Search found 47 matches

by Ellison Gonzales 3F
Sun Nov 29, 2020 11:30 pm
Forum: Hybridization
Topic: e density
Replies: 30
Views: 69

Re: e density

Yes every bond and lone pair are a region of e- density. Even if you have two lone pairs on the same atom ( example :o: ), it would be considered to have two regions of electron density
by Ellison Gonzales 3F
Sun Nov 29, 2020 11:26 pm
Forum: Sigma & Pi Bonds
Topic: Delocalized π bonds
Replies: 6
Views: 23

Re: Delocalized π bonds

What is a pi orbital?
by Ellison Gonzales 3F
Sun Nov 29, 2020 11:25 pm
Forum: Sigma & Pi Bonds
Topic: Delocalized π bonds
Replies: 6
Views: 23

Re: Delocalized π bonds

Delocalized pi bonds can only exist in a resonance structure. Since pi bonds typically exist in double or triple bonds, that double/ triple bond is able to move around in a resonance structure, meaning the pi bond is moving with it too. Therefore, the electrons for the pi bond are never permanently ...
by Ellison Gonzales 3F
Sun Nov 29, 2020 11:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Ring structure
Replies: 1
Views: 7

Ring structure

How are we to know when to draw a possible structure using a ring structure? I ask this question because a hint for sapling #17 was to draw a 3 membered ring structure but I was wondering if there was any advice to know when to do so
by Ellison Gonzales 3F
Sun Nov 29, 2020 11:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Smallest Bond Angle
Replies: 4
Views: 24

Re: Smallest Bond Angle

If you’re talking about the smallest bond angle when comparing the angles within one structure, I see the smallest angle as being the one between two bonding pairs. Since there is more e- repulsion between a lone pair and a bonding pair, that will cause the other angles without lone pairs to be smal...
by Ellison Gonzales 3F
Sun Nov 22, 2020 9:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Electron density in sigma and pi bonds
Replies: 3
Views: 30

Re: Electron density in sigma and pi bonds

If sigma bonds are for single bonds and a double bond involves sigma and pi, does that mean we have to draw out the Lewis structure to figure out how many bonds that density has?
by Ellison Gonzales 3F
Sun Nov 22, 2020 9:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: repulsion strength
Replies: 10
Views: 34

Re: repulsion strength

Just to clarify, lone pair electrons have more repulsions so therefore that angle is wider, correct? In that case, we just have to know that concept? Or is there certain angle degree that is associated with lone pair repulsion? Hi! Yes you are correct, lone pair repulsion is greater than bonding pa...
by Ellison Gonzales 3F
Sun Nov 22, 2020 9:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: repulsion strength
Replies: 10
Views: 34

Re: repulsion strength

Just to clarify, lone pair electrons have more repulsions so therefore that angle is wider, correct? In that case, we just have to know that concept? Or is there certain angle degree that is associated with lone pair repulsion?
by Ellison Gonzales 3F
Sun Nov 22, 2020 8:29 pm
Forum: Lewis Structures
Topic: Lewis acids and bases
Replies: 23
Views: 56

Re: Lewis acids and bases

Just something good to keep in mind is that coordinate covalent bonds are usually formed when dealing with acids and bases
by Ellison Gonzales 3F
Sun Nov 22, 2020 8:16 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic radius
Replies: 18
Views: 54

Re: Ionic radius

Thank you everyone this was super helpful!
by Ellison Gonzales 3F
Sun Nov 15, 2020 11:04 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 11
Views: 63

Re: Resonance

The most stable structure correlates with the atoms’ formal charges in the structure. Also make a note that if the chemical compound has a charge, it is best if the most electronegative atom has that negative charge on it. Typically, the best structure will have the least electronegative atom at the...
by Ellison Gonzales 3F
Sun Nov 15, 2020 10:48 pm
Forum: Lewis Structures
Topic: Lewis acids and bases
Replies: 23
Views: 56

Re: Lewis acids and bases

Do you have to draw the Lewis structure to tell if they’re an acid or a base?
by Ellison Gonzales 3F
Sun Nov 15, 2020 10:19 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic radius
Replies: 18
Views: 54

Ionic radius

Does anyone know if the charge of an ion effects the ionic radius or the size of an ion?
by Ellison Gonzales 3F
Sun Nov 15, 2020 10:06 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent bonds and distortion
Replies: 5
Views: 24

Re: Covalent bonds and distortion

Thank you Dylan, Sophia, and Dominic! This makes a lot more sense to me
by Ellison Gonzales 3F
Sun Nov 15, 2020 10:00 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Distortion
Replies: 8
Views: 43

Re: Distortion

FionaHunter21 wrote:Is an anion always the atom that is polarizable and the cation is what can have high polarizing ability?

