CHEMISTRY COMMUNITY

Uyenvy Nguyen 1D

today was really fun! thank you to everyone who organized this :-)

Uyenvy Nguyen 1D

termolecular reactions involve the simultaneous collision of 3 reactants

Uyenvy Nguyen 1D

Thank you !!!

Uyenvy Nguyen 1D

oops ignore the image being attached 3 times

Uyenvy Nguyen 1D

I put 4Fe(s)+3O2(g)+6H2O(l)↽−−⇀2Fe2O3(s)∙6H2O(s) for the question below, and I also tried it without the phases, but it still says it's incorrect. How would I balance this?: One of the most recognizable corrosion reactions is the rusting of iron. Rust is caused by iron reacting with oxygen gas in th...

Uyenvy Nguyen 1D

kentbui1d wrote:I put the same thing as you, but I got it correct. That's weird

[Pb(OH)4]2-(aq) + ClO-(aq) ---> PbO2(s) + Cl-(aq) + H2O(l) + 2OH-(aq)

Yeah I just realized I had typed it in wrong, but had it correct on paper !

Uyenvy Nguyen 1D

Astha Patel 2J wrote:I had the same question as you and I got the same answer and it was correct. Maybe try rearranging the order of the products, because my products were listed PbO2 + Cl- + H2O + 2OH-

Thank you so much! I just realized I had written down H2O, but forgot to add it into my answer on Sapling.

Uyenvy Nguyen 1D

Hayden Lee 1C wrote:It seems that you balanced the reaction correctly. Did you include the correct phases of each species? This is required in the problem and it may be the reason why you aren't getting it right.

Yeah, I put ClO-(aq) + [Pb(OH)4]2-(aq) --> Cl-(aq) + PbO2(s) + 2OH-(aq), but it's still wrong

Uyenvy Nguyen 1D

Could someone help me with balancing this redox equation: [Pb(OH)4]-2(aq) +ClO−(aq) ⟶ PbO2(s)+Cl−(aq) (basic solution) 'm having trouble balancing this equation and determining the amount of electrons needed to be added. I got [Pb(OH)4]2- + ClO- --> PbO2 + H2O +2OH- +Cl-, but I'm not sure why this i...

Uyenvy Nguyen 1D

I'm a bit confused on how to begin balancing this redox equation: Au(s) + HNO3(aq) +HCl(aq) --> HAuCl4(aq) + NO2(g) +H2O(l).
I am assuming the oxidation half reaction is Au(s) --> HAuCl4(aq), but what would the reduction half reaction be?

Uyenvy Nguyen 1D

Yup, the oxidizing agent is the one that has been reduced, and vice versa.

Uyenvy Nguyen 1D

How do we know when we need to add OH- when balancing redox equations?

Uyenvy Nguyen 1D

I like to plan out the things I have to do each day so that I won't get too overwhelmed by all my assignments and end up forgetting to do important things. It is also nice to check off what you've finished. I would suggest cleaning your work area, switching your work environment once in a while, and...

Uyenvy Nguyen 1D

W=(# of possible states)^(# of particles). For example, 64 molecules all aligned in the same direction would have a degeneracy of 1^64.

Uyenvy Nguyen 1D

Midterm 2 will be proctored the same way Midterm 1 was proctored. I'm assuming the final will be proctored in a similar way, since that's how it was for 14A.

Uyenvy Nguyen 1D

They are pretty difficult, I'd have to agree. There is a possibility that the focus problems will be used though, because they are part of the assigned textbook problems :o

Uyenvy Nguyen 1D

Yes, it probably will! The Van't Hoff equation relates the temperature dependence of the equilibrium constant to the enthalpy change of a process

Uyenvy Nguyen 1D

Can we tell whether expansion work is being done by a reaction based on the number of moles of gas in a reaction equation?

Uyenvy Nguyen 1D

Thank you!!!

Uyenvy Nguyen 1D

You would have to first calculate the change in entropy for heating the water from 58 to 100 degrees. Then you would add this value to the entropy from 100 to 100 degrees which is given to you. The vapor is then cooled back down so calculate the change in entropy from 100 back to 58 degrees. To cal...

