CHEMISTRY COMMUNITY

Jacob Schwarz-Discussion 3I

Because Q isn't always at equilibrium. K always equals Q when Q is at equilibrium.

Jacob Schwarz-Discussion 3I

Thank you so much for sending those links!!

Jacob Schwarz-Discussion 3I

I think Lavelle rounds when there are small decimal points involved

Jacob Schwarz-Discussion 3I

I hope it will be in person and even if it is hybrid I would definitely want to live on campus.

Jacob Schwarz-Discussion 3I

A reducing agent helps another molecule become reduced while an oxidizing agent helps another molecule become oxidized.
In this process, oxidizing agents become reduced and reducing agents become oxidized.

Jacob Schwarz-Discussion 3I

I would go through all your textbook problems one more time.

Jacob Schwarz-Discussion 3I

The relationship between Cp and Cv is that Cp=Cv+R

Jacob Schwarz-Discussion 3I

The more degrees of freedom a molecule has, the higher its heat capacity is.

Jacob Schwarz-Discussion 3I

Is this referring to the final or the 2nd midterm????

Jacob Schwarz-Discussion 3I

The rev is implying reversible- because this equation applies to reversible processes.

Jacob Schwarz-Discussion 3I

This is super helpful!!! For adiabatic systems, doesn't delta q=0?

Jacob Schwarz-Discussion 3I

Kc is the same exact thing as K it is just used for molar concentrations. Similarly, Kp is used for partial pressure.

Jacob Schwarz-Discussion 3I

Argon has no affect on the equilibrium because it is an inert gas

Jacob Schwarz-Discussion 3I

When you reverse a reaction, it turns into 1/K.

Jacob Schwarz-Discussion 3I

Definitely memorize that oxygen is -2 and hydrogen is 1. Besides that, you should be fine!

Jacob Schwarz-Discussion 3I

The reactant quotient stops changing at equilibrium. Therefore the deltaE at equilibrium is equal to zero.

Jacob Schwarz-Discussion 3I

emmaferry2D wrote:When using the Nernst equation and a given pressure of a gas is in bar or Torr do you need to convert it to atm? or are you able to use the different values of R that match that pressure value

I would convert Torr to Atm but with Barr I think you're fine

Jacob Schwarz-Discussion 3I

You need to calculate the number of electrons in the two half reactions and then make sure the number of electrons in both reactions are even then use that # as your n value.

Jacob Schwarz-Discussion 3I

With a salt bridge, the two beakers are separate and the salt bridge transfers the ions whereas in a porous disk the ions can directly transfer through the disk

Jacob Schwarz-Discussion 3I

You calculate e naught by using the standard potentials of the cell in the half rxns. given

Jacob Schwarz-Discussion 3I

How I've done it so far is start by balancing the elements that aren't H or O. Once those are equal, balance the O by using H2O. After that, for reactions in acidic solutions you use H+ to balance the hydrogens. For basic solutions, it's easiest to first balance hydrogens using H+, then for the num...

Jacob Schwarz-Discussion 3I

If a reaction is spontaneous but does not occur due to the presence of a large energy barrier, it is controlled by kinetics. Reversely, if a reaction has a negative delta G and does occur, it is controlled by thermodynamics.

Jacob Schwarz-Discussion 3I

If all of the reactants were to be zero-order, the reaction would be a zero order reaction.

Jacob Schwarz-Discussion 3I

Enzymes also function as catalysts because they also lower the activation energy of a reaction

Jacob Schwarz-Discussion 3I

An intermediate is produced, AND consumed in a reaction

Jacob Schwarz-Discussion 3I

You will need to know the equations but you likely don't need to know how to derive the equations(especially because the test is multiple choice)

Jacob Schwarz-Discussion 3I

You gotta view how the half life changes when the concentration changes. Then use the exponent to make these match up

Jacob Schwarz-Discussion 3I

I usually can tell by knowing that the reactants in the slow step are part of the overall rate law.

Jacob Schwarz-Discussion 3I

Thank you for a great quarter DJ LL!!!

Jacob Schwarz-Discussion 3I

When the reaction doesn't occur under standard conditions.

