Search found 88 matches

by Daria Obukhova 2B
Tue Feb 23, 2021 4:05 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Textbook 6L.5 Part b
Replies: 1
Views: 8

Textbook 6L.5 Part b

Hi, I was a little confused as to why solid Iodine is in the inner most part of the cell diagram. Also, is Pt necessary bc both Ce3+ and Ce4+ are acqeous?
by Daria Obukhova 2B
Tue Feb 23, 2021 3:29 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Textbook Problem 6L.1 Part b
Replies: 1
Views: 15

Textbook Problem 6L.1 Part b

Hi, could anyone explain how you figure out the moles of electrons being transferred in the second part of question 6L.1?
by Daria Obukhova 2B
Tue Feb 23, 2021 3:21 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: mols in calculating gibbs free energy
Replies: 4
Views: 21

Re: mols in calculating gibbs free energy

Thank you! I had the same exact question and this clears it up!
by Daria Obukhova 2B
Sun Feb 21, 2021 4:50 pm
Forum: Student Social/Study Group
Topic: We made it through Midterm 2!
Replies: 58
Views: 159

Re: We made it through Midterm 2!

Yup! We're almost done guys! :)
by Daria Obukhova 2B
Sun Feb 21, 2021 4:48 pm
Forum: Student Social/Study Group
Topic: Fave food
Replies: 99
Views: 204

Re: Fave food

Definitely pasta like someone said above, and always craving pizza!
by Daria Obukhova 2B
Sun Feb 21, 2021 4:47 pm
Forum: Administrative Questions and Class Announcements
Topic: Can We Review our Exams?
Replies: 69
Views: 241

Re: Can We Review our Exams?

You can ask your TA and they'll go over your missed questions with you!
by Daria Obukhova 2B
Thu Feb 18, 2021 5:44 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Textbook Problem 4J.5 Part c
Replies: 2
Views: 40

Textbook Problem 4J.5 Part c

I'm a little confused about the explanation given as to why the standard entropy of formation is smaller than the molar entropy of CO (g). They say that the number of moles of gas is reduced, but isn't it increased if it goes from 1/2 to 1?
by Daria Obukhova 2B
Tue Feb 16, 2021 9:35 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Sapling week 5/6 #20
Replies: 12
Views: 71

Re: Sapling week 5/6 #20

Thank goodness I found this post, I though I'd never find the right answer after trying almost every combo. All I had to do was switch the positions of where I was putting the words and inequalities.
by Daria Obukhova 2B
Sun Feb 14, 2021 8:10 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Entropy in Complex Molecules
Replies: 5
Views: 16

Re: Entropy in Complex Molecules

Michael Iter 2F wrote:I think it is because, as a molecule becomes increasingly complex, there are more possible positions and states for it to exist in. In other words, the degeneracy increases, and since degeneracy is related to entropy, the entropy also increases.

Okay thank you, that makes sense!
by Daria Obukhova 2B
Sun Feb 14, 2021 5:17 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Entropy in Complex Molecules
Replies: 5
Views: 16

Entropy in Complex Molecules

Hi, could anyone explain why standard molar entropies increase as the complexity of a substance increases?
by Daria Obukhova 2B
Sat Feb 13, 2021 4:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook Problem 4D.11 part c
Replies: 1
Views: 14

Textbook Problem 4D.11 part c

Hi, could anyone please explain how to go about solving this question?

When the oxidation of N2 to NO was completed in a bomb calorimeter, the heat absorbed was measured as 492 J. What mass of nitrogen gas was oxidized?
by Daria Obukhova 2B
Sat Feb 13, 2021 4:05 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook Problem 4D.7
Replies: 1
Views: 11

Textbook Problem 4D.7

Hi! I was looking at the solutions manual for problem 4D.7, and they used 298K when they were calculating the work using PV=nRT. This temperature isn't mentioned in the question, so I was wondering where they got it from?
by Daria Obukhova 2B
Sat Feb 13, 2021 12:36 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook Problem 4C.7
Replies: 2
Views: 14

Textbook Problem 4C.7

Hi! Could anyone help out with this problem? I'm stuck with what equation/relationship I need to use. Thanks!

