CHEMISTRY COMMUNITY

Rogelio Bazan 1D

If you look at Dr. Lavelle's midterm solutions it says minus 1pt for not including sig figs. So it is graded but you will not lose a lot of points for it. Just try to keep it in mind. Hope this helps.

Rogelio Bazan 1D

A catalyst brings down the activation energy, effectively increasing the speed at which the reaction occurs. Graphically this would bring down the very top peak on the graph as the activation energy is lowered to make the reaction occur. Hope this helps.

Rogelio Bazan 1D

To my understanding, The rate law is a differential equation, meaning that it describes the change in concentration of the reactant (s) per change in time. The rate law can then be integrated to obtain an integrated rate equation that links concentrations of reactants or products with time directly....

Rogelio Bazan 1D

To my understanding and a brief google search, we do not include zero-order reactions when writing the overall rate because zero order does not affect the overall rate. Hope this helps. If I am wrong someone please correct me.

Rogelio Bazan 1D

Sec^-1 is the units for the first order rate law reactions. Hope this helps.

Rogelio Bazan 1D

Danielle Hoekstra 1C wrote:Is isochoic another way to say a closed system? Are they interchangeable?

Please, someone, correct me if I am wrong, but I think that isochoric is the same thing as Isometric. As in a closed system.

Rogelio Bazan 1D

I do not think we need to know specifics regarding the electrochemical series, but it can be helpful to know what the electronegativity trends along the periodic table. You can look up periodic table trends on google and maybe use that as a source. Hope this helps.

Rogelio Bazan 1D

Hope this helps, from my understanding Dr. Lavelle only wants us to focus on 1st, 2nd, and Oth order reactions but third order is not a scope of this class.

Rogelio Bazan 1D

They are closely related but it is not an inverse relationship. We can say that whenever we have high activation energy that it would correspond to a lower rate.

Rogelio Bazan 1D

Isothermal is key information when solving a problem as it is in reference to the temperature if it is not explicitly stated we assume temperature would be constant when doing our calculations, hope this helps.

Rogelio Bazan 1D

To my understanding something that is more likely to become oxidized means that it is more likely to lose an electron. So if the species has a low electronegativity then it will have a higher oxidizing power (it will have a higher likelihood of giving off an electron and becoming oxidized). Hope thi...

Rogelio Bazan 1D

Conceptually what I find helpful is looking at periodic trends along the periodic table looking at electronegativity as you go up and to the left toward Florine you electronegativity increases on the periodic table. To define Electronegativity it is the chemical property that describes the ability o...

Rogelio Bazan 1D

Since Dr. Llavelle went over this at the end of the lecture I did not get great notes on it, but what I did get was that 'When they collide, it is Frequency Factor A'. So I assume that Frequency A is in reference to the rate at which the molecules collide. According to another user I found on Chemis...

Rogelio Bazan 1D

My guess is that there will probably be an emphasis on Kinetics and possibly Nernst Equation as it was not included in Test 2 but remember to review everything as the final is a cumulative exam. Hope this helps.

Rogelio Bazan 1D

There will probably be an emphasis on kinetics since it was the most recent unit and we spent the longest amount of time on it. Just study everything though. I agree with Meachelle that there will probably be an emphasis on Kinetics and possibly Nernst Equation as it was not included in Test 2 but ...

Rogelio Bazan 1D

In Kinetics and for the scope of this class, the rate constant will never be negative. The Arrhenius equation is always positive (otherwise, the rate constant would be Zero). If the rate constant was zero then this would indicate that the reaction is not occurring at all. Please, someone, correct me...

Rogelio Bazan 1D

To my understanding, if a species has a greater reduction potential then this refers to its electronegativity. If a species is said to have greater reduction potential then it is more electronegative, as such it is going to be more likely to pull electrons off of another species with lower electrone...

