Search found 117 matches
- Mon Mar 15, 2021 12:01 am
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: What was your favorite chem topic?
- Replies: 137
- Views: 7836
Re: What was your favorite chem topic?
Quantum! All the numbers and patterns just made sense!
- Sun Mar 14, 2021 11:59 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in NFE
- Replies: 64
- Views: 2686
Re: n in NFE
N is the number of the electrons being transferred for that given reaction! When you balance the redox reactions and break down how many e- are being transferred between molecules/sides, you can just plug that number in.
- Sun Mar 14, 2021 11:57 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Final Grades
- Replies: 3
- Views: 251
Re: Final Grades
Probably by next week at the latest. He may need to figure out if he plans to add any extra points or curve the grades, similar to what he did last quarter.
- Sun Mar 14, 2021 11:54 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Open vs closed
- Replies: 31
- Views: 2650
Re: Open vs closed
Open system - matter and energy (heat, etc.) can be exchanged with a systems surroundings
Closed system - matter cannot be exchanged, but energy is able to be exchanged with a systems surroundings
Isolated system - both matter and energy cannot be exchanged with a systems surroundings
Closed system - matter cannot be exchanged, but energy is able to be exchanged with a systems surroundings
Isolated system - both matter and energy cannot be exchanged with a systems surroundings
- Sun Mar 14, 2021 11:52 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Q and Gibbs Free energy relationship
- Replies: 1
- Views: 416
Re: Q and Gibbs Free energy relationship
I believe it just has something to do with how a reaction proceeds and the spontaneity of said reaction. If we're given the Gibbs free energy and the K value, and then are able to find a Q to compare to said K value, we can identify which way the reaction naturally wants to move. Because this push f...
- Sun Mar 14, 2021 11:43 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: G° vs G
- Replies: 30
- Views: 2361
Re: G° vs G
Why is important to differentiate G from G naught? Does it affect enthalpy or entropy differently? I think it's important because G naught will always be the same for that reaction, since everything is in standard pressure and temperature, but for normal delta G this isn't the case, so we can't jus...
- Sun Mar 07, 2021 11:18 pm
- Forum: Student Social/Study Group
- Topic: Fave food
- Replies: 266
- Views: 25275
Re: Fave food
I would kill for a slice of my grandmothers noodle kugel! It's a sweet, dessert like pasta dish with a sweet cream sauce with cinnamon and raisins, and it is SO GOOD. Normally we get it when we travel up for the holidays, but with covid I haven't seen her in about a year, but hopefully that will cha...
- Sun Mar 07, 2021 11:13 pm
- Forum: Student Social/Study Group
- Topic: Low Grades & Graduate School
- Replies: 22
- Views: 1431
Re: Low Grades & Graduate School
I think that there is a cap on how low of a grade you need to be able to retake a class to replace a previous letter grade, so you may want to look into that just to be safe, and if you withdraw now it will be marked on your transcript (most grad programs don't want to see to many of those per appli...
- Sun Mar 07, 2021 11:05 pm
- Forum: General Science Questions
- Topic: Final Exam
- Replies: 39
- Views: 1663
Re: Final Exam
Last quarter he put together a very thorough list of all of the different study review options for the different topics, so I think he's going to do that again for this week and we just need to wait for him to post it. If you want a study guide, go over the outlines he has for each topic and make su...
- Sun Mar 07, 2021 11:03 pm
- Forum: Student Social/Study Group
- Topic: Note Taking
- Replies: 145
- Views: 14338
Re: Note Taking
I like to handwrite my notes (but I do it on my Ipad on Notability so I can move things around as I please). Once we've finished the section, I can go through and rewrite my notes/regroup them as I see needed to help me better understand the topics and to do a thorough once over of everything that I...
- Sun Mar 07, 2021 11:00 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Stability Relating to Thermodynamics and Kinetics
- Replies: 7
- Views: 385
Re: Stability Relating to Thermodynamics and Kinetics
I believe that thermodynamic stability is just based on the measure of how likely a reaction is going to occur spontaneously, and normally is tied to a reaction being close to or at equilibrium with its environment. This is what we see with our measurements of Gibbs free energy, entropy, and entropy...
- Sun Mar 07, 2021 10:54 pm
- Forum: Student Social/Study Group
- Topic: What do you miss / What are you looking forward to?
- Replies: 92
- Views: 7870
Re: What do you miss / What are you looking forward to?
I really miss all the cool people that you get to meet just going about life on campus. It's always nice to get to know a stranger or two, and I miss just being able to start conversations with people around me in the coffee shops or dinning halls or classes because something about them caught my ey...
