## Search found 62 matches

Sun Jan 17, 2021 10:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Week 1 Sapling #10
Replies: 6
Views: 41

### Re: Week 1 Sapling #10

I also can't figure out the second part of this problem! I can't seem to figure out what I'm doing wrong.
Sun Jan 17, 2021 10:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #10
Replies: 4
Views: 16

### Sapling #10

I'm having a hard time with the last part of this problem: Calculate the equilibrium concentrations of N2O4 and NO2 after the extra 1.00 mol NO2 is added to 1.00 L of solution. [N2O4]= [NO2]= The Kc that I calculated is 11.2. I think my problem is solving for x. I set the equation up: [NO2]^2 / [N2O...
Sun Jan 17, 2021 6:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #4
Replies: 6
Views: 41

### Sapling #4

Hi! I'm having trouble solving this problem and keep getting the wrong answer. At a certain temperature, the given reaction has an equilibrium constant of Kp=359 . PCl3(g)+Cl2(g)↽−−⇀PCl5(g) PCl5 is placed in a sealed container at an initial pressure of 0.0370 bar . What is the total pressure at equi...
Sat Jan 16, 2021 11:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling HW #2
Replies: 6
Views: 42

### Re: Sapling HW #2

Mitzy Garcia 1k wrote:Yes, use the ICE table. I converted the units for SO3 and O2. I did this by using mol and L to equal to M. I hope that helps.

This is very helpful!! Thank you (:
Sat Jan 16, 2021 9:36 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Using the ICE table
Replies: 32
Views: 77

### Re: Using the ICE table

I believe you would be able to use the ICE table for both concentration and partial pressures! This is a great tool to keep everything organized.
Sat Jan 16, 2021 9:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling HW #2
Replies: 6
Views: 42

### Sapling HW #2

At a certain temperature, 0.860 mol SO3 is placed in a 4.00 L container.

2SO3(g)↽−−⇀2SO2(g)+O2(g)

At equilibrium, 0.180 mol O2 is present. Calculate Kc.

I'm having a little bit of trouble for this question. Would I just start by creating an ICE table?
Sat Jan 16, 2021 9:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Calculator for exams
Replies: 22
Views: 62

### Re: Calculator for exams

Last quarter, my TA said we were fine using any calculator, so I'm assuming it's the same this quarter.
Wed Jan 13, 2021 9:16 pm
Forum: Administrative Questions and Class Announcements
Topic: What units will be in Midterm 1?
Replies: 6
Views: 36

### Re: What units will be in Midterm 1?

I believe it should be Units 1, 2 and maybe some of 3.
Tue Jan 05, 2021 9:01 pm
Forum: Student Social/Study Group
Topic: Learning Sessions
Replies: 24
Views: 118

### Re: Learning Sessions

It really depends on what you prefer! Last quarter I attended more sessions before/during midterms or finals week to prepare. That helped a lot for review and practice.
Wed Dec 16, 2020 2:29 pm
Forum: Student Social/Study Group
Topic: Changing Study Habits
Replies: 35
Views: 166

### Re: Changing Study Habits

Attending the UA sessions were really helpful! I would say going to as many of those as you can and also completing textbook problems because the exam questions are very similar to the homework. Also! I found watching videos from Organic Chemistry Tutor really helpful as well! Hope this helps.
Wed Dec 16, 2020 2:25 pm
Forum: Lewis Acids & Bases
Topic: Acids & Bases
Replies: 9
Views: 72

### Re: Acids & Bases

For me, I go off the name of the compound. Acids usually have a H at the beginning of the name, so I typically identify the acids first and then go off from there.
Wed Dec 16, 2020 12:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: What are the bond angles for T shaped?
Replies: 17
Views: 115

### Re: What are the bond angles for T shaped?

Bond angles for T shapes are a little less than or equal to 90 degrees!
Wed Dec 16, 2020 11:54 am
Forum: *Titrations & Titration Calculations
Topic: Is this a 14B topic? [ENDORSED]
Replies: 8
Views: 78

