Search found 110 matches
- Sun Mar 14, 2021 6:43 pm
- Forum: Administrative Questions and Class Announcements
- Topic: THANK YOU DR LAVELLE!
- Replies: 47
- Views: 6669
Re: THANK YOU DR LAVELLE!
boost!!! also i didn’t thank my classmates on my slide but you all have been amazing and such a supportive group, thank you so much!! :)
- Sun Mar 14, 2021 3:53 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Which R to use
- Replies: 42
- Views: 3022
Re: Which R to use
pay attention to the units of the given values! if it’s multiple choice look at the units of the answer to give you an extra hint :)
- Sun Mar 14, 2021 3:52 pm
- Forum: Student Social/Study Group
- Topic: Playlist
- Replies: 86
- Views: 6967
Re: Playlist
this thread is amazing!! i honestly would love to have access to dr. lavelle’s playlist he has very good taste in jam-worthy music haha
- Sun Mar 14, 2021 3:50 pm
- Forum: Student Social/Study Group
- Topic: How do you deal with burnout?
- Replies: 144
- Views: 15129
Re: How do you deal with burnout?
for me, it helps to have a designated study space so that i don’t feel overwhelmed and i can get away from studying completely when i need a break! also taking walks as study breaks instead of just going on my phone (which i’m guilty of) and it really gives my brain like a power nap! good luck :)
- Sat Mar 13, 2021 1:16 pm
- Forum: General Science Questions
- Topic: Final Exam
- Replies: 39
- Views: 2106
Re: Final Exam
just as an FYI if you're struggling with electrochem and/or kinetics, there's a great worksheet on chemistry community to review tougher concepts in those sections! just search "endgame" and there should be a thread that has the pdf!! it helped me a lot :) good luck on the final everyone!!...
- Sat Mar 06, 2021 11:00 am
- Forum: Balancing Redox Reactions
- Topic: How to Determine if a Reaction is in Basic or Acidic Solution?
- Replies: 53
- Views: 3172
Re: How to Determine if a Reaction is in Basic or Acidic Solution?
I had the same question! Thank you for asking :)
- Sat Mar 06, 2021 10:58 am
- Forum: Student Social/Study Group
- Topic: From pKa to pH
- Replies: 6
- Views: 440
Re: From pKa to pH
These are the main conversions we learned in class!
Ka*Kb=Kw
pKa+pKb=pKw
Kw=[OH-][H+]= 1x10^-14
also for buffer systems only, you can use the henderson-hasselbach equation to convert from pKa to pH.
hope this helps!
Ka*Kb=Kw
pKa+pKb=pKw
Kw=[OH-][H+]= 1x10^-14
also for buffer systems only, you can use the henderson-hasselbach equation to convert from pKa to pH.
hope this helps!
- Sat Mar 06, 2021 10:52 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Video Review
- Replies: 8
- Views: 508
Re: Video Review
organic chemistry tutor helped me a lot with understanding the basics of electrochemistry! the only thing is those videos can be kind of long so not ideal if you are trying to study in a short period of time (which has happened to me before haha)! if that's the case, you can always try 1.5 or 2x spe...
- Sat Mar 06, 2021 10:50 am
- Forum: Student Social/Study Group
- Topic: Note Taking
- Replies: 145
- Views: 16465
Re: Note Taking
for this class, i definitely prefer handwriting my notes! the only time I type notes is when I feel like I will struggle to keep up with the lecture while taking notes by hand. for this class, given that it is recorded, I am able to pause at points if I need to so taking notes by hand is not stressf...
- Sat Mar 06, 2021 10:46 am
- Forum: Administrative Questions and Class Announcements
- Topic: [CHEM 14B KARAOKE]
- Replies: 68
- Views: 6228
Re: [CHEM 14B KARAOKE]
so excited!! thanks for organizing this :))
- Sat Feb 27, 2021 11:12 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridges
- Replies: 41
- Views: 3130
Re: Salt Bridges
The salt bridge prevents ion build-up on either side of the galvanic cell and helps maintain a neutral charge as electrons flow between the two sides.
