Search found 100 matches

by Stacey Phan 2I
Mon Feb 22, 2021 8:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sig Figs
Replies: 5
Views: 19

Sig Figs

Does K contribute to sig figs in equilibrium?
by Stacey Phan 2I
Thu Feb 18, 2021 1:57 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Solids and Liquids?
Replies: 18
Views: 47

Solids and Liquids?

For Le Chatlier, changing the amount of gases and aqueous components affects the reaction but not solids or liquids?
by Stacey Phan 2I
Tue Feb 16, 2021 8:41 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: What does the d in dq mean
Replies: 3
Views: 23

What does the d in dq mean

I am confused what the d in dq means? Does it just mean change like final minus initial?
by Stacey Phan 2I
Tue Feb 16, 2021 2:25 am
Forum: Calculating Work of Expansion
Topic: work and vacuum
Replies: 2
Views: 12

work and vacuum

why is there no work done when there is a vacuum?
by Stacey Phan 2I
Tue Feb 16, 2021 1:28 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: How to solve for q at constant volume?
Replies: 3
Views: 34

Re: How to solve for q at constant volume?

In the textbook, there was a question asking us to solve for q at constant volume of an ideal gas. To do this, you just use q(v) = nC(v)ΔT, using C(v)=(3/2)R, which is the heat capacity of an ideal gas at constant volume. C(v) is given on the equation sheet. To solve for q at constant pressure, do ...
by Stacey Phan 2I
Tue Feb 16, 2021 1:27 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Residual Entropy
Replies: 2
Views: 18

Residual Entropy

If residual entropy ignores thermal entropy, does it only happen at low temperatures or just as T approaches 0?
by Stacey Phan 2I
Mon Feb 15, 2021 8:06 pm
Forum: Calculating Work of Expansion
Topic: Work and Delta V
Replies: 13
Views: 41

Work and Delta V

Can someone confirm that work depends on delta V?
If volume is constant, delta V=0 so work =0?
by Stacey Phan 2I
Mon Feb 15, 2021 8:04 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: How to solve for q at constant volume?
Replies: 3
Views: 34

How to solve for q at constant volume?

I am watching lecture 02/01 and I know that q at constant pressure is delta H but how do you solve for q at constant volume?
by Stacey Phan 2I
Wed Feb 10, 2021 8:14 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook Problem 4.15
Replies: 2
Views: 14

Textbook Problem 4.15

I checked the solutions manual and I saw that there was +2(-167.16 kJ/mol) in the explanation. However, there were only two molecules that were able to be used in the equation and that was the third one. Is this a typo?
by Stacey Phan 2I
Wed Feb 10, 2021 8:11 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: ΔG° vs ΔG
Replies: 20
Views: 63

Re: ΔG° vs ΔG

ΔG° represents Gibbs free energy at standard conditions while ΔG represents Gibbs free energy at any condition.
by Stacey Phan 2I
Wed Feb 10, 2021 8:09 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy
Replies: 5
Views: 17

Re: Gibbs Free Energy

G represents Gibbs free energy.
by Stacey Phan 2I
Wed Feb 10, 2021 8:08 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Thermo Equilibrium
Replies: 4
Views: 21

Re: Thermo Equilibrium

Thermo equilibrium occurs when the temperature of the system is equivalent to the temperature of the surroundings.
by Stacey Phan 2I
Wed Feb 10, 2021 8:07 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: specific/molar heat capacity, intensive property
Replies: 2
Views: 8

Re: specific/molar heat capacity, intensive property

Extensive properties are properties that depend on the amount of substance such as mass. Heat capacities do not depend on the amount of the substance, they are a fixed amount of kJ per mol.
by Stacey Phan 2I
Wed Feb 10, 2021 8:06 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook Problem 4D.15
Replies: 3
Views: 12

Re: Textbook Problem 4D.15

Check the solutions manual! It usually has the explanations along with the answer.
by Stacey Phan 2I
Sun Feb 07, 2021 11:49 pm
Forum: Administrative Questions and Class Announcements
Topic: CC points, where to find?
Replies: 12
Views: 54

Re: CC points, where to find?