At its boiling point, the vaporization of 0.579 mol CH4(l) requires 4.76 kJ of heat. What is the enthalpy of vaporization of methane?
by Daria Obukhova 2B
Sun Feb 07, 2021 12:33 pm
Forum: Student Social/Study Group
Topic: Study tips for thermo
Replies: 14
Views: 54

Re: Study tips for thermo

Hi! Good question, I definitely relate. I agree with the reply above. And, even though this part of the class is difficult, I know you have all the potential to do amazingly on the next midterm. Please don't lose sight of your strength! I have been reading through/responding to study tips/advice po...
by Daria Obukhova 2B
Sun Feb 07, 2021 12:29 pm
Forum: Administrative Questions and Class Announcements
Topic: tips if you're struggling!
Replies: 61
Views: 340

Re: tips if you're struggling!

Thank you! I kind of agree with what you said about textbook problems. I try my best to do them as we're learning the specific topic, but I end up forgetting how to solve them by the time the test rolls around and just end up redoing them all over again.
by Daria Obukhova 2B
Sun Feb 07, 2021 12:27 pm
Forum: Student Social/Study Group
Topic: Study routine.
Replies: 51
Views: 99

Re: Study routine.

I personally find that doing as many practice problems as possible is the most effective way for me to study. So, whether that's doing textbook problems or going to workshop sessions. I also like rewriting my notes as i re-read them. Just the key details, which helps me see the big picture.
by Daria Obukhova 2B
Sat Feb 06, 2021 8:27 pm
Forum: Student Social/Study Group
Topic: Best kdrama?
Replies: 30
Views: 178

Re: Best kdrama?

You need to watch Start-Up! It's super recent (came out in 2020) and is soooooo good! My roommates and I just finished watching it and we loved it.
by Daria Obukhova 2B
Sun Jan 31, 2021 5:16 pm
Forum: Student Social/Study Group
Topic: Go treat yourself after MT1!
Replies: 75
Views: 302

Re: Go treat yourself after MT1!

Definitely want to relax this weekend and take a break before jumping back into thermodynamics. Remember to take things one step at a time!
by Daria Obukhova 2B
Sun Jan 31, 2021 5:14 pm
Forum: Student Social/Study Group
Topic: Midterm Scores
Replies: 25
Views: 138

Re: Midterm Scores

Yeah, I was also thinking somewhere around 1-2 weeks. It's usually not too long!
by Daria Obukhova 2B
Sun Jan 31, 2021 5:12 pm
Forum: Ideal Gases
Topic: Chem BL
Replies: 89
Views: 396

Re: Chem BL

I think I'm planning on taking it next fall quarter, at the same time as 14D. Probably don't have space in my schedule to take it next quarter unfortunately.
by Daria Obukhova 2B
Sun Jan 31, 2021 2:57 pm
Forum: Student Social/Study Group
Topic: Worried About MT 1 Grades
Replies: 39
Views: 237

Re: Worried About MT 1 Grades

I also feel a bit more anxiety after this midterm as compared to last quarter. But I think it's okay to feel like this because the material is truly getting harder, and we just need to try our best.
by Daria Obukhova 2B
Sun Jan 31, 2021 2:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Labs
Replies: 10
Views: 49

Re: Labs

Hi! I'm personally planning to start taking those lab classes next year as a sophomore. I've heard that it's not recommended to take 14BL and 14C in the same quarter, so I'm probably going to try and enroll in 14BL and 14D at the same time (fall quarter). Then take 14CL the quarter after that.
by Daria Obukhova 2B
Tue Jan 26, 2021 3:51 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook Problem 4.29 part b
Replies: 1
Views: 35

Textbook Problem 4.29 part b

Hi!
Would anyone be able to help me with part b of #4.29? It asks: What enthalpy change would be associated with the production of 60.0 kg of sulfur?

