Search found 101 matches
- Sun Mar 14, 2021 4:04 am
- Forum: Second Order Reactions
- Topic: Determining Order Reactions
- Replies: 2
- Views: 274
Re: Determining Order Reactions
If you're given a list of experiments which correspond to certain reactant concentrations, you pick which experiments to compare based on which reactant's concentration is being held constant. If there are two reactants and you're trying to determine the order of the first reactant, you would pick t...
- Sun Mar 14, 2021 1:53 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Outline 5 Learning Objective
- Replies: 5
- Views: 410
Re: Outline 5 Learning Objective
I'm pretty sure it's talking about when a metal electrode is oxidized to form metal cations, which will dissolve into solution. So I guess you'd just have to look at the half-reactions and see which metal is being oxidized.
- Sun Mar 14, 2021 1:49 am
- Forum: Student Social/Study Group
- Topic: Spring Quarter
- Replies: 60
- Views: 3290
Re: Spring Quarter
Not next quarter, but I'll be taking 14C and 14BL over the summer.
- Sun Mar 14, 2021 1:46 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagrams
- Replies: 7
- Views: 484
Re: Cell Diagrams
I was wondering this too, thank you guys for clearing that up.
- Sun Mar 14, 2021 1:42 am
- Forum: General Rate Laws
- Topic: Intermediate
- Replies: 59
- Views: 3797
Re: Intermediate
An intermediate is a species that is produced in an elementary step and consumed in a subsequent elementary step. So an intermediate doesn't appear in either the reactants or products in the overall equation.
- Sun Mar 14, 2021 1:40 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Catalyst
- Replies: 27
- Views: 1151
Re: Catalyst
The forward and reverse reactions follow the same energy pathway except in reverse, so when a catalyst lowers the activation energy for a reaction is makes it so both the forward and reverse reactions need less energy to proceed, meaning they will both go faster.
- Sun Mar 14, 2021 1:33 am
- Forum: Phase Changes & Related Calculations
- Topic: Finals
- Replies: 4
- Views: 414
Re: Finals
Thank you! Good luck to everyone!
- Sun Mar 14, 2021 1:31 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: ΔU
- Replies: 9
- Views: 685
Re: ΔU
deltaU is 0 in an isothermal reversible expansion since the energy lost through work is replaced by heat from the surroundings, meaning q = -w.
- Fri Mar 12, 2021 9:34 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Final
- Replies: 48
- Views: 2838
Re: Final
What seems to work the best for me personally is redoing textbook problems, going over homework problems, watching Khan Academy videos as review, and rewatching Lavelle's lectures and/or rereading the textbook for certain topics I don't feel too confident on. Hope this helps and good luck on the fin...
- Fri Mar 12, 2021 9:30 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Textbook 6L.5b
- Replies: 3
- Views: 192
Re: Textbook 6L.5b
I was wondering about this too. In the textbook it says the reactant of the each half-reaction should come before the product, but the textbook answers don't even seem to consistently follow that so I'm not too sure.
- Thu Feb 25, 2021 3:09 pm
- Forum: Balancing Redox Reactions
- Topic: Textbook Problem 6K.3 part d [ENDORSED]
- Replies: 1
- Views: 202
Textbook Problem 6K.3 part d [ENDORSED]
The question says to balance the skeletal equations by using oxidation and reduction half-reactions (all the reactions take place in acidic solution). The equation in part d is the reaction of chlorine in water: Cl2(g) -> HClO(aq) + Cl2(g). I was wondering if there's possibly a typo in this question...
- Fri Feb 19, 2021 12:39 am
- Forum: Calculating Work of Expansion
- Topic: Positive vs. Negative Work
- Replies: 22
- Views: 895
Re: Positive vs. Negative Work
Yup, that's how I've always thought of it.
- Fri Feb 19, 2021 12:38 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: qrev
- Replies: 27
- Views: 1636
Re: qrev
qrev is the amount of heat generated in a reversible process. So does deltaS = q/T only apply to reversible expansions and compressions? I believe you use this equation when you are at a constant temperature for a reversible process. So then to clarify, when it's an irreversible process and the tem...
