Search found 42 matches

by Isabel Luu 1I
Sun Feb 21, 2021 4:42 pm
Forum: Administrative Questions and Class Announcements
Topic: When is Sapling HW due?
Replies: 15
Views: 51

Re: When is Sapling HW due?

If you go onto the sapling webpage and scroll down it says the due dates right after the assignment title. Sunday of week x, corresponds to the Sunday at the end of the week, not right at the beginning. I was confused about this at first also.
by Isabel Luu 1I
Sun Feb 21, 2021 4:38 pm
Forum: Administrative Questions and Class Announcements
Topic: Tips for Concentrating during a test
Replies: 31
Views: 97

Re: Tips for Concentrating during a test

I have this issue too :( For me I can't focus if I try to take a test in a place where I normally study because I forget that I am taking a test and can't get into the right mindset. I normally have to go somewhere else. I clear my area so that I'm not distracted by other things and it looks more li...
by Isabel Luu 1I
Sun Feb 21, 2021 4:32 pm
Forum: Administrative Questions and Class Announcements
Topic: Can We Review our Exams?
Replies: 69
Views: 242

Re: Can We Review our Exams?

After the first midterm, my TA said that he would be spending next weeks office hours going over the whole test so if you want to check your answers and see them worked out I think you have to go to TA office hours. The office hour links are all listed on the CCLE "site info" section so I ...
by Isabel Luu 1I
Sun Feb 21, 2021 4:30 pm
Forum: Administrative Questions and Class Announcements
Topic: Textbook Problems
Replies: 8
Views: 37

Re: Textbook Problems

Is there a way to find answers to even-number questions? The solution manual only has the answer the odd numbered questions, but the even and odd numbers are normally similar so you can use it as reference to check your process. If you go to your TAs office hours I'm sure they can clarify any even ...
by Isabel Luu 1I
Sun Feb 21, 2021 4:28 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem community points
Replies: 10
Views: 42

Re: Chem community points

On myucla it says I only have 30 points but I think I have over 30 because I asked a few other questions some weeks. Does anyone know if he caps it at 30 in myucla or if some of my posts did not count? But also to answer your questions, we need 5 each week so at the end of week 7 you should have 35
by Isabel Luu 1I
Sun Feb 21, 2021 4:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14 B Final
Replies: 27
Views: 124

Re: Chem 14 B Final

The final will be cumulative. I did not have lavelle for 14a but I am assuming more of the questions will be on content after the second midterm since we haven't been tested on that material yet. We will have more time though so there should be more questions. I think once we get closer to the final...
by Isabel Luu 1I
Fri Feb 12, 2021 4:13 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy: kJ or J?
Replies: 30
Views: 78

Re: Entropy: kJ or J?

Most of the questions in our textbook and Sapling ask for it in J/K. Either is technically correct but it just depends on what the question is asking. Enthalpy tends to be in kJ so you might need to convert on of these quantities when working with the Gibbs Free Energy equation.
by Isabel Luu 1I
Fri Feb 12, 2021 4:10 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: q_rev and enthalpy
Replies: 2
Views: 13

q_rev and enthalpy

I am a little confused on when we can assume that q_rev is equal to the change in enthalpy. We assumed this for question 9 on the sapling homework but I am not sure why. What is the difference between q_rev and enthalpy and how are they related? Thanks!
by Isabel Luu 1I
Fri Feb 12, 2021 4:07 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling #7
Replies: 2
Views: 28

Re: Sapling #7

You can calculate the change in mass from the initial and final masses in the table so you have to convert the mass in grams to moles using the molar mass. Then you can plug it into the equation. It helps me to write out what units I am given and what units I need to see how you can manipulate equat...
by Isabel Luu 1I
Fri Feb 12, 2021 4:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Material
Replies: 10
Views: 40

Midterm Material

Up to what lecture will the midterm cover? Will part of outline 5 be included or is it just the thermochem and thermodynamics stuff from after the first midterm?
by Isabel Luu 1I
Fri Feb 12, 2021 4:02 pm
Forum: Administrative Questions and Class Announcements
Topic: Outline Progess
Replies: 5
Views: 32

Outline Progess

Does anyone know where we should be on the outlines after lecture today? I want to make sure I get caught up this weekend in terms of textbook problems.
by Isabel Luu 1I
Fri Feb 12, 2021 3:56 pm
Forum: Calculating Work of Expansion
Topic: Work Equations
Replies: 2
Views: 19

Re: Work Equations

The first equation is when a reaction is not reversible. The second one is for a reversible and isothermal reaction.
by Isabel Luu 1I
Fri Feb 05, 2021 4:45 pm
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: Microstates vs. Possible positions
Replies: 3
Views: 16

Re: Microstates vs. Possible positions

Yeah I think you are right. X is just the number of positions. For the overall number of microstates, W, you need to use that equation: W = X^n, where n is the number of particles.
by Isabel Luu 1I
Fri Feb 05, 2021 4:41 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Enthalpy vs Entropy
Replies: 7
Views: 35