- Sat Feb 27, 2021 11:10 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Which Nesnst Equation
- Replies: 25
- Views: 1192
Re: Which Nesnst Equation
The ln equation applies in all cases but the log equation can only be used for reactions at 25 degrees Celsius (or 298K).
- Sat Feb 27, 2021 11:06 pm
- Forum: Balancing Redox Reactions
- Topic: Determining which molecule is the oxidizing agent
- Replies: 49
- Views: 1922
Re: Determining which molecule is the oxidizing agent
The oxidizing agent encourages oxidation of the other species by being reduced itself, so yes, you would be correct in saying that the oxidizing agent is the one that is reduced :)
- Sat Feb 27, 2021 11:05 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Sapling #17
- Replies: 8
- Views: 663
Re: Sapling #17
Yes, you would use the Nernst equation but you would use a combination of concentration values and partial pressures when solving for Q so it's a little different than what we're used to! Q = PH2/[H+]^2 Hope that helps!
- Sat Feb 27, 2021 11:03 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Oxidizing agent as anode?
- Replies: 2
- Views: 206
Re: Oxidizing agent as anode?
That would be correct! I was confused by the title of your question and thought you were asking if the oxidizing agent is at the anode haha but what you have here looks accurate :)
- Sun Feb 21, 2021 7:00 pm
- Forum: Calculating Work of Expansion
- Topic: Negative Work
- Replies: 30
- Views: 1296
Re: Negative Work
If work is done on the system, w is a positive value. If the system does work, then w is a negative value. Hope that helps :)
- Sun Feb 21, 2021 6:58 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Open vs closed
- Replies: 31
- Views: 2924
Re: Open vs closed
The difference is in what can be transferred in/out of a system:
Open systems: mass and energy
Closed systems: energy
Isolated systems: neither
It definitely is important to know what kind of system it is, especially for thermochemistry problems!
Open systems: mass and energy
Closed systems: energy
Isolated systems: neither
It definitely is important to know what kind of system it is, especially for thermochemistry problems!
- Sun Feb 21, 2021 6:55 pm
- Forum: Student Social/Study Group
- Topic: Classes for next quarter?
- Replies: 165
- Views: 15729
Re: Classes for next quarter?
I'm planning on taking Math 3C, LS7C, LS23L, a cluster, and a 1 unit seminar! I am a little concerned about the workload haha so I'm thinking about dropping one class depending on how overwhelming the first two weeks are :)
- Sun Feb 21, 2021 6:53 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Forward vs. Reverse
- Replies: 22
- Views: 2149
Re: Forward vs. Reverse
The way the reaction is presented to you in the problem would generally be the forward reaction (unless stated otherwise). So if that reaction is reactants --> products, then its reverse is products --> reactants. Hope this helps :)
- Sun Feb 21, 2021 6:51 pm
- Forum: Calculating Work of Expansion
- Topic: Calculating W
- Replies: 4
- Views: 358
Re: Calculating W
You can use Boltzmann's entropy formula to solve for W in this question: S = (Boltzmann's constant)(lnW) --> W = e^(S/kB)
- Sun Feb 21, 2021 6:47 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: State function?
- Replies: 36
- Views: 1398
Re: State function?
No, cell potential is not a state function but its symbol is a capital letter so I was confused too at first!
- Sun Feb 14, 2021 5:30 pm
- Forum: Student Social/Study Group
- Topic: Fav Shows of the Moment
- Replies: 115
- Views: 47421
Re: Fav Shows of the Moment
schitt's creek!!! it's such a lovable show with a lovable cast and it's pretty light which is great during exam season :) my current favorite for sure!!
- Sun Feb 14, 2021 5:28 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneity at Equilibrium?
- Replies: 10
- Views: 573
Re: Spontaneity at Equilibrium?
A reaction at equilibrium has a delta G equal to 0 so the reaction is not thermodynamically favorable in either direction and therefore nonspontaneous.
- Sun Feb 14, 2021 5:24 pm
- Forum: Ideal Gases
- Topic: R ideal gas constant
- Replies: 31
- Views: 2160
Re: R ideal gas constant
This always trips me up when I'm trying to work quickly haha! The most definite way to know is to look at the units in your calculation and compare them to the units of the two different constants (they are very different!). Hope this helps :)
- Sun Feb 14, 2021 5:23 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm 2
- Replies: 33
- Views: 2188
Re: Midterm 2
I believe he announced that midterm 2 will cover the part of outline 3 that was not on midterm 1 and all of outline 4!