If you hit quick links on the top left the first link says your posts and it should say how many posts you have. If this is your first quarter having Lavelle then the number of posts is the points you have. If this is your second quarter having Lavelle (assuming you hit 50 posts for Chem 14A), subtr...
by Stacey Phan 2I
Fri Feb 05, 2021 3:55 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Lecture 02/05
Replies: 2
Views: 37

Lecture 02/05

Does anyone know what sections (Focus Topics on Sapling) we should have covered on outline 4 yet up to today's lecture?
by Stacey Phan 2I
Thu Feb 04, 2021 9:34 pm
Forum: Phase Changes & Related Calculations
Topic: Sapling week 3 and 4 #10
Replies: 3
Views: 31

Sapling week 3 and 4 #10

Does anyone know how to do this? An ice cube with a mass of 47.8 g at 0.0 ∘C is added to a glass containing 3.60×102 gof water at 45.0 ∘C. Determine the final temperature of the system at equilibrium. The specific heat capacity of water, Cs, is 4.184 J/g⋅∘C, and the standard enthalpy of fusion, ΔH∘f...
by Stacey Phan 2I
Thu Feb 04, 2021 4:44 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Adiabatic and Diathermic Walls
Replies: 3
Views: 23

Adiabatic and Diathermic Walls

I was reading the textbook and looking at the outline. I don't see adiabatic and diathermic walls listed on the bullet points. Will we be required to memorize adiabatic and diathermic definitions?
by Stacey Phan 2I
Wed Feb 03, 2021 5:19 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Units
Replies: 11
Views: 52

Re: Units

I would do it based on the problem but as long as you convert to the correct unit, C and K can be used interchangeably.
by Stacey Phan 2I
Sat Jan 30, 2021 12:39 pm
Forum: Administrative Questions and Class Announcements
Topic: 14BL and CL
Replies: 13
Views: 131

Re: 14BL and CL

I plan on taking 14BL next quarter so if anyone has the knowledge to answer this, that would be extremely helpful!
by Stacey Phan 2I
Sat Jan 30, 2021 12:39 pm
Forum: Student Social/Study Group
Topic: Go treat yourself after MT1!
Replies: 75
Views: 302

Re: Go treat yourself after MT1!

I would treat myself but I still have so much homework so I want to finish that so I have Sunday to chill :)
by Stacey Phan 2I
Sat Jan 30, 2021 12:37 pm
Forum: Student Social/Study Group
Topic: Best kdrama?
Replies: 30
Views: 178

Best kdrama?

Hi I wanted to start a new kdrama with my friend who has never watched one before so I wanted her first one to be a really really good one. I have watched Crash Landing On You and I thought it was really good! Please help me out :)
by Stacey Phan 2I
Sat Jan 30, 2021 12:34 pm
Forum: Student Social/Study Group
Topic: Midterm Scores
Replies: 25
Views: 138

Midterm Scores

Does anyone know when scores will be out?
by Stacey Phan 2I
Mon Jan 25, 2021 4:20 pm
Forum: Student Social/Study Group
Topic: Midterm Materials
Replies: 1
Views: 14

Midterm Materials

What materials do we need for the midterm?

Last quarter we were allowed the periodic table, formula sheet, paper/pencil, and calculator.

Is it the same or are the periodic table and formula sheet unnecessary for the midterm?
by Stacey Phan 2I
Sun Jan 24, 2021 4:43 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH sig figs
Replies: 4
Views: 29

pH sig figs

Does pH contribute to sig figs? If so, is it based on after the decimal? For example, does pH=7.834 have 3 or 4 sig figs?
by Stacey Phan 2I
Sun Jan 24, 2021 4:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant Sig Figs
Replies: 3
Views: 14

Equilibrium Constant Sig Figs

Does the equilibrium constant K contribute to determining sig figs?
Does temperature contribute to determining sig figs?
by Stacey Phan 2I
Sun Jan 24, 2021 4:28 pm
Forum: Student Social/Study Group
Topic: CHEM 14B Midterm 1 Notes
Replies: 23
Views: 142

CHEM 14B Midterm 1 Notes

Hi I summarized the textbook if anyone wants to review concepts!

https://drive.google.com/file/d/1xKtSxeG79tpscaHoFRzJNIQC7Qr0lmnw/view?usp=drivesdk
by Stacey Phan 2I
Sun Jan 24, 2021 1:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Percentage Protonated
Replies: 1
Views: 11