Jacob Schwarz-Discussion 3I

Just take the parentheses out and you should be good!!!

Jacob Schwarz-Discussion 3I

Youtube vids, redo sapling problems, and the textbook problems. That's the best way to study and I recommend doing all of these things for 3 hours a day the week leading up to the final.

Jacob Schwarz-Discussion 3I

The equation to calculate degeneracy (W) is the following: W=(possible positions)^the number of particles

Jacob Schwarz-Discussion 3I

Entropy tells us how much disorder there is in a system. When the volume increases, the entropy increases. When entropy is positive, the process is spontaneous.

Jacob Schwarz-Discussion 3I

In an isolated system, both q and w would equal 0. Isolated systems always have an internal energy of 0

Jacob Schwarz-Discussion 3I

In Lavelle's lecture, he talks about reversible expansion using maximum work whereas irreversible expansion expands instantly and doesn't use as much work(it also isn't as efficient)

Jacob Schwarz-Discussion 3I

Specific heat does not change depending on the amount of substance but specific heat capacity does. Specific heat capacity can be modeled by q=mcdelta or q=ncdeltaT depending on whether you want to find the specific heat in mass or moles.

Jacob Schwarz-Discussion 3I

CdeltaT is normally used for calorimetry problems but when referring to substances we use c=nCdeltaT

Jacob Schwarz-Discussion 3I

You have to use the R value that matches up with your units. For example, when calculating work you would use 8.314 J. Look at the equation sheet and choose the R value that matches up with the units in your problem.

Jacob Schwarz-Discussion 3I

It would be very near to an isolated system. No mass is exchanged and the longer heat is contained in the thermal mug, the closer it is to an isolated system.

Jacob Schwarz-Discussion 3I

No these are different because adding heat is defined by q whereas doing work is defined by w. However, both heat and work do add up to giving the internal energy of the system

Jacob Schwarz-Discussion 3I

It sucks to hear but the easiest way to go about this is to simply just memorize them.

Jacob Schwarz-Discussion 3I

Yes you still do take it into consideration for the exponents. This is because the -2x accounts for the molar concentrations whereas the ^2 exponent is related to the equilibrium concentration.

Jacob Schwarz-Discussion 3I

You need to know the 7 strong acids: HCl, HI, HBr, H2SO4, HNO3, HClO4, and HClO3
as well as the 8 strong bases: (Li) (Na)(K) (Rb) (Cs) (Ca) (Sr) (Ba)
I'm pretty sure this is all you need to memorize for the strong acids/bases but someone please correct me if I'm missing anything

Jacob Schwarz-Discussion 3I

Thats because argon is an inert gas, which basically means that it has 0 affect on the system.

Jacob Schwarz-Discussion 3I

If you change the concentration or partial pressure, the reaction will shift towards the side that has less. This means if you add reactants, the reaction will shift to the products, but if you take away reactants, the reaction will shift to the reactants. If you increase the pressure of the entire...

Jacob Schwarz-Discussion 3I

HCLO3 is considered one of the 7 strong acids that we should know!

Jacob Schwarz-Discussion 3I

Kc and Kp are solved for in the exact same way. Kc uses the concentrations whereas Kp uses the pressures(make sure all the pressures have the same units(ex:atm,barr,etc.)

Jacob Schwarz-Discussion 3I

I believe that real gases have intermolecular attraction and each particle has different volumes. Yet, we assume that all gases are ideal gases in this class im pretty sure.

Jacob Schwarz-Discussion 3I

I'm taking 14C next quarter, and will likely take 14BL fall quarter of next year.

Jacob Schwarz-Discussion 3I

STP stands for standard temp and pressure. STP is 1atm(technically .986 but Lavelle uses 1 atm) and 273.15K.

Jacob Schwarz-Discussion 3I

This equation seems very vague and I'm not totally sure how you would be able to tell if the equation is exo or endothermic. On the test the deltaH will likely be given but I like to think that exothermic is bonds being formed because forming bonds gives off heat whereas endothermic is breaking bond...

Jacob Schwarz-Discussion 3I

Since K is just informing us of a ratio(of Products to Reatants) the units would cancel and that's why K doesn't contain any units.