Thank You!
by Daria Obukhova 2B
Sun Jan 24, 2021 3:24 pm
Forum: Student Social/Study Group
Topic: Comfort Movies
Replies: 128
Views: 343

Re: Comfort Movies

Omg I love Princess Diaries as well! I'd say that I'd watch any Disney movie for comfort, or anything that reminds me of my childhood.
by Daria Obukhova 2B
Sun Jan 24, 2021 3:19 pm
Forum: General Science Questions
Topic: Studying
Replies: 42
Views: 446

Re: Studying

For me personally, doing the textbook problems is what helps the most. As well as reviewing the Sapling homework because reading the solution explanations helps clear up details that I sometimes forget.
by Daria Obukhova 2B
Sun Jan 24, 2021 3:12 pm
Forum: Phase Changes & Related Calculations
Topic: Thermochemistry on Midterm 1
Replies: 4
Views: 33

Re: Thermochemistry on Midterm 1

Hi! Dr Lavelle sent us an email saying Midterm 1 covers Chemical Equilibria, Acid and Base Equilibria, and only these Week 3 topics (4D.3; 4D.4; 4D.5; 4E.3). You can find the problems associated with these chapters on his website under the Learning Outcomes.
by Daria Obukhova 2B
Sun Jan 24, 2021 3:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: pKa
Replies: 14
Views: 54

Re: pKa

If you know the value of Ka, then you can figure out what pKa is by taking the negative log of it (-logKa). It works the same way with concentrations and pH. When you know what the concentration of H3O is, you take its negative log and get pH.
by Daria Obukhova 2B
Sun Jan 24, 2021 12:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 5G.3
Replies: 3
Views: 25

Re: Homework 5G.3

Make sure you include all of them in your K expression since they're all gases! You should also double check if they're giving you the values of their partial pressures of concentrations to work with.
by Daria Obukhova 2B
Sun Jan 17, 2021 8:37 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: When would K be unchanged?
Replies: 31
Views: 93

Re: When would K be unchanged?

The only thing that should cause a change in K value is temperature.
by Daria Obukhova 2B
Sun Jan 17, 2021 8:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE table troubles
Replies: 16
Views: 78

Re: ICE table troubles

A helpful tip I think would be to double check which way your reaction is going so you know if you should be adding or subtracting x (or any changes concentration). It's pretty easy when you're just starting with an initial value of a reactant and the reaction will flow forward until equilibrium. Bu...
by Daria Obukhova 2B
Sun Jan 17, 2021 5:53 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure Increase
Replies: 7
Views: 19

Re: Pressure Increase

I don't remember exactly what the question was, but this probably means that the pressure increase didn't do anything to change the concentrations of the gases.
by Daria Obukhova 2B
Sun Jan 17, 2021 5:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook 6A.23
Replies: 2
Views: 14

Re: Textbook 6A.23

Ba(OH)2 is a strong base and ionizes completely. Start off by writing its chemical equation. Find the molarity of Ba(OH)2 in order to find the concentration of OH-. We did this in class I believe. To find the concentration of H3O+, use the Kw constant equation! Ohhh got it! I completely missed the ...
by Daria Obukhova 2B
Sun Jan 17, 2021 4:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook 6A.23
Replies: 2
Views: 14

Textbook 6A.23

Hi! Could someone help out with starting off this problem?

Calculate the molar concentration of Ba(OH)2(aq) and the molar concentrations of Ba2+, OH-, and H3O+ in an aqueous solution that contains 0.43 g of Ba(OH)2 in 0.100 L of
solution.

Thanks!
by Daria Obukhova 2B
Sun Jan 10, 2021 6:19 pm
Forum: Student Social/Study Group
Topic: Study Habits
Replies: 96
Views: 321

Re: Study Habits

I think it's important to space out your review/learning. Cramming a bunch of practice problems before a midterm or final seems to work poorly and all the knowledge is short-term. So, I think it's nice create a study plan ahead of time where you can work on problems/read the txtbook/attend office ho...
by Daria Obukhova 2B
Sun Jan 10, 2021 5:58 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Cubic equation problems
Replies: 2
Views: 21

Re: Cubic equation problems

I believe that whatever he covered in the module video is pretty much all we need to know. It seems like we shouldn't be over complicating these types of problems, so what Melody ^ said seems right!
by Daria Obukhova 2B
Sun Jan 10, 2021 5:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Problem 5I.13
Replies: 2
Views: 28