- Sun Feb 14, 2021 5:19 pm
- Forum: Student Social/Study Group
- Topic: Balance / Self Care Tips
- Replies: 62
- Views: 3233
Re: Balance / Self Care Tips
My biggest tip during exam season is to get a good amount of sleep the night before! Even if it means you don't get to study as much as you think you need to, your brain will function so much better during the test. In my experience, good sleep is much more effective the night before than last-minut...
- Sun Feb 14, 2021 5:17 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Closed vs Isolated System
- Replies: 30
- Views: 1363
Re: Closed vs Isolated System
A closed system is not insulated so energy transfer can still occur but with an isolated system, energy cannot escape or enter the system.
- Sun Feb 07, 2021 4:36 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Sapling #14
- Replies: 6
- Views: 367
Re: Sapling #14
Since it is an ideal gas, you can use PV=nRT and the given variables to solve for # of moles.
- Sun Feb 07, 2021 4:33 pm
- Forum: Phase Changes & Related Calculations
- Topic: H and q
- Replies: 47
- Views: 1688
Re: H and q
q is the measurement of heat (transfer of heat energy) and H is the measurement of enthalpy! Enthalpy is a state function but heat is not. If the system in question is at constant pressure, then I believe delta H is equal to q.
- Sun Feb 07, 2021 4:30 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Can heat capacities be negative?
- Replies: 52
- Views: 13946
Re: Can heat capacities be negative?
Heat capacities are always positive! Reaction enthalpies can definitely be positive or negative but the heat capacity term will always be positive.
- Sun Feb 07, 2021 4:28 pm
- Forum: Phase Changes & Related Calculations
- Topic: Vapor vs gas
- Replies: 121
- Views: 11293
Re: Vapor vs gas
I believe vapor refers to when a substance that is commonly liquid/solid is in the gas phase. So in calculations, you would treat gases and vapors the same way!
- Sun Feb 07, 2021 4:24 pm
- Forum: Student Social/Study Group
- Topic: Studying When You Don't Want to
- Replies: 48
- Views: 2751
Re: Studying When You Don't Want to
This happens to me a lot and what I try to do is to find a place to study that will give me a change of scenery. Either I go to the library, my backyard, my sister's room, or just somewhere where I don't feel so alone and isolated and that definitely helps me :)
- Sun Jan 31, 2021 6:48 pm
- Forum: Administrative Questions and Class Announcements
- Topic: 14C?
- Replies: 23
- Views: 974
Re: 14C?
I'm planning on waiting until fall 2021! I also thought it made sense to break between gen chem and o chem :)
- Sun Jan 31, 2021 6:45 pm
- Forum: Student Social/Study Group
- Topic: Go treat yourself after MT1!
- Replies: 75
- Views: 5057
Re: Go treat yourself after MT1!
love this positive energy :)) thanks!
- Sun Jan 31, 2021 6:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs. Kc
- Replies: 36
- Views: 1363
Re: K vs. Kc
K is the general variable for equilibrium constant. It can be written more specifically as Kc (concentration) or Kp (partial pressure). The one you use is dependent on the problem you're trying to solve and the given information. Hope that helps :)
- Sun Jan 31, 2021 6:40 pm
- Forum: Student Social/Study Group
- Topic: Spring 2021
- Replies: 106
- Views: 14507
Re: Spring 2021
Hello! I'm currently taking Chem 14BL right now, and I just want to advise that this class, while not the most difficult material, is a lot of work. So if you think you are already going to have a busy schedule next quarter, you might want to consider whether you can handle this extra workload (wee...
- Sun Jan 31, 2021 6:32 pm
- Forum: Student Social/Study Group
- Topic: Work Life Balance
- Replies: 44
- Views: 1737
Re: Work Life Balance
I totally agree!! one thing I've been doing recently to help counteract this a little bit is doing anything that doesn't involve a screen during my breaks between zoom calls. On days where I have a lot of classes back to back, I try to just take a break from screens, including my phone or TV, and go...