### Re: Is this a 14B topic?[ENDORSED]

In Dr.Lavelle's lectures, I remember him mentioning that we'll be going further into acids and bases in Chem 14B.
Wed Dec 16, 2020 11:52 am
Forum: Student Social/Study Group
Replies: 29
Views: 197

Grades should be out Saturday! And I believe that you have until 10am Thursday now to get 50 chem community posts.
Fri Dec 11, 2020 8:53 pm
Forum: Student Social/Study Group
Topic: Studying
Replies: 13
Views: 92

### Re: Studying

I've been referring to Organic Chemistry Tutor and they've really helped me improve a lot!!
Fri Dec 11, 2020 8:49 pm
Forum: Student Social/Study Group
Topic: Struggling on topics
Replies: 6
Views: 47

### Re: Struggling on topics

If there's a topic I'm struggling on, I like to do practice problems (or hw problems) until I'm confident that I know what I'm doing. Organic Chemistry Tutor on YouTube is also a great resource!
Fri Dec 11, 2020 8:46 pm
Forum: General Science Questions
Topic: What time is the final?
Replies: 5
Views: 36

### Re: What time is the final?

If you're international, there's also a time for 8pm - 9:30pm.
Sun Dec 06, 2020 1:19 am
Forum: Student Social/Study Group
Topic: Studying for Final Exam
Replies: 57
Views: 351

### Re: Studying for Final Exam

I'm going to be going through the textbook problems and also attending the UA zoom sessions, as doing that has worked best so far in improving my grade.
Wed Dec 02, 2020 10:05 pm
Forum: General Science Questions
Replies: 32
Views: 349

I'm honestly curious about this as well! As far as I know, and like everyone else has said, 50% is needed to pass with a C. I think the most important thing is to get enough points as you can.
Sun Nov 29, 2020 10:38 pm
Forum: Ionic & Covalent Bonds
Topic: Lewis structure
Replies: 10
Views: 82

### Re: Lewis structure

Hi! What has worked for me is referring to my periodic table. I know that elements that are closer to each other on the periodic table are ionic and elements further away are covalent. Hope this helps!
Sun Nov 29, 2020 10:36 pm
Forum: Sigma & Pi Bonds
Topic: sapling #15
Replies: 24
Views: 136

### Re: sapling #15

I determine how many sigma and pi bonds are in a molecule based on the structure! There is one sigma bond present in every double bond and single bond while pi bonds are found in double and triple bonds. For instance, if there was a triple bond, there would be one sigma bond and two pi bonds. I hope...
Sun Nov 29, 2020 10:33 pm
Forum: Student Social/Study Group
Topic: studying for exams
Replies: 21
Views: 250

### Re: studying for exams

For me, I review sapling and also do the textbook problems as practice. Because Dr. Lavelle takes textbook problems for the test, I find this really helpful since the questions are similar. This helped me do a lot better on the second midterm.
Fri Nov 27, 2020 11:13 pm
Forum: Student Social/Study Group
Topic: Sampling Give Up Option
Replies: 12
Views: 95

### Re: Sampling Give Up Option

Sapling is set up so that if you give up on a question, it makes you lose points. Try doing as many attempts as you can because you get an unlimited number of attempts!
Fri Nov 27, 2020 10:57 pm
Forum: Administrative Questions and Class Announcements
Topic: Outlines for the Final
Replies: 11
Views: 102

### Re: Outlines for the Final

I believe they will be covered before the final since we'll be examined on all of the material.
Sun Nov 22, 2020 6:52 pm
Forum: Student Social/Study Group
Replies: 86
Views: 856

### Re: Big Sad: Midterm 2

I felt the same way the first midterm so I totally understand. Just remember that there are a lot of points you can earn in addition to the midterm! Rooting for you (:
Sun Nov 22, 2020 6:51 pm
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 9
Views: 77

### Re: Midterm 2

I'm assuming they will come out later this week. (:
Wed Nov 18, 2020 11:21 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing Power vs Polarizability
Replies: 4
Views: 51

### Polarizing Power vs Polarizability

Hello! I was completing the text book problems and got a bit confused when asked to arrange cations from increasing polarizing power and anions from increasing polarizability. I mixed the two up at first. What is the difference between polarizing power and polarizability?

