Search found 66 matches

by Hailey Kang 2K
Fri Jan 15, 2021 12:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Discussion section for Week 3
Replies: 2
Views: 22

Re: Discussion section for Week 3

Hi!

Discussion sections still take place unless yours is this coming Monday.
by Hailey Kang 2K
Thu Jan 14, 2021 12:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Using net ionic equations
Replies: 2
Views: 20

Re: Using net ionic equations

Hi!

I don't think we have to worry about that for this unit at least. One of the UAs went over it in their session, but it isn't super relevant for now.
by Hailey Kang 2K
Wed Jan 13, 2021 12:26 pm
Forum: Student Social/Study Group
Topic: Weekly Assignments
Replies: 5
Views: 25

Re: Weekly Assignments

The only things that are graded in this class are chem community, Sapling, and the exams! Everything else is just for your benefit.
by Hailey Kang 2K
Tue Jan 12, 2021 12:00 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 5I.7
Replies: 4
Views: 28

Re: 5I.7

Hi!
In terms of solving the problem, I would probably agree with the people that have already posted. But on a side note, #7 actually isn't in the list of problems he assigned us to do so we might not even be expected to know this exact problem!
by Hailey Kang 2K
Mon Jan 11, 2021 10:58 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Getting a negative during quadratic
Replies: 5
Views: 35

Re: Getting a negative during quadratic

Hi!

I would imagine that that was probably a calculation error. I think the numbers on sapling are different for everybody, but at least for mine, I didn't end up getting any negatives under the root!
by Hailey Kang 2K
Sun Jan 10, 2021 5:39 pm
Forum: General Science Questions
Topic: material
Replies: 4
Views: 21

Re: material

Hi!

I think Dr. Lavelle mentioned during lecture that not too many concepts from 14A would carry over. I've heard 14B has more calculations!
by Hailey Kang 2K
Thu Jan 07, 2021 12:42 pm
Forum: General Science Questions
Topic: mole vs. M
Replies: 16
Views: 99

Re: mole vs. M

Hi!

M refers to molarity which is the same thing as mol/L
by Hailey Kang 2K
Wed Jan 06, 2021 11:44 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Quadratic Equations
Replies: 7
Views: 28

Re: Quadratic Equations

Hi!

If you get 2 positive numbers, you should omit the one that is larger than any of the given initial conditions. Generally, you will use the smaller positive number.
by Hailey Kang 2K
Wed Jan 06, 2021 11:41 am
Forum: Administrative Questions and Class Announcements
Topic: Sapling access issue
Replies: 5
Views: 16

Re: Sapling access issue

Hi!

You need to access Sapling through CCLE in order for it to work. In terms of the code, if you purchased multi-term access, they should have sent you 2 codes (one that you can enter for this quarter).
by Hailey Kang 2K
Wed Jan 06, 2021 11:38 am
Forum: Administrative Questions and Class Announcements
Topic: Audio-Visual focus modules
Replies: 6
Views: 17

Re: Audio-Visual focus modules

Hi!

During 14A, they were only posted for the first unit. I'm assuming this it just because of time and because Dr. Lavelle is giving us a chance to get ahead before the quarter starts.
by Hailey Kang 2K
Tue Dec 15, 2020 10:32 am
Forum: Student Social/Study Group
Topic: Changing Study Habits
Replies: 35
Views: 166

Re: Changing Study Habits

Definitely something that worked for me this quarter was going to all the UA sessions, so that's one thing I will continue next quarter! Also like you said, utilizing the textbook and reading all the information there :)
by Hailey Kang 2K
Sat Dec 12, 2020 12:05 am
Forum: Amphoteric Compounds
Topic: Tricks for Determining
Replies: 5
Views: 65

Re: Tricks for Determining

Hi! A simple way to look at the trend is that metalloid band plus a few more atoms around it will form amphoteric compounds. If it's difficult to tell based on this, you will need to look at if it can accept as well as donate a proton.
by Hailey Kang 2K
Sat Dec 12, 2020 12:02 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: H20
Replies: 6
Views: 49

Re: H20

Hi! Only one of the lone pairs can bond to a central atom.
by Hailey Kang 2K
Fri Dec 11, 2020 11:46 pm
Forum: Electronegativity
Topic: Be vs Cl
Replies: 13
Views: 100

Re: Be vs Cl

Hi! Electronegativity increases up and to the right. Therefore, Cl will be higher. Also, electronegativity refers to the atom's tendency to attract electrons. Since Cl has 7 valence electrons, it really wants to attract one to complete its octet. This means electronegativity will be higher.
by Hailey Kang 2K
Fri Dec 11, 2020 11:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 6f orbital
Replies: 3
Views: 39

Re: 6f orbital

Hi!