- Sun Jan 24, 2021 9:58 pm
- Forum: Student Social/Study Group
- Topic: Midterm Study Tips
- Replies: 41
- Views: 1700
Re: Midterm Study Tips
textbook problems and review sessions!!
- Sun Jan 24, 2021 7:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Learning Q2 Percent Ionization
- Replies: 2
- Views: 154
Re: Sapling Learning Q2 Percent Ionization
When he taught %ionization in lecture, I believe Dr. Lavelle said it was the [conjugate]/[original substance] so the correct notation would be [A-]/[HA]. If the molar ratio of H+ and A- is 1:1, their equilibrium concentrations should be equal as they are both products of the reaction. Therefore, tec...
- Sun Jan 24, 2021 7:12 pm
- Forum: Phase Changes & Related Calculations
- Topic: Adding Heat but Temp remains constant
- Replies: 11
- Views: 423
Re: Adding Heat but Temp remains constant
So in that situation, the heat is being used to break the bonds/intramolecular forces so it doesn't affect the actual temperature of the substance.
- Sun Jan 24, 2021 7:10 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Sapling week 2 #9
- Replies: 8
- Views: 430
Re: Sapling week 2 #9
Hi! When the pH > pKa, the predominant species is charged because the environment around it is more basic (the pH is higher) than the species, so the acid will dissociate and become ionized to make the environment more acidic. When the pH < pKa, the predominant species is neutral because the enviro...
- Sun Jan 24, 2021 7:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Problem 5I.29
- Replies: 4
- Views: 194
Re: Problem 5I.29
Generally if the relevant K value is less than 10^-4, you can approximate when finding equilibrium concentrations! You can also double check by seeing if your value for x is less than 5% of the initial reactant concentration.
- Sun Jan 24, 2021 7:05 pm
- Forum: Student Social/Study Group
- Topic: Calculators
- Replies: 52
- Views: 3313
Re: Calculators
You are allowed a scientific or graphing calculator, the equation/constant sheet, the periodic table, and scratch paper for the exam. Dr. Lavelle's website has the specific periodic table and equation sheet that is permitted for the test.
- Sun Jan 17, 2021 5:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: sapling week #1 Question 6
- Replies: 4
- Views: 127
Re: sapling week #1 Question 6
[H2] should be cubed rather than squared! Hope this helps :)
- Sun Jan 17, 2021 5:55 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pure Liquids (Solutes)
- Replies: 7
- Views: 350
Re: Pure Liquids (Solutes)
This might be an oversimplification but my understanding is that anything labeled in the equation with (s) or (l) should not be included in the K expression. I think only substances that are either gaseous or aqueous should be included.
- Sun Jan 17, 2021 5:50 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Le Chatelier's Principle and Pressure
- Replies: 6
- Views: 330
Re: Le Chatelier's Principle and Pressure
Pressure and volume are inversely related. When pressure increases, volume decreases --> when there is less space to occupy (volume), the reaction will favor the side with fewer moles.
- Sun Jan 17, 2021 5:44 pm
- Forum: Student Social/Study Group
- Topic: Comfort Movies
- Replies: 168
- Views: 26332
Re: Comfort Movies
definitely disney classics!! and also harry potter (especially the early ones which are much less dark than the later ones)
- Sun Jan 17, 2021 5:38 pm
- Forum: Ideal Gases
- Topic: Inverse Kc [ENDORSED]
- Replies: 41
- Views: 2114
Re: Inverse Kc [ENDORSED]
inverse of Kc is to the reverse reaction what Kc is to the forward reaction. that's how I remember it!
- Sun Jan 17, 2021 5:35 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q > K, Q< K
- Replies: 25
- Views: 837
Re: Q > K, Q< K
This visual helps me remember in a really simple way! If Q>K then more reactants will form and if Q<K then more products will form in order to reach equilibrium where Q=K.
- Sun Jan 10, 2021 7:26 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Grading for Chemistry Community Posts
- Replies: 13
- Views: 1075
Re: Grading for Chemistry Community Posts
Emily Tieu 2K wrote:^ This is also my first time taking Professor Lavelle. To clarify, is it 50 times by week 10 or 5 times every week?
