Search found 51 matches
- Mon Mar 16, 2020 4:22 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Voltaic Cells
- Replies: 3
- Views: 325
Re: Voltaic Cells
Yes, they are the same thing. Both are different from concentration cells.
- Sat Mar 14, 2020 10:09 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Lyndon Review: 1D
- Replies: 5
- Views: 527
Re: Lyndon Review: 1D
I believe the Ecell doesn't change. Wasn't there a similar problem on test#2? I wasn't able to get my test back so someone please correct me if I'm wrong.
- Sat Mar 14, 2020 10:08 am
- Forum: Administrative Questions and Class Announcements
- Topic: Thanks From the UA’s!
- Replies: 5
- Views: 698
Re: Thanks From the UA’s!
Awww! This is so sweet <3 Thank you for all that you guys do
- Thu Mar 12, 2020 9:12 am
- Forum: *Enzyme Kinetics
- Topic: How to distinguish the intermediates and catalysts?
- Replies: 9
- Views: 885
Re: How to distinguish the intermediates and catalysts?
You'll find that intermediates are the product of the first reaction step and then the reactant of the second reaction step - that is why it's called an intermediate because it ties the two steps together for the overall reaction. For a catalyst, it appears as a reactant and is not consumed in the r...
- Thu Mar 12, 2020 9:10 am
- Forum: Administrative Questions and Class Announcements
- Topic: FinalReview Sessions
- Replies: 3
- Views: 414
Re: FinalReview Sessions
I believe their worksheet is under "Endgame". I don't think they've posted the answer key yet though.
- Tue Mar 10, 2020 4:26 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Take Home Final?
- Replies: 2
- Views: 347
Take Home Final?
Due to Emily Carter's new email about UCLA switching to online classes, will our final be a take home final or do we still need to be present on campus on Sunday to take the Chem 14B final? I just wanted to confirm. Thanks!!
- Mon Mar 09, 2020 10:50 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: How to determine slow step?
- Replies: 9
- Views: 557
How to determine slow step?
How do you know if a step is slow or fast in a reaction mechanism?
- Tue Mar 03, 2020 4:31 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Oxidizing Power
- Replies: 3
- Views: 281
Re: Oxidizing Power
If something has oxidizing power, it itself is being reduced. If something has HIGH oxidizing power, the potential for itself to be reduced is also HIGH. Therefore, it's standard reduction potential is high.
- Tue Mar 03, 2020 4:28 pm
- Forum: First Order Reactions
- Topic: 1st, 2nd, and 0 Order Reactions
- Replies: 2
- Views: 289
Re: 1st, 2nd, and 0 Order Reactions
The difference between the three reactions is essentially the varying number of molecules needed to collide and react with each other for the reaction to proceed. You can calculate whether a reaction is 1st, 2nd, or 0th order by determining the orders of the individual reactants themselves, which ca...
- Tue Mar 03, 2020 4:25 pm
- Forum: Balancing Redox Reactions
- Topic: Number of Electrons Being Transferred
- Replies: 5
- Views: 419
Re: Number of Electrons Being Transferred
If a substance is going from Fe3+ to Fe2+, you know it gained 1 electron because the charge/oxidation # went up by 1. Then you balance the two half reactions to make sure both transfer the same amount of electrons.
- Tue Mar 03, 2020 4:23 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Reducing Power
- Replies: 3
- Views: 327
Re: Reducing Power
Reducing power is like the ability to give away electrons. A stronger reducing agent with stronger reducing power is more likely to give an electron to another compound.
- Wed Feb 26, 2020 4:28 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standard Cell Potential
- Replies: 3
- Views: 283
Re: Standard Cell Potential
Standard electric potential is the electric potential of a galvanic cell measured under standard conditions. How to calculate: E(cell) = E(cathode) - E(anode). You can get E(cathode) and E(anode) from the half reactions that happen at the cathode and anode.
- Wed Feb 26, 2020 4:24 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3865321
Re: Post All Chemistry Jokes Here
Are you made up of 12 protons? Because you're sodium fine
- Mon Feb 24, 2020 5:30 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Electrolytic Cells
- Replies: 3
- Views: 312
Re: Electrolytic Cells
I believe because of the positive electric potential and also the salt bridge.
- Mon Feb 24, 2020 5:28 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Rechargeable Batteries
- Replies: 4
- Views: 394
Re: Rechargeable Batteries
I don't think it's under the objectives in outline 5 so no.
- Mon Feb 24, 2020 5:27 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Homework Problems from Outline 5 or 6 this week?
- Replies: 2
- Views: 343
Homework Problems from Outline 5 or 6 this week?
For this week, since Dr. Lavelle just finished going over electrochemistry today, do we complete homework problems from outline #5 or outline #6? Thanks!
- Sat Feb 22, 2020 5:15 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Curve?
- Replies: 5
- Views: 361
Curve?
