CHEMISTRY COMMUNITY

Kelly Singh

Hannah_Kim_1I wrote:Rocky by Still Woozy!

he is SO good

Kelly Singh

I think you get partial credit if you finish it after the deadline!!

Kelly Singh

Jaclyn Dang 3B wrote:it depends on the requirement you are trying to fill, but Psych, Classics, and Scand have some easy classes.

Any Classics class w/ Prof Beckmann is great!!

Kelly Singh

I think the classics classes are pretty easy, along with PORT 46, and musicology classes

Kelly Singh

I also would recommend going to the step-up/workshop sessions for practice problems.

Kelly Singh

I definitely did much better on the second test than the first even though I studied more for Midterm 1. I think it has something to do with the amount of concept-based questions which have proven to be easier for me.

Kelly Singh

No, a good giveaway is the delta sign in front of the variable though :)

Kelly Singh

I like to repeat questions until I understand how to do them. Keep your head up, only a few more weeks!

Kelly Singh

A reaction is thermodynamically favorable when enthalpy decreases and entropy increases. This also means when the change in Gibbs Free energy is negative.

Kelly Singh

305405193 wrote:What in chemistry makes flavors in food taste different other than heat?

I have always wondered this!

Kelly Singh

Janna Shakiba wrote:
Mari Williams 1K wrote:My brother and I once shattered a glass pan of brownies after putting it on a cold metal table straight out of the oven...truly tragic

Lmao I've done this too

Me too!!

Kelly Singh

I think they're virtually the same, but it might depend on what information you are given.

Kelly Singh

Thank you so much for this

Kelly Singh

Ashlen Bullock 1H wrote:The constants for Cp and Cv for a monatomic ideal gas should be on the equation sheet. Cp=5/2R and Cv=3/2R. They are different for a diatomic ideal gas though.

Would we be told if the ideal gas was diatomic?

Kelly Singh

Doing the problems mentioned in the outlines and attending the UA workshops really help! Which UA workshops are most helpful? Although I believe all the UA workshops are very helpful (so I'd encourage going to all), I typically go to Justin and Matthew's workshops!! They are AMAZING. Also, to answe...

Kelly Singh

Oh! No worries :)

Kelly Singh

I think my Chemistry Community points are off? How often do they get updated?

Kelly Singh

The gas that we are looking at is the yellow gas. In the top picture, the yellow gas is trapped in the small skinny volume. When you open it up, the gas will spontaneously move into the bigger volume (increase in entropy). This is why there is an arrow with "spontaneously" going from the ...

Kelly Singh

Hi! Can someone explain the difference between intrusive and extrusive properties and how that applies to heat capacity and specific heat capacity? I believe in the lecture Dr. Lavelle mentioned that heat capacity was an extrusive property and specific heat capacity was an intrusive property. Where...

Kelly Singh

I need new book recommendations haha. I've just been rereading my favorite books over this quarantine. Right now I am reading the Heroes of Olympus books by Rick Riordan. LOL i've been rereading the percy jackson series for comfort reading these days hahaha haha I've been rereading the Hunger Games...

Kelly Singh

Lauren Strickland 1B wrote:I really enjoyed Cat's Cradle and Six of Crows.

YES! so good

Kelly Singh

Anna Yakura 2F wrote:Hello, are you allowed to assume that temperature is 298K if the question does not specify? For example, on 4D.7 on the outlines, it didn't state the temperature but when I assumed 298K, I got the right answer. When am I allowed to do this?

I would assume so :)

Kelly Singh

EmilyC_3D wrote:When converting from ml to moles for gases, should we always use PV=nRT?
Alternatively, when converting from ml to moles for solids, should we always use density?

Thank you!

Yes!

Kelly Singh

Siwa Hwang 3G wrote:Watch youtube videos with diagrams that help you visualize the problem

Any youtube video recommendations that have helped a lot?

Kelly Singh

Karen Elrayes 1L wrote:I feel like this section is a lot more challenging because it's a little difficult to know how to start every problem. Any tips?