- Fri Feb 19, 2021 12:30 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Outline 4 Question Applying 1st and 2nd Laws
- Replies: 1
- Views: 118
Re: Outline 4 Question Applying 1st and 2nd Laws
I think it just means that you should know the basics of how the formulas for change in energy and change in entropy are derived from the 1st and 2nd laws of thermodynamics, since both of those are ultimately derived from the basic premises of the first two laws of thermodynamics. I wouldn't worry a...
- Fri Feb 19, 2021 12:27 am
- Forum: Phase Changes & Related Calculations
- Topic: calculating phase change
- Replies: 6
- Views: 521
Re: calculating phase change
I'm pretty sure that's generally how you would do it. I was watching some Khan Academy review videos today and in one of them the guy said you need to calculate how much heat is required to first bring the substance up to the boiling point (or melting point), and then calculate how much heat you nee...
- Fri Feb 19, 2021 12:20 am
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
Let's take all the bad chemistry jokes and Barium.
- Fri Feb 19, 2021 12:20 am
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
Let's take all the bad chemistry jokes and Barium.
- Fri Feb 19, 2021 12:19 am
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
I'm out of chemistry jokes, I should zinc of a new one.
- Fri Feb 19, 2021 12:19 am
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
I'm out of chemistry jokes, I should zinc of a new one.
- Fri Feb 19, 2021 12:17 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3591320
Re: Post All Chemistry Jokes Here
I tell bad chemistry jokes because all the good ones Argon.
- Fri Feb 19, 2021 12:17 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3591320
Re: Post All Chemistry Jokes Here
I try to tell chemistry jokes but there is no REACTION.
- Fri Feb 19, 2021 12:16 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3591320
Re: Post All Chemistry Jokes Here
Two chemists walk into a bar. One tells the bartender, "I'll have an H2O." The other says, "I'll have an H2O too!" The second chemist dies.
- Fri Feb 19, 2021 12:16 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3591320
Re: Post All Chemistry Jokes Here
Why should you go drinking with neutrons? Because wherever they go, there's no charge!
- Fri Feb 19, 2021 12:16 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3591320
Re: Post All Chemistry Jokes Here
Why does a hamburger have less energy than steak? Because it's in the ground state!
- Fri Feb 19, 2021 12:14 am
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
I tell bad chemistry jokes because all the good ones Argon.
- Fri Feb 19, 2021 12:13 am
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
I try to tell chemistry jokes but there is no REACTION.
- Fri Feb 19, 2021 12:13 am
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
Two chemists walk into a bar. One tells the bartender, "I'll have an H2O." The other says, "I'll have an H2O too!" The second chemist dies.
- Fri Feb 19, 2021 12:12 am
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
Why should you go drinking with neutrons? Because wherever they go, there's no charge!
- Fri Feb 19, 2021 12:10 am
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
Why does a hamburger have less energy than steak? Because it's in the ground state!
- Fri Jan 29, 2021 3:15 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies VS Bond Dissociation Energy
- Replies: 4
- Views: 235
Bond Enthalpies VS Bond Dissociation Energy
The book very briefly touched on this, but I was wondering if anyone could explain what the difference is between bond enthalpies and bond dissociation energy.
- Fri Jan 29, 2021 3:12 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Cubic Equations
- Replies: 6
- Views: 368
Cubic Equations
I'm not entirely sure but I think I remember Lavelle saying that we wouldn't need to know how to solve cubic equations for ICE tables since K would be small enough to approximate x if we even received a problem with a cubic equation. However, I noticed on outline 1 that it says we should know how to...
- Wed Jan 27, 2021 9:38 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in Partial Pressure
- Replies: 3
- Views: 333
Re: Change in Partial Pressure
Both of your answers helped to clear that up; thank you!
- Wed Jan 27, 2021 9:34 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentration, Volume, and Pressure
- Replies: 3
- Views: 109
Re: Concentration, Volume, and Pressure
Yes concentration changes anytime the quantity stays the same and the volume changes or vice versa. However, if you were to increase pressure by adding an inert gas, concentration does not change since the number of moles and the volume stay the same.