- Mon Mar 01, 2021 12:00 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Arranging elements with best reduction ability
- Replies: 9
- Views: 484
Re: Arranging elements with best reduction ability
The higher the reduction cell potential, the higher the chance of it being reduced, and therefore the more likely a species is to be an oxidizing agent. This would be for very positive (or in the case of a reaction the more positive) reduction potential value. The opposite would be true for oxidizat...
- Sun Feb 28, 2021 11:56 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Redox
- Replies: 16
- Views: 779
Re: Balancing Redox
You can check by how much the charge of each half changes when it is either oxidized or reduced based on what you are given. They normally give us some sense of how many e- are transferred by how much the charge grows or lesses (so +2 -> 0 charge means 2 electrons are being transferred). Then, for a...
- Sun Feb 28, 2021 11:53 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Log or ln
- Replies: 22
- Views: 1493
Re: Log or ln
I checked this since I was curious too, and the log and ln functions will give different answers for their resulting values, so don't just use them [censored] nilly! Know when you need to use each to get the correct answer, and how to properly use them!
- Sun Feb 28, 2021 11:52 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling Week 7/8: Question 16
- Replies: 2
- Views: 217
Re: Sapling Week 7/8: Question 16
If we double the coefficients, our Q will need to change because suddenly everything must be to the second power (same as squaring the entire fraction). Because E and Eº are constant potential values they really won't be affected, since they don't even depend on coefficients in the first place. For ...
- Sun Feb 28, 2021 11:45 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling Week 8 Q18
- Replies: 3
- Views: 238
Re: Sapling Week 8 Q18
You can just put the coefficient in front of the Fe2O3•3H2O so it looks like 2Fe2O3•3H2O. The •3H2O doesn't need to be modified.
- Sun Feb 28, 2021 11:42 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Sapling Week 7/8 #15
- Replies: 11
- Views: 619
Re: Sapling Week 7/8 #15
Hi! To solve this equation we can break it down into the parts that we will need for it. You have the right E values, so all you need to do is the E(cathode)-E(anode) to get our Eº for the equation. This should look something like (-.14)-(-.76), since you already have these values and we know the mo...
- Sun Feb 28, 2021 11:34 pm
- Forum: Student Social/Study Group
- Topic: Playlist
- Replies: 86
- Views: 6090
Re: Playlist
I'm currently obsessed with anything Mother Mother at the moment, if someone wants to add one of their songs! Their fish album is spectacular!
- Sun Feb 28, 2021 11:20 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in ∆G = -nFE
- Replies: 80
- Views: 3614
Re: n in ∆G = -nFE
N is referring to the number of electrons that are being transferred in a given chemical reaction. We can find this when we write out the half reactions and multiply so that we have even numbers of electrons on each side being transferred, and then you can just plug that number into the equation and...
- Wed Feb 24, 2021 2:13 pm
- Forum: Student Social/Study Group
- Topic: Exercising Our Minds and Bodies
- Replies: 120
- Views: 14552
Re: Exercising Our Minds and Bodies
I take the dogs I pet sit on long walks to the beach or go on hikes with my friends!
- Wed Feb 24, 2021 2:09 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final
- Replies: 48
- Views: 2388
Re: Final
Do the textbook problems! He puts some on all of the tests, so at least its a good way to get some points. Also, go to the extra sessions and ask questions on topics you're confused about!
- Sun Feb 14, 2021 11:52 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Does ∆U depend on q, w, and T?
- Replies: 5
- Views: 275
Re: Does ∆U depend on q, w, and T?
Yes, because the change in energy (U) will depend on the heat (Q) of the system and the work that is done on the system (W). I think that for the first equation you mentioned, that is used for dealing with an ideal gas, where we are able to remove all other forms of energy transfer and only need to ...
- Sun Feb 14, 2021 11:44 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: isochoric / isometric
- Replies: 9
- Views: 538
Re: isochoric / isometric
I think they basically mean the same thing, which is a constant volume process for a closed system.
- Sun Feb 14, 2021 11:42 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated System
- Replies: 6
- Views: 313
Re: Isolated System
Isolated systems are considered impossible because there are so many variables that need to be contained in the real world that deal with the exchange of matter or energy for us to actually create one. We want to study isolated systems because this gives us the best form of understanding energy and ...
- Sun Feb 14, 2021 11:38 pm
- Forum: Calculating Work of Expansion
- Topic: negative vs positive work
- Replies: 21
- Views: 836
Re: negative vs positive work
You would be correct! Work is negative when the system expands and pushes against its surroundings (therefore doing work on them). Work is positive when the surroundings push on the system (compression).
