Search found 87 matches

by Anya Holbrook 1E
Tue Feb 23, 2021 9:27 pm
Forum: Balancing Redox Reactions
Topic: "Leo" Oxidation Numbers
Replies: 26
Views: 66

Re: "Leo" Oxidation Numbers

I like to say in my mind "LEO goes GER", and think of a lion, so Loss of Electrons is Oxidation, and Gain of Electrons is Reduction.
by Anya Holbrook 1E
Thu Feb 18, 2021 8:31 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Cv and Cp
Replies: 11
Views: 48

Cv and Cp

Did we ever learn how to convert between Cv and Cp and vice versa? If we did, what's the equation?
by Anya Holbrook 1E
Thu Feb 18, 2021 6:22 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Adiabatic
Replies: 25
Views: 58

Adiabatic

What exactly does adiabatic mean? I know when a system is adiabatic q=0 so deltaU=w, but what conditions do there have to be for a system to be called adiabatic?
by Anya Holbrook 1E
Thu Feb 18, 2021 5:32 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: State functions
Replies: 13
Views: 29

State functions

Just to double check, entropy (S), enthalpy (H) and internal energy (U) are all state functions correct? Are there any others we've learned that I'm missing?
by Anya Holbrook 1E
Tue Feb 16, 2021 1:43 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Calculating degeneracy
Replies: 16
Views: 47

Calculating degeneracy

What exactly is the equation to calculate degeneracy (W)? I saw in a lecture a few weeks ago he wrote W = 2^(NA), but I'm still confused.
by Anya Holbrook 1E
Sun Feb 14, 2021 3:42 pm
Forum: Administrative Questions and Class Announcements
Topic: MyUCLA Grade
Replies: 27
Views: 165

Re: MyUCLA Grade

I've noticed that myUCLA is rarely updated for this class. Sapling scores should go in automatically, exam scores go in when they're graded, but chemistry community points are updated sporadically, given that they are not automatic and the scores need to be put in by hand.
by Anya Holbrook 1E
Sun Feb 14, 2021 3:36 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Sapling Week 5/6 Question #20
Replies: 2
Views: 12

Re: Sapling Week 5/6 Question #20

If Gibbs free energy is negative, then the reaction is said to be spontaneous in the forwards direction. If it is positive, it is non-spontaneous in the forward direction and spontaneous in the reverse direction. For #20 I just looked at curve, and since at both of the end points (where the arrow be...
by Anya Holbrook 1E
Sun Feb 14, 2021 3:33 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: kJ/K*mol vs J/K*mol
Replies: 7
Views: 25

kJ/K*mol vs J/K*mol

I was just wondering if we can change the 8.314J/K*mol into kJ/K*mol before starting calculations? For one of the Sapling questions I used the J/K*mol gas constant and had to convert my answer at the end into kJ, but I was wondering if I could just convert the gas constant into kJ at the beginning a...
by Anya Holbrook 1E
Sat Feb 13, 2021 8:53 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Bozemann's constant
Replies: 4
Views: 13

Bozemann's constant

In lecture Dr. Lavelle used the equation S = KblnW, where Kb was Bozemann's constant. On our equation sheet it gives us Bozemann's constant as just K, so I was wondering what the difference between K and Kb is, if there is any?
by Anya Holbrook 1E
Sat Feb 13, 2021 8:50 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling question 4
Replies: 9
Views: 27

Re: Sapling question 4

Hi! I used the equation deltaS = nRln(V2/V1), where V2/V1 is the ratio they gave us (mine was 1/5), and n was 1 mole.
by Anya Holbrook 1E
Sun Feb 07, 2021 5:13 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Wks 3 & 4 Sapling Q18
Replies: 6
Views: 73

Re: Wks 3 & 4 Sapling Q18

I would memorize it because it's a really simple equation and if there is ever a trick question on an exam where we need to convert from Cp to Cv or vice versa it would be bad if you didn't know the conversion.
by Anya Holbrook 1E
Sun Feb 07, 2021 5:00 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Sapling Q#19
Replies: 2
Views: 31