- Wed Jan 27, 2021 9:31 pm
- Forum: General Science Questions
- Topic: Careless Mistakes
- Replies: 54
- Views: 3709
Re: Careless Mistakes
I guess this doesn't necessarily apply to simple math or calculator errors, but it's a good idea to write out units when doing calculations to make sure you have the correct values for whatever units you need. I know Lavelle sometimes likes to throw in questions where you need to convert units first...
- Wed Jan 27, 2021 9:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K Values that aren't specified
- Replies: 2
- Views: 141
Re: K Values that aren't specified
I'm not entirely sure but I believe in the book in the table of K values they had a column labeled just as "K" and another column labeled as "Kc" so I guess if it's just K it's referring to Kp.
- Wed Jan 20, 2021 8:55 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Where to find textbook answers
- Replies: 4
- Views: 150
Re: Where to find textbook answers
you can find it on Sapling under Resources. It is a PDF called "Atkins 7e SSM".
- Wed Jan 20, 2021 8:49 pm
- Forum: Phase Changes & Related Calculations
- Topic: bonds and energy
- Replies: 13
- Views: 688
Re: bonds and energy
a vapor becoming a liquid does not need energy to form bonds; forming bonds always gives off energy. this isn't necessarily related to your question, but it might help clarify: an endothermic reaction doesn't mean that it requires energy to form the bonds, it means that the energy required to break ...
- Thu Jan 14, 2021 10:33 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in Partial Pressure
- Replies: 3
- Views: 333
Change in Partial Pressure
Just to clarify, if a question says a reaction is at equilibrium and then asks about the effect of changing the partial pressure of one of the products/reactants, would that not affect the overall pressure of the reaction vessel? For example, question 5J.9 in the textbook gives the equation 3NH3 + 5...
- Thu Jan 14, 2021 7:14 pm
- Forum: Ideal Gases
- Topic: Gas constant
- Replies: 9
- Views: 352
Re: Gas constant
Yeah, so the R is used in the ideal gas law equation PV=nRT, because while PV is proportional to nT, it is the R value that makes the whole ideal gas equation true and helpful for calculations. Now the units for R can be many different things such as J/K·mol, L·atm/K·mol, L·bar/K·mol, and L·Torr/K·...
- Wed Jan 13, 2021 6:06 pm
- Forum: Ideal Gases
- Topic: Gas constant
- Replies: 9
- Views: 352
Gas constant
I noticed that on the equations and constant sheet, there are two values of the gas constant, 8.314 J mol-1 K-1 and 0.08205 L atm mol-1 K-1. I was confused about how to know which one to use because in my discussion section the TA used the first one but with the units of the second one. I thought yo...
- Wed Jan 13, 2021 5:58 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 432159
Re: Rusty on High School Chem [ENDORSED]
I'm a first year and I hadn't taken a chem class since junior year of high school either. For me personally, Khan Academy is a good way to learn and review chemistry topics. That's what helped me get through AP chem haha.
- Wed Jan 13, 2021 5:52 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3591320
Re: Post All Chemistry Jokes Here
Why did the white bear dissolve in water? Because it was polar!
- Wed Jan 13, 2021 5:50 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3591320
Re: Post All Chemistry Jokes Here
Why does a hamburger have less energy than steak? Because it's in the ground state!
- Wed Jan 13, 2021 5:49 pm
- Forum: Student Social/Study Group
- Topic: New Joke Chain
- Replies: 46
- Views: 3086
Re: New Joke Chain
Why does a hamburger have less energy than steak? Because it's in the ground state!
- Fri Jan 08, 2021 3:28 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in pressure = same volume
- Replies: 3
- Views: 158
Re: Change in pressure = same volume
To add on to what Mikayla said, the concentrations of the gases that were already in the container stay the same, but altogether there will be more moles of gas in the container since an inert gas was added. That's why the pressure increases even when the volume stays the same, because if you look a...
- Fri Jan 08, 2021 3:14 pm
- Forum: Student Social/Study Group
- Topic: How to relax
- Replies: 168
- Views: 24710
Re: How to relax
I like to watch Netflix, cuddle with my cat, and read. I also play the piano every once in a while or do cross-stitching or knitting, but unfortunately I haven't had a lot of time to do those things recently.