Percentage Protonated

I know that A- of a weak acid has the same concentration as H3O+ so it can both be interchanged in the percentage deprotonation formula. It did not explicitly say in the textbook if the HB+ of a weak base has same concentration as OH-. I just wanted to make sure so if anyone can answer thank you! Re...
by Stacey Phan 2I
Sat Jan 23, 2021 10:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Convert K to Kc
Replies: 2
Views: 11

Convert K to Kc

I was reading 5H.3 and was wondering if we need to know how to convert K to Kc because the formula is not on our formula sheet.
by Stacey Phan 2I
Sun Jan 17, 2021 2:27 pm
Forum: Student Social/Study Group
Topic: Study Group
Replies: 14
Views: 54

Re: Study Group

Katelyn_Ortega_1D wrote:Yes! Please sign me up, I would love to join


Here's the link! https://groupme.com/join_group/65467571/ZF820tr0
by Stacey Phan 2I
Sun Jan 17, 2021 2:26 pm
Forum: Student Social/Study Group
Topic: Study Group
Replies: 14
Views: 54

Re: Study Group

Zoe FC 1C wrote:I would also love to join! My email is linked to my chem community account.


Here's the link! https://groupme.com/join_group/65467571/ZF820tr0
by Stacey Phan 2I
Sun Jan 17, 2021 2:26 pm
Forum: Student Social/Study Group
Topic: Study Group
Replies: 14
Views: 54

Re: Study Group

Anna Martin 2l wrote:Yes! That would be super helpful!


Here's the link! https://groupme.com/join_group/65467571/ZF820tr0
by Stacey Phan 2I
Sat Jan 16, 2021 4:54 pm
Forum: Student Social/Study Group
Topic: Study Group
Replies: 14
Views: 54

Study Group

Does anyone want to form a study group where we keep each other accountable for this course (doing textbook problems, attending workshops, etc)? Or just a group where we can ask help on homework/textbook problems?
by Stacey Phan 2I
Sat Jan 16, 2021 4:53 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle Basics
Replies: 4
Views: 49

Le Chatelier's Principle Basics

What exactly do we have to memorize for Le Chatelier's Principle?
by Stacey Phan 2I
Sat Jan 16, 2021 4:51 pm
Forum: Student Social/Study Group
Topic: Study Habits
Replies: 96
Views: 321

Re: Study Habits

Last quarter, I made sure I understood all the textbook problems that are assigned on the syllabus. I went to many workshops and took notes on the textbook. I think reading the textbook really solidified what Lavelle would go over in lecture.
by Stacey Phan 2I
Sat Jan 16, 2021 4:50 pm
Forum: Student Social/Study Group
Topic: Thoughts on Switching Majors?
Replies: 31
Views: 288

Re: Thoughts on Switching Majors?

I switched my major once I realized there are many majors that pertain more to my interests. If you are pre-med, the pre-requisites are the same for a majority of life science majors so you should go through the list and see what best interests you :)
by Stacey Phan 2I
Sat Jan 16, 2021 4:48 pm
Forum: Student Social/Study Group
Topic: Best Workshops
Replies: 8
Views: 60

Best Workshops

Hi, I am pretty busy this quarter so I wanted to make the most of all the resources that Professor Lavelle offers for this class. Which UA workshops do you find most helpful?
by Stacey Phan 2I
Sat Jan 16, 2021 4:46 pm
Forum: Student Social/Study Group
Topic: Comfort Movies
Replies: 128
Views: 343

Re: Comfort Movies

I think Brooklyn 99 is really funny (available on Hulu)!
by Stacey Phan 2I
Sat Jan 16, 2021 4:44 pm
Forum: Student Social/Study Group
Topic: Number of Chemistry Community Posts
Replies: 45
Views: 939

Re: Number of Chemistry Community Posts

I am also doing it that way! If you had 50 posts total last quarter you could always just subtract 50 from your current total posts.
by Stacey Phan 2I
Sat Jan 16, 2021 4:43 pm
Forum: Student Social/Study Group
Topic: Midterms During Lecture
Replies: 44
Views: 236