Technically, it is 5 posts per week but I think the grading depends on the TAs. To be on the safe side, try to do 5 posts every week :)
- Sun Jan 10, 2021 7:24 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Sapling homework due date
- Replies: 14
- Views: 715
Re: Sapling homework due date
josephspindler2H wrote:Thanks for clarifying that the homework is due next Sunday 1/17! Out of curiosity, does anyone know if week 2 homework also be due that day?
No, the next homework assignment will include content from weeks 2-4 so it will be due the Sunday of Week 4 I believe.
- Sun Jan 10, 2021 7:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentration
- Replies: 12
- Views: 707
Re: Concentration
The values of volume and moles can never be negative so the ratio of the two (concentration) can also never be negative.
- Sun Jan 10, 2021 7:18 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs. Q
- Replies: 53
- Views: 2116
Re: K vs. Q
You're correct! I believe Q can be calculated at any time during the reaction (including at equilibrium) but if it is specified that the reaction is at equilibrium you can use K instead.
- Sun Jan 10, 2021 7:16 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: increasing total pressure in equilibria
- Replies: 11
- Views: 475
Re: increasing total pressure in equilibria
When pressure is increased, the equilibrium will favor the side that has less moles of gas. When volume is increased, the equilibrium will favor the side with more moles of gas.
- Tue Dec 15, 2020 6:17 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3592222
Re: Post All Chemistry Jokes Here
What does formaldehyde look like on vacation?
Casual-dehyde!
Casual-dehyde!
- Tue Dec 15, 2020 6:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 547621
Re: Saying Thank You to Dr. Lavelle
Thank you so much for this quarter Dr. Lavelle!! Your lectures were engaging and I really wish I could have taken your class in person! Nonetheless, I am really looking forward to next quarter in 14B! I hope you stay safe and enjoy the holidays :)
- Tue Dec 15, 2020 6:04 pm
- Forum: Student Social/Study Group
- Topic: Staying Motivated
- Replies: 38
- Views: 1730
Re: Staying Motivated
Hey I know how you feel, this quarter my home life was more chaotic than usual and mental and physical health issues certainly did not help my motivation. What I found to help was that for classes like this where you dread wanting to go and feel you can fall behind easily, DO IT FIRST! Its harder s...
- Tue Dec 15, 2020 6:02 pm
- Forum: Student Social/Study Group
- Topic: How are you?
- Replies: 154
- Views: 13909
Re: How are you?
Just finished my second final! Slowly running out of mental energy but looking forward to break :))
- Tue Dec 15, 2020 6:01 pm
- Forum: Student Social/Study Group
- Topic: Grades
- Replies: 29
- Views: 1297
Re: Grades
we have until 10 am thursday morning to post on chem community!
- Sun Dec 06, 2020 3:52 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Lectures not loading
- Replies: 6
- Views: 315
Re: Lectures not loading
Zainab Jamali 3I wrote:The same thing happened to me! Once I reconnected to the campus VPN, the video loaded and started playing so maybe try that?
Actually scratch that. I am still connected to the VPN and it just stopped working again :(
- Sun Dec 06, 2020 3:51 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Will fundamentals problems be on our final?
- Replies: 6
- Views: 429
Re: Will fundamentals problems be on our final?
I would think so because the final is cumulative for the whole quarter, but someone please correct me if I'm wrong :)
- Sun Dec 06, 2020 3:49 pm
- Forum: Student Social/Study Group
- Topic: Studying for Final Exam
- Replies: 57
- Views: 2707
Re: Studying for Final Exam
I am definitely going to take advantage of all the review sessions these week as well as Professor Lavelle's review session. I think it is super helpful to do practice problems with other students and be able to ask the UA's questions while doing so! Agreed! Also, hearing the answers to other stude...
- Sun Dec 06, 2020 3:37 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Partial Credit on the Final
- Replies: 6
- Views: 360
Re: Partial Credit on the Final
I was wondering the same thing because midterm 1 did have partial credit opportunities but midterm 2 did not. Since the final will be cumulative, I hope at least some questions will have partial credit opportunities.