Hi!
Yes, “polarizable” applies to anions and “polarizing power”/“polarizability” applies to cations
by Ellison Gonzales 3F
Sun Nov 08, 2020 8:19 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent bonds and distortion
Replies: 5
Views: 24

Covalent bonds and distortion

Hello! I was wondering why the more covalent a bond is, the more distortion there is. I understand covalent bonds and distortion are linked, but why is that? Thank you!
by Ellison Gonzales 3F
Sun Nov 08, 2020 8:13 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 7
Views: 44

Re: Covalent Character

Hi there! Covalent bonds can have ionic character because elements within a bond have differing electronegativities. If one element in a bond has a greater electronegativity than the other, it will attract the electron more than the other element, causing the electron to be unevenly shared (having ...
by Ellison Gonzales 3F
Sun Nov 08, 2020 8:03 pm
Forum: Student Social/Study Group
Topic: Midterm 2 Study Group
Replies: 25
Views: 112

Re: Midterm 2 Study Group

I’m so excited for this! Thank you :)
by Ellison Gonzales 3F
Sun Nov 08, 2020 7:59 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Distortion
Replies: 8
Views: 43

Re: Distortion

What about anions that are more polarizable classifies them as covalent? In other words, why is it that anions that are pulled into the shared region are classified as covalent?
by Ellison Gonzales 3F
Sun Nov 08, 2020 7:42 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Lavelle Lecture 11/6
Replies: 2
Views: 28

Re: Lavelle Lecture 11/6

In his lecture, he also talked about charge density. Is that the same thing as its pulling ability?
by Ellison Gonzales 3F
Sun Nov 08, 2020 7:38 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizable vs Polarizing Power
Replies: 3
Views: 25

Re: Polarizable vs Polarizing Power

Polarizable is the ability to GET pulled (which is the anion pulled by the positive charge).
Polarizing power is the cation’s ability TO pull the anions into the shared region.
by Ellison Gonzales 3F
Sun Nov 01, 2020 11:35 pm
Forum: *Shrodinger Equation
Topic: Transitioning energy levels
Replies: 2
Views: 11

Re: Transitioning energy levels

Hello! I definitely heard several different things regarding this topic. Since I heard opposing answers, I personally always just did (final - initial) instead of thinking of it as n2 and n1. This way always worked for me or at least for the specific problems I used it on. I know this isn’t a scient...
by Ellison Gonzales 3F
Sun Nov 01, 2020 11:26 pm
Forum: Quantum Numbers and The H-Atom
Topic: Determining Quantum Numbers
Replies: 5
Views: 39

Re: Determining Quantum Numbers

I know how to get the answer of ml from l, but what does ml stand for conceptually? I believe in the lecture he said that ml is the allowed values, but I don’t completely understand what that means. Thank you
by Ellison Gonzales 3F
Sun Nov 01, 2020 11:15 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Week 2,3,4 Sapling HW
Replies: 5
Views: 57

Re: Week 2,3,4 Sapling HW

Thank you, Albert and Grace! I now understand that there are different techniques to solving this problem and that the constant R can change if you choose to use a different unit for it, thank you!
by Ellison Gonzales 3F
Sun Nov 01, 2020 11:09 pm
Forum: Trends in The Periodic Table
Topic: positive and negative ion
Replies: 14
Views: 42

Re: positive and negative ion

The reason the radius of an element is larger when the ion is negative is because there is an additional e- going to the outer shell that causes more e- repulsion, therefore making anions much bigger than their neutral atom.
by Ellison Gonzales 3F
Sun Nov 01, 2020 11:07 pm
Forum: Trends in The Periodic Table
Topic: positive and negative ion
Replies: 14
Views: 42

Re: positive and negative ion

The negative ion would have a larger radius because in this case, the nuclear charge stays the same (if they're the same element). The only thing that would be changing is the number of electrons, meaning the radius would be bigger. I understand the size of the radius correlating with whether it is...
by Ellison Gonzales 3F
Sun Oct 25, 2020 9:09 pm
Forum: Properties of Electrons
Topic: Sapling Week 2,3,4 #12
Replies: 7
Views: 60