Enthalpy vs Entropy

Can someone summarize the conceptual difference between entropy and enthalpy? Are they related in any way? I keep getting these two concepts mixed up in my head because the names are so similar
by Isabel Luu 1I
Fri Feb 05, 2021 4:39 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Reversible vs. Irreversible
Replies: 8
Views: 65

Re: Reversible vs. Irreversible

Does it have anything to do with if it is spontaneous? I'm still a little confused on this too.
by Isabel Luu 1I
Fri Feb 05, 2021 4:38 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Reversible Reactions
Replies: 4
Views: 16

Reversible Reactions

I am a little confused on how we can tell when a thermodynamic process is reversible. What are the conditions for when a process is reversible? Does it have to do with if it is spontaneous?
by Isabel Luu 1I
Fri Feb 05, 2021 4:36 pm
Forum: General Science Questions
Topic: Careless Mistakes
Replies: 54
Views: 233

Re: Careless Mistakes

I would say for exams it definitely helps to me talk out loud when I'm doing calculations. I accidentally press the wrong buttons a lot when I'm nervous but if I am also saying out loud what I mean to type it helps me catch my mistakes. Also just trying to take deep breathes and stay calm so that I ...
by Isabel Luu 1I
Fri Feb 05, 2021 4:32 pm
Forum: General Science Questions
Topic: Midterm 1 Reactions
Replies: 70
Views: 351

Re: Midterm 1 Reactions

I was a little unsure what to expect because I took 14a with a different professor but it seemed relatively fair. It wasn't super easy and I didn't feel 100% confident but there weren't any major surprises in my opinion. At least we know what to expect more for the next midterm and can adjust our st...
by Isabel Luu 1I
Fri Feb 05, 2021 4:28 pm
Forum: General Science Questions
Topic: Tips
Replies: 24
Views: 77

Re: Tips

For the thermochem/thermodynamics stuff I would recommend writing down all of the equations we have been using and make sure you understand all of the variables. A lot of the questions are just variations on using the same equations but solving for different variables in the equation. If you write o...
by Isabel Luu 1I
Fri Feb 05, 2021 4:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem Community Grade Error
Replies: 15
Views: 102

Re: Chem Community Grade Error

I'm pretty sure they just count everything at the end. So as long as by the end of the quarter you have 50 points you should be okay. For example if you do 4 one week and 6 the next you'll average at 5 a week and still be able to reach 50 at the end of the quarter.
by Isabel Luu 1I
Fri Feb 05, 2021 4:22 pm
Forum: Administrative Questions and Class Announcements
Topic: tips if you're struggling!
Replies: 61
Views: 340

Re: tips if you're struggling!

Thanks for the tips!! Do you do all of the textbook problems or just the ones that seem more challenging? There are so many problems I think I might have spent too much time redoing the ones that were straightforward so I had less energy to really think about the harder ones.
by Isabel Luu 1I
Fri Jan 29, 2021 12:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D.13 pKa Shortcut?
Replies: 3
Views: 68

Re: 6D.13 pKa Shortcut?

If they were all the same concentration I think you could do that. But since some of them are different concentrations you should probably work out the problem because a low concentration will bring down the pH of a strong acid, so you can't just compare the pKa or Ka values.
by Isabel Luu 1I
Fri Jan 29, 2021 12:42 pm
Forum: Ideal Gases
Topic: pv=nRT
Replies: 16
Views: 70

Re: pv=nRT

An example from the homework for using this formula was when we needed the amount of a substance and were given the temperature, volume, and pressure. We used the equation to solve for n, the number of moles. This equation is helpful for converting to different quantities. You just kind of have to t...
by Isabel Luu 1I
Fri Jan 29, 2021 12:39 pm
Forum: General Science Questions
Topic: Acid/Bases Outline Question [ENDORSED]
Replies: 2
Views: 66

Re: Acid/Bases Outline Question [ENDORSED]

Accidentally posted my question on the chem 14a site so I'm gonna rewrite it here. Does anyone have any tips for getting an intuition about if a compound is an acid or a base? I still trying trying to determine it by just looking at the chemical formula.
by Isabel Luu 1I
Fri Jan 29, 2021 12:33 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Determining relative strength of acids and bases
Replies: 4
Views: 4425

Re: Determining relative strength of acids and bases

Does anyone have any tips for gaining intuition about if a compound is basic or acidic? I am still struggling with figuring out the difference just by looking at the chemical formula.
by Isabel Luu 1I
Fri Jan 29, 2021 12:27 pm
Forum: General Science Questions
Topic: Grades
Replies: 28
Views: 376

Re: Grades

Also, for people that had prof Lavelle for chem 14a, how long does it normally take him to grade midterms?
by Isabel Luu 1I
Fri Jan 29, 2021 12:26 pm
Forum: General Science Questions
Topic: Grades
Replies: 28
Views: 376

Re: Grades

Does anyone know what it means when there is partial credit for the midterms? Like how do we get partial credit when it's a multiple choice question with only one final answer?
by Isabel Luu 1I
Fri Jan 22, 2021 12:01 pm
Forum: Phase Changes & Related Calculations
Topic: Exothermic example
Replies: 9
Views: 55