- Sun Feb 14, 2021 11:27 pm
- Forum: General Science Questions
- Topic: Baking/Cooking Chemistry
- Replies: 1
- Views: 228
Re: Baking/Cooking Chemistry
I can't say for sure the exact science, but I believe that mixing water into oil causes the water to turn to steam rather quickly if the oil is really hot, which might cause the bubbles as it tries to rise to the surface. Maybe that's what happened in this case?
- Mon Feb 08, 2021 12:01 am
- Forum: Administrative Questions and Class Announcements
- Topic: sapling
- Replies: 4
- Views: 223
Re: sapling
I think they come out relative to the week we are addressing that content, but sometimes he has them out a week or so in advance. I'm sure he'll let us know, but I don't think there is a super definitive schedule at the moment.
- Sun Feb 07, 2021 11:57 pm
- Forum: Student Social/Study Group
- Topic: Book Recommendations
- Replies: 135
- Views: 11597
Re: Book Recommendations
Anything by Neil Gaiman has me sold! He has some great novels, like The Ocean at the End of the Lane and Good Omens, and was part of an amazing graphic novel series called Sandman. Just a great writing style all around!
- Sun Feb 07, 2021 11:55 pm
- Forum: Student Social/Study Group
- Topic: Worried About MT 1 Grades
- Replies: 39
- Views: 1581
Re: Worried About MT 1 Grades
Chem is just one of those subjects for me too. I think that it really comes down to practice, practice, practice, but doing so in a way that forces you to think about the concepts and what is happening in the reaction. Hopefully next midterm is more successful for all of us!
- Sun Feb 07, 2021 11:54 pm
- Forum: Calculating Work of Expansion
- Topic: Extra practice problems/videos
- Replies: 13
- Views: 673
Re: Extra practice problems/videos
I have a document in the group chat with old practice tests and other resources I add as I go that might help!
https://docs.google.com/document/d/1r2C ... sp=sharing
I should be adding some more things soon!
https://docs.google.com/document/d/1r2C ... sp=sharing
I should be adding some more things soon!
- Sun Feb 07, 2021 11:52 pm
- Forum: Phase Changes & Related Calculations
- Topic: Midterm Q4
- Replies: 7
- Views: 505
Re: Midterm Q4
HBr is one of the strong acids, meaning that when it dissociates Br- is going to be a very very weak conjugate base, and therefore will have little to no affect on the pH of the overall solution!
- Sun Jan 31, 2021 11:53 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4D.15 Textbook Question
- Replies: 4
- Views: 140
Re: 4D.15 Textbook Question
Yes, you would treat them as combustions since it is delta Hc! Start by writing out balanced equations for each of those molecules you are given knowing combustion is that molecule + 02 <=> Co2 + h20. Then take the original equations the problem gives you, and see how you can manipulate the equation...
- Sun Jan 31, 2021 11:43 pm
- Forum: Student Social/Study Group
- Topic: Work Life Balance
- Replies: 44
- Views: 1335
Re: Work Life Balance
I really try to balance out studies and other hobbies that aren't related to school or my major subject. I think it is important to remember to do things just because you enjoy them sometimes too, not just because you feel like you are required to. Get outside a little bit, get some plants or other ...
- Sun Jan 31, 2021 11:39 pm
- Forum: Phase Changes & Related Calculations
- Topic: Higher Enthalpy
- Replies: 6
- Views: 181
Re: Higher Enthalpy
If you have a reaction that goes from high to low enthalpy, the change is negative and we will see more reactants and less product produced!
- Sun Jan 31, 2021 11:35 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calorimeters
- Replies: 15
- Views: 509
Re: Calorimeters
I think it would be good to know, as they are pretty handy in a lot of experiments! I tend to remember it as a system with a water bath, and the water be able to capture any energy the reaction releases as a change of heat, which we can then measure. We also may see more of this later, so maybe we'l...
- Sun Jan 31, 2021 11:17 pm
- Forum: Student Social/Study Group
- Topic: Congrats!!
- Replies: 21
- Views: 887
Re: Congrats!!
1/3 of the way through this class's tests!
- Sun Jan 24, 2021 11:43 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Week 2 Sapling #5
- Replies: 6
- Views: 282
Re: Week 2 Sapling #5
The way I did it was to first find the pOH (14-pH), then find the concentration of the -OH by using 10^-pOH. This will act as the X in the ICE table Next, we can solve for our missing/needed value by setting up the equation Kb=[BH][OH]/[B] where be is our original base and BH is its conjugate acid,...
- Sun Jan 24, 2021 11:39 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Percent Ionization
- Replies: 7
- Views: 203
Re: Percent Ionization
It mainly helps us determine how strong or weak an acid or base is. The precent ionization is really just the percentage of the molecule that was dissociated/ionized, or separated in the case of acids (they lose a proton). A really strong acid that likes to dissociate and stay that way will be 100 p...