This is possible because when the principle quantum number is n=6, all the l values can be 0-5. l=3 means the f subshell, which is where you would get the 6f.
by Hailey Kang 2K
Fri Dec 11, 2020 11:37 pm
Forum: Octet Exceptions
Topic: Octet Exceptions and Expanded Octet Calculation
Replies: 3
Views: 42

Re: Octet Exceptions and Expanded Octet Calculation

Hi!
The main elements we definitely have to know for this class are P, S, and Cl. Other than that, anything with a d-orbital can have an expanded valence.
by Hailey Kang 2K
Thu Dec 03, 2020 10:40 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Finding Coordination Number
Replies: 14
Views: 92

Re: Finding Coordination Number

The coordination number just refers to the number of points at which ligands are attached to the central metal atom!
by Hailey Kang 2K
Thu Dec 03, 2020 10:36 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelates and Polydentates
Replies: 2
Views: 17

Re: Chelates and Polydentates

Hi! Everything with polydentate ligands is considered a chelating compound.
by Hailey Kang 2K
Thu Dec 03, 2020 10:35 pm
Forum: Hybridization
Topic: pcl3
Replies: 8
Views: 48

Re: pcl3

The hybridization is sp3 because there are 4 regions of electron density (3 bonding pairs and 1 lone pair). 4 regions of electron density corresponds to sp3 hybridization.
by Hailey Kang 2K
Thu Dec 03, 2020 10:33 pm
Forum: Hybridization
Topic: 2.45 b Textbook problem
Replies: 3
Views: 38

Re: 2.45 b Textbook problem

Hi! The composition of the bonds would be the bond all together. So for example in this structure, there's a C single bonded to an H. The composition of this bond would be sigma(H1s, 2Csp2) because the carbon has 3 regions of electron density. The lone pair is strictly referring to that lone pair. S...
by Hailey Kang 2K
Thu Dec 03, 2020 10:29 pm
Forum: Naming
Topic: Sapling 9 #1
Replies: 7
Views: 39

Re: Sapling 9 #1

Hi!

The name of the compound should be pentaamminechlorocobalt(III) chloride.
by Hailey Kang 2K
Thu Dec 03, 2020 10:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Difference between electron geometry and molecular geometry
Replies: 5
Views: 19

Re: Difference between electron geometry and molecular geometry

Hi!

Electronic geometry takes into account all the bonding pairs as well as lone pairs on the central atom. molecular geometry only looks at the bonding pairs.
by Hailey Kang 2K
Sun Nov 29, 2020 7:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: sigma vs pi bonds
Replies: 33
Views: 184

Re: sigma vs pi bonds

Hi! Single bonds are always sigma bonds. Double bonds have 1 sigma and 1 pi, and triple bonds have 1 sigma and 2 pi
by Hailey Kang 2K
Sun Nov 29, 2020 7:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape
Replies: 12
Views: 62

Re: Molecular Shape

Hi! yes, lone pairs affect both electronic arrangement and molecular shape.
by Hailey Kang 2K
Tue Nov 24, 2020 5:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Scores
Replies: 9
Views: 95

Re: Midterm 2 Scores

abby hyman wrote:Does anyone know if there is any way to review the ones you missed on midterm 2?


If you email your TA or go to office hours, they can discuss the ones you missed!
by Hailey Kang 2K
Tue Nov 24, 2020 5:14 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Results
Replies: 10
Views: 108

Re: Midterm 2 Results

The scores have been posted on ccle!
by Hailey Kang 2K
Mon Nov 23, 2020 4:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Grades Chem 14A
Replies: 6
Views: 107

Re: Midterm 2 Grades Chem 14A

I heard that there is a possibility grades will be released tomorrow! Either way, he will send out an email when they are posted :)
by Hailey Kang 2K
Sun Nov 22, 2020 8:49 pm
Forum: Ionic & Covalent Bonds
Topic: Polar/ Nonpolar
Replies: 23
Views: 164

Re: Polar/ Nonpolar

Hi!

You can use shape as a good indicator as to whether a molecule is polar or nonpolar. I would say that you still need to check whether or not the dipole moments cancel, but shape is a good check as well.
by Hailey Kang 2K
Sun Nov 22, 2020 8:48 pm
Forum: Ionic & Covalent Bonds
Topic: Radicals
Replies: 10
Views: 89

Re: Radicals

Hi!