Thank you!
Tue Nov 17, 2020 2:02 pm
Forum: Student Social/Study Group
Topic: Midterm Studying
Replies: 3
Views: 52

### Midterm Studying

In preparation for the midterm, should we be focusing on textbook problems 1D, 1E, 1F and all of outline 3 textbook problems?
Mon Nov 16, 2020 10:07 pm
Forum: Quantum Numbers and The H-Atom
Topic: Textbook Problem 1D.23
Replies: 3
Views: 46

### Re: Textbook Problem 1D.23

Hi! It's true that the 4d subshell has 5 orbitals (-2, -1, 0, +1, +2). However, this information only fits with n = 4 and l = 2. The question adds on that the magnetic quantum number must be -2. This refers to only one of the 5 orbitals (the one marked -2), so the answer is one orbital (only one or...
Mon Nov 16, 2020 10:05 pm
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 31
Views: 296

### Re: Midterm 2

Jasmine Yi 1H wrote:
cady_tran_2G wrote:I believe so! I might be wrong but I think Midterm 2 should cover the last of outline 2 and some of outline 3.

does this mean that Midterm2 doesn't cover all of outline 3?

It covers up to the lecture we had on 11/11.
Mon Nov 16, 2020 10:00 pm
Forum: Quantum Numbers and The H-Atom
Topic: Textbook Problem 1D.23
Replies: 3
Views: 46

### Textbook Problem 1D.23

How many orbitals can have the following quantum numbers in an atom: (b) n=4, l=2, $m_{l}$ = -2

Hi! I'm studying for the midterm and I'm confused as to why when:
n = 4,
l = 2,
$m_{l}$ = -2

The number of orbitals is 1. Shouldn't it be 5 orbitals because the atom is at the 4d state?
Sat Nov 14, 2020 10:54 pm
Forum: Student Social/Study Group
Replies: 110
Views: 1160

I have the same concerns as you did since I didn't do as well as I would have hoped for the first midterm. Hopefully the next midterm and final makes up for it!
Sat Nov 14, 2020 7:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 3d Exceptions
Replies: 3
Views: 35

### Re: 3d Exceptions

I agree with Audrey. This is a really good video that helped me understand this electron configuration exceptions: https://youtu.be/Ur2PuzJ7KWs

Hope this helps!
Sat Nov 14, 2020 7:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2: Lectures
Replies: 5
Views: 66

### Re: Midterm 2: Lectures

I believe that Wednesday was the last lecture that covers material on the midterm. Just note that for midterm 2, it's going to cover the last 8 points of outline 2 and all of outline 3!
Thu Nov 12, 2020 9:38 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm 2
Replies: 6
Views: 79

### Re: Midterm 2

Midterm 2 should cover the last 8 points on outline 2 and everything in outline 3.
Mon Nov 09, 2020 11:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14B and Chem 14BL
Replies: 10
Views: 106

### Re: Chem 14B and Chem 14BL

I'm also considering taking 14B and 14BL together but it honestly depends on what you prefer. I feel like it would be a good to take them during winter quarter, but you also have to consider how many classes you plan to take overall and if this is going to significantly affect your workload. I hope ...
Fri Nov 06, 2020 7:46 pm
Forum: Student Social/Study Group
Topic: Blind sided by Midterm 1 memorization questions, How to study for memorization questions
Replies: 11
Views: 117

### Re: Blind sided by Midterm 1 memorization questions, How to study for memorization questions

Like everyone said previously, writing things down helps me memorize things but also going through Quizlet flashcards really helps as well!
Fri Nov 06, 2020 7:43 pm
Forum: Ionic & Covalent Bonds
Topic: Homework due date
Replies: 49
Views: 336

### Re: Homework due date

This week's homework is due on Sunday of week 6. (:
Tue Nov 03, 2020 7:42 pm
Forum: Lewis Structures
Topic: Octet/Double Bonds when drawing Lewis Structure
Replies: 3
Views: 43

