Search found 52 matches
- Thu Mar 12, 2020 11:09 pm
- Forum: Administrative Questions and Class Announcements
- Topic: How long do we have to complete the final?
- Replies: 1
- Views: 247
How long do we have to complete the final?
I am a bit confused on the wording of Lavelle's last update -- He said that the exam will be about 6 questions (about 3-4 hours) but also said that time will not be an issue. Does this mean that it will be only available for 3-4 hours or that there will be a window of time in which we can complete i...
- Thu Mar 12, 2020 11:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final
- Replies: 2
- Views: 196
Re: Final
He just sent out an email saying that the final will be during the regular hours of the initial exam and that it will be administered online. He also said that no other software would need to be downloaded to take it, so I'm assuming it will be on CCLE to be multiple choice (unlikely) or like a fill...
- Thu Mar 12, 2020 2:13 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Take Home Final
- Replies: 16
- Views: 976
Re: Take Home Final
For my math class final that is now take home, he said he will be doing a final through Gradescope wherr you submit scans of your paper work for the final and gave us a 24 hour window to do it. I hope Lavelle does the same
- Thu Mar 12, 2020 2:11 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Format because I posted in 14A by accident
- Replies: 8
- Views: 566
Re: Format because I posted in 14A by accident
I assume it would be like the previous Tests and probably like the practice final he will be uploading onto the website.
- Thu Mar 12, 2020 2:10 pm
- Forum: First Order Reactions
- Topic: equation derivations
- Replies: 9
- Views: 553
Re: equation derivations
My TA told us that we should memorize the derivation for van't Hoff equation... He strongly suggested us to, so I am still not sure why would need to but I would follow his recommendation
- Thu Mar 12, 2020 2:06 pm
- Forum: Student Social/Study Group
- Topic: Final Exam
- Replies: 22
- Views: 1525
Re: Final Exam
Does anyone know when we will be given our take-home final? Is it still going to be on Sunday? I think it's still going to be sunday, as there's nothing to indicate otherwise Do you know this for sure? My other professors that have take home finals still warned us that there would be a take home fi...
- Wed Mar 11, 2020 8:36 pm
- Forum: Administrative Questions and Class Announcements
- Topic: "Open Book" Final?
- Replies: 30
- Views: 1951
Re: "Open Book" Final?
I believe for "open book" it does entail classroom notes, office hour notes, discussion notes and packets, and everything in between.
- Wed Mar 11, 2020 8:32 pm
- Forum: Administrative Questions and Class Announcements
- Topic: final
- Replies: 14
- Views: 916
Re: final
** It's not on Sunday anymore. **
He said it was cancelled in the email!
He said it was cancelled in the email!
- Tue Mar 10, 2020 11:53 pm
- Forum: Administrative Questions and Class Announcements
- Topic: What is the plan for the final?
- Replies: 16
- Views: 1001
Re: What is the plan for the final?
chari_maya 3B wrote:Does that mean the midterm is going to be wayyyyyy more influential to our grade than it would have been?
Hopefully not.....!!! I'm crossing my fingers that it will stay the same since I'm (and most likely many others) hoping that my final will make up for my midterm score!
- Tue Mar 10, 2020 11:50 pm
- Forum: Student Social/Study Group
- Topic: Final Exam
- Replies: 22
- Views: 1525
Re: Final Exam
Update: The exam on Sunday is cancelled and it will be a take home :) check emails!
- Tue Mar 10, 2020 8:52 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Reviews and Final
- Replies: 1
- Views: 182
Re: Reviews and Final
Hopefully the lecture will be Bruincasted since it will be a review session and also the CS50 room is compatible with Bruincast! However in my experience with asking professors about getting their classes enrolled in Bruincast, it is usually a long process (or so they say) that they need to go throu...
- Tue Mar 10, 2020 8:48 pm
- Forum: Student Social/Study Group
- Topic: Curve?