Uyenvy Nguyen 1D

Hi, I'm a bit confused on this question: Calculate the standard molar entropy of vaporization of water at 58.0 °C , given that its standard molar entropy of vaporization at 100.0 °C is 109.0 J⋅K−1⋅mol−1 and the molar heat capacities at constant pressure for liquid water and water vapor are 75.3 J⋅K−...

Uyenvy Nguyen 1D

Thank you!

Uyenvy Nguyen 1D

This question states: Consider a process in which an ideal gas is compressed to one-fifth of its original volume at constant temperature. Calculate the entropy change per mole of gas. I know that the equation that we can use is delta S = nRln (V2/V1), but I'm not sure how to solve it if we are not g...

Uyenvy Nguyen 1D

I would recommend attending UA sessions, working on textbook problems, and watching review videos on Youtube! If you can't make it to the UA sessions, some of the worksheets can be found on chem community & most of them are posted in the Google folder that someone has created for this class. I'm...

Uyenvy Nguyen 1D

If given NO, N2O, CO2, and Cl2, how do you tell which compounds would be most likely to have a residual entropy in their crystalline forms at T=0 K?

Uyenvy Nguyen 1D

I'm pretty sure we can miss 200 points to pass with a C-, since 50% is a C- in this class. I am assuming 320/400 points would be the minimum for a B-, since that is 80%, but feel free to correct me if I'm wrong.

Uyenvy Nguyen 1D

Thank you!!

Uyenvy Nguyen 1D

Hi, I'm not sure how to begin solving this question. How should I set up the equations? A constant‑volume calorimeter was calibrated by carrying out a reaction known to release 0.882 kJ of heat in 0.700 L of solution in the calorimeter (q=−0.882 kJ) , resulting in a temperature rise of 2.43 ∘C . In ...

Uyenvy Nguyen 1D

Oh I didn't know about the Cv=Cp-R equation! Thank you :D

Uyenvy Nguyen 1D

A 0.305 mol sample of CO2(g), initially at 298 K and 1.00 atm, is held at constant pressure while enough heat is applied to raise the temperature of the gas by 12.3 K. Calculate the amount of heat q required to bring about this temperature change, and find the corresponding total change in the inter...

Uyenvy Nguyen 1D

Thank you! Turns out I had a calculation error!

Uyenvy Nguyen 1D

You and me both! Thermochem is definitely one of the harder topics, and it's tougher since this is midterm season. I am still confused as well, but I am hoping that watching more videos on the topics on YouTube and working on more practice problems would help. Don't worry, you're not alone :,)

Uyenvy Nguyen 1D

Hi, I'm a bit confused on this question: An ice cube with a mass of 46.4 g at 0.0 degrees C is added to a glass containing 365 g of water at 45.0 degrees C . Determine the final temperature of the system at equilibrium. The specific heat capacity of water, Cs , is 4.184 J/g⋅C , and the standard enth...

Uyenvy Nguyen 1D

Yes I'm pretty sure we would assume H2O is in liquid form unless stated otherwise. We would not include water in the equilibrium constant equation.

Uyenvy Nguyen 1D

Yeah, I'm pretty sure we'll be given the enthalpies.

Uyenvy Nguyen 1D

I noticed that when calculating enthalpy, sometimes we do enthalpy of formation of products minus that of reactants. There is also "bonds broken minus bonds formed." Would we only do products-reactants when given enthalpies of formation?

Uyenvy Nguyen 1D

^ I agree, it's important to determine whether heat is a reactant or product first. Increasing temperature would increase the amount of heat, and decreasing temperature would decrease the amount of heat. After determining whether you have gained/decreased the amount of product/reactant, you can then...

Uyenvy Nguyen 1D

I do find it helpful to attend more than one a week just because I feel like each UA has a different style of explaining certain concepts. They are all helpful and go over similar practice problems, but I like to stick to the workshops that fit my learning style most (like someone previously said). ...