Problem 5I.13

Hi! I haven't been able to figure out problem 13 in chapter 5I. Could someone please explain how to do part a)? It states: (a) In an experiment, 2.0 mmol Cl2(g) was sealed into a reaction vessel of volume 2.0 L and heated to 1000. K to study its dissociation into Cl atoms. Use the information in Tab...
by Daria Obukhova 2B
Sat Jan 09, 2021 4:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Problem 5I.3
Replies: 1
Views: 13

Re: Textbook Problem 5I.3

Hi! So I think to solve this problem you do pretty much the same thing as you did for number 5I.1. The reaction they're referring to is H2+I2 <-> 2HI. So if you go to the 5G.2 table you can find the K value for this reaction, and then solve for the concentration of H2.
by Daria Obukhova 2B
Thu Jan 07, 2021 9:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equil. Part 3 Module
Replies: 2
Views: 36

Chemical Equil. Part 3 Module

Hi! Could someone please explain how to do this question on the module. Also, I'm not really sure where the variable "c" came from. Thank You!
by Daria Obukhova 2B
Wed Dec 16, 2020 1:27 pm
Forum: Student Social/Study Group
Topic: Plans for Relaxing After Finals
Replies: 98
Views: 561

Re: Plans for Relaxing After Finals

I'm gonna spend time with my parents and try to get outside because it feels like I've been cooped up for the past two weeks. Definitely catch up on some shows and maybe read for fun. Also sleep in!
by Daria Obukhova 2B
Fri Dec 11, 2020 7:37 pm
Forum: Hybridization
Topic: Today's Review Video: CO2
Replies: 2
Views: 37

Today's Review Video: CO2

In today's review Dr. Lavelle did an example of CO2 hybridization. He showed that the hybridization of C is sp, but I was wondering how you would approach a question asking for the hybridization pertaining to the individual bonds? Like for example would one of the bonds between C and O be C2sp, O2sp...
by Daria Obukhova 2B
Thu Dec 10, 2020 6:16 pm
Forum: Bronsted Acids & Bases
Topic: Week 10 Sapling #11
Replies: 2
Views: 16

Week 10 Sapling #11

It asks to arrange acids according to strength: HIO, HClO, HBrO.
From what I understood, the hydrogen is attached to the oxygen, meaning the oxygen is the central atom. But why is oxygen the central atom in these structures, aren't central atoms supposed to be the least electronegative?
by Daria Obukhova 2B
Wed Dec 09, 2020 5:48 pm
Forum: Bronsted Acids & Bases
Topic: Textbook 6C.19 part f
Replies: 2
Views: 27

Textbook 6C.19 part f

I was wondering why H2CO3 is considered to be stronger than H2GeO3.
by Daria Obukhova 2B
Wed Dec 09, 2020 4:35 pm
Forum: Bronsted Acids & Bases
Topic: Textbook 6A.13
Replies: 2
Views: 12

Textbook 6A.13

This question asks to: Draw the Lewis structure or symbol for each of the following species and identify each one as a Lewis acid or Lewis base:
(a) NH3; (b) BF3; (c) Ag+ ; (d) F- ; (e) H-

I'm having trouble with the single elements...how do we determine if (c) through (e) are acids or bases?
by Daria Obukhova 2B
Sun Dec 06, 2020 5:30 pm
Forum: Student Social/Study Group
Topic: final study
Replies: 42
Views: 176

Re: final study

I think I'll probably review as many of the textbook problems as I can, since that's what's helped me the most for midterms. Definitely skim all the lecture notes. It's kind of scary that it's going to cumulative though.
by Daria Obukhova 2B
Sun Dec 06, 2020 5:25 pm
Forum: Sigma & Pi Bonds
Topic: pi bonds
Replies: 13
Views: 107

Re: pi bonds

Think of pi bonds as a vertical overlapping of bonds, so they cannot rotate, while sigma bonds consist of horizontal overlapping, in which they can rotate. So, since they can't rotate, is that why you get atoms in different planes once you start adding to the central atom? Or is there another reaso...
by Daria Obukhova 2B
Sun Dec 06, 2020 5:17 pm
Forum: Naming
Topic: Helpful Videos for Naming
Replies: 22
Views: 134