Jacob Schwarz-Discussion 3I

This is a very good question because there is not one exactly correct answer that I could give you. In my experience, what I like to do is set up the problem using the given equations(ex: w=-nRTln(V1/V2). In this case I am trying to find the amount of work done. However, sometimes after setting this...

Jacob Schwarz-Discussion 3I

Something I recently learned was the difference between heat-safe and regular glass. Heat-safe glass (like the kind you can use oven, eg. Pyrex) is made of borosilicate glass, which has a low coefficient of thermal expansion and therefore is less likely to break at high temperatures. I think this i...

Jacob Schwarz-Discussion 3I

Yes, a bomb calorimeter is an isolated system and matter/energy can't leave the system therefore it would be considered a "perfect system"

Jacob Schwarz-Discussion 3I

Hey!
Does anyone know up to which lecture we should study for for the midterm?? I believe it was all the content up to the end of Monday's lecture(1/25), but could someone correct me if I'm wrong??

Jacob Schwarz-Discussion 3I

Thank you Matthew!!! Will a question like number 4 appear on the midterm??

Jacob Schwarz-Discussion 3I

Juwan_Madaki_3K wrote:When using the ideal gas law, which units should the temperature be in? Kelvins or Celsius?

You would use Kelvin for the ideal gas law

Jacob Schwarz-Discussion 3I

Did you know that you can cool yourself to -273.15˚C and still be 0k?
This one blew me out of the water

Jacob Schwarz-Discussion 3I

Jacob Schwarz wrote:Because the pH is bigger than the pkA in this problem, the solution therefore has a charge involved in it.

I forgot to clarify on this post but the charge also indicates that it's basic(according to this solution).

Jacob Schwarz-Discussion 3I

Because the pH is bigger than the pkA in this problem, the solution therefore has a charge involved in it.

Jacob Schwarz-Discussion 3I

Don't know how you guys felt about it but just wanna let you know that I hope y'all did good on it and there is nothing we can do now so just wanted to say I love you all!!

Jacob Schwarz-Discussion 3I

For the DeBroglie Equation:

Mass=kilograms(kg)
Velocity=meters per second(m/s)
Wavelength=meters(m)

Jacob Schwarz-Discussion 3I

You would multiply .01 by .05nm, which is the uncertainty in position, and by doing this you find 1% of .05 nm. (+- 1)

Jacob Schwarz-Discussion 3I

If you use the link through the email it will likely help. It's due Wednesday morning though and I think they extended it for the same problems you were having.

Jacob Schwarz-Discussion 3I

Kennedi2J wrote:Does anyone know if Sapling is mandatory?

The sapling is mandatory for points.

Jacob Schwarz-Discussion 3I

They are more stable due to the delocalization of the electrons in resonance structures. The electrons have more options and therefore increased stability. I hope this helps!

Jacob Schwarz-Discussion 3I

1.0*10^6 is used more often, yet both are technically correct. I would stick to the former because it is what is used on the midterms/finals.

Jacob Schwarz-Discussion 3I

You use this constant to convert atoms/electrons/molecules into the number of moles, or conversely the number of moles into atoms/electrons/molecules.

Jacob Schwarz-Discussion 3I

What's the dullest element?
Obviously Bohrium!

Jacob Schwarz-Discussion 3I

Hey Rusty!! If you watch lavelles audio visual concepts on his website, this should help a lot. I also recommend taking his post module tests multiple times. These caught me up, but he also reviews everything during his lectures. He doesn’t expect you to know much coming in, and reviews everything w...

Jacob Schwarz-Discussion 3I

Sigma bonds are single bonds and Pi bonds are double or triple bonds. Every bond contains a sigma bond. Ex: double bond=1 sigma + 1pi, triple bond=1 sigma +2 pi

Jacob Schwarz-Discussion 3I

Because Carbon has 4 valence electrons, it forms 4 bonds. 1 electron in the S state and three unpaired electrons in the P state. Therefore sp3

Jacob Schwarz-Discussion 3I

Because of the additional lone pair, the bond angles will be slightly lower than 109.5. Answers such as 109,108,or 107 would likely be sufficient