- Replies: 50
- Views: 6026
Re: Curve?
Does that line in the syllabus also mean that anyone who receives over 50% of the points will pass? Yes,,, I had a conversation with Lavelle in his office hours about this and he said that as long as you get a 50%, no matter what or how, you will PASS the class! I think we can agree this is at leas...
- Tue Mar 10, 2020 8:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Office Hours/Review Sessions
- Replies: 1
- Views: 121
Re: Office Hours/Review Sessions
I posted this response in another thread but I think it is still relevant and helpful: "I think it would be best to keep checking Lyndon's ENDGAME Review Session thread to be kept updated on the status of his review session! But for Lavelle's review sessions, since classes have been deemed canc...
- Tue Mar 10, 2020 8:44 pm
- Forum: Student Social/Study Group
- Topic: Final Exam
- Replies: 22
- Views: 1525
Re: Final Exam
Are the review sessions still going on? I think it would be best to keep checking Lyndon's ENDGAME Review Session thread to be kept updated on the status of his review session! But for Lavelle's review sessions, since classes have been deemed cancelled by Gene Block, I think we would just have to w...
- Tue Mar 10, 2020 8:41 pm
- Forum: Phase Changes & Related Calculations
- Topic: Fusion = Melting?
- Replies: 7
- Views: 974
Re: Fusion = Melting?
I believe fusion is actually a phase change between liquid and solid, which could mean either melting or freezing because those are both phase changes between liquids and solids (melting= solid -> liquid; freezing= liquid -> solid)
- Tue Mar 10, 2020 8:38 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Class Cancellation
- Replies: 3
- Views: 394
Re: Class Cancellation
I'm sure that homework should still be turned in (via email with a picture or PDF file) since the discussions that happened today (like mine) still had to turn it in!
- Tue Mar 10, 2020 8:36 pm
- Forum: Biological Examples
- Topic: Chem Final Review Worksheet
- Replies: 2
- Views: 746
Re: Chem Final Review Worksheet
Lyndon (a UA) has recently posted a thread called "ENDGAME" that will have his review session packet linked in it.
Also he said he will be posting the answer key to the packet shortly after the review session (Friday 6pm)!
Also he said he will be posting the answer key to the packet shortly after the review session (Friday 6pm)!
- Tue Mar 10, 2020 8:33 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ENDGAME Review Session
- Replies: 71
- Views: 5467
Re: ENDGAME Review Session
Thank you SO MUCH for gracing us with your review sessions even though you aren't being mandated nor paid to do so!!! I think I speak for everyone when I say I love you 3000 x 3000 x 3000 x 3000!!! Also... will this review still be going on regarding the recent notification by Gene Block that classe...
- Tue Mar 10, 2020 4:19 pm
- Forum: Administrative Questions and Class Announcements
- Topic: ***New Coronavirus Update from UCLA***
- Replies: 2
- Views: 284
***New Coronavirus Update from UCLA***
https://newsroom.ucla.edu/releases/ucla-transitions-to-online-instruction?fbclid=IwAR2kgLjNSUH3uzaToY0F5mtUoGQ9ZG1B9J7krbfIB2KeTXAhX3TwRj-6hrI I am merely posting this for announcement purposes since it was circulated through links rather than through an official email. However it is from the UCLA w...
- Mon Mar 09, 2020 11:21 pm
- Forum: Zero Order Reactions
- Topic: Graphs
- Replies: 13
- Views: 1310
Re: Graphs
Does this still apply to winter 20!? Re: We won't be required to draw graphs but be able to interpret them. I don't think we would be, since none of the homework problems I've looked over have a drawing aspect in them. However I think it would be wise to understand what zeroth/first/second order gr...
- Mon Mar 09, 2020 11:18 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: 6N.15
- Replies: 2
- Views: 215
Re: 6N.15
I think that you are supposed to use [ Ecell = Ecell* - (RT/nrF) ln K ] for this problem because the related example in section 6N used this. It's on page 565 in the textbook if you need further clarification!