Re: Midterms During Lecture

I signed up for this class because I thought lectures were asynchronous. I have a time conflict with another class so does anyone know if will I be able to take the midterm during a different lecture?
by Stacey Phan 2I
Sat Jan 16, 2021 4:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5
Replies: 5
Views: 64

Re: Sapling #5

I also had a hard time solving this at first. I just used the K values whose chemical equations matched the original chemical equation. I used Ka and Kc since the components matched the original equation. Multiply the Ka equation by 3 so Ka would be multiplied to the power of 3. I used Kc which need...
by Stacey Phan 2I
Sat Jan 16, 2021 4:37 pm
Forum: Student Social/Study Group
Topic: Chemistry Community Posts
Replies: 22
Views: 68

Re: Chemistry Community Posts

Say if I made up the 5 posts that were due last Sunday for week one.. would I get full credit or be docked down for being late?
by Stacey Phan 2I
Sat Jan 16, 2021 4:35 pm
Forum: Student Social/Study Group
Topic: Chemistry Community Posts
Replies: 22
Views: 68

Chemistry Community Posts

I enrolled in this class at the end of week 2 so I was wondering if chemistry community posts are due by each week or is it just 50 posts by the end of week 10?
by Stacey Phan 2I
Wed Dec 09, 2020 1:12 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity forumla
Replies: 2
Views: 45

Re: Molarity forumla

I had this question too. I found someone who answered this question last year on chem community. They said: when using the first equation, n=cV, you are solving for moles: moles = concentration * volume the second equation, m=cMV should be used when mass (grams) is involved: mass = concentration * m...
by Stacey Phan 2I
Wed Dec 09, 2020 1:07 pm
Forum: Significant Figures
Topic: 12/07 Lecture sig figs
Replies: 4
Views: 82

Re: 12/07 Lecture sig figs

I think I remember Lavelle saying that the sig figs for this problem is 3. He might have just written it incorrectly by mistake.
by Stacey Phan 2I
Wed Dec 09, 2020 1:05 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 25 degrees celsius [ENDORSED]
Replies: 6
Views: 38

Re: 25 degrees celsius [ENDORSED]

pH decreases as temperature increases. In pure water at 25 °C, the molar concentrations of [H3O+] and [OH-} are equal (the liquid is electrically neutral overall). Therefore, 25 °C is the only temperature we consider, unless otherwise stated.
by Stacey Phan 2I
Wed Dec 09, 2020 12:59 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH>pKA
Replies: 3
Views: 41

pH>pKA

Can someone explain pH>pKa and pH>pKa and why it results in charged or neutral?
by Stacey Phan 2I
Wed Dec 09, 2020 12:56 pm
Forum: Bronsted Acids & Bases
Topic: Ions as Bases/Acids
Replies: 3
Views: 40

Re: Ions as Bases/Acids

In terms of looking at salts, you can tell which salts will behave as acids or bases. For example, NH4+ Cl- + H2O -> NH3 + H3O+ Cl-, chlorine does not affect the pH which means it has no effect as an acid or base. However, H3O+ concentration increases, which lowers the pH. You will need to see whic...
by Stacey Phan 2I
Wed Dec 09, 2020 12:08 pm
Forum: Bronsted Acids & Bases
Topic: Ions as Bases/Acids
Replies: 3
Views: 40

Ions as Bases/Acids

Can someone explain how to determine when an ion is basic or acidic?
by Stacey Phan 2I
Thu Dec 03, 2020 1:08 am
Forum: Calculating the pH of Salt Solutions
Topic: pH formula?
Replies: 46
Views: 965

Re: pH formula?

You can use the formula pH = - log[H+]
by Stacey Phan 2I
Thu Dec 03, 2020 1:06 am
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Date
Replies: 21
Views: 244

Re: Final Exam Date

Helena Hu 3E wrote:Will week 10 be review then?