I was just wondering if Dr. Lavelle has curved exams in the past or just giving the class an additional 10 points at the end of the quarter? Does anyone know his pattern of curving? Thanks :)
- Sat Feb 22, 2020 5:14 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3865321
Re: Post All Chemistry Jokes Here
Instead of "LOL", Helium atoms text "HeHe" instead :)
- Sat Feb 22, 2020 5:13 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3865321
Re: Post All Chemistry Jokes Here
Atom A said, "I lost an electron"
Atom B asked, "Are you sure?"
Atom A said "Yeah, I'm positive"
Atom B said, "Well, you better keep an ion (eye on) them"
Atom B asked, "Are you sure?"
Atom A said "Yeah, I'm positive"
Atom B said, "Well, you better keep an ion (eye on) them"
- Sat Feb 22, 2020 5:12 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3865321
Re: Post All Chemistry Jokes Here
A man was frozen to absolute zero. But don't worry - he's 0K now :D
- Tue Feb 18, 2020 10:06 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Study Advice
- Replies: 73
- Views: 7287
Re: Study Advice
Lyndron Bui and Michael Zalgari's sessions are helpful!
- Tue Feb 18, 2020 10:04 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Grade [ENDORSED]
- Replies: 1
- Views: 291
Midterm Grade [ENDORSED]
Dr. Lavelle said midterm grades would be coming out today (Tuesday, 2/18). Does anyone see their grade on myUCLA yet or is it posted somewhere else? Thanks!
- Mon Feb 10, 2020 9:49 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Entropy Change due to Changes in Temperature
- Replies: 2
- Views: 157
Entropy Change due to Changes in Temperature
For the ratio fo T2/T1 in the ln for the entropy change equation, do they always have to be in kelvin or can the ratio be in celsius as well? I noticed a discrepancy in this. Thanks!
- Mon Feb 10, 2020 9:47 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Correct Calculator for Midterm
- Replies: 2
- Views: 305
Correct Calculator for Midterm
I just wanted to double check that a TI-30XIIS calculator is okay for the midterm? It isn't able to graph or record information. Thanks!
- Mon Feb 10, 2020 9:46 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Free energy
- Replies: 6
- Views: 546
Re: Free energy
Standard free energy is measured in a lab under standard conditions (usually is denoted with a degree symbol). Delta G can be measured in a situation that isn't in standard conditions like in a biological system. So would we need to know anything more than just the sources of error/ comparison betw...
- Sat Feb 08, 2020 8:53 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Pizza Rolls REVIEW Session DOWNLOAD HERE
- Replies: 67
- Views: 5937
Re: Pizza Rolls REVIEW Session DOWNLOAD HERE
Is the Sunday review session only for going over the practice questions and then the one on Monday is content-based review?
- Sat Feb 08, 2020 3:37 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Pizza Rolls REVIEW Session DOWNLOAD HERE
- Replies: 67
- Views: 5937
Re: Pizza Rolls REVIEW Session
Are you only going over the answers at the Sunday review session or the Monday one as well? Thank you so much :)))
- Thu Feb 06, 2020 9:07 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Keeping equations straight
- Replies: 2
- Views: 94
Re: Keeping equations straight
I like to take a blank piece of printer paper and write down equations based on category. Also, for internal energy = heat + work, it's helpful for me to work out when there is constant volume, delta V = 0 and thus there is no work done so internal energy = work instead of simply memorizing internal...
- Thu Feb 06, 2020 9:05 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: chen discussion [ENDORSED]
- Replies: 5
- Views: 217
Re: chen discussion [ENDORSED]
Diana_Diep2I wrote:When do we use C and when do we use R?
C = 3/2R at constant volume and C = 5/2R at constant pressure.
- Thu Feb 06, 2020 9:04 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: reversible vs irreversible work
- Replies: 4
- Views: 283
Re: reversible vs irreversible work
A reversible system is usually one where the reactants and products fluctuate slowly to reach equilibrium.
- Thu Feb 06, 2020 9:02 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Free energy
- Replies: 6
- Views: 546
Re: Free energy
Standard free energy is measured in a lab under standard conditions (usually is denoted with a degree symbol). Delta G can be measured in a situation that isn't in standard conditions like in a biological system.
- Sun Feb 02, 2020 2:01 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: degeneracy
- Replies: 3
- Views: 146
Re: degeneracy
The equation to calculate degeneracy is W = x^n where x = # of states (in this case is 2) and n = # of particles (in this case is 3). Therefore, w = 2^3 = 8.
- Sun Feb 02, 2020 12:58 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Week 5 Homework
- Replies: 7
- Views: 274
Week 5 Homework
For Week 5's homework, do we do problems from outline #4 again?
- Thu Jan 30, 2020 9:49 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Material
- Replies: 13
- Views: 766
Midterm Material
What material is going to be covered for the midterm? Are there usually review sessions beforehand that are taught by Dr. Lavelle or the TAs?