I have been having a difficult time too. It has helped to write out all of my known values and the unknown values that I need. Then I write out all relevant equations.

Kelly Singh

It helps to stay consistent with whichever one you use, though.

Kelly Singh

They are interchangeable :)

Kelly Singh

It is all dependent on the info given. Generally, entropy is the amount of disorder in a system. Systems naturally move towards more entropy.

Kelly Singh

There are 4 different constants, depends on what you are using it for.

Kelly Singh

Thank you!

Kelly Singh

just know how to convert I think

Kelly Singh

no lecture! but there is a midterm :)

Kelly Singh

Does anyone know who teaches 14C?

Kelly Singh

So, the correct answer is that the reaction would shift towards the products?

Kelly Singh

this is called the conjugate seesaw! Conjugate bases of strong acids are weak and conjugate acids of strong bases are weak.

Kelly Singh

sum of equilibrium pressures in a system.

Kelly Singh

There is a list of strong acids and bases in the textbook. But generally, strong acids will contain halogens (Cl, Br, I) and strong bases will contain elements from group 1 & 2 (Li, Na, K, Rb, Cs, Ca, Sr, Ba). https://sites.google.com/site/chempendix/strong-acids-bases?authuser=0#h.p_ID_32 Than...

Kelly Singh

Alara Aygen 3K wrote:Doing the problems mentioned in the outlines and attending the UA workshops really help!

Which UA workshops are most helpful?

Kelly Singh

I haven't taken an exam for Lavelle before. What material should i use to study and practice for the midterm? Is there anything other than the workshops, homework and textbook problems? Where do i find old problems from previous midterms? I like to fill out the outlines and make sure I know all of ...

Kelly Singh

I like to fill out the outlines and write info for all of the learning objectives.

Kelly Singh

Since the system is being compressed, which applies to pressure, we are only looking at moles of gas. Therefore, since there are 6 moles of gas on either side of the equation, the system would not favor either side when compressed. Why don't you take the six moles of gaseous water into account on t...

Kelly Singh

I usually just try both and use the most reasonable one

Kelly Singh

thank you all!

Kelly Singh

I think he also mentioned that midterms will be during lecture times

Kelly Singh

If I had 5 extra posts from last quarter (55) do they carry over to this quarter? or do I still have to complete 50 total

Kelly Singh

are "bars" an SI unit?

Kelly Singh

Why do we have to take the reciprocal of the Kc/Kp when using the reverse reactions? we have to take the reciprocal because it is always products/reactants, and when the reaction is reversed the original products become reactants and the original reactants become products. You can think about it li...

Kelly Singh

My understanding is that when you add more reactant to an reaction that is already at equilibrium, the reaction shifts to the right (forward reaction) and more product is produced, allowing the reaction to regain equilibrium. However, when you add more product to an equation that is already at equi...

Kelly Singh

but in all honesty I'm a little confused by it also haha

Kelly Singh

I think its just a way to generalize the K value so that it has no units. Since K can be taken from concentration or partial pressure values, we call the input activities.

Kelly Singh

This would be different than the K value right?

Kelly Singh

When solving for the equilibrium constant, how do you know if the problem requires an ICE table? Is it when initial concentrations are given but not the equilibrium concentrations, so they must be solved for? I think ICE tables are usually used when you are given at least one initial or final conce...

Kelly Singh

I think your answer is correct since Sulfur can have an expanded octet. The compound has resonance and can be drawn in different ways.

Kelly Singh

It is +2

Kelly Singh

Can someone explain more in detail of what bidentate means in a coordination compound and how it is different from a monodentate? Bidentate ligands are able to attach/bond to the transition metal twice. (Tridentate= three times, polydentate= multiple bonds) Sorry, forgot to add this. This means tha...

Kelly Singh

lwong Dis1L wrote:Can someone explain more in detail of what bidentate means in a coordination compound and how it is different from a monodentate?