I'm going to assume we have lecture week 10 for Monday and Wednesday since Professor Lavelle usually doesn't teach test material the lecture day before the test if that makes sense.
by Stacey Phan 2I
Thu Dec 03, 2020 1:04 am
Forum: Naming
Topic: Memorizing ligand names
Replies: 6
Views: 60

Re: Memorizing ligand names

I don't think we are allowed to use a sheet so I would just memorize the chart in the textbook.
by Stacey Phan 2I
Thu Dec 03, 2020 1:02 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determining Coordination Numbers
Replies: 5
Views: 48

Re: Determining Coordination Numbers

According to the lecture the number of bonds equals the coordination number.
by Stacey Phan 2I
Thu Dec 03, 2020 1:00 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: -ate ion ending
Replies: 4
Views: 38

Re: -ate ion ending

I think it is when the formula in the bracket comes up with a negative charge
by Stacey Phan 2I
Thu Dec 03, 2020 12:59 am
Forum: Naming
Topic: Ligands
Replies: 3
Views: 22

Ligands

Hi I was wondering if anyone knows which ligands we should have memorized.
by Stacey Phan 2I
Sat Nov 28, 2020 11:34 am
Forum: Student Social/Study Group
Topic: Midterm/Final Success?
Replies: 17
Views: 148

Re: Midterm/Final Success?

Hi Brendan, I optimized my success on these midterms by doing the following things: 1. Attending UA workshop sessions. They are incredibly useful for additional practice and to clarify any little misconceptions. 2. Reading through notes I've taken in my textbook so I don't have to sit through and r...
by Stacey Phan 2I
Sat Nov 28, 2020 11:29 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Which shapes to memorize
Replies: 11
Views: 140

Re: Which shapes to memorize

I would recommend googling a lookup table as well as there is sort of a pattern to the molecular shapes. Electron groups: 2, Bonding Groups: 2, Lone Pairs: 0 = Linear Electron groups: 3, Bonding Groups: 3, Lone Pairs: 0 = Trigonal Planar Electron groups: 3, Bonding Groups: 2, Lone Pairs: 1 = Bent E...
by Stacey Phan 2I
Sat Nov 28, 2020 11:28 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Which shapes to memorize
Replies: 11
Views: 140

Re: Which shapes to memorize

I'm assuming it's all the shapes that Dr. Lavelle mentioned in the lectures: - linear : central atom has 2 bonding pairs; 180 degree bond angle - trigonal planar: central atom has 3 bonding pairs, 120 degree bond angles - tetrahedral: central atom has 4 bonding pairs, 109.5 degree bond angle - trig...
by Stacey Phan 2I
Sat Nov 28, 2020 11:27 am
Forum: Student Social/Study Group
Topic: Midterm Exam Questions
Replies: 16
Views: 167

Midterm Exam Questions

Are we allowed to ask about midterm questions on here now? I am unsure of which questions I got wrong and I wanted to improve my understanding on midterm 2's concepts before the final.
by Stacey Phan 2I
Sat Nov 28, 2020 11:24 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape Names
Replies: 50
Views: 309

Re: Shape Names

The textbook refers it to angular but bent is also acceptable.
by Stacey Phan 2I
Sat Nov 28, 2020 11:23 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR identification of carbonate ion (CO3(2-))
Replies: 4
Views: 36

Re: VSEPR identification of carbonate ion (CO3(2-))

I believe Professor Lavelle just regarded them as regions of electron density which is the only thing considered in determining shapes.
by Stacey Phan 2I
Mon Nov 23, 2020 1:31 am
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Date
Replies: 21
Views: 244

Final Exam Date

I was wondering if anyone knows whether we are taking the final exam on December 13th (which my Study List on my.ucla.edu says) or during discussion times like our past midterms?
by Stacey Phan 2I
Sat Nov 21, 2020 1:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Which shapes to memorize
Replies: 11
Views: 140

Which shapes to memorize

I was wondering if someone could tell me all the shapes we should memorize with their description?
by Stacey Phan 2I
Sat Nov 21, 2020 1:08 pm
Forum: Student Social/Study Group
Topic: Study Tips for Final Exam
Replies: 57
Views: 440

Re: Study Tips for Final Exam

I mainly focused on reading the textbook and doing outline notes on it while doing the textbook problems. Workshops are helpful too I definitely recommend Justin’s on Saturdays!
by Stacey Phan 2I
Thu Nov 19, 2020 12:54 am
Forum: Lewis Structures
Topic: NO+
Replies: 3
Views: 32

Re: NO+

Andrew Wang 1G wrote:A triple bond between the N and O is the only way for both atoms to have a full octet.