Rogelio Bazan 1D

That is my bad, I apologize for not explaining which k I was referring to but in this case, I am referring to lowercase k (rate constant). The picture helps clarifies my confusion, I appreciate it. Just to make sure. As temperature increases, k increases, and when activation energy increases, then k...

Rogelio Bazan 1D

Thank you so much, this is really helpful. So just to clarify, according to which order reaction we are dealing with we use the corresponding equation.
For example) zero order; rate = k: t½ = [Ao] / 2k, first order; rate = k[A]: t½ = 0.693 / k, second order; rate = k[A]2: t½ = 1 / k [Ao]

Rogelio Bazan 1D

Since Dr. Llavelle went over this at the end of the lecture I did not get great notes on it, but what I did get was that 'When they collide, it is Frequency Factor A'. So I assume that Frequency A is in reference to the rate at which the molecules collide. Hope this helps.

Rogelio Bazan 1D

Reading online, I think it is just for convenience to make the plot appear to be a straight line and allow us to analyze the data with greater ease. Hope this helps.

Rogelio Bazan 1D

In lector today (3/11) Dr. Llavelle briefly spoke about what determines the magnitude of K, can someone clarify what he meant by this? It was toward the end of the lecture so I wasn't able to write everything down. Thank you.

Rogelio Bazan 1D

I was confused by what Dr. Llavelle meant by 'bottleneck' when referring to the intermediate step, could someone please explain/clarify? Thank you.

Rogelio Bazan 1D

To clarify my notes from the lecture, there is a different half-life equation based on which Reaction Order that we are dealing with? For example, zero order has its own half-life equation so on and so forth? Thank you.

Rogelio Bazan 1D

To my understanding and looking at the textbook first order reactions will have a negative (-) slope, second-order reactions will have a positive (+) slope, and zero order reactions will have a negative (-) slope. This is due to the value of k either being positive or negative which affect the slope...

Rogelio Bazan 1D

My TA has brought it up in our discussion section and he told us to be familiar with the derivation, but it is unlikely that he will ask on an exam but I still think we should know it as he spent some time in class talking about the derivations. Llavelle did mention why he did that in lecture and it...

Rogelio Bazan 1D

As I am going through Kinetics in the textbook I am still having trouble understanding Half-life. If someone can help me clarify the concepts to Half-life and the equation(s) involved it would be of great help. Thank you.

Rogelio Bazan 1D

Can someone please explain to me what Dr. Llavelle meant by the Arrhenius equation? In what situation would we use this equation? Thank you.

Rogelio Bazan 1D

The rate law is only composed of the reactants that are in the total reaction. Intermediates cannot be in the rate law as they are not found in the total reaction which is why we get rid of them when doing the general rate law. Hope this helps.

Rogelio Bazan 1D

In today's lector (3/11) Dr. Llavelle went into detail with the pre-equilibrium approach and yes, in my notes I have that k1 is the K for the first step as in k1[NO]^2
still trying to wrap my head around this pre-equilibrium approach. Hope this helps.

Rogelio Bazan 1D

According to my understanding of how Dr. Llavelle explains incorporating gases into our equations, we always assume ideal behavior unless we are told otherwise but I don't think for our level we need to understand anything other than assuming ideal behavior. Hope this helps.

Rogelio Bazan 1D

When in a problem are we supposed to use the quadratic formula when solving for equilibrium? I know Dr. Lavelle in lecture showed we are supposed to get the terms in relation to ax^2+bx+c but what I am confused about is what type of problem requires this type of calculation in which we have to apply...

Rogelio Bazan 1D

I know that Dr. Lavelle stated that both Solids and Liquids are excluded during equilibrium calculations as there is an excess of both the solids in the liquids so we exclude them during calculations. I am still confused with subjects in the reaction that is in an aqueous state do we exclude these a...

Rogelio Bazan 1D

I am reviewing the modules for equilibrium under Dr. Lavelle's website and I was hoping that I could get some help understanding what is the difference when solving for both Q and K while working on an equilibrium equation. I know that to solve for K you put products over reactants. Example) aA+bB⇋c...