Re: Sapling Week 2,3,4 #12

When Sapling would suggest using R=1.0974*10^7m^-1, it confused me a ton. But just to understand their reasoning, they only used this value for R when solving for wavelength to match the units for wavelength? But they did this just to fit all the work into one equation? Thank you!
by Ellison Gonzales 3F
Sun Oct 25, 2020 9:03 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation and Negative Signs
Replies: 11
Views: 82

Re: Rydberg Equation and Negative Signs

Hi! I wanted to add something that really helped me understand the right sign to use. For the Rydberg equation, we get a negative value because we are calculating the decrease in energy as the electron moves from a higher shell to a lower shell. However, when we use that value to calculate the freq...
by Ellison Gonzales 3F
Sun Oct 25, 2020 8:59 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation and Negative Signs
Replies: 11
Views: 82

Re: Rydberg Equation and Negative Signs

Hi! I agree with all the other answers here - in general, there is never going to be a loss of energy in the system because it is conserved and just transformed into different types of energy or transmitted to another object. I would say only if the question has wording similar to "total chang...
by Ellison Gonzales 3F
Sun Oct 25, 2020 8:32 pm
Forum: Limiting Reactant Calculations
Topic: Double Check my Understanding
Replies: 10
Views: 111

Re: Double Check my Understanding

You are indeed correct: when calculating the molar mass of a compound, you do not take into account the stoichiometric coefficient in front of the compound in the balanced chemical equation. A situation you would use the stoichiometric coefficient times the molar mass of a compound would be when yo...
by Ellison Gonzales 3F
Sun Oct 25, 2020 4:47 pm
Forum: Limiting Reactant Calculations
Topic: Midterm
Replies: 7
Views: 90

Re: Midterm

I believe the more complicated ones will be given, but like someone else said, be comfortable with the diatomics. In one of Dr. Lavelle’s office hours, he said that since we haven’t technically gone over naming elements and chemical reactions, he won’t try to trick us with that.
by Ellison Gonzales 3F
Wed Oct 21, 2020 3:16 pm
Forum: Einstein Equation
Topic: HW problem 5
Replies: 6
Views: 80

Re: HW problem 5

Yes, that is exactly correct. Conceptually, the equations we are solving are PER photon. So at the end we would just need to figure out how many of the energy per photon we would need to get the 32.74J. First you would want to find the frequency so do c=lambda v this would give you 3.08 x 10^11 hz ...
by Ellison Gonzales 3F
Sun Oct 18, 2020 9:48 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1A15
Replies: 4
Views: 44

Re: 1A15

Hi Natallie, I found this challenging the first time I did it as well. Here's a step by step method to solve it: Step 1) When you read this problem the first time, you should be able to identify that we are discussing atomic spectroscopy in which a hydrogen atom is emitting a certain wavelength of ...
by Ellison Gonzales 3F
Sun Oct 18, 2020 9:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1A15
Replies: 4
Views: 44

Re: 1A15

Hi, I understand the above work, but how come we can't use the equation: En=(\frac{-hR}{n^{2}}) . How come we have to use the frequency equation? Can we not use En=(-hR/n^2)? I didn’t use the equation you wrote, but I read from other explanations on chemistry community about this question, ...
by Ellison Gonzales 3F
Sun Oct 18, 2020 9:06 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Sapling Week 2 & 3 HW Problem 5
Replies: 7
Views: 93

Re: Sapling Week 2 & 3 HW Problem 5

The posts above ^ helped me figure this out. Basically, going from a higher level to a lower level causes spectral lines. To find the range of wavelengths, you must use the Rydberg equation. You use the n=7 to n=6 for the first wavelength and n=7 to n=1 for the second wavelength. The equation is v ...
by Ellison Gonzales 3F
Sun Oct 18, 2020 8:44 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Week 2,3,4 Sapling HW
Replies: 5
Views: 57

Re: Week 2,3,4 Sapling HW

For this question, you first have to look at the given wavelength, which is 6.563 *10^-7 m (converted from nanometers). Matching this with the numbers given on the EM spectrum tells us that this light is on the wavelength of visible light, which fits in the Balmer series, which means that the light...
by Ellison Gonzales 3F
Sun Oct 18, 2020 4:52 pm
Forum: Einstein Equation
Topic: HW problem 5
Replies: 6
Views: 80

