Search found 18 matches
- Sun Mar 19, 2017 1:23 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Saying Thank You to Dr. Lavelle
- Replies: 490
- Views: 621798
Re: Saying Thank You to Dr. Lavelle
Dr. Lavelle, Thank you for your diligence, love, and enthusiasm for teaching Chemistry at UCLA. You are the only professor I know of who gives so many resources to his students in hopes that they succeed in the course/develop a true interest in the topic taught. You go above and beyond what UCLA req...
- Sun Mar 19, 2017 1:17 pm
- Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
- Topic: Chair conformation drawing
- Replies: 2
- Views: 1710
Re: Chair conformation drawing
Hi!
I think if you draw it the other way, it might be considered flipped, in which the equatorial and axial hydrogens will also switch positions.
Best be safe and draw like the way in the book, just to be consistent :)
I think if you draw it the other way, it might be considered flipped, in which the equatorial and axial hydrogens will also switch positions.
Best be safe and draw like the way in the book, just to be consistent :)
- Fri Feb 17, 2017 2:46 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Figuring out overall order of reaction based on balanced reaction
- Replies: 1
- Views: 438
Figuring out overall order of reaction based on balanced reaction
Hello! Not sure if this is the right location for this question, but how would I solve a problem like this: Given: Fe2+ +O2 + H2O ---> Fe3+ +OH- Rate: k[Fe2+]*[OH-]^2*[O2] The overall order of the rxn and the order with respect to OH- are: __________ Do I just look at the powers of the concentration...
- Sat Feb 04, 2017 8:24 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: E- Transfer Diagram
- Replies: 1
- Views: 356
E- Transfer Diagram
I was wondering why there is no salt bridge/porous disk in the diagram for electrolysis. Is it because there is already something that is transferring ions (the electron current). Do Ion-selective electrode redox reactions also not have a salt bridge/porous disk, because the electrode helps drive th...
- Sat Jan 21, 2017 4:28 pm
- Forum: Calculating Work of Expansion
- Topic: Work Equation, changing V and P
- Replies: 2
- Views: 648
Work Equation, changing V and P
This relates to midterm 2013 question 4 part A in back of course reader
Why is it that when volume and pressure are both changing that work can equal:
w=-nRTln(V2/V1) or w=-nRTln (P1/P2)
Is it because the pressure is inversely related to the volume?
Why is it that when volume and pressure are both changing that work can equal:
w=-nRTln(V2/V1) or w=-nRTln (P1/P2)
Is it because the pressure is inversely related to the volume?
- Fri Jan 13, 2017 3:57 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Calorimeters
- Replies: 3
- Views: 688
Re: Calorimeters
To add on to this question/for clarification, is it correct to say;
Isolated: The universe
Bomb Calorimeter: Closed
constant P calorimetry: Open
???
Thank you!
Isolated: The universe
Bomb Calorimeter: Closed
constant P calorimetry: Open
???
Thank you!
- Tue Nov 22, 2016 5:28 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Using ICE Table
- Replies: 1
- Views: 748
Re: Using ICE Table
Hi! ICE table really confused me at first but basically: I stands for Initial C stands for change E stands for equilibrium You will usually have to use the ICE table in order to find concentrations or partial pressure at equilibrium when the system is not at equilibrium, or to find Kp, Kc, Ka, or Kb...
- Mon Nov 14, 2016 12:51 pm
- Forum: Ideal Gases
- Topic: Quiz 3 Prep
- Replies: 2
- Views: 713
Re: Quiz 3 Prep
To add on to the last comment, when figuring out whether to lower or raise the pressure, it's helpful to look at the # of moles of gas for reactant and products! Reactants: 2 mols Products: 3 mols Increasing pressure shifts the position of the equilibrium to the side with fewer moles of gas, which w...