that makes so much more sense thank you!
by Stacey Phan 2I
Thu Nov 19, 2020 12:28 am
Forum: Lewis Structures
Topic: NO+
Replies: 3
Views: 32

NO+

Hi, I was doing one of the textbook questions (2B.19 part a) and I was wondering why there is a triple bond between N and O. Is it because you want the more positive formal charge on the less electronegative atom?
by Stacey Phan 2I
Tue Nov 17, 2020 10:55 pm
Forum: Administrative Questions and Class Announcements
Topic: 14B Enrollment [ENDORSED]
Replies: 31
Views: 1444

14B Enrollment [ENDORSED]

I read one of Professor Lavelle's emails regarding waitlisted students for 14A. He wrote that "All waitlisted students are always admitted in my classes. If you ware waitlisted, relax. Do everything as if you are enrolled (because you will be)." So for my enrollment appointment, I signed u...
by Stacey Phan 2I
Mon Nov 16, 2020 5:55 pm
Forum: Lewis Structures
Topic: Radicals
Replies: 1
Views: 23

Radicals

I was doing Topic 2C.5 part A which asked for the Lewis Structure for Chlorine Monoxide (ClO). I assumed it had a double bond since there is a 0 charge on the compound however, it was a single bond. Since it is a radical, does oxygen have a single bond and -1 formal charge because radicals have high...
by Stacey Phan 2I
Thu Nov 12, 2020 8:24 am
Forum: Sigma & Pi Bonds
Topic: Triple bond?
Replies: 21
Views: 169

Triple bond?

If single bond is sigma bond and double bond is pi bond, what is a triple bond?
by Stacey Phan 2I
Thu Nov 12, 2020 8:22 am
Forum: Coordinate Covalent Bonds
Topic: When do we use it
Replies: 9
Views: 59

When do we use it

When do we make a coordinate covalent bond between two atoms?
by Stacey Phan 2I
Thu Nov 12, 2020 8:20 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 9
Views: 55

Polarizability

Can someone summarize polarizability? Is it just the ability for a molecule’s electrons to be delocalized?
by Stacey Phan 2I
Thu Nov 12, 2020 8:17 am
Forum: Octet Exceptions
Topic: Radicals
Replies: 1
Views: 21

Radicals

I was taking notes from the textbook and it said a radical has at least one unpaired electron and a biradical has two unpaired electrons. Does this mean a biradical can also be a radical?
by Stacey Phan 2I
Thu Nov 12, 2020 8:15 am
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidization Numbers
Replies: 10
Views: 79

Re: Oxidization Numbers

I don’t remember Lavelle going over oxidation numbers either, however, I saw a question regarding oxidation numbers on Sapling so I would assume we need to know the basics?
by Stacey Phan 2I
Sat Nov 07, 2020 7:33 pm
Forum: Quantum Numbers and The H-Atom
Topic: when n=5 and l=4
Replies: 16
Views: 160

Re: when n=5 and l=4

When n=5, l can has the possible values of 0,1,2,3,or 4 as in S,P,D,F, etc. orbitals. The formula to finding l is 0,1,2,...(n-1)
by Stacey Phan 2I
Sat Nov 07, 2020 7:30 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 3
Views: 25

Magnetic Quantum Number

When you find out the magnetic quantum number and you get either -3,-2,-1,0,1,2,3, etc., does the order of the numbers matter? For instance when you fill up the sub shells, does it fill up from negative values to positive values or is it just a method to find out how many orbitals there are in a sub...
by Stacey Phan 2I
Sat Nov 07, 2020 12:06 pm
Forum: Resonance Structures
Topic: Resonance Lecture Question
Replies: 10
Views: 75

Re: Resonance Lecture Question

Jonathan Batac - 1K wrote:L stands for the actual number of electrons (or dots, if you will), not the total amount of lone pairs. For example, there may be two lone pairs of electrons, but L will be 4 because there are four individual electrons.