Re: HW problem 5

How would I approach this problem? A liquid is exposed to infrared radiation with a wavelength of 9.74×10−4 cm. Assume that all the radiation is absorbed and converted to heat. How many photons are required for the liquid to absorb 32.74 J of heat? Do I need to use both E=hv and C=lambda(V)? Anothe...
by Ellison Gonzales 3F
Sun Oct 18, 2020 12:45 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Sapling Week 2 & 3 HW Problem 5
Replies: 7
Views: 93

Re: Sapling Week 2 & 3 HW Problem 5

The posts above ^ helped me figure this out. Basically, going from a higher level to a lower level causes spectral lines. To find the range of wavelengths, you must use the Rydberg equation. You use the n=7 to n=6 for the first wavelength and n=7 to n=1 for the second wavelength. The equation is v ...
by Ellison Gonzales 3F
Sat Oct 17, 2020 2:43 am
Forum: Photoelectric Effect
Topic: Sapling #4 Homework Part 2
Replies: 9
Views: 114

Re: Sapling #4 Homework Part 2

Divide the total energy by the work function to see how many electrons the energy can displace. 6.78×10−7 J/4.28494×10−19 J/photon Important concepts: One photon with enough energy to displace an electron will only displace one electron. In other words, there is a one-photon to one electron ratio i...
by Ellison Gonzales 3F
Fri Oct 09, 2020 2:59 pm
Forum: Administrative Questions and Class Announcements
Topic: Step Up Sessions
Replies: 71
Views: 4431

Re: Step Up Sessions

I had a question on what the difference between the workshops and set up sessions are? My understanding is that step up sessions are for if you have a specific question or concept you want solved and explained step by step. Workshops I believe are a tad more accelerated and you do problems with the...
by Ellison Gonzales 3F
Fri Oct 09, 2020 1:01 am
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 58
Views: 6396

Re: Accessing the E-textbook [ENDORSED]

For anyone who ordered their textbook from the UCLA store and already received it, was it a physical copy? and if so, did it include an access code for sapling and/or the e-book? It’s an e book for this course because there’s videos and links inside the book. You should get your code on a piece of ...
by Ellison Gonzales 3F
Fri Oct 09, 2020 12:46 am
Forum: Molarity, Solutions, Dilutions
Topic: G5
Replies: 8
Views: 105

Re: G5

Regarding finding the volume of solution for b.) Co32-, does Co32- have only one mole? I don’t exactly remember how the 2- here effects the moles. Since we multiplied the molarity by 2 for Na2 for part a, I assumed we would multiply the molarity by 3 for Co32-, but the solution says otherwise.
by Ellison Gonzales 3F
Fri Oct 09, 2020 12:11 am
Forum: Administrative Questions and Class Announcements
Topic: Step Up Sessions
Replies: 71
Views: 4431

Re: Step Up Sessions

Hello! I am an incoming Freshman in the Chem 14A class. I took Honors Chem in 11th grade and AP Chem in 12th grade. Any recommendations on taking a step-up session? I know I'm not as rusty since I took the course recently, but I feel that having my second semester of Chem last year being very rushe...
by Ellison Gonzales 3F
Fri Oct 09, 2020 12:04 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E15
Replies: 6
Views: 70

Re: E15

Yes, thank you, Emily! Your reasoning helps me better understand this question.
by Ellison Gonzales 3F
Wed Oct 07, 2020 9:00 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E15
Replies: 6
Views: 70

Re: E15

This helps a lot thank you, but I was wondering how you knew to isolate M or what concept is used to know to subtract (OH)2
by Ellison Gonzales 3F
Wed Oct 07, 2020 12:49 am
Forum: Administrative Questions and Class Announcements
Topic: Step Up Sessions
Replies: 71
Views: 4431

Re: Step Up Sessions

Are “step up sessions”, “UA peer learning”, and a “UA session” all the same resource with just different names for the resource? I just want to clarify because I see a lot of similar terms for these sessions.
by Ellison Gonzales 3F
Wed Oct 07, 2020 12:18 am
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 58
Views: 6396

Re: Accessing the E-textbook [ENDORSED]

You said that you heard that the sapling questions were extra practice, and that is true that there are extra practice sections (math review, practice drawing molecules, and chemical equations training). Though like others mentioned, sapling also holds the questions that are required homework for th...

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