CHEMISTRY COMMUNITY

Phoebe Joseph

Dr Lavelle explains it best! Here you go:

https://lavelle.chem.ucla.edu/wp-conten ... itions.pdf

https://lavelle.chem.ucla.edu/wp-conten ... itions.pdf

Phoebe Joseph

Yes, you just flip the sign of E naught! This is because if you have a potential voltage in a specific direction of your reaction you know that the reverse reaction will have to have the exact opposite potential voltage.

Phoebe Joseph

E max is the maximum voltage so it is basically the E naught value right when the system starts reacting. Remember how Dr Lavelle talked about how systems degenerate over time? Well we know that the maximum voltage potential (Emax) would be at the very very beginning before the system had time to de...

Phoebe Joseph

The irreversible pathway allows for constant external pressure. In order to maintain this constant internal pressure you have to move in infinitesimally small increments so you don't disturb the external pressure. In the reversible pathway you can somewhat ignore the entropy of the surroundings and ...

Phoebe Joseph

Reversible work of expansion does more work than irreversible work of expansion because the small increments that you have to use in reversible expansions require a lot more work than just letting the system expand. I think about it like blowing up a balloon. Say you had to blow this balloon up and ...

Phoebe Joseph

Hello Dr Lavelle, Thank you so much for being such a caring and helpful professor. Even online you have truly created a welcoming and resourceful environment - something I wouldn't say about any other professor at UCLA. I am so sad that I didn't get to have you in person for this class. Your fun DJ-...

Phoebe Joseph

Yes, as other people have answered: enthalpy(H) is a measure of heat transfer while entropy(S) is a measure of disorder. If you say enthalpy increases (delta H is positive) then the system is using heat and needs an external supply of heat to process - this is non-spontaneous and endothermic. A nega...

Phoebe Joseph

Alexis Sanft 1E wrote:Is water the only thing not included?

Yes, water is the only thing not included because it is the solvent.

Phoebe Joseph

Could someone please explain how to do this questions?

Phoebe Joseph

You can use the molarities/partial pressures given in the cell diagram to calculate Q, by dividing the concentrations of the products/reactants of the overall reaction. Oh, thank you! Also, why does the solutions manual use 0.025 instead of 0.059 (as written on our equation sheet) for the value at ...

Phoebe Joseph

Could someone explain to me how they knew what value to use for Q in their final equation?

Phoebe Joseph

hi! I have heard the general rule is: add Pt(s) when no solid is available in the given reaction. I am not sure if this is 100% accurate though. would appreciate someone clarifying this! Thank you! Do you know if the order of compounds within the same section within a Galvanic cell matter? Like the...

Phoebe Joseph

How are we supposed to know which solid to add for our Galvanic Cell Diagram (the electrode) when we just have a skeletal equation? There is a good example of a question like this -> 6L.5 part b.

Phoebe Joseph

Could someone just explain how to do these in general I am so confused.

Thank you!

Phoebe Joseph

When writing half reactions for Galvanic Cells, do we just ignore the solid of the electrode if it is different than what is happening in the half reaction? Here is an example. (part b)

Phoebe Joseph

claire ikemiya_2I wrote:I tried circling it, sorry if its hard to see but on the home page of sapling, where you access textbook. hope this helps.

Thank you!

Phoebe Joseph

Thank you for posting the solutions manual error, I couldn't figure out why they chose Cl-!

Phoebe Joseph

Allan Nguyen 2G wrote:50 points but don't forget that extra posts from previous weeks don't count I think

What do you mean extra posts from previous weeks don't count?

Phoebe Joseph

How did you solve the first couple parts? For the first couple parts, you want to look at the chart and see how changes of each of the concentrations impact the rate. From the changes to the rate, you can determine if the the reactant is zero, first, or second order. Hope this helps. Yes thank you ...

Phoebe Joseph

I will try and give an analogy that helps me visualize this. Think about a very wealthy community. Imagine giving each individual $2000. Now think about a much poorer community. Imagine giving each individual $2000. The money will have a much greater impact on the poorer community than the wealthie...

Phoebe Joseph

Where do I find the solutions manual for the textbook again? I can never seem to remember.

Phoebe Joseph

I know Dr Lavelle mentioned Angular Dependance in lecture yesterday, but what exactly do we need to know about this for the final? Like what time of questions would involve this?

Phoebe Joseph

Since cell potential in an intensive property, it does not depend on moles.