- Thu Nov 03, 2016 11:26 am
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: sigma and pi bonds in p orbital
- Replies: 1
- Views: 702
Re: sigma and pi bonds in p orbital
Hello! Pi bonds occur due to side by side overlapping of atomic orbitals in a plane Sigma bonds occur due to end to end overlapping of atomic orbitals Overlapping p orbitals can either form pi or sigma bonds. The way the bond orients and overlaps depends which one it is. Here is a picture that I fou...
- Thu Oct 27, 2016 7:18 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3890420
Re: Post All Chemistry Jokes Here
From ASAPScience.
- Fri Oct 21, 2016 8:17 pm
- Forum: Lewis Structures
- Topic: Lewis structure for O3 (ozone) [ENDORSED]
- Replies: 3
- Views: 6332
Lewis structure for O3 (ozone) [ENDORSED]
Hi Chemistry Friends! I was wondering why the Lewis structure for O3 is O-O=O (where the Formal charge from left to right is -1,+1,0) (3 e- pairs on left oxygen, 1 e- pair on middle oxygen, 2 e- pairs on right oxygen) and not O=O=O (where all formal charges are 0) (2 e- pairs on left and right oxyge...
- Thu Oct 20, 2016 12:10 pm
- Forum: Electronegativity
- Topic: Units for electronegativity
- Replies: 4
- Views: 2401
Re: Units for electronegativity
I think it is because electronegativity is the tendency of atoms to attract a bonding pair of electrons, and is calculated, not experimentally measured
- Wed Oct 19, 2016 4:51 pm
- Forum: Lewis Structures
- Topic: Formal Charge vs. Octet [ENDORSED]
- Replies: 1
- Views: 671
Re: Formal Charge vs. Octet [ENDORSED]
Formal Charge = 0 is the most stable, and is an important component in determining the Lewis Structure of a molecule. If we add a double bond to one of the Flourines, the Boron would have an octet but the flourine would have a formal charge of +1, and boron would have an extra electron that it norma...
- Tue Oct 11, 2016 3:03 pm
- Forum: Significant Figures
- Topic: Electron Emission Sig Figs
- Replies: 2
- Views: 578
Re: Electron Emission Sig Figs
Hello! I had a similar questions and asked my TA... I had put 4 sig figs in my answer, which I derived from Planck's Constant (6.626*10^-34), and he said that would be the best, since the energy levels (n=#) are constants. Use the number of sigfigs in Planck's Constant, which is 4! (I hope this is a...
- Thu Oct 06, 2016 7:17 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Boundary Surface of Orbitals [ENDORSED]
- Replies: 2
- Views: 1587
Re: Boundary Surface of Orbitals [ENDORSED]
Well... this is awkward because I'm answering my own question. But just in case anybody clicked on this because they were also confused, I found the answer to my question in the textbook! Boundary Surfaces: Shapes of atomic orbitals s-orbital: Spherical p-orbital: Dumbbell or peanut d-orbital: Four ...
- Thu Oct 06, 2016 5:28 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Boundary Surface of Orbitals [ENDORSED]
- Replies: 2
- Views: 1587
Boundary Surface of Orbitals [ENDORSED]
I noticed in the course reader that it stated we should know the boundary surface of orbitals. Is that the shape of the region in which electrons can be found (for example: the s orbital is a ping pong ball shape in which there is a high probability of finding electrons inside of it, the p orbital h...
- Thu Oct 06, 2016 10:34 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals [ENDORSED]
- Replies: 9
- Views: 1855
Re: Orbitals [ENDORSED]
This was a concept that I was pretty confused about as well, but from my understanding: Electrons are located in different energy levels (n=1,2,3, etc) Each energy level has a certain space where there is a high percentage that electrons might be located in. These are called orbitals, and are differ...
- Thu Sep 29, 2016 1:13 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect [ENDORSED]
- Replies: 12
- Views: 2704
Re: Photoelectric Effect [ENDORSED]
I understand that you need the threshold energy to in order to get the kinetic energy, but I don't really understand what it is. What does threshold energy mean in the photoelectric effect and where do you get it from? Hi! From my understanding, the threshold energy (also known as work function/Gre...