- Fri Jan 08, 2021 3:13 pm
- Forum: Student Social/Study Group
- Topic: How to relax
- Replies: 168
- Views: 24710
Re: How to relax
I like to watch Netflix, cuddle with my cat, and read. I also play the piano every once in a while or do cross-stitching or knitting, but unfortunately I haven't had a lot of time to do those things recently.
- Fri Jan 08, 2021 3:12 pm
- Forum: Student Social/Study Group
- Topic: How to relax
- Replies: 168
- Views: 24710
Re: How to relax
I like to watch Netflix, cuddle with my cat, and read. I also play the piano every once in a while or do cross-stitching or knitting, but unfortunately I haven't had a lot of time to do those things recently.
- Fri Jan 08, 2021 3:09 pm
- Forum: Student Social/Study Group
- Topic: Final Exam Study Tips
- Replies: 48
- Views: 2519
Re: Final Exam Study Tips
I definitely learned from my mistakes in 14A and have changed my study habits for this quarter. Going to the UA workshops and step up sessions are super helpful and it's something I totally regret not starting earlier last quarter!! Same, I never went to any of the sessions last quarter but I'm gon...
- Fri Jan 08, 2021 3:09 pm
- Forum: Student Social/Study Group
- Topic: Final Exam Study Tips
- Replies: 48
- Views: 2519
Re: Final Exam Study Tips
I definitely learned from my mistakes in 14A and have changed my study habits for this quarter. Going to the UA workshops and step up sessions are super helpful and it's something I totally regret not starting earlier last quarter!! Same, I never went to any of the sessions last quarter but I'm gon...
- Fri Jan 08, 2021 3:06 pm
- Forum: Student Social/Study Group
- Topic: Final Exam Study Tips
- Replies: 48
- Views: 2519
Re: Final Exam Study Tips
Hi! I was wondering how everyone will be studying for the final. Since it will be cumulative I don't know where to start studying. Does anyone have any tips? Thank you in advance! Hi, personally, I didn't study incredibly well last quarter and did worse than I wanted to, so this quarter I'm trying ...
- Sat Dec 12, 2020 9:45 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate Ligands
- Replies: 5
- Views: 380
Re: Polydentate Ligands
For those textbook problems, I drew out the Lewis structures and looked for atoms that had lone pairs. For example, for water, the oxygen has lone pairs, so it can be a monodentate ligand (it's not a bidentate ligand because the two lone pairs are on the same bonding site). At the UA session earlie...
- Fri Dec 11, 2020 5:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 6
- Views: 318
Re: Bond Angles
As others have said, lone pairs are spread out more since they are not held between two positively charged nuclei. So if an atom has a lone pair the bond angles will be slightly less than the normal angles for that shape. You don't need to know the exact angle, just that it will be slightly less due...
- Fri Dec 11, 2020 5:15 pm
- Forum: Lewis Structures
- Topic: Tips on drawing Lewis structures
- Replies: 21
- Views: 2244
Re: Tips on drawing Lewis structures
Hi! So I like to calculate how many valence electrons I should have and then count the electrons again to make sure that I have drawn the lewis structure correctly. Also calculate the formal charges and remember you want the most stable/less charged structure. However, if you do have a charge like ...
- Fri Dec 11, 2020 5:10 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: Hard Water vs. Soft Water
- Replies: 9
- Views: 847
Re: Hard Water vs. Soft Water
I thought Dr. Lavelle said soft water is more alkaline and that's why it feels soapy, but when I looked it up it says hard water is more alkaline because it has more minerals in it, so I'm really not sure anymore.
- Fri Dec 11, 2020 5:06 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Relative Acidity
- Replies: 7
- Views: 338
Re: Relative Acidity
Steph Du 2B wrote:If the bond being broken for the compounds you are comparing is different, you compare bond length (ex. HCl and HBr). If the bond being broken is the same, then you compare electronegativity (ex. CCl3COOH and CH3COOH).
Thanks for that explanation, it really clears everything up nicely.