- Mon Mar 09, 2020 11:15 pm
- Forum: General Rate Laws
- Topic: Rounding "a"
- Replies: 1
- Views: 153
Re: Rounding "a"
Yes -- I'm pretty sure we do since the reaction rates are usually in terms of the coefficients of the reactants/products in the reaction, which are basically always in whole number terms. I also think it should be in whole numbers for the sake of simplicity for test calculations!
- Mon Mar 09, 2020 11:12 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Tips for Test
- Replies: 23
- Views: 1076
Re: Tips for Test
The homework problems at the end of every focus section are the most helpful because they combine lots of topics into 1 problem like the test. (i.e. 4.21, 4.43, 6.43) Would you recommend the ones in sections 5 and 6? Just for clarification which sections were the most helpful related to the Test 2?...
- Mon Mar 09, 2020 11:08 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: exothermic reaction
- Replies: 4
- Views: 355
Re: exothermic reaction
Since the delta H is negative, the reaction is therefore exothermic, which means that there is a release of energy in the reaction process. This wouldn't necessarily mean that energy is 'added' but actually released as a product! (through the formation of bonds in reactants A and B to create C)
- Mon Mar 09, 2020 11:05 pm
- Forum: General Rate Laws
- Topic: Homework 7A.1
- Replies: 4
- Views: 406
Homework 7A.1
Hii I was wondering if I could get some help with parts (b) and (c) for this homework question? Complete the following statements relating to the production of ammonia by the Haber process, for which the overall reaction is N2(g) + 3 H2(g) --> 2 NH3(g). (a) The rate of consumption of N2 is _________...
- Sat Mar 07, 2020 12:31 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Determining the cathode/anode
- Replies: 9
- Views: 726
Re: Determining the cathode/anode
You can use the equation Ecell = Eright - Eleft to deduce the cathode and anode. Eright would be the cathode and Eleft would be the anode.
- Sat Mar 07, 2020 12:28 am
- Forum: Balancing Redox Reactions
- Topic: Half rxns
- Replies: 27
- Views: 1358
Re: Half rxns
I do know that H+ is added in acidic reactions and OH- is added in basic, but I was wondering in which situations H3O+ would be used?
- Sat Mar 07, 2020 12:26 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Kelvin or Celsius?
- Replies: 86
- Views: 5176
Re: Kelvin or Celsius?
Since the STP (standard temperature and pressure) and R constant are in units of Kelvin, you should be using Kelvin for your calculations. If the problem does ask for the answer in units of Celsius, just do the calculations in Kelvin and then convert to Celsius after completing the calculations so y...
- Mon Mar 02, 2020 7:17 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: delta G equations
- Replies: 3
- Views: 296
Re: delta G equations
My TA also said it would be important to memorize the van't Hoff equation and its derivation from the delta G standard equations of deltaG=-RTlnK. He said it was because the van't Hoff equation isn't on the formula sheet but it is highly likely to be needed on the test...
- Mon Mar 02, 2020 7:14 pm
- Forum: Balancing Redox Reactions
- Topic: Acidic vs. Basic Solutions
- Replies: 8
- Views: 629
Re: Acidic vs. Basic Solutions
Hey, I understand that you add H2O to both basic/acidic solutions and add OH-/H+ to balance the H's for them respectively, but how do you know whether a question is in a basic or acidic solution if it is not mentioned in the question description?
Thanks!
Thanks!
- Mon Mar 02, 2020 6:15 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Homework 5.55
- Replies: 1
- Views: 80
Homework 5.55
A reaction used in the production of gaseous fuels from coal, which is mainly carbon, is C(s) 1 H2O(g) ∆CO(g) 1 H2(g). (a) Evaluate K At 900 K, given that the standard Gibbs free energies of formation of CO(g) and H2O(g) at 900 K are 2191.28 kJ?mol21 and 2198.08 kJ?mol21, respectively. (b) A sample ...