Rogelio Bazan 1D

By large electronegativity difference we are referring to the periodic trends on the periodic table. Electronegativity increases as you move from left to right across a period on the periodic table. So the top right-hand corner on the periodic table where Florine is at will be the most electronegati...

Rogelio Bazan 1D

Yes, this is correct, a good example of a dipole moment is the interaction that H20 has with Oxygen being more electronegative. A dipole moment has both a magnitude and a direction which is important to keep in mind. Best, Roger.

Rogelio Bazan 1D

The final is tomorrow, I really wish everyone nothing but positive vibes just put your best foot forward and try your best. We can do this good luck to everyone!

Rogelio Bazan 1D

A conjugate acid and conjugate base to my understanding is just the opposite of an acid or a base? Once it goes through an acid-base reaction whats on the opposite side of the reaction is the conjugate acid and conjugate base?

Rogelio Bazan 1D

I am reading this post and looking at the book, I think that there should be a transfer of protons because it is an acid-base reaction and as such there should be a proton donor and a proton acceptor. Not sure I am also a bit confused by this.

Best, Roger

Rogelio Bazan 1D

Hello, I hope you are well, I think it has to do with the Brønsted-Lowry Definition of what an acid and what a base is that determines which one accepts the H+. Brønsted-Lowry Acid is a proton (hydrogen ion), donor. A Brønsted-Lowry base is a proton (hydrogen ion), acceptor. I hope this helps.

Rogelio Bazan 1D

I know this is an old one but what is the difference between polar and non-polar covalent bonds?

Rogelio Bazan 1D

Yeah, I think we do need to know how to draw them if you need help I think this video I found on youtube will help I know it helped me.

https://youtu.be/IaVlh3kol9Q

Best, Roger

Rogelio Bazan 1D

Do we need to know Le Chatelier's Principles for solving chemical equilibrium problems? I know that it has to do with the proportions in a chemical equation/solutions as chemical reactions go on. I am not sure if that's even right. Thanks.

Rogelio Bazan 1D

Do we need to memorize our Neutral LIgands and Anionic Ligands or more so understand the conceptual basis of them? I know this was one of the later topics to be covered but I do recall Dr. Lavelle saying that we needed to understand the biological significance? Thanks.

Rogelio Bazan 1D

Hi, I feel like I might be over stressing. How well do we need to know Coulomb's law I saw it in the book like once and to be completely honest it just confused me but thinking back will I need to know the specifics of Coulomb's law or is it more just an explanation of just how molecules interact wi...

Rogelio Bazan 1D

The ionic character which is just Ionic Bonding which to my understanding corresponds to periodic trends in which a bond between two molecules in which a large electronegativity difference exists between the two atoms would cause them to be more electronegative. I hope this helps with any confusion.

Rogelio Bazan 1D

To my understanding, an amphoteric compound is a molecule or ion that can react both as an acid as well as a base.
Beryllium oxide is amphoteric because it can react with both acidic and basic solutions.
BeO + H2SO4 -------- BeSO4 + H2O; BeO + 2NaOH ------------- Na2BO2 + H2O

Best, Roger

Rogelio Bazan 1D

Yes, this is correct, I also think but I am not sure that they are inversely proportional. So as the height of the wave increases at position x,y,z then the probability will be much smaller and if the probability of finding the electron increases then the height of the wave is much smaller. Best, Ro...

Rogelio Bazan 1D

I know that in some cases for Lewis Structures there are exceptions to the octet rule and some elements take more electrons than fit in an octet, I found a problem online which just for review I want to go over. Can someone tell me what the Lewis Structure for PCl3O is?

Rogelio Bazan 1D

The molecular Orbital theory states: it describes the molecular structure in which electrons occupy orbitals that spread throughout a molecule. With this information, we are able to determine that there is what is called an 'anti-bond' so if we are given an anti-bond can we determine the complimenta...