- Fri Dec 11, 2020 4:56 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: angular and radial nodes
- Replies: 2
- Views: 757
Re: angular and radial nodes
I was wondering this as well and here is what I found online: "Radial node is a spherical surface where the probability of finding an electron is zero. The number of radial nodes increases with the principal quantum number (n). Angular node is also called a nodal plane. It is a plane that passe...
- Tue Dec 01, 2020 10:22 pm
- Forum: Student Social/Study Group
- Topic: Happy Thanksgiving!
- Replies: 39
- Views: 1969
Re: Happy Thanksgiving!
Happy late Thanksgiving! Our family doesn't really have a special tradition other than eating dinner together with my grandparents and watching football, but that's good enough for me :)
- Tue Dec 01, 2020 10:17 pm
- Forum: Naming
- Topic: order of ligands [ENDORSED]
- Replies: 6
- Views: 427
Re: order of ligands [ENDORSED]
I was wondering about this too, but I don't think it matters too much since you're still able to determine the formula of the molecule.
- Tue Dec 01, 2020 10:05 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate Ligands
- Replies: 5
- Views: 380
Polydentate Ligands
To determine if a ligand is polydentate and to specifically find how many places it can bind, do you have to draw the Lewis structure or is there some other intuitive way of knowing how many lone pairs it has? Asking because textbook exercise 9C.5 lists ligands and asks to identify which can be poly...
- Thu Nov 26, 2020 12:54 pm
- Forum: Hybridization
- Topic: Sp3d or dsp3
- Replies: 22
- Views: 2195
Re: Sp3d or dsp3
Dr. Lavelle said in his lecture that you can write it either way.
- Thu Nov 26, 2020 12:51 pm
- Forum: Student Social/Study Group
- Topic: Big Sad: Midterm 2
- Replies: 86
- Views: 6143
Re: Big Sad: Midterm 2
I did slightly better on this midterm than the last. When I was looking at my grade for the second midterm though, I realized that the grade shown in the Grades tab on CCLE was the number of points out of 110 rather than the percentage, meaning I actually did worse on both midterms than I initially ...
- Thu Nov 26, 2020 12:40 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: coordination number
- Replies: 13
- Views: 614
Re: coordination number
Yes, the coordination number is the number of bonds.
- Mon Nov 16, 2020 2:40 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Textbook problems 2A9 and 2A11
- Replies: 3
- Views: 121
Re: Textbook problems 2A9 and 2A11
It's asking for exactly what it says, M is an unknown metal whose ground-state electron configuration is given and we need to figure out what element M is. So you basically need to work backwards from how you normally would write an element's electron configuration. Just count the number of electron...
- Mon Nov 16, 2020 2:35 pm
- Forum: Electronegativity
- Topic: Sapling #20
- Replies: 2
- Views: 1151
Re: Sapling #20
1 is incorrect because fluorine actually has a smaller atomic radius; atomic radius decreases across a period due to higher effective nuclear charge. 4 is incorrect because oxygen and fluorine both have the 1s and 2s orbitals filled, so the 2p orbitals in both of them experience the same amount of s...
- Mon Nov 16, 2020 2:23 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Textbook 2D.9
- Replies: 4
- Views: 261
Re: Textbook 2D.9
The bigger the atom is the more polarizing power it has, because it has more protons pulling on the electrons. Hence, Be would be the smallest and lowest, then Rb, then Sr. This means polarizing power goes up across a period and increases as u go down a group. It's true that a cation with a higher ...
- Mon Nov 16, 2020 2:13 pm
- Forum: Ionic & Covalent Bonds
- Topic: hydrogen bonds
- Replies: 21
- Views: 782
Re: hydrogen bonds
Hydrogen bonds form between a hydrogen attached to a highly electronegative atom (N, O, or F) and another N, O, or F on another molecule.
- Mon Nov 16, 2020 2:11 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Quantum number ms
- Replies: 3
- Views: 257
Re: Quantum number ms
I don't think we actually need to be able to determine if an electron is spin-up or spin-down; we just need to know +1/2 is spin up and -1/2 is spin down and that two electrons in the same orbital can't have the same spin state.