Any time there's an uneven number of electrons it's a radical, so as others have said I would assume it's an error on the textbook's part.
by Hailey Kang 2K
Sun Nov 22, 2020 8:46 pm
Forum: Lewis Structures
Topic: Electron Density
Replies: 14
Views: 115

Re: Electron Density

Hi!

Electron density refers to the probability that you will find an electron in that region.
by Hailey Kang 2K
Tue Nov 17, 2020 11:38 pm
Forum: Quantum Numbers and The H-Atom
Topic: n=6,l=5
Replies: 6
Views: 75

Re: n=6,l=5

Hi!

l=5 would be a valid answer. Your l value can be all the number leading up to n-1. so for example, if n=5, all your possible l values would be 0,1,2,3,4.
by Hailey Kang 2K
Tue Nov 17, 2020 11:36 pm
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 19
Views: 179

Re: Midterm 2

Hi!

Definitely going to as many UA sessions has been the most helpful for me. Other than that, the textbook problems/sections are very helpful.
by Hailey Kang 2K
Sat Nov 14, 2020 11:49 am
Forum: Resonance Structures
Topic: Delocalized Electrons
Replies: 7
Views: 25

Re: Delocalized Electrons

Hi!

Simply put, electrons that are delocalized are shared between atoms. Because resonance structures are a blend of all the possible lewis structures, this means that on a diagram, you can find these electrons in any position.
by Hailey Kang 2K
Sat Nov 14, 2020 11:47 am
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 31
Views: 296

Re: Midterm 2

Hi!

The midterm will cover the last 8 bullets of outline 2 as well as all of outline 3.
by Hailey Kang 2K
Sat Nov 14, 2020 11:46 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 9
Views: 55

Re: Polarizability

Hi! Basically,atoms or ions with electron clouds that readily undergo a large distortion are highly polarizable. Because of this principle, anions that are large can expect to be highly polarizable. This is because the anion is so large, that the nucleus only has weak control over its outermost elec...
by Hailey Kang 2K
Sat Nov 14, 2020 11:42 am
Forum: Trends in The Periodic Table
Topic: N 3- vs S 2-
Replies: 4
Views: 41

Re: N 3- vs S 2-

Hi!

I don't think it has a huge affect so I believe nitrogen will still be smaller.
by Hailey Kang 2K
Sat Nov 14, 2020 11:41 am
Forum: Dipole Moments
Topic: Textbook discrepancy
Replies: 6
Views: 45

Re: Textbook discrepancy

Hi! I was wondering this also. The textbook did mention that the arrow pointing towards the partial positive atom is a modern notation, and the arrow pointing towards the partial negative atom is older. Since the example he did in class has it pointing towards the partial negative atom, I would go w...
by Hailey Kang 2K
Sat Nov 14, 2020 11:38 am
Forum: Dipole Moments
Topic: H-Bonds
Replies: 14
Views: 107

Re: H-Bonds

Hi!

Hydrogen bonds occur between atoms with lone pairs, but they also can only bond with Nitrogen, Oxygen and Fluorine
by Hailey Kang 2K
Wed Nov 11, 2020 11:56 pm
Forum: Dipole Moments
Topic: Polar covalent bonds
Replies: 5
Views: 18

Re: Polar covalent bonds

Hi!

The difference between the two is that a dipole-dipole attraction is the force between molecules, while the polar covalent is in between atoms.
by Hailey Kang 2K
Wed Nov 11, 2020 11:53 pm
Forum: Bond Lengths & Energies
Topic: 2D #13
Replies: 2
Views: 29

Re: 2D #13

Hi! How I solved it was I drew out the Lewis structures for all of them and looked at the different bonds. For multiple bonds (double & triple bonds), they are going to be "shorter and stronger".So for example, in part a, CO has a triple bond, so it will be the strongest. I will attach...
by Hailey Kang 2K
Sun Nov 08, 2020 11:37 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Identify these type if problems
Replies: 4
Views: 21

Re: Identify these type if problems

Hi!

Normally when the question is asking for the most stable structure, you are going to want to find the formal charge.
by Hailey Kang 2K
Fri Nov 06, 2020 11:33 pm
Forum: Student Social/Study Group
Topic: Making it through Midterm Results
Replies: 13
Views: 140

Re: Making it through Midterm Results

Hi!

One of the things that probably helped me the most was definitely attending as many UA sessions as possible. The worksheets are super helpful, but also a lot of people will ask questions that you didn't even think up but end up being super important. Textbook problems were very helpful as well!
by Hailey Kang 2K
Fri Nov 06, 2020 1:58 am
Forum: Formal Charge and Oxidation Numbers
Topic: Shortcut for Formal Charge
Replies: 19
Views: 583

Re: Shortcut for Formal Charge

Hi!