- Sun Dec 06, 2020 3:17 pm
- Forum: Naming
- Topic: HW Question #1
- Replies: 7
- Views: 451
Re: HW Question #1
Why is it dichloro? I thought there were 3 chlorine atoms. There are only two chlorine ligands within the complex ion (within the brackets). When you name the first part of a coordination compound, you are naming only the complex ion so it would be "dichloro" and the third chlorine in the...
- Sun Dec 06, 2020 3:10 pm
- Forum: Naming
- Topic: Order of Ligands/naming
- Replies: 28
- Views: 1212
Re: Order of Ligands/naming
Ligands are listed in alphabetical order by the first letter of the ligand (not the numerical prefix). Hope this helps!
- Sun Dec 06, 2020 3:10 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Lectures not loading
- Replies: 6
- Views: 315
Re: Lectures not loading
The same thing happened to me! Once I reconnected to the campus VPN, the video loaded and started playing so maybe try that?
- Sun Nov 29, 2020 4:49 pm
- Forum: Resonance Structures
- Topic: Sapling Week 8 Q17
- Replies: 6
- Views: 447
Re: Sapling Week 8 Q17
reva_bajjuri wrote:does anyone know why exactly the ring structure is stable/what the benefit of forming a ring is?
I'm wondering the same thing!
- Sun Nov 29, 2020 4:47 pm
- Forum: Student Social/Study Group
- Topic: Tips for Staying Focused
- Replies: 64
- Views: 3879
Re: Tips for Staying Focused
I have been struggling with the same thing so this thread is really helpful! Thank you :)
- Sun Nov 29, 2020 4:46 pm
- Forum: Coordinate Covalent Bonds
- Topic: Hydrogen bonds
- Replies: 20
- Views: 1327
Re: Hydrogen bonds
The hydrogen bond relies partially on a partial positive charge on the hydrogen. When the H is attached to a carbon, there is very little polarity and the partial charge on hydrogen isn't there to bond to the partial negative on the bonding atom.
- Sun Nov 29, 2020 4:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Angle Masterlist
- Replies: 5
- Views: 280
Re: Angle Masterlist
This is really helpful, thank you!!
- Sun Nov 29, 2020 4:36 pm
- Forum: Student Social/Study Group
- Topic: Final Study
- Replies: 32
- Views: 1511
Re: Final Study
I have been reviewing problems in the book and on Sapling. Are there any specific Youtube channels anyone can recommend that effectively review this course's material? Personally, I watch organic chemistry tutor on youtube when I need clarification on concepts! The videos are very detailed, clear, ...
- Sat Nov 21, 2020 1:48 pm
- Forum: Student Social/Study Group
- Topic: Study Tips for Final Exam
- Replies: 57
- Views: 2762
Re: Study Tips for Final Exam
I find that reading the textbook in conjunction with Dr. Lavelle's lectures is very helpful. If there are concepts I still can't quite grasp I definitely rely on Organic Chemistry Tutor on youtube haha. Once you have reviewed content, try testing yourself with practice textbook questions.
- Sat Nov 21, 2020 1:46 pm
- Forum: Octet Exceptions
- Topic: Octet Rule Exceptions
- Replies: 20
- Views: 1412
Re: Octet Rule Exceptions
Thanks for asking this question! This thread is very helpful :)
- Sat Nov 21, 2020 1:43 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3592222
Re: Post All Chemistry Jokes Here
The name's Bond. Ionic Bond. Taken, not shared.
- Sat Nov 21, 2020 1:39 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3592222
Re: Post All Chemistry Jokes Here
A photon checks into a hotel and is asked if he needs any help with his luggage. He says, "No, I'm traveling light." :)
- Sat Nov 21, 2020 1:32 pm
- Forum: Administrative Questions and Class Announcements
- Topic: 14B and 14BL
- Replies: 13
- Views: 843
Re: 14B and 14BL
I think I will be taking 14B in winter and BL in spring, as I personally want to have a stronger foundation first before delving into lab stuff, but I've heard that either way you do it is fine! I'm planning on doing the same thing! I feel like knowing the textbook content well before taking the la...