- Mon Nov 16, 2020 2:07 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Updating Respondus Lockdown Browser
- Replies: 8
- Views: 659
Re: Updating Respondus Lockdown Browser
Open the LockDown Browser and in the upper left corner there's a button that has an i in a circle. Press on that and a box will pop up with a button in the middle that says "Check for newer version". Press on that and it'll say get newer version or something like that; press on that button...
- Wed Nov 11, 2020 8:09 pm
- Forum: Dipole Moments
- Topic: Induced Dipole in Non Polar Molecules
- Replies: 2
- Views: 111
Re: Induced Dipole in Non Polar Molecules
Induced dipole induced dipole interactions occur in all molecules whether they are polar or nonpolar because induced dipole induced dipole refers to temporary fluctuations in electron density that cause dipoles to form. Thus, induced dipole induced dipole interactions occur in all molecules since al...
- Wed Nov 11, 2020 8:05 pm
- Forum: Student Social/Study Group
- Topic: How are you studying?
- Replies: 204
- Views: 20025
Re: How are you studying?
I personally don't have any significant studying techniques. I just take notes on stuff mentioned in lecture that is new to me and/or that seems important. Additionally, I just make sure to do the homework and all of the textbook problems for practice and obviously go over problems I miss and try to...
- Wed Nov 11, 2020 8:01 pm
- Forum: Dipole Moments
- Topic: Induced dipole interactions and H bonds
- Replies: 2
- Views: 71
Re: Induced dipole interactions and H bonds
Yes, that is correct. That's why in his lecture Dr. Lavelle showed examples of how molecules with the same molecular formula but different shapes can have different boiling points, since molecules of certain shapes have stronger induced dipole induced dipole interactions than others (which would inc...
- Wed Nov 11, 2020 7:55 pm
- Forum: Bond Lengths & Energies
- Topic: Van der Waals
- Replies: 7
- Views: 505
Re: Van der Waals
Van der Waals interactions are induced dipole induced dipoles. They are just temporary fluctuations in electron density that can cause dipoles to form, leading different molecules to be attracted to each other.
- Wed Nov 11, 2020 7:53 pm
- Forum: Dipole Moments
- Topic: Induced dipole vs permanent dipole
- Replies: 3
- Views: 214
Re: Induced dipole vs permanent dipole
Just as you said, permanent dipoles are from two atoms having different electronegativities (thus one atom will always be partially positive and the other partially negative). On the other hand, induced dipoles are temporary fluctuations in electron density that randomly cause dipoles to form.
- Sat Nov 07, 2020 6:18 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Reviewing Answers for Midterm 1
- Replies: 13
- Views: 599
Re: Reviewing Answers for Midterm 1
I was about to ask this too, unfortunately I guess we can't review them. :/
- Sat Nov 07, 2020 6:13 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Participation Points [ENDORSED]
- Replies: 62
- Views: 3643
Re: Participation Points [ENDORSED]
I was wondering this too and couldn't figure out where I'm supposed to click on my name, but I noticed that if you look at one of your posts, on the right hand side it says how many posts you've made, so as long as you have 5 posts per week you should get full credit.
- Sat Nov 07, 2020 6:10 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: 4th quantum number
- Replies: 8
- Views: 247
Re: 4th quantum number
I don't think we need to actually "determine" any of the quantum numbers, we just need to know what they mean. So you just need to know that +1/2 is spin-up and -1/2 is spin-down.
- Sat Nov 07, 2020 6:08 pm
- Forum: Electronegativity
- Topic: Confusion between electronegativity and electron affinity
- Replies: 15
- Views: 805
Re: Confusion between electronegativity and electron affinity
I was also wondering about this because I remember learning about electronegativity but not electron affinity when discussing periodicity in high school chem, but now we only talked about electron affinity and not electronegativity. Also, they sound pretty similar, but I am not sure if they are the ...
- Sat Nov 07, 2020 5:59 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Can you have the same 3 quantem number but not the 4 same quantem numbers
- Replies: 12
- Views: 490
Re: Can you have the same 3 quantem number but not the 4 same quantem numbers
Yes you can have the same 3 quantum numbers since each orbital can hold two electrons. Thus, two electrons in the same orbital would have the same first three quantum numbers but have a different spin state.