### Octet/Double Bonds when drawing Lewis Structure

Hello! I might have missed this in the lecture, but when you're drawing a Lewis Structure, how do you identify whether or not an element is octet?
Mon Nov 02, 2020 1:47 pm
Forum: Administrative Questions and Class Announcements
Topic: Fundamentals for Midterm 2
Replies: 5
Views: 48

### Re: Fundamentals for Midterm 2

Dr. Lavelle hasn't specified yet, but I'm assuming the last bullets of outline 2 and some of outline 3. Hope this helps!
Mon Nov 02, 2020 1:44 pm
Forum: Student Social/Study Group
Topic: Midterm 2
Replies: 31
Views: 296

### Re: Midterm 2

I believe so! I might be wrong but I think Midterm 2 should cover the last of outline 2 and some of outline 3.
Fri Oct 30, 2020 11:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Sapling Access Code
Replies: 5
Views: 62

### Re: Sapling Access Code

I know a few people have had this problem and they've all emailed the UCLA store, as Tianjian suggested. I think that would be the best solution to get your code ASAP.
Fri Oct 30, 2020 11:47 pm
Forum: Properties of Light
Topic: How to remember what v is in equations
Replies: 46
Views: 257

### Re: How to remember what v is in equations

When I refer to velocity, I know that it is the standard, "v" but when I'm doing an equation that involves frequency, I know that the font for "v" is different.
Fri Oct 30, 2020 11:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Exam Scores
Replies: 15
Views: 114

### Re: Midterm Exam Scores

I'm also unsure! But as everyone has said, there was an error so I'm sure the TA's will have them all reviewed by the upcoming week or so. Hopefully soon!
Wed Oct 28, 2020 8:07 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect post module
Replies: 4
Views: 59

### Photoelectric Effect post module

Hi! I'm a bit lost on how to solve problem 31) on the post assessment. The problem is:

A. If 3.607 x 10-19 J is required to remove an electron with zero kinetic energy from a metal surface, what would be the longest wavelength light that could do this?
Mon Oct 26, 2020 11:04 pm
Forum: DeBroglie Equation
Topic: De Broglie wavelength
Replies: 3
Views: 20

### Re: De Broglie wavelength

Hi! I agree with Justin. From the previous lectures, Dr. Lavelle mentioned that anything after 10^-15 would be observable. Anything under that would not be. Hope this helps!
Fri Oct 23, 2020 10:30 pm
Forum: General Science Questions
Topic: Practice problems for midterm
Replies: 3
Views: 40

### Re: Practice problems for midterm

My TA said that the midterm is probably going to be similar to the post module assessments and that doing the assessments up to quantum world would be a great tool for studying. Hope this helps!
Fri Oct 23, 2020 10:27 pm
Forum: Properties of Electrons
Topic: Rydberg
Replies: 10
Views: 83

### Re: Rydberg

I think nf and ni is the same as n1 and n2, but to be safe, I would also stick to using n1 and n2.
Thu Oct 22, 2020 8:47 am
Forum: Einstein Equation
Topic: Sapling
Replies: 2
Views: 48

### Sapling

Hi! The question is: When a metal was exposed to photons at a frequency of 1.00×1015 s−1, electrons were emitted with a maximum kinetic energy of 3.90×10^−19 J. Calculate the work function, Φ, of this metal. What is the maximum number of electrons that could be ejected from this metal by a burst of ...
Wed Oct 21, 2020 11:31 pm
Forum: Properties of Electrons
Topic: intensity vs energy
Replies: 29
Views: 239

### Re: intensity vs energy

Like everyone said, this is false. I was confused about this too, but from what I gathered, a higher intensity doesn't increase the energy, it just increases the number of photons. The photoelectric effects states that if the energy of the photon is greater or equal to the energy to remove an electr...
Mon Oct 19, 2020 7:38 pm
Forum: SI Units, Unit Conversions
Topic: SI units
Replies: 9
Views: 46