- Mon Mar 02, 2020 11:53 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Tips for Test
- Replies: 23
- Views: 1076
Re: Tips for Test
DesireBrown1J wrote:The homework problems at the end of every focus section are the most helpful because they combine lots of topics into 1 problem like the test. (i.e. 4.21, 4.43, 6.43)
Would you recommend the ones in sections 5 and 6? Just for clarification which sections were the most helpful related to the Test 2?
- Mon Mar 02, 2020 11:48 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Ways to calculate Gibbs free energy
- Replies: 5
- Views: 344
Re: Ways to calculate Gibbs free energy
I think it mostly just depends on what they give you. If you're given a table with delta G of different molecules, then you use the second one. I understand this, but for one of the homework questions (5J 15), we were supposed to use different methods of finding deltaG at different temperatures (25...
- Tue Feb 25, 2020 9:20 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6N.1
- Replies: 1
- Views: 140
Re: 6N.1
I'm pretty sure you are right since it would only take 1 electron to change In^3+ to In^2+.
- Tue Feb 25, 2020 9:19 pm
- Forum: Balancing Redox Reactions
- Topic: reducing agent
- Replies: 5
- Views: 314
Re: reducing agent
The reducing agent is the compound that is doing the reducing, in other words it is the one being oxidized/ in the oxidation half reaction. The opposite is said of the oxidizing agent, that it is the one doing the oxidizing, aka the one in the reduction half reaction. For me, the OIL RIG method help...
- Tue Feb 25, 2020 9:16 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Today in lecture, Dr. Lavelle
- Replies: 4
- Views: 302
Re: Today in lecture, Dr. Lavelle
Did he play this in all the lectures? I don't recall this playing on Monday, and I wish I did haha
- Tue Feb 25, 2020 9:15 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagrams
- Replies: 3
- Views: 268
Re: Cell Diagrams
In discussion today my TA told me that it should be the solid form of the anode/cathode that is on the inner parts of the cell diagram. But he also did an example with Platinum and said that was the best conductor
- Tue Feb 25, 2020 9:13 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L.7
- Replies: 1
- Views: 151
Re: 6L.7
Yes, I believe you're correct. The reduction potentials can be found in the appendix of the textbook. And I'm not sure about the question you have about balancing in an acidic/basic condition. I think I remember in the book that it mentioned that you should balance in acidic conditions unless otherw...
- Tue Feb 11, 2020 6:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 7th edition 6A.23
- Replies: 1
- Views: 64
7th edition 6A.23
Calculate the molar concentration of Ba(OH)2(aq) and the molar concentrations of Ba2+, OH2, and H3O+ in an aqueous solution that contains 0.43 g of Ba(OH)2 in 0.100 L of solution. I was wondering if someone could let me know how I can find the concentration of Ba2? I know that you can find [OH-] by ...
- Tue Feb 11, 2020 5:31 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Pizza Rolls 3b
- Replies: 1
- Views: 96
Re: Pizza Rolls 3b
The formula is q= mc delta T + 1/2 m delta Hfus
The 1/2 is due to the fact that half of it melts.
The 1/2 is due to the fact that half of it melts.
- Sat Feb 08, 2020 12:04 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Spontaneous vs Nonspontaneous
- Replies: 4
- Views: 171
Re: Spontaneous vs Nonspontaneous
One thing I remember from lecture is that systems tend to go from degree of least entropy to a degree of more entropy, and that it is unnatural for a system to go to a state with less entropy. This comes from the concept with the glass flask and having the gas be secured off to one half the glass (l...