- Wed Oct 28, 2020 9:24 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation
- Replies: 9
- Views: 327
Re: Rydberg Equation
n2 represents the excited state the electron is in, while n1 represents the energy level that the electron returns to. n2 is always greater than n1. I may be wrong, but that's the way I think about the Rydberg Equation. Yeah, that's what I realized is probably the case as I thought about it more, w...
- Wed Oct 28, 2020 9:16 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation
- Replies: 9
- Views: 327
Rydberg Equation
I'm kind of confused about the Rydberg equation v=R[1/n1^2 - 1/n2^2]. When doing problems involving emission spectrums, my TA did 1/nfinal - 1/ninitial, but the n1 and n2 make it seem like you would subtract the final energy level from the initial energy level. Are you just supposed to subtract the ...
- Wed Oct 28, 2020 12:20 am
- Forum: SI Units, Unit Conversions
- Topic: Angstrom
- Replies: 6
- Views: 546
Re: Angstrom
You're right in that 6.001 x 10^-7 m converts to 6001 angstroms. You shouldn't be multiplying by 10^-10 though since you're not actually converting between different units. They're both in meters, just in different forms of scientific notation, if that makes sense. Basically all you need to do is th...
- Wed Oct 28, 2020 12:07 am
- Forum: Photoelectric Effect
- Topic: Sapling Week 2,3,4 Q 9
- Replies: 4
- Views: 219
Re: Sapling Week 2,3,4 Q 9
Since the problem asks for the maximum wavelength that will reject electrons, KE=0, so the work function is equal to the energy of the photon. Therefore, you can set 4.810 x 10^-19 J equal to hv. Since we want to find wavelength, you can make v=c/lambda, making the equation 4.810 x 10^-19 J=hc/lamb...
- Tue Oct 27, 2020 11:56 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Sapling hw #19
- Replies: 4
- Views: 393
Re: Sapling hw #19
Like Mohamed said, for questions like this that ask for the minimum uncertainty of something (whether it be position or velocity), you just need to know how to rearrange the ΔxΔp ≥ h/4π equation to solve for what you need. For questions that ask about an electron, a proton, or a neutron, the mass is...
- Tue Oct 27, 2020 11:42 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration
- Replies: 4
- Views: 189
Re: Electron Configuration
I think on a test it might be considered wrong since Lavelle explicitly stated it is written the second way since it shows that the 3d orbital is lower in energy than the 4s orbital once the 4s orbital is full.
- Tue Oct 27, 2020 11:36 pm
- Forum: Properties of Light
- Topic: rydberg's constant
- Replies: 11
- Views: 997
Re: rydberg's constant
"The value of the Rydberg constant R∞ is 1.0973731568508 × 10^7 per metre. When used in this form in the mathematical description of series of spectral lines, the result is the number of waves per unit length, or the wave numbers. Multiplication by the speed of light yields the frequencies of t...
- Fri Oct 23, 2020 3:48 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Spin Magnetic Quantum Number
- Replies: 6
- Views: 349
Re: Spin Magnetic Quantum Number
I don't think we need to know how to actually determine it; I'm pretty sure that has to do with Schrodinger's equation. We just need to know which number signifies which spin.
- Fri Oct 23, 2020 3:15 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Magnetic Quantum Numbers
- Replies: 6
- Views: 172
Re: Magnetic Quantum Numbers
Like Rose said, m sub l ranges from l to -l. That way, there are enough different values of m sub l to signify each configuration for each type of orbital. For example, for an s-orbital (l=o), m sub l can only be 0, signifying the only configuration for the s-orbital. For a p-orbital (l=1), which ha...
- Fri Oct 23, 2020 3:09 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Electrons in Orbitals
- Replies: 5
- Views: 198
Re: Electrons in Orbitals
I don't know why the first electron in an orbital is specifically spin-up, but I'm pretty sure they occupy different orbitals before filling them up because of the repulsion forces between them, so they'd want to be as far away as possible and thus occupy different orbitals.
- Fri Oct 23, 2020 3:04 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Spin States
- Replies: 4
- Views: 231
Re: Spin States
I'm pretty sure if a problem asked for the quantum numbers of an electron it would tell us whether it was spin-up or spin-down. +1/2 signifies spin-up, while -1/2 signifies spin-down.
