CHEMISTRY COMMUNITY

Navdha Sharma 3J

Thank you Dr. Lavelle!!

Your lectures, sapling, the step-up sessions, the workshops, the final review sessions, and especially the music and CHEMISTRY COMMUNITY!! Chem 14A and Chem 14B made me fall in love with chemistry again!!

Navdha Sharma 3J

electrochemistry for sure!

Navdha Sharma 3J

omg thank you so much!!

Navdha Sharma 3J

I didn't get a seat in chem 14C :(
I guess I won't be taking any chem classes in the spring

Navdha Sharma 3J

just take deep breaths and close your eyes to shut out the world. it really helps a lot!

Navdha Sharma 3J

It would depend on the stoichiometric coefficients. A would vary accordingly and doesn't always have to be 1.

Navdha Sharma 3J

A zero order reaction means that the rate of reaction is independent of concentration of reactants.

https://www.toppr.com/ask/question/what ... e-example/

Navdha Sharma 3J

Last quarter, in Chem 14A, the final was equally cumulative. So, I guess studying all of the units will be really helpful on the Chem 14B final too!

Navdha Sharma 3J

Same here! I used Organic Chemistry Tutor videos to prepare for the Midterms, and it really helped me understand the conceptual topics easily.

Navdha Sharma 3J

Right now I have been listening to 'Folklore' by Taylor Swift on repeat!

Navdha Sharma 3J

i am craving something spicy like Indian chaat!

Navdha Sharma 3J

If you have to balance the redox reaction which is taking place in a BASIC solutions, then we use OH- and H₂O.

Navdha Sharma 3J

n represents the number of moles of electrons transferred in the balanced reaction.

Navdha Sharma 3J

Yes. If E cell is positive, then $\Delta$ G will be negative. Thus, the reaction will be spontaneous.

Navdha Sharma 3J

For acidic solutions, we use H+ and H₂O to balance but in basic solutions we use OH^- and H₂O.

Navdha Sharma 3J

I planning on taking Stats 10, Anthro 2, and Chem 14C if I get a spot!

Navdha Sharma 3J

I think you need a C- to pass which means that you have to have 200 points for that.

Navdha Sharma 3J

I have two midterms on Monday!! So, unfortunately i'll be chilling after that. There are a couple of Bollywood movies on my watchlist. I'm planning on watching at least two of them! :)

Navdha Sharma 3J

The value of R which has to be used depends on the units: 8.314 J mol^-1 K^-1 or 0.08206 L.atm mol^-1 K^-1
Also, you don't have to remember these, just look it up on the equation sheet!

Navdha Sharma 3J

C_p is the heat capacity at constant pressure while C_v is the heat capacity at constant volume.
Also, C_p = C_v + R

Navdha Sharma 3J

From what I understood from this week's sapling HW:

$\Delta$ S of the system can be found by $\Delta$ S_products - $\Delta$ S_reactants

$\Delta$ S of surroundings = - $\Delta$ H_system/T

Navdha Sharma 3J

The change in temperature in Celsius or kelvin is the same. So, you don't have to worry about units.

Navdha Sharma 3J

While solving a problem, I think having all of the quantities in similar units is a must. So, I like to convert joules to kilojoules or vice-versa before starting the calculations so that it becomes easier to solve the problem without making mistakes.

Navdha Sharma 3J

delta G --> free energy change of a reaction
delta G knot --> free energy change of a reaction under standard conditions(like 1 atm, 298 K, 1M concentration)

Navdha Sharma 3J

Happy Valentine's Day everyone! Please don't forget to relax and recharge during the long weekend.

Navdha Sharma 3J

I think Cp = Cv + R

Navdha Sharma 3J

Q --> heat
H --> enthalpy

Navdha Sharma 3J

the different values of R just correspond to the different units. Just being aware of the units in the problem helps to know whether to use 8.314 or 0.0821 as the R value.

Navdha Sharma 3J

i think keeping up with the lectures as they are released has really helped me. Also doing textbook problems is a good way to practice other than sapling. Lastly, try to attend as many review sessions as possible.

