CHEMISTRY COMMUNITY

LeannaPhan14BDis1D

just for the 1st order reactions

LeannaPhan14BDis1D

Destiny Diaz 4D wrote:so to find delta n you would take the moles from products subtracted from moles from reactants?

yes i think so?

LeannaPhan14BDis1D

in general, you shouldn't assume anything in terms of spontaneity since it fluctuates with each reaction

LeannaPhan14BDis1D

Yes they are the same thing.

LeannaPhan14BDis1D

it shouldn't change when rxn is multiplied

LeannaPhan14BDis1D

it doesn't seem like it should matter but i could easily be wrong

LeannaPhan14BDis1D

Free energy is the one that changes and is influenced by temperature

LeannaPhan14BDis1D

Angela Cong 3C wrote:A simple acronym that helps to remember which is OIL RIG
OIL= Oxidation Is Loss (of electrons)
RIG= Reduction Is Gain (of electrons)

That's a really good way of memorizing it thank you

LeannaPhan14BDis1D

I did it too and the people above say it's bc k doesn't have units

LeannaPhan14BDis1D

He sent out an email saying thermodynamics and Gibbs free energy should be what we turn in

LeannaPhan14BDis1D

When the reaction is isothermal

LeannaPhan14BDis1D

Will reversible reactions be on the next test?

LeannaPhan14BDis1D

Reversible isn't that necessary to know since they're theoretical.

LeannaPhan14BDis1D

What would work most would be w= -pdeltav

LeannaPhan14BDis1D

It's best to use H+ even though it doesn't matter too much

LeannaPhan14BDis1D

the surroundings is just a broad concept and depending on what is being talked about the "surroundings" could be infinite to the universe and yet be any small part in the universe as well.

LeannaPhan14BDis1D

a closed system is capable of influence with outer environments and variables while an isolated system cannot be changed whatsoever.

LeannaPhan14BDis1D

In short, heat is energy while temperature itself is not and it measures the speed of the molecules moving about.

LeannaPhan14BDis1D

They both are essentially the same I believe but q with a p subscript means it's processed under constant pressure like the other person said.

LeannaPhan14BDis1D

no you do not have to have same states

LeannaPhan14BDis1D

and last quarter with lavelle the forum posts are due every sunday and I'm sure it is the same for this quarter.

LeannaPhan14BDis1D

In the end game result for K or Q solids and pure liquids will not affect the results.

LeannaPhan14BDis1D

for the example he gave, he used Q since the equation wasn't at equilibrium

LeannaPhan14BDis1D

For the most part you will kinda just have to memorize whether or not it is a base or an acid

LeannaPhan14BDis1D

IN the lecture today he wrote/ said
when pressure changes
when k does change
If rxn requires heat (endothermic) while forming product then heating will favor P formation.
If rxn gives off heat (exothermic) while forming product then heating will favor R formation.
hope this helps :)

LeannaPhan14BDis1D

Lavelle said due to the absolute 0 K we use Kelvin like the other people said

LeannaPhan14BDis1D

K is a constant but it is supposed to stay the same regardless of the different P/R right?

LeannaPhan14BDis1D

the quick links tab works best for me and it gives you the number of posts you put up and the comments people wrote after you.

LeannaPhan14BDis1D

this was really helpful and so was the review session thank you!

LeannaPhan14BDis1D

this was very helpful thank you!

LeannaPhan14BDis1D

It is most likely going to be covered on the final but that is dependent on whether or not we get it covered next week before the test.

LeannaPhan14BDis1D

The easier it is to dissociate into H+ and OH-, the weaker the acid or base is.

LeannaPhan14BDis1D

It mainly depends on what you believe you need most help in. If you understand all of the topics and just want to concrete your knowledge go to the one you are most confident in to see if you missed anything. Go to the step ups if you are struggling with a topic too.

LeannaPhan14BDis1D

I mean it is possible he would put it on but I'd refer to the outlines for test 3 he put up.

LeannaPhan14BDis1D

This applies to the angles?