Re: Helpful Videos for Naming

Omg thank you so much! I was struggling a bit with naming so this is super helpful. And I agree with Lea up above...Bozeman is what helped me get through AP Bio!
by Daria Obukhova 2B
Sun Dec 06, 2020 5:14 pm
Forum: Hybridization
Topic: Good video about hybridization
Replies: 7
Views: 57

Re: Good video about hybridization

Awesome thank you! I love the Organic Chemistry Turtor channel it's so helpful!
by Daria Obukhova 2B
Sun Dec 06, 2020 5:12 pm
Forum: Administrative Questions and Class Announcements
Topic: CCLE fixed?
Replies: 19
Views: 125

Re: CCLE fixed?

Hmmm, I just checked mine right now, and it's working.
by Daria Obukhova 2B
Sun Nov 29, 2020 8:46 pm
Forum: Electronegativity
Topic: Does electronegativity cancel?
Replies: 4
Views: 52

Re: Does electronegativity cancel?

I may be wrong, but I'm pretty sure molecules don't have a measured electronegavity, because electronegativity is a measure of how strongly an atom attracts the electrons in a bond. So, I think it's mostly applied to just atoms.
by Daria Obukhova 2B
Sun Nov 29, 2020 8:41 pm
Forum: Lewis Structures
Topic: Sapling #12
Replies: 3
Views: 13

Re: Sapling #12

Yes it is! Because when you add up the molar mass of CH4O you also get 32.04.
by Daria Obukhova 2B
Sun Nov 29, 2020 8:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling #20 AsO43- polarity
Replies: 6
Views: 35

Re: Sapling #20 AsO43- polarity

I don't think you are looking at formal charge when doing polarity, so you can tell it's nonpolar since it's a symmetrical tetrahedral shape.
by Daria Obukhova 2B
Sat Nov 28, 2020 2:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook 2E #25 part a
Replies: 3
Views: 25

Textbook 2E #25 part a

This question asks to predict whether CH2Cl2 is polar or nonpolar. In the solution they draw the two Cl atoms adjacent to each other, which would make it polar. But, if they were opposite of each other, would this molecule be nonpolar? If so, how do we know which structure to draw?
by Daria Obukhova 2B
Sat Nov 28, 2020 2:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook 2E #19 part b
Replies: 1
Views: 23

Textbook 2E #19 part b

This question asks to predict the shape and estimate the bond angle of (CH3)2Be. Can someone please explain the shape of this molecule because I thought it would just be linear with three hydrogens attached to each carbon. But apparently it should be tetrahedral, so are there two hydrogens and two c...
by Daria Obukhova 2B
Sun Nov 22, 2020 9:04 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8731
Views: 1489324

Re: Post All Chemistry Jokes Here

What did the molecule say to the atom after he got in trouble?

I’ve got my ion you.
by Daria Obukhova 2B
Sun Nov 22, 2020 9:00 pm
Forum: Student Social/Study Group
Topic: How to relax after midterms
Replies: 54
Views: 295

Re: How to relax after midterms

I try to take a small break from that class, even if it's just for the day, or else my brain feels fried. The days leading up to a midterm are super intense and focused, so I try to go outside for a bit and do some physical activity so that my brain takes a break, while I do something good for my bo...
by Daria Obukhova 2B
Sun Nov 22, 2020 8:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Incorrect Lewis Structure
Replies: 3
Views: 52

Re: Incorrect Lewis Structure

I'm pretty sure that it's because the number of regions of electron densities doesn't change when you draw different resonance structures.
by Daria Obukhova 2B
Sun Nov 22, 2020 8:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: shape, structure
Replies: 4
Views: 15

Re: shape, structure

I think we'll probably need to determine the shapes by drawing the Lewis structures. You'd count up the bonds and lone pairs and go from there. You might have to memorize a couple things but it's often not too hard to tell what the shape is after drawing the structure.
by Daria Obukhova 2B
Sun Nov 22, 2020 8:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lecture 20 Example 2
Replies: 1
Views: 12