Navdha Sharma 3J

The Language Instinct by Steven Pinker is really a cool book if you are interested in linguistics!

Navdha Sharma 3J

Sunny Wu 3A wrote:Chemical Principles: The Quest for Insight Seventh Edition by Atkins et al.

Just kidding, I second Crime and Punishment and Fahrenheit 451 :)

lol!

Navdha Sharma 3J

universe is an isolated system because it literally contains everything and so there is no room for exchange with anything.

Navdha Sharma 3J

I think it will take about a week or longer for the grades to be released(that was my experience last quarter in Chem 14A).

Navdha Sharma 3J

The values will be provided on exams just like we have them available while solving sapling or textbook problems!

Navdha Sharma 3J

Endothermic reactions involve absorption of energy to break bonds. So, phase changes of solid to liquid, liquid to gas, and solid to gas will be endothermic reactions.

Exothermic reactions release energy during formation of bonds. So, the phase changes of liquid to solid, gas to liquid.

Navdha Sharma 3J

I remember that Dr. Lavelle said in his lectures that whenever K is less than 10^-4. Also, you can always check it. If the value of x is less than 5% of the initial molarity, you are good to go!

Navdha Sharma 3J

I was just reading about non-stove cooking and stumbled across a passage describing how marination not only imbibes food with extra flavor but also breaks down proteins in meat dishes - when the marinade contains an acidic element, as it usually does - essentially "cooking" it without req...

Navdha Sharma 3J

Fiona Huang 3C wrote:Thank you guys! So is it the opposite for bases? When pH>pka, the neutral species would be predominant?

Yes! When pH>pka, neutral species would dominate and when pH<pka charged species dominate.

Navdha Sharma 3J

The first midterm is during our class on Friday so I think that it will be proctored like our final in Chem 14A.

Navdha Sharma 3J

The C row or the change row is determined by the stoichiometric coefficients in the reaction equation.

For ex: H2 + Cl2 ---> 2HCl

In the forward reaction the change for H2 will be -x, for Cl2 will be -x, and HCl will be +2x(because of its coefficients).

Navdha Sharma 3J

Some things that helped me while doing Chem 14A with Dr. Lavelle last quarter:
1. Attending UA sessions
2. Reading the textbook
3. Doing the textbook problems
4. Revisiting the sapling HW problems

Hope this helps!

Navdha Sharma 3J

I think the some things that really helped me on the midterm in Chem 14A last quarter were attending the UA sessions and doing the textbook reading along with doing the textbook problems.

Navdha Sharma 3J

Q and K are calculated in the same way but Q is the calculation that is not done at equilibrium.

Navdha Sharma 3J

If H2O is a gas, you should include it in the ICE table!

Navdha Sharma 3J

This problem can be solved in the way we solve simultaneous linear equations in algebra. So in this particular question, you will have to add the first reaction equation and the REVERSE of the third reaction equation. Also you might have multiply one of the equations by a constant and don't forget t...

Navdha Sharma 3J

Basically Le Chatelier's principle states that when a system experiences a disturbance (such as concentration, temperature, or pressure changes), it will respond to restore a new equilibrium state. For instance, if there is an increase in the concentration of products, the equilibrium will shift tow...

Navdha Sharma 3J

I did the same mistake! The numerator should be 4x^2 and not 2x^2

Navdha Sharma 3J

I think the textbook questions helped me a lot. Also, the step-up sessions and workshops really help too! Being regular and keeping up with the lectures also help.

Navdha Sharma 3J

The points for participation can bee seen on your gradebook on ccle. But I don't think that they are updated regularly. Last quarter when I took chem 14A, it took about 3 weeks for the first set of participation points to be uploaded.

Navdha Sharma 3J

Jada3K wrote:Hopefully, someone sees this I was wondering if our chem community post carries over if we went over 50 from last quarter.

I don't think so Jada though I might be wrong!

Navdha Sharma 3J

The deadline for completing your 5 posts of the week is Sunday midnight!