- Sun Jan 24, 2021 11:34 pm
- Forum: Student Social/Study Group
- Topic: Exam Duration
- Replies: 7
- Views: 263
Re: Exam Duration
They most likely want you to get there 10-5 minutes early for set up, so that we can all start at the same time. I think the duration is 50 minutes, same as 14A, and judging by the online format we have a pretty strict time limit from when we start.
- Sun Jan 24, 2021 11:30 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Sapling Week 2 #5
- Replies: 3
- Views: 177
Re: Sapling Week 2 #5
The way I did it was to first find the pOH (14-pH), then find the concentration of the -OH by using 10^-pOH. This will act as the X in the ICE table Next, we can solve for our missing/needed value by setting up the equation Kb=[BH][OH]/[B] where be is our original base and BH is its conjugate acid, ...
- Sun Jan 24, 2021 11:26 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Week 2 Sapling #5
- Replies: 6
- Views: 282
Re: Week 2 Sapling #5
The way I did it was to first find the pOH (14-pH), then find the concentration of the -OH by using 10^-pOH. This will act as the X in the ICE table Next, we can solve for our missing/needed value by setting up the equation Kb=[BH][OH]/[B] where be is our original base and BH is its conjugate acid, ...
- Sun Jan 24, 2021 11:17 pm
- Forum: Phase Changes & Related Calculations
- Topic: weak/strong bases and acids
- Replies: 7
- Views: 405
Re: weak/strong bases and acids
The textbook has a list of what it considers strong acids and bases, so anything other than those is normally considered weak as a start point. Other things to look at include how well the molecules dissociate and stay that way, which would suggest something strong. If we were really looking to exam...
- Sun Jan 17, 2021 11:50 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc and Kp and Keq and Q
- Replies: 6
- Views: 1191
Re: Kc and Kp and Keq and Q
Kc and Kp are both K equilibrium equations, but Kc is for when we are dealing with aqueous forms and Kp is for pressure, so for gas forms. The equation for finding them is the same though! Q is kind of like our K value, but this can change as we try to get it closer and closer to equilibrium. So, ba...
- Sun Jan 17, 2021 11:44 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Combining chemical equations
- Replies: 5
- Views: 250
Re: Combining chemical equations
I don't know if there is a more efficient way, but as long as we all remember to use the radical when the reaction is reversed, and know to make whatever our multiplying coefficient for a reaction equation is our power for that K, we should be fine. think this method itself is probably straightforwa...
- Sun Jan 17, 2021 11:39 pm
- Forum: Student Social/Study Group
- Topic: Midterms During Lecture
- Replies: 44
- Views: 1741
Re: Midterms During Lecture
On the topic of exams and midterms, has anyone heard anything about the format? Is it still going to be similar to a few questions worth a lot of points each? I know the syllabus had different percentages going towards tests now out of the class total, so I am curious.
- Sun Jan 17, 2021 11:35 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Question Week 1 #10
- Replies: 7
- Views: 215
Re: Sapling Question Week 1 #10
You should use the smaller one, since the bigger one is larger than the initial concentrations! Always choose the value that is non negative and is less than the initial concentrations given!
- Sun Jan 17, 2021 11:32 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Box
- Replies: 10
- Views: 481
Re: ICE Box
It will depend on the equation itself, and if it moving in a forward or reverse direction. If we are suddenly given more reactants or start off with reactant concentrations, we need to subtract something from the reactant side and add it to the product side to create a product. If we are given a pro...
- Sun Jan 10, 2021 10:53 pm
- Forum: Student Social/Study Group
- Topic: Answering Questions with Responses
- Replies: 5
- Views: 271
Re: Answering Questions with Responses
You can also ask other questions that relate to the original post to help encourage discussion, and to clear up any confusion you might have! A lot of the questions that get asked on here are really useful to dive deeper into!
- Sun Jan 10, 2021 10:50 pm
- Forum: Student Social/Study Group
- Topic: Sapling Homework
- Replies: 15
- Views: 730
Re: Sapling Homework
I think it really just depends on how Lavelle decides to post the assignments. I can't say there was ever a very rigid schedule, since there were times where sapling would go down and homework due dates would get pushed back a week.
- Sun Jan 10, 2021 10:48 pm
- Forum: Student Social/Study Group
- Topic: Exam Changes
- Replies: 12
- Views: 450
Re: Exam Changes
I think that they are now occurring during lecture, so whatever lecture time you have will dictate when you need to take the test. I also believe that all of the midterms were scheduled for Fridays, if that helps with any schedule or class planning.