Phoebe Joseph

I know this is a basic question, but what exactly is "cell potential". I know how to analyze it and do problems with it but I don't really know what it is in general...

Phoebe Joseph

Also, the solid that the reaction is taking place on are always at the very edges of the diagram, correct? (except liquid mercury that is an exceptional liquid conductor)

Phoebe Joseph

davidryan3f wrote:
jane_ni_2d wrote:how can you tell which is the anode and which is the cathode?

the anode is always on the right of the cell diagram and the cathode is on the right.

Do you mean the anode is always on the left?

Phoebe Joseph

Also for this problem it is good to remember that wen "canceling out" your intermediates, you should be using the equation that has the bidirectional arrows and the intermediate in it.

Phoebe Joseph

I got this problem wrong because I didn't realize they gave up value of A and not B. So make sure you make the proper conversion from given data to what they are asking you to solve for. Also, don't forget to include 1 over the stoichiometric coefficient for B!

Hope I helped a little!

Phoebe Joseph

So if we have a total of 50 points by the end of the quarter (Friday the 12th) then we will be able to get full credit for Chemistry Community? Because my posts have varies week to week but I will have 5o by Friday...

Phoebe Joseph

Is it because of the Pre-Equilibrium principle?

Phoebe Joseph

Why would you set the forward reactant concentrations equal to the reverse reactant concentrations?

Phoebe Joseph

Oh my gosh thank you, that is so embarrassing lol

Phoebe Joseph

Yes, this helped a lot. What is the correlation between instantaneous rate of change and k? Thank you

Phoebe Joseph

Thank you so much!

Phoebe Joseph

Why would we know to use the equation for 0 order integrated rate law for this question?

Phoebe Joseph

How did you solve the first couple parts?

Phoebe Joseph

Could someone walk me through their logic on this question? I got the right answer but I just want to make sure I'm not making any wild assumptions to get to my answers... Thank you so much!!!

Phoebe Joseph

And could someone give me a clear explanation of how the overall reaction rate relates to the reaction rate of the products?

Phoebe Joseph

Could someone please explain to me how the overall rate of the reaction relates to k in this question?

Phoebe Joseph

here may be a better image I am having trouble uploading an image in the textbox

Phoebe Joseph

I keep keeping this message on one of the textbook entries for #5 and dont know what to do about it! Please let me know if anyone has any ideas!

Phoebe Joseph

Why dont you need to balance electrons through half reactions in this equation?

Phoebe Joseph

Oh thank you so much!

Phoebe Joseph

My question reads: Which of the reagents would oxidize Cr to Cr3+, but not Pb to Pb2+?
I am very confused on how to solve this.. could someone lead me in the right direction?

Phoebe Joseph

I am using the values given in the table but continue to get the wrong answer. How exactly did you get the right answer?

Phoebe Joseph

I thought that the weeks 3/4 Sapling homework was sue this upcoming Sunday (ie Sunday of Week 5)... but I received a 65% on it because I didn't finish it by last Sunday. I am confused.

Phoebe Joseph

Do we all have the same password or something?

Phoebe Joseph

I'm using the same password I've always used so thats why I'm confused.

Phoebe Joseph

A similar question, how do I find my classmates posts. The wides range of dates are a bit confusing.

Phoebe Joseph

How do I see that someone has replied to my question or answer. Do I have to continuously check? I did not use Chemistry community last quarter so I am very confused. Thank you!

Phoebe Joseph

I cannot log into the Lavelle 14B class website, is anyone else having this trouble? How do I solve this?

Phoebe Joseph

Since this was a 3 day weekend, will my posts today count for my Chemistry community grade for last week?

Phoebe Joseph

Also, he said you generally use Partial Pressure for gases, so I think it will help to know that in a lot of problems.

Phoebe Joseph

I think he also mentioned in lecture that ideal gases do not transition between different states, as do regular gases in different temperatures and pressures.

Phoebe Joseph

Make sure to always use Kelvin!

Phoebe Joseph

I understand this isn't necessarily chemistry related, however does anyone know what the deadlines are for applying to the honors program? Also, what are the requirements and where can I find them?

Phoebe Joseph

Yes I think they will be administered at our scheduled lecture time.

Phoebe Joseph

I purchased the Sapling textbook from the UCLA store about a week ago but it has still not arrived. When is this weeks sapling homework due? If my textbook does not arrive in time, what should I do?

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