- Sun Nov 15, 2020 12:24 pm
- Forum: Lewis Structures
- Topic: breaking the octet rule
- Replies: 4
- Views: 305
breaking the octet rule
Does anyone have a good way to remember which atoms can break the ocet rule during bonding, like which atoms can have an expanded octet and which atoms can have an incomplete octet (besides the first 4 elements)?
- Sun Nov 15, 2020 12:20 pm
- Forum: Lewis Structures
- Topic: Sapling Question -- Formula of Ions
- Replies: 1
- Views: 132
Re: Sapling Question -- Formula of Ions
I was wondering the same thing. The question did not give the formulas for these polyatomic ions. Are we meant to know basic polyatomic ion names and charges for the midterm or will Dr. Lavelle provide the formulas on the exam?
- Sun Nov 15, 2020 12:19 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Clarification
- Replies: 8
- Views: 429
Re: Clarification
Right! I find the overall charge helps me check to make sure I have assigned the individual formal charges correctly.
- Sun Nov 15, 2020 12:16 pm
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 19
- Views: 759
Re: Resonance
Resonance structures have delocalized electrons which are very stable and contribute to the overall stability of the molecule.
- Mon Nov 09, 2020 10:49 am
- Forum: Resonance Structures
- Topic: Formal charges in regards to resonance strucures
- Replies: 3
- Views: 102
Re: Formal charges in regards to resonance strucures
I believe formal charge is allocated per atom, but the collective formal charges of all atoms in a molecule add up to the total formal charge of the molecule. Right, that makes sense! I still would like to know if there is a way to determine which atom will hold that formal charge in resonance stru...
- Sun Nov 08, 2020 10:42 pm
- Forum: Resonance Structures
- Topic: Formal charges in regards to resonance strucures
- Replies: 3
- Views: 102
Formal charges in regards to resonance strucures
During last Monday's lecture, Dr. Lavelle discussed how multiple bond character was spread over the molecule in the case of resonance structures. Since adding a double bond would change the formal charge of one atom in the molecule, how is that formal charge allocated? Is it also spread over the mol...
- Sun Nov 08, 2020 7:39 pm
- Forum: Lewis Structures
- Topic: Lewis Acids/Bases
- Replies: 4
- Views: 351
Lewis Acids/Bases
Hi! I was wondering if someone could clarify what distinguishes a Lewis acid from a Lewis base? Is it based on whether they lose or gain electrons during bonding?
- Sun Nov 08, 2020 7:36 pm
- Forum: Student Social/Study Group
- Topic: Lecture on Veteran's Day
- Replies: 10
- Views: 370
Re: Lecture on Veteran's Day
Professor Lavelle also mentioned at one point that he would not be holding office hours on Wednesday due to the national holiday so I assume that means he will not have a lecture either.
- Sun Nov 08, 2020 7:31 pm
- Forum: Bond Lengths & Energies
- Topic: Delocalized Electrons
- Replies: 5
- Views: 349
Re: Delocalized Electrons
In addition, when electrons are delocalized due to resonance, it results in a more stable molecule.
- Sun Nov 08, 2020 7:03 pm
- Forum: Resonance Structures
- Topic: Electron spin
- Replies: 12
- Views: 457
Re: Electron spin
There really isn't a way to determine if the electron is spinning +1/2 or -1/2. Pretty much the only practical reason why those two numbers exist is to communicate that the two electrons in the state are spinning in opposite directions, in that they are not parallel. I agree, it is simply to differ...
- Sun Nov 08, 2020 6:58 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3592222
Re: Post All Chemistry Jokes Here
I would post another chemistry joke, but all the good ones Argon :)
- Sun Nov 01, 2020 9:17 pm
- Forum: Student Social/Study Group
- Topic: Textbook vs Lectures vs Other Methods
- Replies: 17
- Views: 746
Re: Textbook vs Lectures vs Other Methods
Hi! I am currently in 14a. Personally, I have found that the lectures and sapling assignments cover the material really well. I use the textbook to review concepts and the textbook problems to prepare for the midterm exam (especially for concepts I have more difficulty with).