- Sun Jan 10, 2021 10:45 pm
- Forum: Ideal Gases
- Topic: Chemical Equilibrium Part 1A Post-Module Assessment
- Replies: 4
- Views: 230
Re: Chemical Equilibrium Part 1A Post-Module Assessment
The correct answer is that both the forward and reverse reactions still occur, just at equal rates. This is because, even though the mixture is at equilibrium, reactions will still naturally want to occur as loose atoms and molecules mix with each other/break apart due to instability. However, these...
- Sun Jan 10, 2021 10:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Chemical Equilibrium Part 2 Question 26
- Replies: 1
- Views: 121
Re: Chemical Equilibrium Part 2 Question 26
To specifically find the concentration of N2 all you need to do is look at the bottom row of the ICE table you make with this equation and the values given. There, you should be able to see how to calculate the final concentration at equilibrium, since the E row is all of the concentrations for each...
- Sun Jan 10, 2021 10:34 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Chemical Equilibrium Part 2 Question 29
- Replies: 2
- Views: 150
Re: Chemical Equilibrium Part 2 Question 29
For incorporating the 18.3 into this problem, I simply multiplied it by the original amount of BrCl we were given in order to help me find the amount that remained. This is then what I chose to use for the last row of my ICE table for BrCl, since this would account for a change from the original 1.8...
- Mon Dec 07, 2020 10:49 am
- Forum: Lewis Acids & Bases
- Topic: Comparing strength of acids and bases
- Replies: 3
- Views: 157
Re: Comparing strength of acids and bases
We can look at the stability of the molecules/atoms! For example HCl is a strong acid, because it really likes to separate into H+ and Cl- and stay that way. If we look at Cl-, we can see that it has a full valence, and from what we’ve learned this class full valences are the most stable state for a...
- Mon Dec 07, 2020 10:42 am
- Forum: Conjugate Acids & Bases
- Topic: What is a conjugate acid or base?
- Replies: 13
- Views: 1365
Re: What is a conjugate acid or base?
A conjugate base is what remains after the acid has given up a proton (So the acid - one H+). A conjugate acid is the base once it has gained that proton (so the base + one H+). Because acid/base reactions also have the ability to go in the reverse direction, I like to think of the conjugates as wha...
- Mon Dec 07, 2020 10:36 am
- Forum: Bronsted Acids & Bases
- Topic: pKA and KA
- Replies: 4
- Views: 197
Re: pKA and KA
Ka is a measure of the H+ or protons in a solution, so it can tell us how strong or weak of an acid/base we have (since a strong acid would completely separate into protons and it’s conjugate bases, and a weak acid would fail to fully separate, leading to reverse reactions and a low Ka number.) The ...
- Sun Dec 06, 2020 11:28 pm
- Forum: Student Social/Study Group
- Topic: Finals Study Things
- Replies: 27
- Views: 1206
Finals Study Things
Hey everybody! I did a few review sessions for each of the topics we've covered, and have recorded them for use for people who couldn't make it to the zoom. I also put them on a google doc, along with links to any of my notes I took this class that correspond to them and links to both the UA workshe...
- Sun Dec 06, 2020 11:24 pm
- Forum: Student Social/Study Group
- Topic: Final on 12/13
- Replies: 5
- Views: 334
Re: Final on 12/13
I think he said that the topics we've covered would be pretty evenly spread across the midterm. For a study guide, I would just use the ones that pertain to each chapter and combine them all to make sure you cover all the bases. I've heard the final is going to be 30 multiple choice questions too, i...
- Sun Dec 06, 2020 10:07 pm
- Forum: Bronsted Acids & Bases
- Topic: Strong & Weak Acid
- Replies: 6
- Views: 181
Re: Strong & Weak Acid
You can kind of tell by looking at if the valence of an atom/stability of molecules. If the atom/molecule is stable (i.e. if an atom has a full octet or if a molecule has little to no formal charges and a lot of double/triple bonds that would be hard to break) then it is not very likely to react in ...
- Sun Dec 06, 2020 9:53 pm
- Forum: Conjugate Acids & Bases
- Topic: HSO4- conjugate base
- Replies: 4
- Views: 427
Re: HSO4- conjugate base
A conjugate base is what molecule would be the base if you reversed the reaction, so it would be the product after the acid has given away it’s proton. You are right that a base is a proton acceptor, which is why in a reverse reaction SO42- would want to gain a proton.
- Sun Dec 06, 2020 9:48 pm
- Forum: Conjugate Acids & Bases
- Topic: Formula of conjugate base and acids
- Replies: 2
- Views: 203
Re: Formula of conjugate base and acids
The formula for a conjugate base is the acid minus one proton (H+), since the acid is the molecule that likes to give protons away. For the conjugate acid, its just the base plus one proton or H+ atom, since the base is the proton accepter. You can kind of think of the conjugate acids and bases as w...