Uyenvy Nguyen 1D

Hi! I feel like we aren't expected to memorize any Ka/Kb values, because they'll most likely be given to us. In some cases, they may not, but this may be because we won't need it to solve the problem.

Uyenvy Nguyen 1D

thank u guys !

Uyenvy Nguyen 1D

Is there a difference in calculation between a question that asks for percentage protonated and one that asks for percent ionization?

Uyenvy Nguyen 1D

Hi, I've been trying to solve this question, but I'm not sure if I keep getting calculation errors or if I am completely missing the question: The Kb for an amine is 7.384×10−5. What percentage of the amine is protonated if the pH of a solution of the amine is 9.149 ? Assume that all OH− came from t...

Uyenvy Nguyen 1D

It will be very similar in format to last years midterms. The only major difference is that it won't be during your discussion time, meaning that everyone is taking the midterm at the same time. So, midterms will be held during our lecture times? Yes, I believe midterms will be held on the Friday o...

Uyenvy Nguyen 1D

I do not think percent ionization is Ka as a percent. It is the concentration of de-protonated species over the initial concentration of the original acid times 100%. ( [A-]/[HA]initial ) * 100%

Uyenvy Nguyen 1D

I remember in a workshop with Michael, he mentioned that there is a trick:
if K>Q, the reaction proceeds right, since the arrow is pointing to the right,
and if K<Q, the reaction proceeds left, since the arrow is pointing to the left.
This trick only works if K is written before the Q.

Uyenvy Nguyen 1D

Hi! I would definitely recommend going to at least 1 UA session per week. If that is not possible, I would say to work on the worksheets that they send out for practice. Working on textbook problems and Sapling seem to be very helpful as well. I did not really touch the textbook problems last quarte...

Uyenvy Nguyen 1D

Hi! I would definitely recommend going to at least 1 UA session per week. If that is not possible, I would say to work on the worksheets that they send out for practice. Working on textbook problems and Sapling seem to be very helpful as well. I did not really touch the textbook problems last quarte...

Uyenvy Nguyen 1D

concentration is mol/liters, and n represents the number of moles and V represents volume, which can be measured in liters

Uyenvy Nguyen 1D

I believe the above reply is correct. Decreasing temperature would increase the K value for exothermic reactions decrease the K value for endothermic reactions.

Uyenvy Nguyen 1D

I like childhood movies and shows like Wizards of Waverly Place, Victorious, etc. & I love coming of age movies (Perks of Being a Wallflower, Lady Bird, etc.) like a few others who replied as well!! Lmk if anyone has recommendations :-)

Uyenvy Nguyen 1D

it would be on the constant sheet :-)

Uyenvy Nguyen 1D

hi can someone explain the steps to solve this? i keep getting it wrong Consider the reaction of NH3 and I2 to give N2 and HI. 2NH3(g)+3I2(g)↽−−⇀N2(g)+6HI(g) ; K Using two or more of the given equations, determine the equilibrium constant, K , for the reaction of NH3 with I2. H2(g)+I2(g)↽−−⇀2HI(g) ;...

Uyenvy Nguyen 1D

It depends on how well you understand the material for that week! I find them very helpful, so I would try to attend at least 1-2 per week!

Uyenvy Nguyen 1D

All your posts will still be under the account you are currently using, so as long as you have 5 posts per week, you should be fine!

Uyenvy Nguyen 1D

If Q < K, the forward reaction is favored. If Q > K, the reverse reaction is favored.

Uyenvy Nguyen 1D

I thought the same thing as you did, but I am pretty sure that it means that you need 50% overall to pass.

Uyenvy Nguyen 1D

I definitely felt super rushed, but I'm glad we are receiving extra 10 bonus points, because I really needed that.