Sapling Q#19

Hi, I'm really confused about sapling #19 on the Week3/4 homework. I was able to calculate the Cv of the first reaction, but to find the deltaU of the second reaction with 350.0mL of HClO3 and 350.0mL of NaOH all I needed to do was multiply the heat change of the second reaction by the Cv of the cal...
by Anya Holbrook 1E
Thu Feb 04, 2021 6:05 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Compressing a system
Replies: 2
Views: 19

Compressing a system

How does compressing a system affect the energy of a system? Does decreasing the volume of the system increase the energy or decrease the energy?
by Anya Holbrook 1E
Thu Feb 04, 2021 5:48 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: R Constant
Replies: 88
Views: 242

Re: R Constant

I'm not sure if this works for all occasions when you are using PV=nRT, but I found that when looking for work I have used the 8.206x10^-2 L*atm*K^-1*mol^-1 R constant and converted my final answer to J instead of using the 8.314 R constant and got the same answer. So I don't know if this would work...
by Anya Holbrook 1E
Thu Feb 04, 2021 5:43 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Biological Reactions
Replies: 3
Views: 20

Re: Biological Reactions

Basically, I think of the organism participating in the biological reaction as the system and everything else as the surroundings, and because both matter and energy can be transferred with the surroundings in biological reactions, it is an open system.
by Anya Holbrook 1E
Mon Feb 01, 2021 1:38 pm
Forum: Student Social/Study Group
Topic: Work Life Balance
Replies: 44
Views: 131

Re: Work Life Balance

Hi! My biggest advice is to make sure you get a good amount of sleep every night! I find that the days where I get less sleep than normal are more difficult to get through, and I find myself spacing out a lot. Other than sleep, making sure that you're not constantly doing homework or work for classe...
by Anya Holbrook 1E
Mon Feb 01, 2021 1:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Can We Review our Exams?
Replies: 69
Views: 242

Re: Can We Review our Exams?

My best guess is that it's going to be last 14A where you can review it with your TA's! My TA last quarter had us sign up for a time where we could go over the questions one on one.
by Anya Holbrook 1E
Thu Jan 28, 2021 6:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How to tell if products or reactants is more stable
Replies: 3
Views: 18

How to tell if products or reactants is more stable

Hi, I am a little confused on how to tell if a reactant or product is more stable at equilibrium given a K value? Can someone explain please?
by Anya Holbrook 1E
Wed Jan 27, 2021 8:55 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: K vs Reaction Enthalpies
Replies: 2
Views: 13

K vs Reaction Enthalpies

Just to double check, when we have chemical equations and we are manipulating them to give us a desired equation, if we have the reaction enthalpies we just do to them what we did to the reactions, but if we have a k value we square them or square root them right? Like if I multiplied an equation by...
by Anya Holbrook 1E
Wed Jan 27, 2021 10:33 am
Forum: Administrative Questions and Class Announcements
Topic: Chem 14CL
Replies: 2
Views: 21

Chem 14CL

Hi, I was wondering if Chem 14CL was like Chem 14BL where you can take it at the same time as Chem 14C?
by Anya Holbrook 1E
Mon Jan 25, 2021 12:48 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State Functions
Replies: 3
Views: 18

Re: State Functions

A state function is some property where the only value we are looking for is the final value, not the paths taken. Enthalpy is additive because it's a state function, meaning all we are looking at are the initial and final states, rather than any in-between states.
by Anya Holbrook 1E
Mon Jan 25, 2021 12:41 am
Forum: Student Social/Study Group
Topic: UA Sessions
Replies: 2
Views: 22

UA Sessions

Hi, where can I find the list of UA sessions? Are they on Dr. Lavelle's website?
by Anya Holbrook 1E
Sat Jan 23, 2021 11:18 pm
Forum: General Science Questions
Topic: Lecture Question
Replies: 4
Views: 29

Re: Lecture Question

These are the known bond enthalpies for the two elements! Dr. Lavelle mentioned that you can look them up, but to make sure that when we are accounting for bonds being formed (release of energy) we need to flip the sign of the bond enthalpy, because that value is energy required to break a bond.
by Anya Holbrook 1E
Sat Jan 23, 2021 11:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Diatomic Molecules
Replies: 6
Views: 51