Jacob Schwarz-Discussion 3I

You first need to calculate how many regions of electron density you have. From there if you have 4 regions, it will be sp3, 5 regions, sp3d, and so on

Jacob Schwarz-Discussion 3I

I do try to read the textbook but quite honestly, at times it is very difficult to read. I would definitely recommend trying your best, but I’ve found the textbook problems the most helpful

Jacob Schwarz-Discussion 3I

If the central atom is bonded to a more electronegative atom, the central atom will be pulled towards that atom, creating a polar atom. The symmetry of an atom also determines whether the molecule is polar. If the molecule is symmetrical, it is likely non-polar, and vice-versa

Jacob Schwarz-Discussion 3I

Hey Karina!!
Although Be is one row higher than Cl, Cl is much farther to the right than Be. Because it is much farther to the right, this outweighs the fact that Be is one row higher. Cl therefore has the higher electronegativity.

Jacob Schwarz-Discussion 3I

I would recommend doing both. The textbook problems are extremely helpful, but I’ve found that supplementing these with attending the step up sessions is the best. It also depends on how you learn best

Jacob Schwarz-Discussion 3I

For anyone on this thread,
we don't need to worry about Sig Figs for the midterm!!

Jacob Schwarz-Discussion 3I

I don't think you will use it mathematically, but knowing how to find either the +1/2 or -1/2 spin state is important!

Jacob Schwarz-Discussion 3I

What did one ion say to the other?

I've got my ion you.

Jacob Schwarz-Discussion 3I

No! You just need to know the concepts. For example, multiple bonds have a shorter bond length. Weaker bonds are longer. Lone pairs on neighboring atoms also repel each other, which then in turn weakens the bond.

Jacob Schwarz-Discussion 3I

I would think of it like this:
If you have the formula NO3-, and you are asked for the oxidation number of N.
You know the final charge is -1 and you know the oxidation number of O is -2. So -2 times 3 is -6 and so the oxidation of N would 5 in order to get you back to the final output of -1

Jacob Schwarz-Discussion 3I

This is because it needs to bond to something with a higher electronegativity rating like oxygen, nitrogen, or fluorine

Jacob Schwarz-Discussion 3I

Double bonds are shorter because more bonding means more attraction. Therefore because double bonds have more bonds and more attraction, they are closer to each other with shorter bonds

Jacob Schwarz-Discussion 3I

Thank you Dr. Lavelle. You have seriously inspired me with your passion for chemistry, even despite the online environment. I appreciate you so much!!!
-Jacob Schwarz

Jacob Schwarz-Discussion 3I

Yes, if they Lyman series is mentioned, you should assume n=1 as the final state.

Jacob Schwarz-Discussion 3I

Do the points get calculated weekly or once at the end of the quarter?

Jacob Schwarz-Discussion 3I

For the next midterm or the final, do I need to buy a webcam?

Jacob Schwarz-Discussion 3I

They just don't want to confuse it with velocity so sometimes they use E=hf

Jacob Schwarz-Discussion 3I

You would solve normally using E=hv and then divide by Avogadro's constant

Jacob Schwarz-Discussion 3I

It's 100E because there are 100 photons-each photon adds more energy-therefore 100E

Jacob Schwarz-Discussion 3I

Dr. Lavelle said not to worry about it. It wasn't on my midterm and I believe he said it wouldn't be on any of them

Jacob Schwarz-Discussion 3I

My interpretation was that a diffraction pattern is caused by waves!!!

Jacob Schwarz-Discussion 3I

Where did you order it to? I ordered it to the Ackerman union and it worked for me.

Jacob Schwarz-Discussion 3I

Dr. Lavelle,
I know you have an insane amount of students and to make it even harder, you are in an online environment. I can't imagine how many emails and daily notifications you have to respond to. Yet, you always have a smile on your face. Just wanted to say thank you! Appreciate you Dr. Lavelle!!

Jacob Schwarz-Discussion 3I

It really depends. Doing the step up sessions have helped me to refine my skills but I usually already know the content. The more help and practice you do, the easier the midterms will be.

Jacob Schwarz-Discussion 3I

Lavelle is okay with 3*10^8! You don't need to worry about 2.999 he wants us to stick with 3 (:

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