Navdha Sharma 3J

I think it will. If you look at the syllabus on the chemistry 14B website, it says that midterms will be 50 minute long while the final will be 1 hour and 30 minutes long. It also says that both will be proctored, which is sounds exactly like chem 14A!

Navdha Sharma 3J

i really liked this one!

Navdha Sharma 3J

Anxiety is normal. All of us want to do well and push ourselves to new limits. But I find that while trying to do well, I often forget the importance of taking breaks. It is crucial to step away from what you have been doing. As mentioned above a change of scenery really helps a lot! All the best! Y...

Navdha Sharma 3J

HF is a weak acid as F is highly electronegative and does not readily give up proton.

Navdha Sharma 3J

The above answer has included almost all the common strong acids. I think that strong bases include the oxides and hydroxides of both Group 1 and group 2 metals.

Navdha Sharma 3J

2H₂O is named as dihydrate and not diaqua as it is not included in the coordination sphere.

Navdha Sharma 3J

An amphoteric compound is one that can act as both an acid and a base. Basically, it can accept and lose protons.

Navdha Sharma 3J

I think that you can go to your TA's office hours for the review!

Navdha Sharma 3J

I am just waiting for our finals to get over! The last couple of weeks have been really tiring though.

Navdha Sharma 3J

en stands for ethylenediamine, which is a bidendate ligand.

Navdha Sharma 3J

Pi-bonds overlap side-by-side. If they rotate, they will break. Hence, pi bonds do not rotate.

Navdha Sharma 3J

The coordination number can be easily found by calculating the number of bonds formed by the central transition atom

Navdha Sharma 3J

It's the same thing. I personally like to use the first one because it follows the order we are used to!

Navdha Sharma 3J

From what I understand, if the central atom has lone pairs only then we will see lone pairs affecting molecular geometry.

Navdha Sharma 3J

Yes, the shape of the water molecule is bent or angular.

Navdha Sharma 3J

I think all bonds have atleast one sigma bonds and the rest are pi bonds.

Navdha Sharma 3J

I like to understand the text as a go through it rather than blindly taking notes. Also, I think doing the textbook problems really helped me in the second midterm.

Navdha Sharma 3J

'l' will determine which subshell it is: s, p, d, or f.

l=0 --> s
l=1 --> p
l=2 --> d
l=3 --> f

Navdha Sharma 3J

You would look at the intermolecular forces. As the intramolecular forces don't contribute towards the melting/boiling points.

Navdha Sharma 3J

G-C bonds are stronger as they are triple bonds while A-T bonds are only double bonds. Due to larger bond strength, G-C bonds are more stable too.

Navdha Sharma 3J

I think they will be released sometime next week. As a couple of people mentioned above, they could be released sooner as there are no partial points this time.

Navdha Sharma 3J

You are not alone! I am sure a lot of us(including me) are super stressed about grades. But just know that if you stress too much or put pressure on yourself, you won't be able to perform your best. So just chill!

Navdha Sharma 3J

A triple bond has one sigma and one pi bond

Basically, multiple bonds have both sigma and pi bonds.

Navdha Sharma 3J

I don't think that we went over this in lectures, but as there is a homework question I assume that we need to know the basics. The link below really helped me!

https://www.thoughtco.com/rules-for-ass ... ers-607567

Navdha Sharma 3J

I think you have interpreted the relationship between the atomic radius of O and S incorrectly. S has a larger atomic radius as atomic radii increases down the group.

Navdha Sharma 3J

Chlorine will have lower ionization energy. This is so as it is one period below oxygen and so its electrons will be less tightly held.

Navdha Sharma 3J

I don't think that it is necessary to find the formal charge every time, but it certainly helps in checking your work. It could also help in calculating the formal charge of the central atom without many calculations. Like in the last week's lecture, Lavelle used the formal charges along with the ov...

Navdha Sharma 3J

I don't think that we actually have to draw the double bonds shorter. Knowing that double bonds are shorter is enough!

Navdha Sharma 3J

Electron density is just the probability of an electron being present.

The electron density or the probability of finding electrons in a nodal plane is zero.

