiling point, for example. These are the temperatures where such phase changes can occur.

josephspindler2H

Q is for heat and H is for enthalpy!

josephspindler2H

Yeah Q will become K, Q is indeed the value when not at equilibrium. Q wants to become closer and closer to K in order to reach equilibrium.

josephspindler2H

Shifting to the right means that the products are favored (more will be produced to fit the equilibrium) while shifting to the left means the reactants are favored (again more will be produced). It can helpful to think of the products being on the right side of the chemical equation while the reacta...

josephspindler2H

The key point that leads to us being able to approximate is that .20 is so much larger than 10^-4 (relatively speaking) that the result will be just about .20 after the subtraction. It's less that x is close to zero and more that the relative operation is not impactful on the initial quantities.

josephspindler2H

Amphiprotic molecules can act as either a proton acceptor or donor (bronsted-lowry base or acid). It's a similar term to amphoteric but specific to proton acceptance and donation.

josephspindler2H

I'm pretty sure things will be slightly different this quarter and will be during lecture time instead of discussion section. I asked my TA about it and he told us that the logistics are still being ironed out. We will find out for sure soon.

josephspindler2H

The preferred unit will be atm! You should not give an answer in moles per liter as that would be the unit for concentration rather than pressure. You can easily convert between the two as Dr. Lavelle taught in lecture.

josephspindler2H

We will be using atm. As Dr. Lavelle stated in lecture, 1 bar is very close to 1 atm, so for our purposes we can just use atm.

josephspindler2H

Thanks for clarifying that the homework is due next Sunday 1/17! Out of curiosity, does anyone know if week 2 homework also be due that day?

josephspindler2H

I heavily rely on the "Quick links" tab on the top left to navigate chemistry community, from there you can best explore the newest posts and the differing topics you may need help in or what to help someone out in.

josephspindler2H

I've always been a big star wars guy, so any of the original three help me unwind. But I don't usually like having movies or tv shows play in the background while I work or study; I feel like I end up getting easily distracted.

josephspindler2H

I listen to a lot of classical music for studying and doing work. Study's tend to say it's conducive to a good working environment. Also, apparently listening to new and different songs is beneficial!

josephspindler2H

I think in terms of what we will be exposed to in this course, we can determine if something is amphoteric based on what it is being exposed to. The outcome can tell us if it is amphoteric. I believe it is helpful know some of the most common ones, such as water.

josephspindler2H

Look at the areas of electron density! So that's bonds and lone pairs. Keep in mind that double and triple bonds only count as one area of electron density, they don't increase the count. That's why you can have a double bond and have trigonal planar instead of tetrahedral. In this case, it would be...

josephspindler2H

It seems like the best strategy is to memorize the most common ones and more specifically those within the textbook problems.

josephspindler2H

It seems like the review sessions depend on the UA and the format, as the one I attended was not recorded.

josephspindler2H

I am going to be taking them together, though it is totally acceptable to do them at separate times like 7C and 23L. At the end of the day, it's more about what works for you and your schedule.

josephspindler2H

As others have stated, it will be pretty much the same as our past two midterms. The final will be 30 questions that are each 6 points, however.

josephspindler2H

Thank you so much! Good luck studying!

josephspindler2H

Emily and Serena both had solid answers and covered much of what I was thinking. It's important to know the base bond angles (180, 120, 109.5) and where they come from, but the effect of lone pairs doesn't need to be memorized quantitatively (i.e. just know that bond angles will be smaller due to th...

josephspindler2H

The best place to start is 100% the textbook problems. They best reflect what's gonna be covered on the test, also look into going to some of these review sessions that Dr. Lavelle has planned.

josephspindler2H

Yes we are in the process of completing or will complete learning about these two outlines. As others have stated, they are relatively shorter in comparison to the outlines on the past two midterms.

josephspindler2H

There was similar post about this, and it seems the consensus is all over the place. The syllabus does not give an exact breakdown and there are disagreements over them. I would say not to worry too much about the numbers and focus on doing your best!

josephspindler2H

As with the consensus here, the textbook problems are very helpful, though the textbook can be a bit greater in scale at times. Lavelle's lectures and videos online can be greatly helpful in understanding the concepts, while the textbook problems help with their application.

josephspindler2H

Every class does grade distributions differently, so i am not sure what the points will translate to. I was also curious about the 50% and C- thing on the syllabus. If I recall correctly, the syllabus does not say the percentages needed for each level of grade either. Some classes have A+ as only ov...

josephspindler2H

Certainly, the one constant so far has been doing the textbook problems. Although, I too have revamped how I have been taking notes in class. Another important strategy I have adopted is to ask myself if I can explain each topic and see if I really can define key terms. It helps me better understand...

josephspindler2H

We need 35 posts by tonight at midnight. Each week has a requirement of 5 posts, so 40 next week, then 45 for week 9, and finally 50 by week 10.

josephspindler2H

Hey all, I was just wondering if there will be lectures and discussion on wednesday and/or friday. Some classes have cancelled both, though I am unsure what 14A's plan is for this upcoming week.

josephspindler2H

12 is the minimum! That's what you need to be a full-time student. Don't worry about this too much, everything will work out!

josephspindler2H

I would say textbook problems and the UA worksheets are our best bet for studying. They're solid resources and help build understanding. I definitely think I will be attending more UA sessions in preparation for this exam.

josephspindler2H

I've been running a few miles or so each week, nothing too crazy. It's nice to go out to trails if possible.

josephspindler2H

For enrollment, do we need to take both these courses at the same time, or is it like LS 7C and LS23L where we have the option to take 7C first and 23L later on?

josephspindler2H

Thank you, Cassidy! I just wanted to double check. Good luck studying!

josephspindler2H

It is a good idea to check and see if you can define each of the bullet points as Simer said. Sometimes, we think we know certain topics or ideas, but it can be difficult to explain. If we can explain them effectively, then we have a much better understanding of the topic and it will show on the test.

josephspindler2H

Are you going to continue this series of posts? Many of us--myself included--would like to know where you're going with this.