Re: Lecture 20 Example 2

I think if you turn one of the single bonds into a double bond, you will still keep the lone pair on the S atom. It will be an expanded octet. So, you still end up with 4 regions of electron density.
by Daria Obukhova 2B
Sun Nov 15, 2020 5:15 pm
Forum: General Science Questions
Topic: Midterm #2
Replies: 11
Views: 84

Midterm #2

Does anyone know if the last bullet points from Outline 2 that were omitted from the last midterm are going to be tested on this midterm?
by Daria Obukhova 2B
Sun Nov 15, 2020 5:06 pm
Forum: Administrative Questions and Class Announcements
Topic: enrollment/waitlist for 14B
Replies: 1
Views: 33

Re: enrollment/waitlist for 14B

I'm pretty sure I saw Dr. Lavelle answer someone's post that asked this same question. He said that everyone gets admitted off of the waitlist for 14B as well:)
by Daria Obukhova 2B
Sun Nov 15, 2020 4:58 pm
Forum: Electronegativity
Topic: Sapling Question 13
Replies: 7
Views: 36

Re: Sapling Question 13

All of the atoms, except for the carbon are going to form hydrogen bonds with water. And oxygen will form two because of its two lone pairs. Basically, the electronegative atoms like nitrogen and oxygen will have a slightly negative charge and so they will form a bond with the slightly positively ch...
by Daria Obukhova 2B
Sun Nov 15, 2020 4:51 pm
Forum: Quantum Numbers and The H-Atom
Topic: Textbook 1D#17
Replies: 3
Views: 31

Re: Textbook 1D#17

First you can use the periodic table to tell how many orbitals each of the sublevels (s,p,d,f) has. For example in the s-block you can count two elements, which represents two electrons, and since an orbital fits two electrons, there's just one orbital for the s-block. Then, for the p-block elements...
by Daria Obukhova 2B
Sat Nov 14, 2020 5:36 pm
Forum: Resonance Structures
Topic: Textbook 2B.15
Replies: 1
Views: 10

Textbook 2B.15

Why can't this structure have a double bond with Cl? I calculated the formal charge in that situation, and it still seems to have a charge of 0. What am I doing wrong?
by Daria Obukhova 2B
Sun Nov 08, 2020 12:29 pm
Forum: Lewis Structures
Topic: Lone Pairs Question
Replies: 22
Views: 124

Re: Lone Pairs Question

Yeah! Lone pairs are super important to molecular structure/shape, so it's important that you show them. They're the electrons that are being shared and are represented by two dots (if a pair and not a single electron).
by Daria Obukhova 2B
Sun Nov 08, 2020 12:26 pm
Forum: Administrative Questions and Class Announcements
Topic: Is CCLE Down?
Replies: 5
Views: 24

Re: Is CCLE Down?

Mahika More 1H wrote:It's down for me too! I like to check "downforeveryoneorjustme.com" whenever this happens (i found this to be super helpful). Should be back up now though

Woah! I never knew this site existed, that's actually super helpful. Thanks for sharing!
by Daria Obukhova 2B
Sun Nov 08, 2020 12:20 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 7
Views: 55

Re: Covalent Character

Covalent character arises from the unequal sharing of electrons. One of the ions is exerting a greater electrostatic attraction on the other ion's electrons and pulls them in quite close. The electrons end up being shared between the two ions. This doesn't happen with ionic bonds between the same el...
by Daria Obukhova 2B
Sun Nov 08, 2020 12:14 pm
Forum: Student Social/Study Group
Topic: Test Anxiety
Replies: 62
Views: 355

Re: Test Anxiety

Controlling anxiety can be super hard for me, but it usually stems from negative thoughts and doubt. So, if I ever feel like I'm starting to doubt myself on a problem or if a feel like it's hard, I skip it and move on right away. I don't want that feeling of doubt to carry on into the rest of the te...
by Daria Obukhova 2B
Sun Nov 08, 2020 12:07 pm
Forum: Quantum Numbers and The H-Atom
Topic: Principle Quantum #
Replies: 3
Views: 43