Bidentate ligands are able to attach/bond to the transition metal twice. (Tridentate= three times, polydentate= multiple bonds)

Kelly Singh

claire ikemiya_2I wrote:And if you are ever asked which acid is stronger than another, remember the elements with a smaller atomic radii is stronger since it has a shorter bond with H, which is requires more energy to break.

This is so helpful, thank you!

Kelly Singh

Lizbeth Garcia 1F wrote:I believe it is similar, just, maybe more questions since they are giving us more time to complete it.

Do you know how much time we're being given?

Kelly Singh

I don't know very much about tattoo removal but I thought this was a very interesting post. Since its an acid, I would imagine that TCA works by promoting cell turnover (destroying cells) which causes new skin growth, and thereby lightening the tattoo. Definitely doesn't sound like the most efficien...

Kelly Singh

claire ikemiya_2I wrote:So if all we know is that 50% is a passing grade, do we project that the passing range is larger or that the grade is going to be curved?

I don't think that he usually curves grades

Kelly Singh

almost_ethan wrote:
tholz11 wrote:I believe you need a 93% to receive an A in the class

Does anyone else know if this is true? :0

Yes, that's what I remember from the syllabus.

Kelly Singh

How come hexagonal planar is not a possible geometry for a compound with a coordination number of 6? Just like Jasmine said, you have to remember that the compounds exist in 3-dimensions. Each region of electron density moves as far away from other regions. If you think about it, the points on a he...

Kelly Singh

Daniela_Martinez_3B wrote:en is ethylenediamine (H2NCH2CH2NH2)

Do you know if there are any other shorthand versions of compounds that we should know?

Kelly Singh

KA measures the strength of an acid whereas pKA is the negative log of that value. It's just an easier and more convenient way to refer to the KA value as far as I know. =)

Kelly Singh

I tend to do much better with the calculation/mathematical portions of this class and not as well with the conceptual parts. I did a lot better on the first midterm than the second one. Does anyone have a specific way that they study for conceptual things like hybridization because I have a hard tim...

Kelly Singh

Why did the noble gas cry?

His friends Argon

Kelly Singh

^exactly. If there are multiple lone pairs available for other compounds to bond to, it is more likely to form a coordinate compound.

Kelly Singh

Thank you for letting us know!

Kelly Singh

You have to take into account all electron densities when making the initial shape, then, to determine the actual shape of the molecules, you only look at how many actual atoms there are. Just as Dr. Lavelle had shown in his lectures, it does not matter which point of electron density you call the l...

Kelly Singh

705324760 wrote:Two chemists walk into a bar.

One says, “I’ll have an ‎H2O.” The other says, “I’ll have an ‎H2O, too.” The second chemist dies.

I laughed at this, thank you

Kelly Singh

Why did Avogadro love golf?

He always got a MOLE in one!

Kelly Singh

Why should you go drinking with neutrons?

When you go, there's no charge!

Kelly Singh

Determine the difference in electronegativities between the two atoms in the molecule you are examining, and which ever molecule produces the greater difference is the molecule that is more ionic. To add to this, elements on the right side of the periodic table are generally more electronegative th...

Kelly Singh

The only difference would be the presence of water! Aqueous means dissolved in water :)

Kelly Singh

Hi! So just confirming my understanding: Ion--ion interactions are stronger because they have full negative and positive charges which attract each other. Other interactions are not as strong because the charges are only partial. Please let me know if this looks like a complete and accurate summati...

Kelly Singh

I thought that the midterm only covered up to the end of Outline 2?

Kelly Singh

almost_ethan wrote:Does anyone know if Dr. Lavelle will hold a review session for Midterm 2?

Not sure about Dr. Lavelle, but I know that the UA who has a workshop on Saturday is having a review session.

Kelly Singh

almost_ethan wrote:
Kelly Singh wrote:Is the next midterm during week 7 or 8?

Midterm 2 is Week 7, during discussion.

Thank you!

Kelly Singh

Thank you!

Kelly Singh

Do you think it might have something to do with atoms' tendencies to fill their shells halfway? hence the 3d^5?

Kelly Singh

From what I understand, theoretically, the n value can increase indefinitely. Are there more letters (subshells, ie. spdf...) that correspond to the higher values?