- Fri Feb 07, 2020 11:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5H.2 Clarifications
- Replies: 3
- Views: 178
Re: 5H.2 Clarifications
They simply added the 1st and 2nd equations together and kept the molecules on their respective sides. 2 P(g) + 3 Cl2(g) <—-> 2 PCl3(g) + 2 PCl3(g) + 2 Cl2(g) <—-> 2 PCl5(g) = 2 P + 3 Cl2 + 2 PCl3 + 2 Cl2 <-> 2 PCl3 + 2 PCl5 and you could subtract 2 PCl3 from each side and therefore removing them, ...
- Fri Feb 07, 2020 11:56 pm
- Forum: Ideal Gases
- Topic: Temperature
- Replies: 17
- Views: 730
Re: Temperature
As many students started above, K is usually your best bet. The reason for this, however, is that K is an SI unit and therefore is usually used in multiple occasions/circumstances unless it is specifically stated that the answer should be in C or even F. My old high school chemistry teacher ingraine...
- Fri Feb 07, 2020 11:53 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5H.2 Clarifications
- Replies: 3
- Views: 178
Re: 5H.2 Clarifications
They simply added the 1st and 2nd equations together and kept the molecules on their respective sides. 2 P(g) + 3 Cl2(g) <—-> 2 PCl3(g) + 2 PCl3(g) + 2 Cl2(g) <—-> 2 PCl5(g) = 2 P + 3 Cl2 + 2 PCl3 + 2 Cl2 <-> 2 PCl3 + 2 PCl5 and you could subtract 2 PCl3 from each side and therefore removing them, a...
- Tue Feb 04, 2020 4:33 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Step Up Sessions
- Replies: 71
- Views: 6732
Re: Step Up Sessions
Will the current week's step up sessions be posted on here as well?
I would also like an insight to how the step up sessions are structured and how helpful they are like the posted reply above mine.
I would also like an insight to how the step up sessions are structured and how helpful they are like the posted reply above mine.
- Tue Feb 04, 2020 4:32 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 1 Distribution
- Replies: 9
- Views: 300
Test 1 Distribution
Will we get a distribution curve for the Test 1 results? I just got my test back from my TA today in Discussion but I would like to know my score in comparison to other students to know where I stand and where I should be focusing my efforts on.
- Mon Jan 27, 2020 10:52 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 9.27
- Replies: 4
- Views: 2711
Re: 9.27
Can someone please explain why HBr has a higher molar entropy than HF because I thought that you should also take into account the amount of elements available to align in such directions. I.e. HBr and HF both have 2 different elements so they can only really be aligned in similar types of directions
- Fri Jan 24, 2020 10:27 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Reaction Enthalpies calculation
- Replies: 2
- Views: 55
Re: Reaction Enthalpies calculation
I believe the 3rd method is the most accurate because it includes the calculations regarding phase changes, followed by the 1st, and the 2nd as the least accurate.
- Fri Jan 24, 2020 10:25 pm
- Forum: Phase Changes & Related Calculations
- Topic: Heat, energy, and work
- Replies: 2
- Views: 56
Re: Heat, energy, and work
Heat and energy are similar I believe because when you break bonds, you release energy, and when you form them you use energy. And work is a form of energy from what I remember in physics 5 series
- Fri Jan 24, 2020 10:21 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: When to use Standard enthalpies of formation
- Replies: 3
- Views: 96
Re: When to use Standard enthalpies of formation
I don't think you can do this for problems that are not set in standard condition because the equation for the method requires delta H ° and that only applies to bonds in standard condition.
- Fri Jan 24, 2020 10:18 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Using different methods
- Replies: 4
- Views: 114
Re: Using different methods
I believe you would use the second method if he's posed the question in a way that shows the Lewis structures. That's how he presented an example question in class today
- Fri Jan 24, 2020 10:16 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Calculation methods
- Replies: 6
- Views: 241
Re: Calculation methods
Dr. Lavelle also stressed that the second method (using bond enthalpy) was the least accurate. I don't know if that was important but I thought it was worth noting since he said it a couple times in lecture.