Re: Diatomic Molecules

Hi! Diatomic molecules are elements that form molecules consisting of two atoms bounded together. The examples you wrote are diatomic elements, not diatomic molecules like HBr.
by Anya Holbrook 1E
Wed Jan 20, 2021 3:33 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: delta H vs delta U
Replies: 2
Views: 37

delta H vs delta U

In my discussion today my TA mentioned that delta H is enthalpy or the change in energy of the reaction, and that delta U represented constant volume but also enthalpy under different conditions. My question is what exactly is delta U and when we want to calculate enthalpy do we calculate delta H or...
by Anya Holbrook 1E
Sun Jan 17, 2021 3:41 pm
Forum: Student Social/Study Group
Topic: Comfort Movies
Replies: 128
Views: 343

Re: Comfort Movies

This is such a cute question, but my all time favorite comfort movie is Thor: Ragnarok, I could watch it forever and never ever get sick of it, it's so funny and the CGI is so visually appealing, it's my favorite movie ever.
by Anya Holbrook 1E
Sun Jan 17, 2021 3:37 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem Community and Sapling Grades
Replies: 25
Views: 98

Re: Chem Community and Sapling Grades

I found that most of my sapling grades were updated automatically to my.ucla. Like if I had only finished 1 question out of 10 there would be a 10% grade on there for that week until I finished the rest of the questions.
by Anya Holbrook 1E
Sun Jan 17, 2021 3:35 pm
Forum: Administrative Questions and Class Announcements
Topic: Posting on Chem Community
Replies: 6
Views: 55

Re: Posting on Chem Community

They need to be in the correct topics! I heard once last quarter that Dr. Lavelle and our TA's won't count posts towards our total post count if they are not in the proper topic section.
by Anya Holbrook 1E
Sun Jan 17, 2021 3:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterms
Replies: 24
Views: 66

Midterms

Do we know if the midterms are going to be administered during discussion like 14A or are we going to be taking them during lecture?
by Anya Holbrook 1E
Mon Jan 11, 2021 4:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Super acids and super bases
Replies: 4
Views: 24

Super acids and super bases

Dr. Lavelle mentioned that there are situations where the pH is below zero or above 14 (super acids and super bases) but will we have any situations in this class where we have to deal with them?
by Anya Holbrook 1E
Sun Jan 10, 2021 3:03 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Are there reactions that just do not/ can not ever reach equilibrium?
Replies: 18
Views: 71

Re: Are there reactions that just do not/ can not ever reach equilibrium?

I believe that every reaction that has a double arrow can go to equilibrium, just the amount of time it takes or the temperature it needs differs, but reactions with only a forward pointing arrow cannot, because the reactants are used to completion in those cases.
by Anya Holbrook 1E
Sun Jan 10, 2021 2:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reactions at Equilibrium
Replies: 6
Views: 51

Re: Reactions at Equilibrium

Yes! At chemical equilibrium, the reaction is still going, but the rate in which both products and reactants are formed is equal so it appears as if it has stopped.
by Anya Holbrook 1E
Sun Jan 10, 2021 2:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Changing K
Replies: 4
Views: 40

Re: Changing K

K is the equilibrium constant for a chemical equation, and if you add more products or more reactants, the reaction will run in either the forward or reverse direction to bring the system back to equilibrium, and given that K is a ratio, its value will not change.
by Anya Holbrook 1E
Thu Jan 07, 2021 4:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial pressure vs concentration
Replies: 6
Views: 48

Partial pressure vs concentration

In the textbook it says that when a chemical equation is made up of all gases, that we can use the partial pressure in the equilibrium constant equation rather than the concentration, but we can use either, correct?
by Anya Holbrook 1E
Thu Jan 07, 2021 4:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Temperature and Kc
Replies: 4
Views: 27

Temperature and Kc

Dr. Lavelle mentioned in lecture that temperature affect equilibrium, but how does it factor into the equation for the equilibrium constant?
by Anya Holbrook 1E
Sat Dec 12, 2020 7:20 pm
Forum: Naming
Topic: Latin names
Replies: 10
Views: 68