Thank you for this example this cleared everything up!
by Stacey Phan 2I
Thu Nov 05, 2020 1:14 am
Forum: Resonance Structures
Topic: Resonance Lecture Question
Replies: 10
Views: 75

Resonance Lecture Question

I’m wondering what the L stands for in the formal charge formula: FC = V - (S/2 + L)
Does it stand for lone paired electrons (number of electrons in all the lone pairs) or lone pairs (number of lone pairs)?
by Stacey Phan 2I
Tue Nov 03, 2020 9:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Second Midterm Date
Replies: 9
Views: 73

Second Midterm Date

When is our second midterm?
by Stacey Phan 2I
Mon Nov 02, 2020 12:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Fundamentals for Midterm 2
Replies: 5
Views: 48

Fundamentals for Midterm 2

Hi I was wondering which fundamental problems I should be doing for the second midterm. Is it the rest of outline 2 and outline 3?
by Stacey Phan 2I
Fri Oct 30, 2020 9:14 pm
Forum: Student Social/Study Group
Topic: Midterm scratch paper
Replies: 9
Views: 53

Re: Midterm scratch paper

You won’t be turning in your scratch paper so you don’t need to show work.
by Stacey Phan 2I
Fri Oct 30, 2020 9:12 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Units for Uncertainty in Position
Replies: 6
Views: 53

Re: Units for Uncertainty in Position

Use meters so the units cancel out correctly!
by Stacey Phan 2I
Fri Oct 30, 2020 9:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 and Final
Replies: 9
Views: 98

Re: Midterm 2 and Final

I’m assuming that midterm won’t be cumulative since it’ll probably be a similar number of questions but I think the final will be cumulative.
by Stacey Phan 2I
Fri Oct 30, 2020 9:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Curve on Midterm
Replies: 9
Views: 118

Re: Curve on Midterm

I don’t think there will be a curve on the midterm but it did say there are going to be partial points for certain questions!
by Stacey Phan 2I
Wed Oct 28, 2020 1:21 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula - Whole Number Ratio
Replies: 9
Views: 86

Empirical Formula - Whole Number Ratio

I was wondering what the cutoff for rounding the moles to a whole number is. I am assuming if its less than .10 away you can round it to the nearest number?
by Stacey Phan 2I
Fri Oct 23, 2020 4:19 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Clarification on the Rydberg constant
Replies: 5
Views: 36

Re: Clarification on the Rydberg constant

If there is no Rydberg constant given, you should use 3.29E15 Hz. However, I attended a workshop and the UA said if there is a different Rydberg constant given in the problem, use that for the problem because it is probably modified to the units (something that is not Hz) that the question is asking...
by Stacey Phan 2I
Fri Oct 23, 2020 4:14 am
Forum: Photoelectric Effect
Topic: Photoelectric Effect Module Question
Replies: 4
Views: 87

Re: Photoelectric Effect Module Question

Hi so I'm going to explain part A and part B in case anyone is wondering how to do part A as well. Part A) You are given a frequency of 1.09E15 Hz so you want to use an equation that involves energy and frequency. Use equation E=hv. E=(6.626E-34 Js) * (1.09E15 Hz) = 7.22234E-19 J. This is the thresh...
by Stacey Phan 2I
Fri Oct 23, 2020 3:43 am
Forum: Molarity, Solutions, Dilutions
Topic: Fundamental G Problem Help
Replies: 3
Views: 57

Re: Fundamental G Problem Help

I completely understand your thinking and I got the same answer too when I first tried it! Let me try to clear things up. First, I think you are applying the concept that even if you dilute a solution, the amount of moles stays the same. This is because you are simply adding more solution, but the ...
by Stacey Phan 2I
Thu Oct 22, 2020 11:13 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamental G Problem Help
Replies: 3
Views: 57

Fundamental G Problem Help

To prepare a fertilizer solution, a florist dilutes 1.0 L of 0.20 M NH4NO3(aq) by adding 3.0 L of water. The florist then adds 100. mL of the diluted solution to each plant. How many moles of nitrogen atoms will each plant receive? Solve this exercise without using a calculator. The answer key said ...
by Stacey Phan 2I
Thu Oct 22, 2020 2:37 am
Forum: *Shrodinger Equation
Topic: Schrodinger's Equation
Replies: 5
Views: 85

Schrodinger's Equation

Can someone explain the concept between Schrodinger's Equation and wave functions and orbitals?