### Re: SI units

Hi! You should use meters because when you calculate the equations, the units will cancel out so you're left with meters. If the question asks you for the answer in nm, you would then convert m to nm.
Fri Oct 16, 2020 4:59 pm
Forum: Einstein Equation
Topic: m vs nm
Replies: 66
Views: 433

### Re: m vs nm

It definitely depends on the question, but if it doesn't specifically state what units to use, I think it would be okay to stick with meters.
Thu Oct 15, 2020 7:40 am
Forum: Photoelectric Effect
Topic: Frequency vs. Intensity
Replies: 16
Views: 131

### Frequency vs. Intensity

Hi! In the lecture, Dr. Lavelle mentioned that high intensity light would not emit electrons, but higher frequency light would. What's the difference between frequency and intensity?
Wed Oct 14, 2020 8:08 pm
Forum: Photoelectric Effect
Topic: Electron not emitted even for high intensity light
Replies: 9
Views: 92

### Re: Electron not emitted even for high intensity light

Hi! I'm not sure if this will be much help, but in my notes I wrote that even though there is high intensity light, the energy of the light has to be equal to or larger than the energy to remove in order for the electrons to be emitted. Also, if the intensity increases, the number of photons double....
Tue Oct 13, 2020 7:59 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Textbook Homework E9
Replies: 6
Views: 105

### Re: Textbook Homework E9

Hi! Like the previous reply, we're going to be tested on content and I remember Dr. Lavelle mentioning we'd be provided with compounds on a test.
Tue Oct 13, 2020 7:52 pm
Forum: SI Units, Unit Conversions
Topic: How to Show Your Work
Replies: 16
Views: 144

### Re: How to Show Your Work

Hello! I know my TA mentioned that it would be better to show your work and be as precise as possible. Even though it's not required, it's always best to do so.
Fri Oct 09, 2020 7:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Exam Regulations
Replies: 7
Views: 64

### Re: Exam Regulations

I remember seeing on the syllabus that everything would be closed book.
Fri Oct 09, 2020 7:15 pm
Forum: Limiting Reactant Calculations
Topic: Week 1 Sapling Q. 10
Replies: 5
Views: 95

### Re: Week 1 Sapling Q. 10

What I did was I determined the molecular formulas by counting up the number of carbon and hydrogens. This is a really good reference video if you can't remember: https://youtu.be/FbaXQ8u6IP8

From there, I calculated the molar mass.
Wed Oct 07, 2020 7:04 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: HW Problem E.9
Replies: 7
Views: 91

### Re: HW Problem E.9

Hi Cady! You can look at the periodic table to see that the ion of Mg has a charge of +2 because of its 2 valence electrons, and the polyatomic ion sulfate is SO4 with a charge of -2. This means that MgSO4 is magnesium sulfate. Magnesium sulfate heptahydrate is MgSO4 plus 7H2O because hydrate repre...
Wed Oct 07, 2020 5:19 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: HW Problem E.9
Replies: 7
Views: 91

### HW Problem E.9

Epsom salts consist of magnesium sulfate heptahydrate. Write its formula. (a) How many atoms of oxygen are in 5.15 g of Epsom salts? (b) How many formula units of the compound are present in 5.15 g? (c) How many moles of water molecules are in 5.15 g of Epsom salts? In order to start the problem, I ...
Tue Oct 06, 2020 5:57 pm
Forum: Administrative Questions and Class Announcements
Topic: Posting during the weekends
Replies: 7
Views: 63

### Re: Posting during the weekends

I interpret that by having until Sunday to post but I'm not really sure!
Tue Oct 06, 2020 5:56 pm
Forum: Molarity, Solutions, Dilutions
Topic: G.19
Replies: 3
Views: 22

### Re: G.19

For this problem, I would start by creating an equation: (1.345 mol/1000 mL) = (x mol/12.56 mL). "x" should give you the amount of moles in the 12.56 mL that has just been taken out. Once you've done that, you just divide the amount of moles you got by 250.0 mL since that is the volume tha...