Latin names

When naming coordination compounds, do we only use the latin name of elements if the element is the anion of the molecule? Or do we just always use the latin names no matter what?
by Anya Holbrook 1E
Fri Dec 11, 2020 4:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Wednesday Review Qs
Replies: 4
Views: 75

Wednesday Review Qs

I was wondering if the questions on the slides that Dr. Lavelle posted on Wednesday are the type of questions that we should expect on the final? Or should we expect something more difficult/conceptual?
by Anya Holbrook 1E
Thu Dec 10, 2020 5:21 pm
Forum: Identifying Acidic & Basic Salts
Topic: Classifying salts as acidic, basic, or neutral
Replies: 3
Views: 30

Classifying salts as acidic, basic, or neutral

Hi, I'm super confused on how to classify salts based on whether they are acidic, basic, or neutral? I looked it up and it said to add H+ to the anion and OH- to the cation and see if they are on the list of strong acids/strong bases, but is there another way to classify the salts? For example, like...
by Anya Holbrook 1E
Thu Dec 10, 2020 3:57 pm
Forum: Identifying Acidic & Basic Salts
Topic: Titration
Replies: 4
Views: 41

Titration

Hi, in Dr. Lavelle's lecture he mentioned that titration can help us determine what the concentration of an acid or a base is, but I was wondering if you absolutely had to know whether the sample is an acid or a base before performing the experiment? Is there any way to use titration to determine if...
by Anya Holbrook 1E
Mon Dec 07, 2020 5:50 pm
Forum: Calculating the pH of Salt Solutions
Topic: -OH vs OH-
Replies: 13
Views: 90

-OH vs OH-

This doesn't really have anything to do with calculating pH, but why is it that sometimes in Dr. Lavelle's notes he put -OH instead of OH-? Don't charges on a molecule or ion go after the naming?
by Anya Holbrook 1E
Mon Dec 07, 2020 4:09 pm
Forum: Identifying Acidic & Basic Salts
Topic: Ions as acids
Replies: 2
Views: 32

Ions as acids

In Dr. Lavelle's lecture, the example he used for ions as acids was ammonium chloride. I was wondering why we disregard the Cl-?Is it just because it has no affect on the H3O+ concentration?
by Anya Holbrook 1E
Sun Dec 06, 2020 3:39 pm
Forum: Naming
Topic: Helpful Videos for Naming
Replies: 22
Views: 134

Re: Helpful Videos for Naming

Thank you thank you! Naming has been super hard for me to figure out, so this is super helpful!!
by Anya Holbrook 1E
Wed Dec 02, 2020 2:40 pm
Forum: Naming
Topic: Sapling Question 6
Replies: 4
Views: 52

Sapling Question 6

In the feedback for question 6 Sapling says you have to account for the counterion charge when determining the oxidation state of the metal species in the complex. I'm just checking, but this means that you have to account for the oxidation numbers of elements outside the brackets when determining t...
by Anya Holbrook 1E
Wed Dec 02, 2020 2:34 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Numbers in Molecules
Replies: 3
Views: 42

Coordination Numbers in Molecules

If you have found a coordination number for a molecule (i.e. [Fe(CO)5] which is 5), does that mean that each species in the molecule has a coordination number of 5 or just the central atom? Like would F and CO both be 5 or would that only be F because it is the central atom? If that's the case, woul...
by Anya Holbrook 1E
Wed Dec 02, 2020 2:24 pm
Forum: Naming
Topic: Ligand Names Table on Final
Replies: 10
Views: 103

Re: Ligand Names Table on Final

We will not be given the ligand names sheet, but we are expected to memorize at least the most popular ones, instead of the entire sheet.
by Anya Holbrook 1E
Tue Dec 01, 2020 5:01 pm
Forum: Naming
Topic: order of ligands [ENDORSED]
Replies: 6
Views: 110

Re: order of ligands [ENDORSED]

Yeah, I think this was a mistake. I would just go off of what Dr. Lavelle said, which is that the ligands are named in alphabetical order.
by Anya Holbrook 1E
Sat Nov 28, 2020 3:24 pm
Forum: Hybridization
Topic: Hybridization in bonding groups
Replies: 5
Views: 50