- Sun Nov 01, 2020 9:15 pm
- Forum: DeBroglie Equation
- Topic: When to Use De Broglie
- Replies: 16
- Views: 1557
Re: When to Use De Broglie
The simplest way to think about it is that E = hv and c = v(lambda) applies to electromagnetic radiation and deBroglie's equation applies to particles with mass, including all the subatomic particles.
- Sun Nov 01, 2020 9:12 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Sapling Question (excited-state, ground-state)
- Replies: 4
- Views: 293
Re: Sapling Question (excited-state, ground-state)
For this question, you can start by finding the total number of electrons. That number is equivalent to the atomic number of the atom so, using the periodic table, you can determine what element it is.
- Fri Oct 30, 2020 5:54 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Exam Scores
- Replies: 15
- Views: 718
Midterm Exam Scores
Hi! Does anyone know where and how to access midterm exam scores when they're posted?
- Fri Oct 30, 2020 5:52 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Textbook Question 1B.27
- Replies: 3
- Views: 136
Re: Textbook Question 1B.27
Hi! It is a typo in the answer key. So you're correct, \Delta v = 10 m/s. You can find the correct solution in Solution Manual Errors (https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/Solution_Manual_Errors_7Ed.pdf), which is also posted on Dr. Lavelle's website. Hope this helps :)...
- Fri Oct 30, 2020 11:22 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Textbook Question 1B.27
- Replies: 3
- Views: 136
Textbook Question 1B.27
Hi everyone! I am a little confused on the procedure for this question: "A bowling ball of mass 8.00 kg is rolled down a bowling alley lane at 5.00 +/- 5.0 m/s. What is the minimum uncertainty in its position?" I set up the equation using delta v = 10 because of the +/- but the answer key ...
- Sun Oct 25, 2020 2:26 pm
- Forum: Student Social/Study Group
- Topic: Textbook sections on the midterm?
- Replies: 3
- Views: 139
Textbook sections on the midterm?
Hi! Could someone clarify exactly which sections of the textbook will be on the midterm? I have heard a couple different answers and I just want to make sure I don't miss anything :)
- Sun Oct 25, 2020 2:22 pm
- Forum: Student Social/Study Group
- Topic: Study Groups/Zoom Sessions?
- Replies: 3
- Views: 135
Study Groups/Zoom Sessions?
Hi all! Does anyone know of any study/review sessions, official or unofficial, coming up this week? I could use the extra structured practice/study time before my exam on Friday! Thanks :)
- Sun Oct 25, 2020 2:19 pm
- Forum: Student Social/Study Group
- Topic: How are you studying?
- Replies: 204
- Views: 20027
Re: How are you studying?
I have found that taking notes by hand and doing practice problems are the two best ways to really lock down certain concepts! However, for some of the tougher topics I turn to youtube for some helpful tips and tricks and it can be very useful if you're having trouble conceptualizing or visualizing ...
- Sun Oct 25, 2020 2:18 pm
- Forum: Student Social/Study Group
- Topic: Midterm Question
- Replies: 9
- Views: 522
Re: Midterm Question
As a follow up question, will we have access to the electromagnetic spectrum or are we expected to memorize the wavelength ranges for the different wave type?
- Sat Oct 24, 2020 12:55 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Sapling question 8
- Replies: 2
- Views: 177
Sapling question 8
The question is: A blue line is observed at 486.1 nm in the spectrum of atomic hydrogen. Determine the values of n for the beginning and ending energy levels of the electron during the emission of energy that leads to this spectral line. What I'm wondering is how do you determine based on wavelength...
- Thu Oct 22, 2020 5:18 pm
- Forum: Student Social/Study Group
- Topic: Official midterm review sessions
- Replies: 3
- Views: 245
Re: Official midterm review sessions
I heard that Justin (a UA) is hosting a midterm review during his workshop on Saturday from 12-1!
- Sat Oct 17, 2020 10:20 pm
- Forum: Properties of Light
- Topic: Study Advice
- Replies: 50
- Views: 2295
Re: Study Advice
How do I go about accessing the step-up sessions? And is there a pre-decided set of problems that they go over in each session and if so, would I need to complete them before attending?