Re: Principle Quantum #

Quantum numbers are basically like an address for electrons. They give us a better understanding of where an electron might be located. "n" is for the energy level, which can be found from the rows of the periodic table. "l" represents the sublevels s,p,d,f (0=s, 1=p, 2=d, 3=f). ...
by Daria Obukhova 2B
Sun Nov 01, 2020 1:23 pm
Forum: Student Social/Study Group
Topic: Tips for Staying Focused
Replies: 52
Views: 590

Re: Tips for Staying Focused

I always try to find a new environment to study in even if it's just moving from my desk to the dining table because after a while I start to feel unproductive at a certain place. Also sometimes you just have to stick ear plugs in to minimize sound distraction. I find that that helps me.
by Daria Obukhova 2B
Sun Nov 01, 2020 1:20 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8731
Views: 1489324

Re: Post All Chemistry Jokes Here

What do you get when you cut an avocado into 6.022x10^23 pieces?

Guacamole
by Daria Obukhova 2B
Sat Oct 31, 2020 2:21 pm
Forum: Quantum Numbers and The H-Atom
Topic: explanation of ml
Replies: 4
Views: 30

Re: explanation of ml

So ml represents the orbitals. The s sublevel has 1, p has 3, d has 5, and f has 7. Each orbital has space for two electrons so an easy way to remind yourself how many orbitals there are in a sublevel is to count the elements on the periodic table and divide by two. For example, in the 2 row, in the...
by Daria Obukhova 2B
Sat Oct 31, 2020 2:10 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Sapling weeks 2-4 #16
Replies: 4
Views: 67

Re: Sapling weeks 2-4 #16

The excited electron would go down an energy level and the notation would become 1s2 2s2 2p5. Although, I think you may have made a typo because in Sapling it says the excited state is 1s2 2s2 2p3 3s1. So instead of Fluorine, the element would actually be Oxygen. First, you can count the total numbe...
by Daria Obukhova 2B
Sat Oct 31, 2020 2:05 pm
Forum: Quantum Numbers and The H-Atom
Topic: Textbook 1D #23
Replies: 4
Views: 25

Re: Textbook 1D #23

In this question when it says ml, it will be one orbital. For example, if n=2 and l=1, there'd be three possible orbitals px,py,pz. Then, the ml number specifies which one it is.
Also for part d, there would technically be 5 possible orbitals, but they specified it with the ml number.
by Daria Obukhova 2B
Sun Oct 25, 2020 7:14 pm
Forum: Photoelectric Effect
Topic: Frequency and energy
Replies: 15
Views: 78

Re: Frequency and energy

Yes.
When you're using the E=hv equation, h is a constant so it doesn't change. Therefore, if you increase the frequency (v), energy will also increase.
by Daria Obukhova 2B
Sun Oct 25, 2020 7:13 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Textbook problem 1A.15
Replies: 3
Views: 40

Re: Textbook problem 1A.15

First, you'd want to convert 102.6 nm into meters. Then, you could go on to use this to find energy using
Then you'd use this to solve for the energy level
by Daria Obukhova 2B
Sat Oct 24, 2020 8:26 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Amplitude
Replies: 16
Views: 85

Re: Amplitude

Changing the amplitude shouldn't change the frequency or wavelength.
by Daria Obukhova 2B
Sat Oct 24, 2020 8:23 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Frequency Condition: v
Replies: 3
Views: 46

Re: Bohr Frequency Condition: v

They both stand for frequency. I'm pretty sure that in the photoelectric experiment it's having to do with the frequency of the incident light, but in the Bohr Frequency Condition: "the frequency of an individual line in a spectrum is related to the energy difference between two energy levels i...
by Daria Obukhova 2B
Sat Oct 24, 2020 2:52 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra PostModule #29
Replies: 1
Views: 20

Atomic Spectra PostModule #29

In this question it says that there's a 60 W bulb, which also means 60J/s. So, if its a 60J/s, and 1 second has passed according to the problem, why isn't it 60J being emitted. Because instead, it says 11J. How does that work? Is 60J just the maximum amount of energy the bulb can emit, or what is ha...
by Daria Obukhova 2B
Sun Oct 18, 2020 5:23 pm
Forum: SI Units, Unit Conversions
Topic: (M1)(V1)=(M2)(V2) with L vs mL
Replies: 5
Views: 40