- Sun Dec 06, 2020 9:40 pm
- Forum: Student Social/Study Group
- Topic: chelating compounds- i just thought this was funny
- Replies: 1
- Views: 135
Re: chelating compounds- i just thought this was funny
What a unique way of remembering it!
- Sun Nov 29, 2020 10:43 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: When is the bond order 0?
- Replies: 13
- Views: 2261
Re: When is the bond order 0?
Normally if something has a bond order of 0 it is very unstable and can't exist. It is really just saying that no bond can be formed, and thus you get 0. I don't think we will be dealing with any unstable molecules in this class, so just sticking to single, double, and triple bonds should be fine.
- Sun Nov 29, 2020 10:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Delocalized Pi Bond
- Replies: 3
- Views: 283
Re: Delocalized Pi Bond
A pi bond is a bond where two side to side P orbitals overlap one another (you can look up some images to get a better grasp of this). You would be right when it means that it would have to be greater than a single bond, either being a double or triple (each with have pi bonds). The pi orbital phras...
- Sun Nov 29, 2020 10:35 pm
- Forum: Ionic & Covalent Bonds
- Topic: Lewis structure
- Replies: 13
- Views: 587
Re: Lewis structure
The best way to tell is based on electronegativity. If the difference is larger that 1.5, the molecule will tend to be ionic. If it is less than 1.5 the electrons will be shared more evenly and therefore it will be more covalent. Once you start to memorize some of the trends, such as electronegativi...
- Sun Nov 29, 2020 10:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sapling #7
- Replies: 3
- Views: 215
Re: Sapling #7
I believe it has something to do with the difference in polarity of the bonded atoms (the C-H and the C-Cl bonds), so they don't actually line up evenly like we think. If you actually look at a picture of what the molecule looks like when you can see it's angles, you are able to see that the two set...
- Sun Nov 29, 2020 10:22 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sapling #15
- Replies: 4
- Views: 297
Re: Sapling #15
I think the important thing to note is that sigma bonds are the true determiners of a molecules shape. Pi bonds are the overlap of side to side orbitals, and is something we normally see in either double or triple bonds where you have many P orbitals (since each P has 3 orbitals in it), and sigma is...
- Sun Nov 22, 2020 11:57 pm
- Forum: Student Social/Study Group
- Topic: Final Format
- Replies: 35
- Views: 1507
Re: Final Format
Do we know if it will also be all multiple choice if it is similar to the midterms? Thanks!
- Sun Nov 22, 2020 11:55 pm
- Forum: Hybridization
- Topic: Confusion on Hybridization
- Replies: 1
- Views: 88
Re: Confusion on Hybridization
If it is a large molecule, then we might get the case were one atom is bonded to two other atoms by double bonds (like the central C in 2HCCCCH2). In this case, that C would have an sp bond (since it would be attached to on S and one P). For this same molecule, if we look at one of the C on the end ...
- Sun Nov 22, 2020 11:47 pm
- Forum: Lewis Structures
- Topic: Week 8 Sapling Homework #18
- Replies: 2
- Views: 176
Re: Week 8 Sapling Homework #18
For big formulas like this, they tend to give you the exact orientation for how to draw it out! For H2CCCCH2, we are given two hydrogen at the beginning, and from how it is written (H2C) we know these two h are attached to the first C. Then we can figure out that the four C's are attached to each ot...
- Sun Nov 22, 2020 11:27 pm
- Forum: Hybridization
- Topic: Determining Hybridization
- Replies: 1
- Views: 109
Re: Determining Hybridization
The most helpful way I use to calculate hybridization is to use the formula (number of atoms connect to + number of lone pairs). Note that it is the number of atoms connected to, no the number of bonds. The steric number is just the total number of outer atoms and lone pairs, so the formula above fo...
- Sun Nov 22, 2020 11:14 pm
- Forum: Hybridization
- Topic: Electron Configuration
- Replies: 2
- Views: 128
Re: Electron Configuration
I believe we tend to leave our atom notation as what we have standardly seen and do not include the hybridization since hybridization is more of a mathematical thing we do in order to determine an atoms ability to bond/type of bond, but if a questions asks for the hybridization notation specifically...
- Sun Nov 15, 2020 10:23 pm
- Forum: Electronegativity
- Topic: Zeff and Shielding
- Replies: 3
- Views: 140
Re: Zeff and Shielding
Zeff is basically the net positive charge attracting a valence electron in an atom. Shielding is when electrons that are in a lower shell actually block part of the attraction energy/pull from reaching electrons that are further away in higher shells. It's like if you have a bright flashlight shinni...