Anything is helpful, I am just really lost on the topic.
by Stacey Phan 2I
Tue Oct 20, 2020 10:46 pm
Forum: Properties of Electrons
Topic: 1A.1
Replies: 1
Views: 39

1A.1

At the time that J. J. Thomson conducted his experiments on cathode rays, the nature of the electron was in doubt. Some considered it to be a form of radiation, like light; others believed the electron to be a particle. Some of the observations made on cathode rays were used to advance one view or t...
by Stacey Phan 2I
Fri Oct 16, 2020 3:20 pm
Forum: Photoelectric Effect
Topic: Excess energy
Replies: 20
Views: 135

Re: Excess energy

The equation 1/2mv^2 is used to find the kinetic energy of the emitted electrons. This is the energy that exceeds the threshold energy required to remove an electron.
by Stacey Phan 2I
Fri Oct 16, 2020 3:13 pm
Forum: Properties of Light
Topic: rydberg equation
Replies: 7
Views: 61

Re: rydberg equation

You can solve using it by the professor's method. You don't have to memorize the Rydberg constant or the equation that Lavelle used in the lecture. There is an equation sheet we can access on his website: https://lavelle.chem.ucla.edu/wp-conten ... ations.pdf
by Stacey Phan 2I
Fri Oct 16, 2020 3:09 pm
Forum: Properties of Electrons
Topic: Grading System
Replies: 7
Views: 95

Grading System

Does anyone know how Lavelle's grading system works? I looked at the syllabus and sapling and chemistry community are both 50 points total, midterms are 110 points each, and the final is 180 points. Under the grading, it says 50% or higher is required to pass with a C- or higher. Does that mean ther...
by Stacey Phan 2I
Fri Oct 16, 2020 3:07 pm
Forum: Properties of Light
Topic: "in phase" vs "out of phase" [ENDORSED]
Replies: 4
Views: 66

Re: "in phase" vs "out of phase" [ENDORSED]

Two waves are in phase with each other if their peaks line up together and their troughs line up together. This results in constructive interference where when combined, the amplitude of the new wave is larger. Out of phase is the opposite and means that the peaks and troughs of the two waves are mi...
by Stacey Phan 2I
Fri Oct 16, 2020 3:02 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bound energy versus free energy
Replies: 2
Views: 30

Bound energy versus free energy

I was watching Lavelle's 10/16 lecture and I am a little confuse on by the concept: The negative sign means the bound e- has lower energy than free e-

If anyone can explain it in more depth that would be great!
by Stacey Phan 2I
Mon Oct 05, 2020 6:10 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Calculation
Replies: 5
Views: 74

Re: Limiting Reactant Calculation

Convert the 1 kg CaCO3 (s) to grams. (1 kg = 1000 g)

Use stoichiometry to convert the 1000 g CaCO3 to moles. (1000g) / (100.09 aka CaCO3 molar mass)

Convert the CaCO3 to CO2.

Since the equation is a 1:1 coefficient ratio between CaCO3 and CO2, the answer should be approximately 10 moles.
by Stacey Phan 2I
Mon Oct 05, 2020 6:03 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molar mass for O2 vs O
Replies: 11
Views: 119

Re: Molar mass for O2 vs O

The molar mass of O is 16 grams, as stated in the periodic table. The molar mass of O2 is 32 grams (16g + 16g).
by Stacey Phan 2I
Mon Oct 05, 2020 6:02 pm
Forum: Molarity, Solutions, Dilutions
Topic: Mol VS Mole
Replies: 17
Views: 213

Re: Mol VS Mole

The terms "mol" and "mole" represent the same thing. People tend to write mol as an abbreviation.
by Stacey Phan 2I
Mon Oct 05, 2020 5:57 pm
Forum: Significant Figures
Topic: Molar Mass Sig Figs
Replies: 9
Views: 81

Re: Molar Mass Sig Figs

When you write the molar masses from the periodic table, people typically use four sig figs (to the hundredths place).
by Stacey Phan 2I
Mon Oct 05, 2020 5:53 pm
Forum: Empirical & Molecular Formulas
Topic: Emprical Formulas Ever Larger than Molecular? [ENDORSED]
Replies: 26
Views: 462

Re: Emprical Formulas Ever Larger than Molecular? [ENDORSED]

Empirical formulas will never be larger than molecular formulas because empirical formulas are the simplest ratios of atoms in a molecule. However, empirical formulas can be the same as molecular formulas (ex: H2O).

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