Hybridization in bonding groups

Just to check my knowledge, when considering the hybridization of an element in a molecule, we only consider the total number of bonding groups (i.e. lone pair groups and bonding atoms) rather than total number of bonds right? So for example, if there was an element with one lone pair, 2 single bond...
by Anya Holbrook 1E
Sat Nov 28, 2020 2:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Axial vs Equatorial
Replies: 4
Views: 64

Axial vs Equatorial

Hi, can someone please explain to me how to easily identify if an atom is axial or equatorial?
by Anya Holbrook 1E
Tue Nov 24, 2020 1:47 pm
Forum: Administrative Questions and Class Announcements
Topic: 14BL Waitlist
Replies: 1
Views: 36

14BL Waitlist

Does anyone know the probability of getting off the Chem 14BL waitlist? I'm like 99% sure that I took the first waitlist position for the lab I chose...
by Anya Holbrook 1E
Tue Nov 24, 2020 1:44 pm
Forum: Administrative Questions and Class Announcements
Topic: grades
Replies: 10
Views: 155

Re: grades

Dr. Lavelle said that a 50% is needed to pass, but I think the rest of the grades follow the same scale where 90-93% is an A-, 93-97% is an A, 97-100% is an A+, and the rest of the grades follow the same pattern? I'm not 100% sure but that's what I've been going off of.
by Anya Holbrook 1E
Tue Nov 24, 2020 1:40 pm
Forum: Sigma & Pi Bonds
Topic: Rotation of sigma and pi bonds
Replies: 5
Views: 17

Rotation of sigma and pi bonds

I know Dr. Lavelle said that sigma bonds can rotate around their axis and that pi bonds break if the molecule can rotate, but how can you tell if there is rotation or not?
by Anya Holbrook 1E
Fri Nov 20, 2020 1:59 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14BL
Replies: 5
Views: 57

Chem 14BL

Just in case I'm not able to get 14BL during my second pass, we're still allowed to take the course later right? Like we don't have to do it at the same time as we're taking 14B?
by Anya Holbrook 1E
Fri Nov 20, 2020 1:54 pm
Forum: Student Social/Study Group
Topic: post midterm 2
Replies: 27
Views: 306

Re: post midterm 2

I was super nervous coming into the second midterm because I didn't do so well on the first midterm, but I'm hoping? that I did better this time around. And much unfortunately I had to take a quiz in another class right after I finished my midterm so I am super stressed right now but I will 100? be ...
by Anya Holbrook 1E
Fri Nov 20, 2020 1:51 pm
Forum: Student Social/Study Group
Topic: grade worries
Replies: 110
Views: 1220

Re: grade worries

Oh for sure I feel the same way. I did much worse than I had hoped for on midterm 1 so I kinda don't have much hope for getting an A or an A+ in this class, but I just hope that I did okay enough on midterm 2 to still allow me to get a B/B+ :(
by Anya Holbrook 1E
Mon Nov 16, 2020 5:35 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8731
Views: 1489497

Re: Post All Chemistry Jokes Here

Are you made up of copper and tellurium? Because you're CuTe.
by Anya Holbrook 1E
Mon Nov 16, 2020 5:32 pm
Forum: Student Social/Study Group
Topic: Studying for Midterm 2
Replies: 4
Views: 30

Studying for Midterm 2

Hi, how would you guys recomment studying for the midterm? I've been going over my notes and homework problems, but I feel like that isn't enough. Is there something else I could do?
by Anya Holbrook 1E
Sat Nov 14, 2020 9:05 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Set oxidation numbers?
Replies: 1
Views: 10

Set oxidation numbers?