- Sun Nov 15, 2020 10:12 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Determining Number of Orbitals
- Replies: 3
- Views: 221
Re: Determining Number of Orbitals
Each orbital is capable of fitting 2 electrons in it. For example, a 1s orbital can hold 2 electrons and has one orientation, and a 2p orbital has three aspects/orientations (x,y,z) and therefore three different orbitals in different directions that each hold two electrons, and so on. For part C, we...
- Sun Nov 15, 2020 9:53 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: The most plausible structure
- Replies: 4
- Views: 151
Re: The most plausible structure
We would want the negative formal charge on the most electronegative element, or the element that is going to want to gain an extra electron the most (therefore giving it a negative charge), since this is most likely what will occur in the real world. If you have two magnets, one that is a lot stron...
- Sun Nov 15, 2020 9:48 pm
- Forum: Ionic & Covalent Bonds
- Topic: Bond Length
- Replies: 6
- Views: 732
Re: Bond Length
When bond length is shorter, the greater the energy in the bond. The greater the energy, the harder it is for that bond to be broken apart, meaning it is far more stable than a lower (or longer) bond. A shorter bond just means that the atoms are a lot closer together, and therefore when we see doubl...
- Sun Nov 15, 2020 9:43 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Sapling 9
- Replies: 6
- Views: 389
Re: Oxidation Sapling 9
For number nine in the homework we are given ClO4- and are asked to find the oxidation number of Cl. The oxidation numbers of the entire molecule, when added together, should add up to the charge of the molecule overall. If we look at the periodic table, we can see that oxygen requires two more elec...
- Sun Nov 08, 2020 11:39 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: What are orbitals?
- Replies: 10
- Views: 630
Re: What are orbitals?
Orbitals can really be thought of a cloud like areas around a nucleus where you can predictably find electrons at any given time, as it is based off of a mathematical wave function type equation. I think that they do tend to form the general shapes we see in our chemistry textbooks, mainly because i...
- Sun Nov 08, 2020 11:30 pm
- Forum: Ionic & Covalent Bonds
- Topic: Atomic Radii
- Replies: 5
- Views: 247
Re: Atomic Radii
When you move from the 1s to 2p orbital you are moving further away and into a higher energy state. It tends to be that case that as n increases your radius will also be increasing.
- Sun Nov 08, 2020 11:24 pm
- Forum: Trends in The Periodic Table
- Topic: Electron-Electron Repulsion
- Replies: 2
- Views: 78
Re: Electron-Electron Repulsion
I think it would be the orbital, especially the valence orbitals/electrons, that sees most of this effect. I'm assuming it will also affect the other electrons present, but the most measurable affect could be found in the valence of that atom.
- Sun Nov 08, 2020 11:16 pm
- Forum: Lewis Structures
- Topic: Oxygen Valence Electrons
- Replies: 1
- Views: 116
Re: Oxygen Valence Electrons
I'm not sure how well I understand the question, but by only having one shared electron its actually sharing a pair of them, so technically all of the oxygens in that model have a full valence. For your point about d orbitals, I believe that oxygen does in fact have a 3d orbital (since orbitals are ...
- Sun Nov 08, 2020 11:06 pm
- Forum: Student Social/Study Group
- Topic: midterm
- Replies: 6
- Views: 204
Re: midterm
I think last time for one of the extra study sessions/step up sessions people were able to vote on if they would like practice midterm questions or not, but i'm not sure anything is set in stone. We might hear more stuff as we get closer to the midterm.
- Sun Nov 01, 2020 10:37 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Sapling #8 week2-4
- Replies: 5
- Views: 312
Re: Sapling #8 week2-4
I think it just wants you to solve for wavelength by making it wavelength=1/r(1/n-1/n2), which would in this case be the inverse.
- Sun Nov 01, 2020 10:33 pm
- Forum: Trends in The Periodic Table
- Topic: sapling #23
- Replies: 6
- Views: 239
Re: sapling #23
For the second person on here, its asking you to convert back to kJ, and then multiply by Avogadro's number since your first answer was in eV/atoms. You can write this out like we do when converting mass to moles/etc. for other stoichiometric problems.
- Sun Nov 01, 2020 10:29 pm
- Forum: Trends in The Periodic Table
- Topic: sapling #23
- Replies: 6
- Views: 239
Re: sapling #23
1 eV is 1.602 x 10^-19 Joules, so all you have to do is multiply your calculated energy!
- Sun Nov 01, 2020 10:27 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Audio-Visual Focus
- Replies: 2
- Views: 128
Re: Audio-Visual Focus
From what I've heard, I don't think he will be. I think they may take too much time to make for him to have new ones out for us in a timely manner. However, the textbook always has a lot of practice problems!