I would say the easiest way to remember it is # of valence electrons- # of lines & dots around that element
by Hailey Kang 2K
Wed Nov 04, 2020 11:35 pm
Forum: Ionic & Covalent Bonds
Topic: Learning Outline 3
Replies: 6
Views: 67

Re: Learning Outline 3

Hi!

I would definitely recommend going to the UA sessions. They have really helpful worksheets and give very detailed and helpful explanations for everything!
by Hailey Kang 2K
Wed Nov 04, 2020 11:32 pm
Forum: Quantum Numbers and The H-Atom
Topic: Are there subshells past f?
Replies: 28
Views: 166

Re: Are there subshells past f?

Hi!

Dr. Lavelle said there are subshells past f but the only ones we need to worry about for this class are s,p,d,f.
by Hailey Kang 2K
Tue Nov 03, 2020 12:23 am
Forum: Trends in The Periodic Table
Topic: # of electrons
Replies: 23
Views: 118

Re: # of electrons

Hi!

The total number of electrons is equal to the atomic number.
by Hailey Kang 2K
Thu Oct 29, 2020 10:19 am
Forum: DeBroglie Equation
Topic: p
Replies: 19
Views: 155

Re: p

P represent momentum! The equation to find momentum is p=(mass)(velocity).Also remember to convert to SI units!
by Hailey Kang 2K
Thu Oct 29, 2020 10:17 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: position units
Replies: 19
Views: 112

Re: position units

Hi!

While you're solving the problem, you should always convert to meters since it is an SI unit. Sometimes the question will ask for the wavelength in other units like nm, but that should only be converted at the very end.
by Hailey Kang 2K
Thu Oct 29, 2020 10:15 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg's
Replies: 7
Views: 56

Re: Rydberg's

Hi!

The Rydberg's equation only work for for Hydrogen atoms and other single electron atoms.
by Hailey Kang 2K
Wed Oct 28, 2020 1:38 am
Forum: Einstein Equation
Topic: Work Function and Energy of Photons
Replies: 4
Views: 49

Re: Work Function and Energy of Photons

Hi!

If the kinetic energy is equal to 0, you would set hv equal to the work function. This is because in order to remove an electron from the surface, the energy of the photon must be at least equal to or greater to the work function.
by Hailey Kang 2K
Tue Oct 27, 2020 1:12 am
Forum: Administrative Questions and Class Announcements
Topic: how far in the sapling hw does midterm 1 go to
Replies: 5
Views: 71

Re: how far in the sapling hw does midterm 1 go to

Hi!

Sapling randomized the homework questions so it's hard to tell which is which. Dr. Lavelle said we definitely need to know 19 of them, so I just picked out the 19 questions with topics that we have learned.
by Hailey Kang 2K
Sat Oct 24, 2020 6:00 pm
Forum: Properties of Light
Topic: Constants
Replies: 21
Views: 106

Re: Constants

Hi!

For the midterm, I would recommend using exactly what is on the constants and equations sheet. Since the test is multiple choice, I'm sure all the answers will be rounded, but you will get a more accurate answer that way.
by Hailey Kang 2K
Thu Oct 22, 2020 12:07 am
Forum: Properties of Light
Topic: Frequency and Wavelength on Light Spectrum
Replies: 5
Views: 58

Re: Frequency and Wavelength on Light Spectrum

Hi!
I would definitely memorize some of the wavelengths such as:

Balmer series (visible light): 700nm-400nm
Lyman series (Uv region): less than 400nm
Infrared region: greater than 800nm
by Hailey Kang 2K
Tue Oct 20, 2020 11:51 pm
Forum: Einstein Equation
Topic: HW problem 5
Replies: 6
Views: 86

Re: HW problem 5

Hi!

The first thing you need to do is calculate the energy with the equation E=hc/lambda. Then, because it is asking for the photons required to absorb a specific energy, you will do the given energy divided by what you just solved.
by Hailey Kang 2K
Mon Oct 19, 2020 10:45 pm
Forum: Properties of Light
Topic: Sapling Week 2-4 Homework Question #4
Replies: 3
Views: 48

Re: Sapling Week 2-4 Homework Question #4

Hello! The first thing you need to do is solve for the energy of one photon, which you can do through the equation E=hc/λ. After that, you divide the given energy by the one that you found and that should give you the correct answer. I think everybody's numbers are different but I can attach my work...
by Hailey Kang 2K
Sun Oct 18, 2020 4:17 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Textbook Example 1B.5
Replies: 1
Views: 18