Uyenvy Nguyen 1D

I like to listen to mellow music while I study! I also like to remind myself that it'll be over with soon, and since the final is early on in the week, I'll have time to study for other classes throughout the week without worrying about chem

Uyenvy Nguyen 1D

thank you! good luck to you too ! :-)

Uyenvy Nguyen 1D

The bigger an anion in an acid, the stronger the acid is, right? For #11 on the week 10 Sapling homework, the acids given were HClO, HBrO, and HIO. It asked to list the acids from most acidic to least acidic. How come they considered the electronegativity of Cl, Br, and I instead of considering the ...

Uyenvy Nguyen 1D

In general, how would I be able to easily determine which salts are acidic, basic, or neutral? The salts given in this question are K3PO4, NaCN, LiNO3, NH4ClO4, and KCl.

Uyenvy Nguyen 1D

Thank you! The Organic Chemistry Tutor is definitely my go-to!

Uyenvy Nguyen 1D

It is most likely that the final will be very similar to the midterms. I believe it is zoom proctored and we would still need a second device to show our set-up.

Uyenvy Nguyen 1D

that looks good to me

Uyenvy Nguyen 1D

My family usually just eats a big dinner together, but most years, my dad would make carbonated fruit punch with orange slices in it! We didn't do that this year, but we still ate dinner together so that was nice.

Uyenvy Nguyen 1D

Midterm 2 was a bit more difficult for me compared to the first one we took. It does make me nervous thinking about my final grade as well, but it's important to not let past exams discourage us from putting in our best effort when it's time for finals!

Uyenvy Nguyen 1D

I also believe the order of the ligands do not matter as long as they come after the cation!

Uyenvy Nguyen 1D

thank u!

Uyenvy Nguyen 1D

I am pretty sure we are using the same book and Sapling for 14B. For the class itself, I'm not sure if it will be asynchronous like right now or not.

Uyenvy Nguyen 1D

How do determine whether or not atoms of certain structures lie in the same plane? Question #18 on the Sapling homework from weeks 7 & 8 asked about the orientation of hydrogen atoms, but I'm not sure how to tell if the atoms are coplanar.

Uyenvy Nguyen 1D

I would personally use sp3d, but like everyone has stated, it doesn't really matter which one you decide to use!

Uyenvy Nguyen 1D

I used to pronounce it like "vesper," but that made me misspell it every time I wrote it in my notes. Now, I just read the letters "V-S-E-P-R" out loud whenever I write it down, and eventually, it just began rolling off the tip of my tongue. I think if you keep reading it out lou...

Uyenvy Nguyen 1D

Since there are 2 bonded groups and 2 lone pairs on Sulfur, there are 4 regions of electron density. This means that the molecule forms a tetrahedral shape with bonded groups at 109.5 degrees, which is not linear.

Uyenvy Nguyen 1D

What are the steps to determine the hybridization of an element in a molecule/ion/etc.? I'm not sure what to consider when looking at the Lewis structures.

Uyenvy Nguyen 1D

Hey girl! I would say attending workshop sessions is super helpful for me, but it can be hard because everyone has different schedules. I think I am going to study by doing practice problems from the textbooks, worksheets from the UA sessions, going over my notes (and maybe re-write the important co...

Uyenvy Nguyen 1D

We would look at the intermolecular forces!
Intermolecular: between molecules
Intramolecular: within molecules

Uyenvy Nguyen 1D

I watched a lot of Youtube videos on topics that I wasn't too strong on! I like to watch the Organic Chemistry Tutor on Youtube. I also read over all my notes, looked over the outlines, and did questions from the UA sessions.

Uyenvy Nguyen 1D

I remember Dr. Lavelle mentioning the Cu is an exception, so it would be written like that. I'm assuming Au and Ag are exceptions as well.

Uyenvy Nguyen 1D

Yes, I'm also thinking about my final grade and the upcoming midterm and final exam. It does make me a bit nervous when I think about the amount of points that I can miss to keep a certain grade. Just be sure to do the Sapling homework and get those Chemistry Community points, because every point is...