Hi, I'm kinda confused about how there seem to be some atoms whose oxidation numbers won't change no matter the molecule they are in? Like for example oxygen is always 2-? What other atoms have these set oxidation numbers?
by Anya Holbrook 1E
Thu Nov 12, 2020 4:54 pm
Forum: Bond Lengths & Energies
Topic: Increasing strengths of dispersion forces
Replies: 2
Views: 13

Increasing strengths of dispersion forces

Hi, can some please explain to me why the increasing strength of dispersion forces explains why F2 and Cl2 are gases at room temperature but Br2 is liquid and I2 is solid? I'm pretty sure it has something to with the number of electrons that the molecules have but I'm not 100% sure?
by Anya Holbrook 1E
Thu Nov 12, 2020 4:08 pm
Forum: Bond Lengths & Energies
Topic: Bond Strengths
Replies: 10
Views: 97

Re: Bond Strengths

I agree with what the others have said about bond type (i.e. single, double, triple) having the largest effect on bond strength but the way I have been thinking about it is that all of those factors that you mentioned affect bond strength in their own ways. For example, bond strength wouldn't be as ...
by Anya Holbrook 1E
Thu Nov 12, 2020 4:05 pm
Forum: Bond Lengths & Energies
Topic: Interaction Potential Energy
Replies: 4
Views: 28

Re: Interaction Potential Energy

From what I understood, the interaction potential energies are always negative because that is the amount of energy that needs to be input in order to break the force of attraction between the two molecules, rather than the amount of energy the attraction generates or something.
by Anya Holbrook 1E
Thu Nov 12, 2020 4:01 pm
Forum: Dipole Moments
Topic: Determining Polarity
Replies: 3
Views: 36

Re: Determining Polarity

Hi, so it's as Neel said, but I just wanted to add that the general rule for determining polarity based on electronegativity is that if there is a difference in electronegativity is from 0.4-1.6, then the bond is polar covalent! Also, if the difference is from 0-0.4, then it is nonpolar covalent.
by Anya Holbrook 1E
Sun Nov 08, 2020 11:20 am
Forum: Resonance Structures
Topic: Valence Electrons [ENDORSED]
Replies: 43
Views: 371

Re: Valence Electrons [ENDORSED]

Yes, you're right! The column number that the element is in, is the number of valence electrons that the element has. Keep in mind that wwhen I say column number, it only applies to the s and p blocks, not the d block.
by Anya Holbrook 1E
Wed Nov 04, 2020 1:56 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate covalent bond lecture example
Replies: 4
Views: 32

Coordinate covalent bond lecture example

In the coordinate covalent bond example that Dr. Lavelle used in lecture (BF3), where did the extra fluorine atom that formed the bond come from?
by Anya Holbrook 1E
Wed Nov 04, 2020 1:54 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate covalent bond
Replies: 3
Views: 38

Coordinate covalent bond

Just to check my understanding of coordinate covalent bonds, they only occur when a molecule does not have the proper number of electrons to fulfill an octet, right? But also, they only occur when the element in need of more electrons has a certain number of electrons in a factor of 2 (i.e. 2 electr...
by Anya Holbrook 1E
Wed Nov 04, 2020 12:51 pm
Forum: Octet Exceptions
Topic: Expanded Octate
Replies: 4
Views: 37

Expanded Octate

In lecutre, Dr. Lavelle mentioned that we can have expanded octate's whenever an element is in the p-block in row 3 or later. I know that s-block elements typically lose their electrons to elements with higher electronegativity, but can there be expanded octates in the d-block?
by Anya Holbrook 1E
Tue Nov 03, 2020 2:46 pm
Forum: Lewis Structures
Topic: charge by square bracket
Replies: 8
Views: 85

Re: charge by square bracket

Charges on the outside of a lewis structure depict the ionic charge of the molecule. For example, if the molecule is an anion, there would be a negative charge outside the brackets, with the coefficient depending on the molecule, and the same for cations as a positive charge.
by Anya Holbrook 1E
Sat Oct 31, 2020 11:34 pm
Forum: Properties of Light
Topic: Midterm
Replies: 6
Views: 73

Midterm

Hi, does anyone know how the midterm is going to be graded? I heard that there was going to be partial credit points offered, is that true? And do we know if it's going to be curved or not?
by Anya Holbrook 1E
Wed Oct 28, 2020 1:19 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Simplification for Electron Configuration
Replies: 3
Views: 44