Re: (M1)(V1)=(M2)(V2) with L vs mL

In this situation you don't need to change any units. Unless the question asks for your answer specifically in Liters, or if the units of the two volumes simply don't match, then you don't have to worry about it.
by Daria Obukhova 2B
Sun Oct 18, 2020 5:15 pm
Forum: Properties of Light
Topic: Work Function
Replies: 4
Views: 24

Re: Work Function

I think you were partially correct. Electrons WILL be emitted if the energy of the incident light is greater than OR equal to the work function. Electrons will NOT be emitted if the energy of the incident light is less than the work function. Kinetic energy will equal 0 if the energy of the incident...
by Daria Obukhova 2B
Fri Oct 16, 2020 5:13 pm
Forum: Properties of Light
Topic: "Intensity"
Replies: 20
Views: 158

Re: "Intensity"

According to the textbook, in the wave model: intensity is proportional to the square of the amplitude of the wave (A^2). In the particle model: intensity is proportional to the number of photons present.
by Daria Obukhova 2B
Fri Oct 16, 2020 5:06 pm
Forum: Properties of Light
Topic: Textbook Problem 1B.9
Replies: 2
Views: 21

Textbook Problem 1B.9

Hi, could anyone please help with textbook problem 1b.9 QUESTION: A lamp rated at 32 W (1 W=1 J⋅s−1) emits violet light of wavelength 420 nm. How many photons of violet light can the lamp generate in 2.0 s? So when it's asking for amount of photons, would that just be frequency? Because I tried to d...
by Daria Obukhova 2B
Mon Oct 12, 2020 3:01 pm
Forum: Properties of Light
Topic: Lecture 5 "Quantized"
Replies: 3
Views: 35

Lecture 5 "Quantized"

During Lecture #5, Professor Lavelle was using the term "quantized" when talking about photons and light. Could someone explain what that term means, because I'm a bit confused?
by Daria Obukhova 2B
Sun Oct 11, 2020 4:57 pm
Forum: Significant Figures
Topic: Empirical vs Molecular Formula?
Replies: 7
Views: 42

Re: Empirical vs Molecular Formula?

Hi!
I'm not sure about the second question. But yes, you can only know the molar mass if it's given to us, in a situation when you only know the empirical formula.
by Daria Obukhova 2B
Fri Oct 09, 2020 6:39 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Module Assesment #29
Replies: 1
Views: 25

Photoelectric Effect Module Assesment #29

Hi! Could someone please explain how to go about solving number 29 from the post-assessment of the photoelectric module? The previous question stated that the velocity of the ejected electron is 6.61x10^5 (m.s^-1). And the work function for sodium is (150.6 kJ.mol^-1). I got the kinetic energy as be...
by Daria Obukhova 2B
Fri Oct 09, 2020 6:13 pm
Forum: Balancing Chemical Reactions
Topic: Fundamentals Exercise M9
Replies: 3
Views: 47

Re: Fundamentals Exercise M9

Yeah! The net ionic only includes the elements involved in forming the precipitate (because it's what you care about most). You generally ignore those extra elements like the sodium ion and nitrate because they are soluble in water, which is why they didn't say what happens to them.
by Daria Obukhova 2B
Thu Oct 08, 2020 12:12 pm
Forum: Limiting Reactant Calculations
Topic: Sapling Homework #10
Replies: 5
Views: 60

Re: Sapling Homework #10

It might've been a typo in your post, but make sure that you actually have 0.35 mL of 2-butanone, not 0.25! The moles of 2-butanone should be around 0.0038788 mol (i also got the molar mass of 2-butanone to be 73.09 g.mol). Then you multiply by the molar ratio 1:1 (to go from the moles of 2-butanone...
by Daria Obukhova 2B
Thu Oct 08, 2020 12:25 am
Forum: Empirical & Molecular Formulas
Topic: L 35
Replies: 1
Views: 44

Re: L 35

Yes! You're going to work backwards in order to solve this problem. You are given the mass of NaBr , which appears in the last equation, which you will then convert into moles. Since you have also balanced the equations, you have the stoichiometric coefficients and are ready to start working through...

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