Navdha Sharma 3J

I personally did not expect memorization problems on the midterm, but my previous knowledge helped me there. I think what you did in terms of preparing for the first midterm is perfect. Instead of skimming over the memorization based topics, make notes on them. Usually, memorization topics include t...

Navdha Sharma 3J

I think I need to first understand the octet rule, can anyone help with that? The octet rule refers to the tendency of atoms preferring to have eight electrons in the valence shell. Basically, the tendency of elements to have the electronic configuration of the nearest noble gas(which has fully fil...

Navdha Sharma 3J

Yes, it is the same thing.

We know, kinetic energy = energy of incident light - threshold energy. Thus, it is evident from the equation that the excess energy corresponds to kinetic energy

Navdha Sharma 3J

All the elements in a period have the same number of shells(just the number of valence electrons vary). But, the number of protons across a period increases, and so the effective nuclear charge increases which causes the size to decrease across a period.

Navdha Sharma 3J

Happy Halloween!

I watched my missed chemistry lectures and The Mandalorian simultaneously while gorging on the pumpkin choco-chip cookies I baked!

Navdha Sharma 3J

The atomic radius depends upon the effective nuclear charge and number of shells. Across a period, the nuclear charge increases, and the number of shells remain the same, so the size decreases. However down the group, though both the effective nuclear charge and the number of shells increases, the m...

Navdha Sharma 3J

This class requires us to know c as the speed light which is 3 X 10^8 m/s

Navdha Sharma 3J

I really liked this one!

Navdha Sharma 3J

I personally like to use the Aufbau principle that states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. The arrows in the figure really help to determine which comes first.

Navdha Sharma 3J

I think that's because of the Aufbau principle which states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels.

Navdha Sharma 3J

All light(EM radiations) travel at the same speed, i.e approx 3 X 10^8 m/s. But as the observed speed is LESS THAN the speed of light, it supports the particle model. Hope it helps!

Navdha Sharma 3J

The photoelectric experiment can only give accurate results under vacuum. If not conducted in a vacuum, the ejected electrons can collide with the particles present in the air and interfere with the data.

Navdha Sharma 3J

I think you meant to ask the difference between E = hv and E= hc/λ. They are essentially the same thing.

We know, c = λv
=> v = c/λ --- equation 1

So, E = hv
=> E = hc/λ (from equation 1)

Hope it helps!

Navdha Sharma 3J

As stated in the previous responses, Planck's constant(h) = 6.626 X 10^(-34). I had trouble remembering its value earlier, but as I started doing the textbook questions in the syllabus, I realized that it was being used regularly. So, the repeated usage has permanently etched the value in my head! B...

Navdha Sharma 3J

I first go through all the pre-modules. Even though they are a bit lengthy and take up a lot of time, they are really useful. Then I watch the lectures and take notes on the topics that I might have not understood in the pre-modules. Then I do the textbook questions given in the syllabus - THEY ARE ...

Navdha Sharma 3J

The majority of the compound names will be given on the test. But, it is always helpful to know the compounds that occur repeatedly like CO2, H20 (as someone already mentioned above).

I found this really helpful link : https://youtu.be/ptAw20kem90

Navdha Sharma 3J

The molecular formula can be determined from the figure simply by counting the number of atoms of each element in the compound. For instance, you can figure out that the compound has three elements: C, O, and H. Now just count the number of C, H, and O. That will be your molecular formula: C6H8O6. T...

Navdha Sharma 3J

CO4 will mean that C=1 and O=4. However, if the compound had been (CO)4, it would have meant that C=4 and O=4. Usually, the parentheses(if present) around the atoms of the compound will help you to determine the number of those atoms.

Navdha Sharma 3J

Whenever you see 'm', it implies 'milli'. So, the unit mmol means millimolar. Also, milli corresponds to 10^(-3).

Navdha Sharma 3J

950000 has only two significant figures as all the trailing zeroes to the non-zero numbers are NOT SIGNIFICANT

80060 has 4 significant figures as the zeroes between two non zero numbers are significant. The last zero won't be significant as trailing zeroes to any non-zero number isn't significant.

Search found 106 matches