Also, I would call out green.

josephspindler2H

Just to confirm, the last lecture that will have content on Midterm 2 is Wednesday from last week, right? I just want to be certain before going into the test.

josephspindler2H

Based on your question, it seems you dealing with Chem 14A material though you posted in the Chem 14B section. Just a reminder to take note of that, you'll probably get more answers from fellow 14A students if you post in the right class section.

josephspindler2H

As many have already stated, lewis structures is a key focus for this section. It would be helpful to do the sapling textbook problems to practice making these. I believe this midterm stops content-wise at hydrogen bonding.

josephspindler2H

Each element has a number of electrons equal to its atomic number. However, it can have more or less depending on if it is an ion or not (loses as a cation (+), gains as an anion (-)).

josephspindler2H

Will there be a lecture posted this Wednesday? Just checking to see as it's Veteran's Day.

josephspindler2H

As many have already stated, Noble Gases are exempt from the electronegativity trend, as they already have a full octet and are within the most stable position.

josephspindler2H

I'm heading to reactor. Not gonna risk it with Green

josephspindler2H

Mr. Robot is ridiculously good. It has some of the best writing on TV ever, great performances from the cast, and spectacular direction.

josephspindler2H

It will depend on the problem asked! Some will ask for the full configuration and other won't. If they don't, it is easiest to refer to the latest noble gas and build your configuration from there.

josephspindler2H

Yes, the constant c will remain a constant 2.99792 x 10^8 m/s. c will always refer to the speed of light for the purposes of our classes (as far as I am aware).

josephspindler2H

Electron affinity is the change in energy when a negative ion is formed (an electron joins a neutral atom). For example, it looks at the change in energy from an F atom to an F^-1 atom.

josephspindler2H

I took a mental day and watched The Addams Family with some friends! I probably should have done some more homework but it was nice to have a day off.

josephspindler2H

The first four elements do not abide by the octet rule (H, He, Li, Be) as they only fill the 1s and 2s subshells.

josephspindler2H

On the constants and equations worksheet from Professor Lavelle's chem14a website, there is something listed as "1 atm = 101.325 kPa" Could someone please explain what this means? We haven't gotten to this section of chemistry (pressure) yet, so you do not have to worry about it for the u...

josephspindler2H

As many have already discussed, this statement is decidedly false. When we go to the quantum level, the level of one photon, the energy will not increase. This is because increasing intensity increases the number of photons of light, rather than the individual energy of each photon. More photons doe...

josephspindler2H

I haven't heard anything about graphs specifically on the midterm. From what I have gathered, the midterm will be split between conceptual problems and more mathematical ones. A graph could pop up based on this information, but we will likely have see it before or be able to interpret it.

josephspindler2H

As some such as Halle have already stated, the equations and constants sheets will have the mass of protons, electrons, and neutrons provided. We'll be using kg as the unit of choice as other constants/equations will be dependent on this unit.

josephspindler2H

Am I correct in thinking that electrons possess both wave-like and particle-like properties? Additionally, basically all matter possesses particle-like properties, but can matter's wavelike properties only be detected at very small scales?

josephspindler2H

I think it would be helpful to familiarize yourself with the equations, so that you can recognize when to use them on the exam. If you do not know its name, be able to name its purpose and the components that make up the formula.

josephspindler2H

Yes, you are correct! If they had changed the wavelength or frequency, they would have changed the type of light being shown. As many have already stated, increasing the intensity led to an increase in total photons rather than individual photon energy. This is a problem on the quantum level where a...

josephspindler2H

Hi! You can access them on the chemistry 14a website under "constants and equations" (right below the tab "Everything you want to know about Sig Fig"). If you do not see it, I have the link to it: https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/constants_equati...

josephspindler2H

I am not sure if this is the same concept in action. From what I recall Dr. Lavelle discussing, black body radiation is a theoretical discussion as nothing we know of absorbs all wavelengths of light. Though, color and light absorption would be an interesting discussion. Polar bears are known for th...

josephspindler2H

I believe a keV is a kiloelectron volt, a thousand electron volts, and a unit of energy. What is an electron volt? An electron volt is the unit equal to the amount of kinetic energy gained by an electron accelerating through a electric potential difference of one volt from rest. One eV is equal to 1...

josephspindler2H

My understanding is that amplitude does not affect wave velocity. However, amplitude has more to do with the energy or intensity of the light? I'm not 100% sure though, anyone can feel free to correct me. I think you're correct. Amplitude is independent of frequency in simple harmonic motion which ...

josephspindler2H

As a few have already stated, the convention is to make the stoichiometric coefficients whole numbers. I think it generally makes the balanced equation easier to grasp and look neater overall. Having fractions unnecessarily complicates things, but it can be a bit of work to get there depending on th...

josephspindler2H

I am not well versed in salt-burning-coloration, however I do believe it is important to note the difference between a physical and chemical change. The element's color (a physical property) does not necessarily have an impact on what color it will burn (a chemical property). For example, you know N...

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