- Sun Nov 01, 2020 10:25 pm
- Forum: Photoelectric Effect
- Topic: Sapling HW (Max Wavelength of Radiation)
- Replies: 6
- Views: 806
Re: Sapling HW (Max Wavelength of Radiation)
For starters, you need to know workfunction=Energy - KEnergy, which is also written as hv-.5mv^2. To find the minimum energy needed, there is no extra kinetic energy being released, so kE is zero. This will give us workfunction=hv-0, which you can manipulate to find v (frequency). Angstroms are meas...
- Sun Nov 01, 2020 10:05 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Atom Radius
- Replies: 6
- Views: 327
Re: Atom Radius
I think understanding the general patterns of atom radius will be good to know. For normal atoms, know that radius tends to get smaller as you move from the left to the right on the periodic table. For any ions, know that when you add more electrons, there will suddenly be more same-same negative fo...
- Sun Nov 01, 2020 10:01 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg's Equation, final minus initial or initial minus final?
- Replies: 10
- Views: 2001
Re: Rydberg's Equation, final minus initial or initial minus final?
I think it's final minus initial, since that would give you a positive value to multiply with the Rydberg constant.
- Sun Nov 01, 2020 9:57 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Sapling Week 2-4 #21
- Replies: 4
- Views: 99
Re: Sapling Week 2-4 #21
N=5 represents the orbital level/energy level you are on, which is basically saying you have filled up the previous 4 orbital levels and are now on your fifth. L=2 correlates to the subshell (0 is s, 1 is p, 2 is d, 3 is f). The d subshell (since l is 2) can hold up to 10 electrons, so your answer i...
- Sun Nov 01, 2020 9:47 pm
- Forum: Photoelectric Effect
- Topic: Sapling Homework #6
- Replies: 3
- Views: 206
Re: Sapling Homework #6
Once you have the first part of that question (the work function), the next step to find the maximum number of electrons is to divide the total energy by that work function. This is because the work functions is the smallest amount of energy needed to eject just one electron.
- Sun Nov 01, 2020 9:42 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Avogadro constant
- Replies: 40
- Views: 2143
Re: Avogadro constant
Normally you'd want to use it when converting some other unit measurement into atoms/molecules or the other way around (1 mole of anything = 6.022 x 10^23). It's also included in some of the equations we use, but that just means you need to plug it in with the rest of your values. I think the main t...
- Sun Nov 01, 2020 9:37 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Noble Gas Configuration
- Replies: 13
- Views: 455
Re: Noble Gas Configuration
Yes, you need to write it based on the previous noble gas. I think it may have something to do with the importance of the configuration of valence electrons in reactions, which is why they use the previous noble gas and then just write the valence level out (not that noble gasses are very reactive o...
- Sun Oct 25, 2020 11:56 pm
- Forum: *Black Body Radiation
- Topic: Black body radiation
- Replies: 3
- Views: 295
Re: Black body radiation
I believe my TA said that it would not be on the test.
- Sun Oct 25, 2020 11:31 pm
- Forum: DeBroglie Equation
- Topic: MIDTERM INSTRUCTIONS HELP
- Replies: 2
- Views: 107
Re: MIDTERM INSTRUCTIONS HELP
You should have two devices set up for the test, one being a computer you have respondus on and the other being some kind of camera device (phone, ipad, etc) that you are able to join the discussion section zoom on. The second device will be placed so that the TA can see your workspace as you take t...
- Sun Oct 25, 2020 11:25 pm
- Forum: General Science Questions
- Topic: Webcams for Midterm
- Replies: 6
- Views: 198
Re: Webcams for Midterm
You can use your phone, just angle it towards your workspace so the TA can see.
- Sun Oct 25, 2020 11:24 pm
- Forum: Properties of Light
- Topic: Webcam for midterm
- Replies: 6
- Views: 331
Re: Webcam for midterm
If you have some kind of phone or other device that you can get zoom on and can angle towards your workspace so the TA can see all of your papers/desk, that should work. I would also ask your TA if they would recommend any specific setup method, but you shouldn't need to go out and get a webcam if y...
- Sun Oct 25, 2020 11:20 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Way to search posts for similarity?
- Replies: 9
- Views: 280
Re: Way to search posts for similarity?
For the person who wants to know how to make a post, if you go to the broad index scroll down to 14A topics and choose one, and then hit a specific forum page for 14A in that topic you should see a new post button that will allow you to create one.
- Sun Oct 25, 2020 11:17 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Way to search posts for similarity?
- Replies: 9
- Views: 280
Re: Way to search posts for similarity?
You could try looking under the specific topic that the question relates to, which while still a broad area may narrow down where you could find something similar. That and you can try to look up some key words that relate to that question with the search bar.