- Mon Oct 19, 2020 1:43 pm
- Forum: Properties of Light
- Topic: Photoelectric Experiment
- Replies: 3
- Views: 93
Re: Photoelectric Experiment
In the photoelectric experiment, they had initially assumed that light acted as a wave, so when electrons were not initially ejected, they expected that increasing the intensity of the light would cause electrons to be ejected since increasing the intensity would increase the energy of the light if ...
- Fri Oct 16, 2020 10:33 pm
- Forum: *Particle in a Box
- Topic: Textbook example 1C.1
- Replies: 1
- Views: 429
Re: Textbook example 1C.1
If you go up to Figure 1C.4, there is a paragraph above that figure and then an equation above that paragraph. That is Equation 4, the equation they're talking about in step 1. Equation 4 is simply derived from Equation 3, which you'll find if you go up a little more; it's right above the green subt...
- Fri Oct 16, 2020 10:16 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Finding the amount of molecules in compounds using mole conversions
- Replies: 3
- Views: 296
Re: Finding the amount of molecules in compounds using mole conversions
6.022x10^23 is a constant that can apply to anything, it's just an easier way of describing quantities of atoms or molecules without having to work with big, complicated numbers. Pretty much how kilo- means 1000 of whatever it is you're working with (grams, meters, etc.), a mole is just 6.022x10^23 ...
- Fri Oct 16, 2020 9:54 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Multiple Choice Format
- Replies: 6
- Views: 172
Re: Midterm Multiple Choice Format
I might be wrong, but I think I remember my TA saying that partial credit would be available; however, if the midterm actually is going to be multiple choice I'm not sure how that would work. You should ask your TA.
- Fri Oct 16, 2020 9:47 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Webcam application, Zoom Session, and Midterm
- Replies: 2
- Views: 164
Re: Webcam application, Zoom Session, and Midterm
We're supposed to have our webcam pointing down at our work and have our hands in view at all times. So to do this you can either have an external webcam that you can point down toward your desk while being able to still see your screen (if you're using a laptop). Or, you can use a separate monitor ...
- Fri Oct 16, 2020 9:13 pm
- Forum: Einstein Equation
- Topic: Lecture Example 10/16/20
- Replies: 4
- Views: 229
Re: Lecture Example 10/16/20
If you're talking about how he switched the -4.09x10^(-19) to 4.09x10^19 I'm pretty sure it's because the negative represents the energy the electron lost, meaning that the electron would release a photon with that amount of energy (a positive value) because of the law of conservation of energy. So ...
- Wed Oct 07, 2020 4:22 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: precision for molar masses
- Replies: 14
- Views: 510
Re: precision for molar masses
I always wait to round till the very end and make sure I'm using correct significant figures for my end answer. Dr. Lavelle may have another method but this is what I was taught in high school. Regarding different numbers on the periodic table, I'd use the periodic table in the book considering it ...
- Wed Oct 07, 2020 4:18 pm
- Forum: Empirical & Molecular Formulas
- Topic: Rounding EF to Integers
- Replies: 6
- Views: 345
Re: Rounding EF to Integers
As everyone else said, I think it would be easier to just convert it to integers, but if you like to leave it with decimals you probably can as long as the question doesn't actually ask for the empirical formula.
- Wed Oct 07, 2020 4:13 pm
- Forum: Significant Figures
- Topic: Clarification on Significant Figures
- Replies: 9
- Views: 458
Re: Clarification on Significant Figures
I could possibly be wrong here, but I think that leading zeros are the zeros that do not count. For instance, 0.034 would have only 2 sig figs, whereas 0.304 would have 3 sig figs since the zero second zero is in the middle and not leading. However, I am a bit rusty on sig fig rules, so feel free t...
- Wed Oct 07, 2020 4:06 pm
- Forum: Limiting Reactant Calculations
- Topic: Limiting Reactants
- Replies: 9
- Views: 207
Re: Limiting Reactants
I'm pretty sure there can only be one limiting reactant because either one reactant will limit the other(s) or the reactants will all be present in proportionate amounts according to the chemical equation in which case they would not limit each other. The only case I can think of where there might b...