Uyenvy Nguyen 1D

When writing the electron configurations, when do you put 3d before 4s? Do you usually just do this for transition elements? & When I searched up the e-configuration for Bromine (Br), it says it's [Ar] 4s² 3d¹⁰ 4p⁵, and the e-configuration for Selenium (Se) is [Ar] 3d10 4s2 4p4, so I'm a bit con...

Uyenvy Nguyen 1D

Ohh I didn't realize dipole-induced dipole was the same as London dispersion forces! Thank you!

Uyenvy Nguyen 1D

What is the order of all interionic/intermolecular forces from weakest to strongest? & What is the difference between dipole-dipole and dipole-induced dipole interactions?

Uyenvy Nguyen 1D

thank you!

Uyenvy Nguyen 1D

I think Cl would have a lower ionization energy , since chlorine is one period below oxygen and would have valence electrons that aren't bounded as tightly as those of oxygen.

Uyenvy Nguyen 1D

This question shows the Lewis structure of a carbamate ion, and it asks us to the 2 other major resonance structures. I was able to correctly draw the one with a double bond between N and C (N=C), but I keep getting the other resonance structure with a single bond between N and C wrong. Can someone ...

Uyenvy Nguyen 1D

I read that nonmetal oxides are usually Lewis acids, and SO2 is a nonmetal oxide, so it would be a Lewis acid. I am not too sure why though.

Uyenvy Nguyen 1D

I'm not sure about your second question, but I know that NH3 is a Lewis base, it has a lone pair that can be donated to a Lewis acid to form a a coordinate covalent bond. It is easier to see if you draw out the Lew structure for NH3. Lewis bases are lone pair donors, while Lewis acids are lone pair ...

Uyenvy Nguyen 1D · Re: Homework due date ^ yup it would be 11:59 pm on Sunday!

^ yup it would be 11:59 pm on Sunday!

Uyenvy Nguyen 1D

I know that helium only has room for two electrons in its only valence shell, and it is stable (it's a noble gas), so it doesn't follow the octet rule

Uyenvy Nguyen 1D

From what I've read online, this is because an electron being added to an already half full orbital in oxygen results in electron-electron repulsion, which lowers the ionization energy. Nitrogen also has the added stability of a half filled shell of electrons in the 2p shell, which probably contribu...

Uyenvy Nguyen 1D

Do people usually take Chem 14B with Chem 14BL? I'm planning on doing that, but I'm not sure which one will fill up faster.

Uyenvy Nguyen 1D

If the element before Si was a noble gas, we would use that element in the bracket, but since it is not a noble gas, we would use the noble gas that comes before Si, which is [Ne]. You don't have to write your electron configuration this way, but it does come in handy for an element like Lead, whose...

Uyenvy Nguyen 1D

Yes you could definitely use the second formula! I find the second formula much quicker and easier to use. It's good to know that you can use either one and still end up with the correct answer.

Uyenvy Nguyen 1D

I usually relax by taking naps or laying in bed while listening to music! I also like watching YouTube or facetiming my friends to get my mind off school :-)

Uyenvy Nguyen 1D

I've read somewhere that the wavelength of gamma rays would be less than or equal to 0.01 nm. These are listed in the order of longest to shortest wavelengths: radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma-rays.

Uyenvy Nguyen 1D

Did you get a negative value for your frequency? For the frequency, I got positive 3.08*10^15, and I plugged it into the equation wavelength=c/frequency and got 9.73*10^-8 meters. This would be in the UV region.

Uyenvy Nguyen 1D

Hi. Can someone help me solve this problem? I'm not sure what I should solve for first if I'm just given the work function. As you may well know, placing metal objects inside a microwave oven can generate sparks. Two of your friends are arguing over the cause of the sparking, with one stating that ...

Uyenvy Nguyen 1D

thank you!

Uyenvy Nguyen 1D

Hi. Can someone help me solve this problem? I'm not sure what I should solve for first if I'm just given the work function. As you may well know, placing metal objects inside a microwave oven can generate sparks. Two of your friends are arguing over the cause of the sparking, with one stating that t...

Uyenvy Nguyen 1D

How would you solve this question? I keep getting D.

Search found 116 matches