Textbook Example 1B.5

Hello! I'm going through this textbook example Screen Shot 2020-10-18 at 4.10.47 PM.png Screen Shot 2020-10-18 at 4.10.47 PM.png In the explanation, it says that the uncertainty in the speed is 2(1.0e-3m/s) and I was wondering where the 2 is coming from, or why you would multiply that by 2. Thank you!
by Hailey Kang 2K
Fri Oct 16, 2020 7:38 pm
Forum: Properties of Light
Topic: Balmer and Lyman series
Replies: 7
Views: 56

Re: Balmer and Lyman series

Hi!
In the Balmer series, the excited electron will go to level 1 (n1), and in Lyman it will go to n2. One way you can figure out which series it is is by looking at the wavelength. The Balmer series will be the visible region (700nm- 400nm) and the Lyman will be the UV region (less than 400nm)
by Hailey Kang 2K
Thu Oct 15, 2020 9:04 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Determining Electron Energy Levels When Given Wavelength
Replies: 2
Views: 30

Re: Determining Electron Energy Levels When Given Wavelength

Hi! In general, the visible light range is 700nm-400nm. Because the red light is 656.3nm, we can infer that it is within the visible region. According to the Balmer series, the starting level for visible light is n=2. This means in the Rydberg equation, n1 will be equal to 2, and then you can use th...
by Hailey Kang 2K
Wed Oct 14, 2020 7:17 pm
Forum: Properties of Light
Topic: Example 1 in Wk 2 Lec 2
Replies: 3
Views: 21

Re: Example 1 in Wk 2 Lec 2

IMG_0053.jpg


hope this helps!
by Hailey Kang 2K
Tue Oct 13, 2020 11:12 am
Forum: Empirical & Molecular Formulas
Topic: Empirical or Molecular
Replies: 11
Views: 110

Re: Empirical or Molecular

Hi! When you are asked to find the molecular formula, the molar mass of the compound will be given (which is found through mass spectrometry). You need to calculate the molar mass of the empirical formula, and divide the given molar mass by the one you found. If they do not equal each other, you kno...
by Hailey Kang 2K
Tue Oct 13, 2020 11:08 am
Forum: SI Units, Unit Conversions
Topic: Avogadro's Constant
Replies: 12
Views: 105

Re: Avogadro's Constant

Hi! Avogadro's number (6.022e23) basically represents the number of "things" (molecules, atoms, compounds) per mole of a certain substance. The explanation from the textbook says, "exactly 12 g of carbon-12 corresponds to exactly 1 mol of carbon-12 atoms.", so essential there are...
by Hailey Kang 2K
Fri Oct 09, 2020 4:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 228
Views: 117561

Re: Advice from a Medical Student [ENDORSED]

Hello!

Thank you so much for this! I'm not sure if this was already asked, but how long would you say you studied for the MCAT before taking it?

Thank you!
by Hailey Kang 2K
Thu Oct 08, 2020 11:33 pm
Forum: Balancing Chemical Reactions
Topic: How moles should be balanced on each side
Replies: 11
Views: 64

Re: How moles should be balanced on each side

Hi! When balancing an equation you have to look at the total number of the individual moles. Each side of the equation does not necessarily have to have the same coefficients. In this example, you have 2 Na on each side, 4 H on each side, and 2 O on each side. This means the equation is balanced. Ho...
by Hailey Kang 2K
Wed Oct 07, 2020 6:15 pm
Forum: Molarity, Solutions, Dilutions
Topic: Audio Visual Modules
Replies: 4
Views: 51

Re: Audio Visual Modules

Hi!

He said that they should all be completed before week 2, and he also said that we should finish the fundamentals by the end of week 1.
by Hailey Kang 2K
Tue Oct 06, 2020 9:09 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Mass of A Product Procued? (Q#22 Post Assessment LR)
Replies: 5
Views: 49

Re: Mass of A Product Procued? (Q#22 Post Assessment LR)

Hi!! When it says AgCl precipitates out, it essentially just means that it is a product of the reaction. To find the mass, you first balance the equation, and then find the molar mass of C6H9Cl3, AgNO3, and AgCl using the ratios found in the balanced equation. Then you divide each of the given masse...
by Hailey Kang 2K
Mon Oct 05, 2020 1:24 pm
Forum: Limiting Reactant Calculations
Topic: Sapling Homework Question 10
Replies: 16
Views: 239

Sapling Homework Question 10

I was wondering if someone could help me with the Week 1 Sapling homework question 10.
Screen Shot 2020-10-05 at 1.21.52 PM.png


I'm unsure of how to start it off.
Thank you!

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