Kelly Singh

A little late but Happy Halloween! I celebrated at the #2 public university (UC Berkeley)

Kelly Singh

Is the next midterm during week 7 or 8?

Kelly Singh

From what I know, bond length in double bonds is around 1.34 angstrom and single bonds is 1.54 angstrom. Bond length is inversely proportional to bond energy, so less bond length means more energy, making it a harder bond to break.

Kelly Singh

If you think about the wave like a function on a graph, the "extent of change" would refer to the slope. A wave with a lower frequency would have a smaller slope, or extent of change, than a wave with a higher frequency. This question is definitely hard to visualize, but I hope this helps :)

Kelly Singh

Where do you find the solution manual? Is it different from the odd-number exercise answer key on the back of the textbook? When you click on the link to sapling from CCLE, the homepage that pops up has a column that says "Resources" right in the middle. If you click on the last link unde...

Kelly Singh

While studying the textbook, I would make sure to focus on the conceptual information related to what we've discussed in lecture in addition to solving the textbook problems. My guess is that the midterm will have conceptual questions in addition to the calculation-based questions. I'm kind of nerv...

Kelly Singh

While studying the textbook, I would make sure to focus on the conceptual information related to what we've discussed in lecture in addition to solving the textbook problems. My guess is that the midterm will have conceptual questions in addition to the calculation-based questions. I'm kind of nerv...

Kelly Singh

All of the topics covered in his lectures up until last Wednesday will be covered. So, I think the basic principles of quantum numbers may be included. Nothing in depth, though.

Kelly Singh

Darren1e wrote:I understand what the uncertainty is, because we cannot measure the exact momentum and position of an electron but how do they even determine the "amount" of uncertainty.

The "amount" of uncertainty is the range of values in which the actual value could fall within.

Kelly Singh

Hello! The De Broglie equation is used to the find the wavelength of a particle (i.e. an electron) with wave-like properties . Basically, for very small particles, the De Broglie equation measures the wavelength of the wave-like property that particle exhibits. The other equation you mentioned, suc...

Kelly Singh

The values should be the same, it just depends on what information you are given/need to find. If you are dealing with momentum (mass and/or velocity) then you should use DeBroglie's equation. If you are dealing with energy and/or frequency, you should use one of the other two. Hope this helps! Yes...

Kelly Singh

I think it has something to do with the photoelectric effect. I remember hearing someone say that just as light diffracts if passed through two slits, electrons will diffract when passed through the same structure. I hope this helps a little bit.

Kelly Singh

What is the difference between using the DeBroglie equation vs using c=(wavelength)(frequency) and/or E=(h)(frequency) to calculate wavelength? Will the values be exactly the same?

Kelly Singh

Is the electron volt just a different way to measure energy or are there situations in which using the eV more useful than just Joules? An 3lectron volt is the energy required to ionize a single atom so it is extremely small compared to a joule. In terms of when each should be used, eV is more comm...

Kelly Singh

Yeprem wrote:and are we supposed to remember what eV equals to?

My TA said that since if it was included in a question on a test, the conversion would most likely be given on the formula sheet.

Kelly Singh

When I was reading Focus Topic 1B, I came across the units "eV". I have never seen this before but I think they are units of energy? Can someone explain how they compare to Joules and how to convert them?

Kelly Singh

Wow that makes so much sense. Thank you!!!!

Kelly Singh

The question is: Which of the following happens when the frequency of electromagnetic radiation decreases? Explain your reasoning. (a) The speed of the radiation decreases. (b) The wavelength of the radiation decreases. (c) The extent of the change in the electrical field at a given point decreases....

Kelly Singh

On the same problem M.9, does anyone know how to solve for part b.) Calculate the maximum mass of copper(II) hydroxide that can be formed when 2.00 g of sodium hydroxide is added to 80.0 mL of .500M Cu(NO3)2 (aq)... thank you! First, convert 2g NaOH to mols by dividing by its molar mass--39.997. Yo...

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