- Wed Jan 29, 2020 1:33 pm
- Forum: General Science Questions
- Topic: Sig Figs
- Replies: 3
- Views: 334
Sig Figs
When you have conversion factors in your calculations, do you also take the sig figs of those numbers into account? For example, 1L = 1000mL, would you take the sig figs into account when calculating the rest of the problem? Thanks!
- Sun Jan 26, 2020 9:27 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Week 4 Homework
- Replies: 11
- Views: 367
Re: Week 4 Homework
Just wanted to comment so I can follow this post :)
- Thu Jan 23, 2020 10:59 pm
- Forum: Phase Changes & Related Calculations
- Topic: Celsius and Kelvin
- Replies: 11
- Views: 460
Re: Celsius and Kelvin
You always have to convert between kelvins and celsius. It's better to do K = 273.15 + C because it is more exact.
- Thu Jan 23, 2020 10:48 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Best Way To Study?
- Replies: 13
- Views: 669
Re: Best Way To Study?
Thank you all for so many helpful suggestions! I will definitely start looking into going to the UA sessions because I forgot those existed :)
- Wed Jan 22, 2020 9:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Autoprotolysis
- Replies: 8
- Views: 250
Re: Autoprotolysis
Daria Azizad 1K wrote:ELu 1J wrote:It occurs naturally and emphasizes the amphoteric nature of water (the ability to both give and accept a proton).
The ability to accept and donate a proton is amphiprotic, while amphoteric is the ability to react with both acids and bases. :)
Oh my bad - thank you for the correction :)
- Wed Jan 22, 2020 9:37 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Best Way To Study?
- Replies: 13
- Views: 669
Best Way To Study?
Hi, here's a question for those who have had Lavelle previously: what method of studying for exams did you find most effective? Doing all of the assigned textbook problems or sapling problems or other things? Thanks for sharing :)
- Tue Jan 14, 2020 8:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: equilibrium concentration with gases
- Replies: 7
- Views: 248
Re: equilibrium concentration with gases
Yes, because the context of the problem is moles, that is what leads you to calculate Kc instead of Kp even though all substances are in gas phase.
- Tue Jan 14, 2020 8:24 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Are Lectures Bruincasted?
- Replies: 10
- Views: 401
Re: Are Lectures Bruincasted?
Where can you view modules?
- Tue Jan 14, 2020 8:20 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Hw 5J.11
- Replies: 2
- Views: 122
Re: Hw 5J.11
I think you just have to memorize that if delta H is negative, the reaction is exothermic and if delta H is positive, the reaction is endothermic.
- Tue Jan 14, 2020 8:19 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Endothermic and exothermic reactions
- Replies: 11
- Views: 1121
Re: Endothermic and exothermic reactions
I've heard someone explain it like this before: think of heat as either another reactant or product. If the reaction is endothermic, the system absorbs heat and heat is considered a reactant. Say you heat up the system, you're adding heat (a "reactant"), which means the reaction will favor...
- Tue Jan 14, 2020 8:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Autoprotolysis
- Replies: 8
- Views: 250
Re: Autoprotolysis
It occurs naturally and emphasizes the amphoteric nature of water (the ability to both give and accept a proton).
- Mon Jan 13, 2020 4:42 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Are Lectures Bruincasted?
- Replies: 10
- Views: 401
Are Lectures Bruincasted?
I was wondering if Dr. Lavelle's lectures are bruincasted and if so, where may I find them? Thanks!
- Sun Jan 12, 2020 1:36 pm
- Forum: Administrative Questions and Class Announcements
- Topic: General HW question
- Replies: 9
- Views: 413
Re: General HW question
I thought it was graded based on the correctness of our 5 problems we turned in.
- Sun Jan 12, 2020 1:35 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test 1 date
- Replies: 4
- Views: 289
Re: Test 1 date
It's during your discussion during week 3 (1/20-1/24).
- Sat Jan 11, 2020 2:48 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Changes in Pressure
- Replies: 3
- Views: 172
Re: Changes in Pressure
I think he was talking about how if the pressure is increased for a particular reaction, it isn't an adequate explanation to say that it will cause a shift to the right because there are more moles of reactants than products. Instead, the correct explanation would be that an increase in pressure wou...
- Wed Jan 08, 2020 9:16 pm
- Forum: Ideal Gases
- Topic: PV=nRT equation manipulation
- Replies: 13
- Views: 734
Re: PV=nRT equation manipulation
I think the purpose is just based on the context of the problem. The problem could give the initial concentration of a gas but then ask you to find the partial pressure at equilibrium or something that requires you to be able to convert one to another when the substance is a gas.
- Wed Jan 08, 2020 9:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Problem 5G.1b
- Replies: 1
- Views: 140
Problem 5G.1b
5G.1 State whether the following statements are true or false. If false, explain why. (b) An equilibrium reaction is not affected by increasing the concentrations of products. I just wanted to clarify that the statement is saying that the concentration of the products is increased AFTER the reaction...