Rogelio Bazan 1D

Hello, I am a bit confused I am reviewing VESPER and Bond types for the final, I know that there are pi-bonds and sigma bonds. Is there any way to determine the type of bond other than like a single bond is a sigma bond and a double bond being a sigma and a pi bond? I feel like I am still unclear wi...

Rogelio Bazan 1D

I know we haven't exactly gone over dipoles in class I was reading ahead in the textbook and I am a bit curious of how we determine a dipole moment I understand that H2O is an example of a dipole moment as it has something to do with electronegativity? Oxygen is more electronegative than Hydrogen so...

Rogelio Bazan 1D

So I understand that the equation for the formal charge is the following: Formal Charge = [# valence electrons on neutral atom] – [(# lone electron pairs) + (½ # bonding electrons)] What I don't understand is that yes the best formal charge should be the 0 (zero) but there are times in which the oct...

Rogelio Bazan 1D

Whenever we are asked for a resonance structure of a compound, do we have to do all different ways that the compound can be given or will one be sufficient? or is this just a matter of how the question is asked? Like for example if I am asked to give all resonance structures of -blank- vs. give a re...

Rogelio Bazan 1D

To my understanding, Dr. Lavelle is okay with us using abbreviated electron configurations? but if we have an element whose electron configuration equals that of just another element do we simply leave it as [Ar] or would we have the use the previous element one row above and write the electron conf...

Rogelio Bazan 1D

Is the photoelectric effect just conceptual or is there actual computation for these equations? Do we just need to understand the graphs that depict the photoelectric effect and how this was revolutionary as a photon behaved as both a particle and a wave? Thank you-Roger.

Rogelio Bazan 1D

This is just a clarifying question, I don't recall this being on our 2nd quiz will Heisenberg show up on the midterm? If so can someone help and give me an example of a Heisenberg equation I still get confused at times with Heisenberg. Thank you-Roger.

Rogelio Bazan 1D

This is more of a conceptual question, but can the photoelectric effect be demonstrated upon any other material besides a metal like I don't know plastic maybe? or does the photoelectric effect only apply to metals? and if it only applies to metals then why?

Thank you,
Roger Bazan

Rogelio Bazan 1D

If by visual representation you mean Lewis structures? Then I would assume yes because if the structure is already at the lowest possible ratio then that would be the empirical formula. For your example, CH70 that cannot be simplified further, therefore, it would be the empirical formula as well but...

Rogelio Bazan 1D

Dr. Lavelle in lecture began to explain in class about the classical behavior of a light wave, but what got me confused was toward the end of the lecture we began to talk about light as if it was a particle and not a wave. Why is this? Does it have anything to do with what we discussed, the Photoele...

Rogelio Bazan 1D

I recall Dr. Lavelle going over Black Body Radiation briefly in lecture and just out of curiosity I wanted to know what Black Bodies are and how do they apply to the development of science? What is so significant about Black Body Radiation?

Thank you,
Roger Bazan

Rogelio Bazan 1D

I am reviewing the photoelectric effect and the behavior of light is described as photons but I am unsure where to use Planck's constant in an equation all I know is that Planck's constant is 6.63x10^-34 J*sec
Anyone mind telling me where to go from here I am just feeling confused, Thank you.

Rogelio Bazan 1D

I just use 15.999 as I believe it would give a more accurate answer and at the end of all my work I use Sig. Figs or round if the question asks me too.

Best,
Roger Bazan

Rogelio Bazan 1D

Molecular Mass to my understanding is the entire weight of a compound together, for example, a single water molecule is H20 in which Hydrogen has an atomic weight of 1.008 while Oxygen has an atomic weight of 15.999. You have H2O so you grab the value of Hydrogen 1.008 and multiply it by 2; 1.008*2 ...

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