Re: Exothermic example

An exothermic reaction releases heat. An endothermic reaction needs heat. The engine is exothermic because the reaction will give off heat as a product of the combustion reaction.
by Isabel Luu 1I
Fri Jan 22, 2021 11:58 am
Forum: Phase Changes & Related Calculations
Topic: Non-State Properties
Replies: 9
Views: 61

Re: Non-State Properties

A state property does not depend on the path taken to get from initial to final. In lecture he did an example about how if there are two paths to the top of a mountain, the change in altitude will be the same for each path, meaning it does not depend on the path. For work, one path could be much har...
by Isabel Luu 1I
Fri Jan 22, 2021 11:54 am
Forum: Phase Changes & Related Calculations
Topic: Exo and Endothermic reactions
Replies: 7
Views: 47

Re: Exo and Endothermic reactions

Since enthalpy is a state function when we want to find out if the overall reaction is endothermic we can just do final - initial and not worry about the steps in between. And then from the overall reaction it should tell you if it is exothermic (negative enthalpy) or endothermic (positive enthalpy).
by Isabel Luu 1I
Fri Jan 22, 2021 11:51 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: midterms [ENDORSED]
Replies: 10
Views: 335

Re: midterms [ENDORSED]

alebenavides wrote:does anyone know what time the midterm is ?


The midterm is during lecture time so next Friday from 11-11:50. I think we log into our discussion zooms so the TAs can proctor the test.
by Isabel Luu 1I
Fri Jan 22, 2021 11:47 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 3 methods for calculation change in enthalpy
Replies: 5
Views: 17

3 methods for calculation change in enthalpy

In lecture today we talked about 3 ways to calculate reaction enthalpies. So can we choose any of these methods to solve a problem or do certain problems have to be solved a specific way using one of the methods?
by Isabel Luu 1I
Fri Jan 15, 2021 8:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Exam Format
Replies: 15
Views: 102

Re: Exam Format

So we have just the 50 minute lecture time for the exam? And about how long did you have for each question? Like were there a lot of shorter questions or was it just a few questions that took a while?
by Isabel Luu 1I
Fri Jan 15, 2021 8:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 1
Replies: 24
Views: 156

Re: Midterm 1

Part of unit 3, which is on thermochemistry will likely be on the first midterm since we still have two weeks until the midterm. I think he will probably talk more about what will be on the midterm in lecture next week or send out an email when we get closer to the date.
by Isabel Luu 1I
Wed Jan 13, 2021 3:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Approximations when K is small
Replies: 2
Views: 10

Approximations when K is small

In lecture Professor Lavelle said that you can approximate reactants and ignore x when K is small, which is considered 10^-3. Does this mean you can use this approximation when K is 10^-3 or does it have to be less than that, meaning 10^-4?
by Isabel Luu 1I
Wed Jan 13, 2021 3:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Logarithms Sig Fig Rule?
Replies: 4
Views: 30

Re: Logarithms Sig Fig Rule?

If you are still confused, on his website there is a section called "Math Assistance" where he explains sig fig rules with a lot of examples.
by Isabel Luu 1I
Thu Jan 07, 2021 11:29 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 107
Views: 7294

Re: Accessing the E-textbook [ENDORSED]

I am not sure if anyone has already covered this, but regarding what is due on Sapling, are the problems posted on Sapling the only problems each week that we are graded on? I know you are supposed complete the assigned work each week, but are the additional practice problems from the textbook just...
by Isabel Luu 1I
Wed Jan 06, 2021 6:36 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 107
Views: 7294

Re: Accessing the E-textbook [ENDORSED]

Are there solutions posted anywhere for the extra practice textbook problems (not the Sapling questions)?
by Isabel Luu 1I
Wed Jan 06, 2021 6:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Posts in 14B
Replies: 153
Views: 2283

Re: Chemistry Posts in 14B

Sorry if someone already asked this but do the points roll over to the next week? Like do we have to do 5 per week or would 4 one week and then 6 the next be okay?
by Isabel Luu 1I
Tue Jan 05, 2021 1:10 pm
Forum: Student Social/Study Group
Topic: Advice for someone who didn't take 14A with professor Lavelle
Replies: 61
Views: 327

Re: Advice for someone who didn't take 14A with professor Lavelle

So the step up sessions basically where people go through practice problems? I'm a little confused on the different between step up sessions and UA sessions.
by Isabel Luu 1I
Tue Jan 05, 2021 1:04 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Posts in 14B
Replies: 153
Views: 2283

Re: Chemistry Posts in 14B

Hannah_Butler_2E wrote:Do all five of the weekly posts for credit have to be related to class content or are they also counted for credit if they concern administrative or general class questions?


I believe any post will count, even if it they are not directly related to course content.
by Isabel Luu 1I
Mon Jan 04, 2021 1:12 pm
Forum: Student Social/Study Group
Topic: Advice for someone who didn't take 14A with professor Lavelle
Replies: 61
Views: 327

Advice for someone who didn't take 14A with professor Lavelle

Hi guys! I took 14A last spring, with a different professor. For those that took 14A with Professor Lavelle, were any of his extra resources particularly helpful to you or do you have any general advice on how to be successful in his class? Thanks!

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