Simplification for Electron Configuration

In lecture, Dr. Lavelle showed an example for shortening the electron configuration for Carbon from 1s^2 2s^2 2px^1 2py^1 to [He] 2s^2 2px^1 2py^1. Is it possible to simplify it further to [Be] 2px^1 2py^1? Or are we only able to shorten it for earlier shells? For example, if the atom has three shel...
by Anya Holbrook 1E
Wed Oct 28, 2020 12:49 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Orbitals vs shells
Replies: 2
Views: 23

Orbitals vs shells

Just to clarify, in Pauli's Exclusion Principle, when it states that there are no more than two electrons per orbital, this does not relate to the shells right? Like, there is only 1 orbital in a s shell (l=0), 3 orbitals in a p-shell (l=1), 5 orbitals in a d-shell (l=), etc.?
by Anya Holbrook 1E
Wed Oct 28, 2020 12:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing Electron Configurations
Replies: 5
Views: 35

Re: Writing Electron Configurations

I'm not 100% sure if this is correct but I think it may have something to do with how the periodic table is laid out? Like if you go from left to right, top to bottom, along the table then the electron configuration you get goes from lower to higher energy. From what I remember from high school chem...
by Anya Holbrook 1E
Wed Oct 28, 2020 12:40 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 4
Views: 29

Re: Electron Configuration

My guess is that it would be considered wrong because the order that we were taught would put the 3d^1 before the 4s^2, considering their energy levels. I think if you were just writing the configuration based off the order that you see on the periodic table (i.e. going left to right, top to bottom)...
by Anya Holbrook 1E
Sun Oct 25, 2020 3:18 pm
Forum: *Shrodinger Equation
Topic: Conceptual understanding of Shrodinger Equation
Replies: 1
Views: 40

Conceptual understanding of Shrodinger Equation

I know that for the midterm we do not have to fully understand how to mathematically apply Schrodinger's equation, but we have to conceptually understand it. Can someone help explain what concepts we need to understand on this topic?
by Anya Holbrook 1E
Sun Oct 25, 2020 3:15 pm
Forum: Properties of Light
Topic: Speed of light
Replies: 25
Views: 161

Re: Speed of light

I've been using 2.998 x 10^8 rather than 3.00 x 10^8, and just rounding my final answer to the correct number of sigfigs, and it seems to have been working so far!
by Anya Holbrook 1E
Sun Oct 25, 2020 3:13 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg details
Replies: 3
Views: 39

Heisenberg details

In my discussion this week, we were working on practice problems and one of them was using Heisenberg's equation to find the minimum uncertainty on the speed of an electron. In the end, the solution was a value for delta v (velocity) so I was wondering if we should just always assume that speed is t...
by Anya Holbrook 1E
Wed Oct 21, 2020 4:36 pm
Forum: DeBroglie Equation
Topic: De Brogile vs Heisenberg vs Schrodinger
Replies: 2
Views: 38

De Brogile vs Heisenberg vs Schrodinger

In Dr. Lavelle's 10/19/2020 lecture he mentioned that De Broglie's wave equation, Heisenberg's uncertainty principle, and Schrodinger's wave function equation are all concepts that build off one another in some way. How exactly do they connect?
by Anya Holbrook 1E
Tue Oct 20, 2020 12:07 pm
Forum: Ionic & Covalent Bonds
Topic: Constants
Replies: 5
Views: 86

Constants

Hi, this is unrelated to this week's content but does anyone know if we will be given the values for constants on our exams? (i.e. Rydberg constant, Planck's constant, speed of light, etc.)
by Anya Holbrook 1E
Sun Oct 18, 2020 2:31 pm
Forum: *Black Body Radiation
Topic: Black Body Radiation
Replies: 6
Views: 104

Re: Black Body Radiation

From what I've understood from Dr. Lavelle's lectures, black body radiation is something that absorbs all wavelengths of light. I think black clothes have properties of this concept in that the darker color material absorbs more wavelengths that lighter color material, but it technically cannot be c...
by Anya Holbrook 1E
Sun Oct 18, 2020 2:27 pm
Forum: Properties of Light
Topic: Energy from shorter wavelength
Replies: 5
Views: 47