LeannaPhan14BDis1D

Chem_Mod wrote:All discussions will happen on Wednesday as usual.
All students should turn in homework for week 8 and 9 during week 9 discussion. This means you need 14 homework problems next week.

So for this weeks discussion we do not need to turn in week 8 homework?

LeannaPhan14BDis1D

I think it is just the molecular shapes and structure from those outlines

LeannaPhan14BDis1D

are there any more exceptions to the rule of polar and nonpolar with the vespr?

LeannaPhan14BDis1D

double bonds = one pi bond + one sigma bond
triple bonds = one sigma bond + two pi bonds
this is all i know

LeannaPhan14BDis1D

When we put the angles being 90 and 120 it is mainly a ballpark answer unless you calculated it being on the dot. it is around 90 or slightly less than 90.

LeannaPhan14BDis1D

I am sure you can due the easier ones on outline 4 since we went over shapes and angles too.

LeannaPhan14BDis1D

is there any other challenging molecule someone can provide as an example to help further help with my knowledge on how the shapes and angles work?

LeannaPhan14BDis1D

Is there a way to figure out which ones are allowed to contradict the octet rule or is it all of the ones from 3 and down.??

LeannaPhan14BDis1D

Are there any simple tricks to seeing how many resonance structures there could be for a single compound? What about for the resonance structures with formal charge that is not 0, would we have to include all the structures or do we exclude a certain number of formal charge when making resonance str...

LeannaPhan14BDis1D

If the angles are determined by something we haven't gone over will we be tested and graded on specificity of our structures with those angles or will it not matter as much for this midterm.

LeannaPhan14BDis1D

It has something to do with the stability of the element and how it likes a specific configuration. The sublevels when they are completely filled are more stable than those that are partially filled. Sorry this is a kind of convoluted explanation but it is the only one I have. I hope more people can...

LeannaPhan14BDis1D

What equation do you mean? is there a specific equation you are referring to? The test requires you to answer with correct units and sig figs. I do not believe that they give you the units.

LeannaPhan14BDis1D

You have to know its function and how it can be applied.

LeannaPhan14BDis1D

Dr. Lavelle mentioned that E = hv can only be used for light. However, De Broglie's equation of lambda=h/p can only be used for objects with "rest" mass and velocity. "Rest" mass basically means anything that has mass when stationary. why is rest in quotes.. is there a significa...

LeannaPhan14BDis1D

Why is it that when you have an angular node the wave function changes sign?

LeannaPhan14BDis1D

I would think it is due to the s orbitals having lower energy, but this is a very good question. Now that I think about it I do not understand it either...

LeannaPhan14BDis1D

I cannot conceptualize light being both photon (PACKETS) of energy and wavelengths. I find it difficult to exercise this into equations when I do not understand how it can be both and have one number. Please explain and possibly use equations in your explanation if possible. If not that is okay, any...

LeannaPhan14BDis1D

In the atomic spectra model, the hydrogen atoms are ideally in a vacuum and then there comes a white light going through it. This makes the hydrogen excited and this is where I get foggy. Does the hydrogen become an isotope giving off an electron into the air and then coming back together after the ...

LeannaPhan14BDis1D

I do not understand when Lavelle spoke on the length of the wavelength and how it ejects electrons. Please advice since the reading makes it only slightly less confusing. I get how the shorter the wavelength is it will eject more electrons, but I do not understand how. Thank you.

LeannaPhan14BDis1D

I am not sure I understand the complete difference between Extensive v. Intensive Property. Please send as many examples as possible.

LeannaPhan14BDis1D

For most of the problems in the set, you need to just start by changing the mass to moles. In this problem add to get the total number of moles of ions after and then divide over the volume given. After that you will get the molarity. :)

LeannaPhan14BDis1D

When doing stoichiometry (7.55molCl2)*(2mol AlCl3/3mol Cl2) = 5.03 mol AlCl3 -- the limiting reactant I know how to get to the answer, but I am confused conceptually as to why when you already have the mol for AlCl3 and the stoichiometric coefficient being 2.. why do we need to do more towards it to...

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