Energy from shorter wavelength

I know that a shorter wavelength means higher frequency and higher energy, but does that mean higher energy coming in from an outside source like UV (energy of photon), or does it mean that it produces more energy (kinetic energy)?
by Anya Holbrook 1E
Wed Oct 14, 2020 5:44 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Infared Energy Levels
Replies: 2
Views: 36

Infared Energy Levels

In the lecture on atomic spectra, Dr. Lavelle mentioned that the level for infrared is from "some higher energy level down to n=3". Considering how the UV is from n=2 to n=1 and visible light is from n=3 to n=2, should we assume that the visible light region is from n=4 to n=3?
by Anya Holbrook 1E
Wed Oct 14, 2020 4:45 pm
Forum: Properties of Light
Topic: GroupMe
Replies: 2
Views: 55

GroupMe

Hi, is there a GroupMe for this class? If there is, can someone please link it? Thank you!
by Anya Holbrook 1E
Tue Oct 13, 2020 1:13 pm
Forum: Properties of Electrons
Topic: Quanta vs Photons
Replies: 4
Views: 69

Quanta vs Photons

Can someone please give me a basic description of quanta and photons and the main difference between them? I know they both are used to measure light but how are they different?
by Anya Holbrook 1E
Sun Oct 11, 2020 4:12 pm
Forum: Empirical & Molecular Formulas
Topic: Percent Yield in Sapling HW #10
Replies: 1
Views: 46

Percent Yield in Sapling HW #10

For problem 10 in Sapling, I calculated the theoretical yield for my values which turned out to be 0.216g of 3-methyl-3-hexanol. My problem states that the actual yield is 0.24g of 3-methyl-3-hexanol. I used the equation of actual yield/theoretical yield x 100% = percent yield but Sapling keeps sayi...
by Anya Holbrook 1E
Thu Oct 08, 2020 3:36 pm
Forum: SI Units, Unit Conversions
Topic: Sig figs and molar mass
Replies: 18
Views: 120

Re: Sig figs and molar mass

Hi! I find that it's usually best to use what's given on the periodic table (I've heard from others that we'll be given one for exams?). Usually most periodic tables you find just by looking online have three decimal places but I've found that rounding to two doesn't make that much of a different in...
by Anya Holbrook 1E
Wed Oct 07, 2020 4:30 pm
Forum: Limiting Reactant Calculations
Topic: Actual and Theoretical yields
Replies: 14
Views: 145

Re: Actual and Theoretical yields

I think there wouldn't be any cases where the actual and theoretical yields are exactly the same, considering how clean the experiment must me? (i.e. no side reactions). In theory, if there were a case where there is no impurity, no side reactions, etc. they technically yes, actual and theoretical y...
by Anya Holbrook 1E
Wed Oct 07, 2020 4:25 pm
Forum: SI Units, Unit Conversions
Topic: Significant Figures Using the Periodic Table
Replies: 13
Views: 145

Re: Significant Figures Using the Periodic Table

I think most periodic tables you find on the internet will show three decimal places, but I've found that rounding to two decimal places doesn't change much in the grand scheme of things. All in all, I think it'll ultimately depend on what Dr. Lavelle says he wants on exams!
by Anya Holbrook 1E
Wed Oct 07, 2020 4:04 pm
Forum: Empirical & Molecular Formulas
Topic: Rounding EF to Integers
Replies: 6
Views: 63

Rounding EF to Integers

If we have to find the empirical formula before finding the molecular formula of a compound (where the molecular formula is what we are looking for in the end), is it absolutely necessary that we make the empirical formula integers only? Or can we leave the EF as decimals if necessary then just cont...
by Anya Holbrook 1E
Wed Oct 07, 2020 4:00 pm
Forum: Significant Figures
Topic: Clarification on Significant Figures
Replies: 9
Views: 68

Clarification on Significant Figures

Just to make sure, when determining the number of significant figures zeros would only count if they are not at the end of a decimal correct? For example, 0.034 and 0.304 would both have 3 significant figures while 0.340 would only have two, correct? Thanks!

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