Search found 66 matches
- Sat Mar 16, 2019 5:28 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Final [ENDORSED]
- Replies: 9
- Views: 1161
Re: Final [ENDORSED]
Just to be sure, steady state is not included in finals right?
- Sat Mar 16, 2019 5:26 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nernst
- Replies: 14
- Views: 1234
Re: Nernst
josephperez_2C wrote:Just making sure, n could never equal 0 since there is always a transfer of electrons right?
Yes I think so
- Sat Mar 16, 2019 5:24 pm
- Forum: Administrative Questions and Class Announcements
- Topic: LYNDON'S PORK RAMEN REVIEW
- Replies: 37
- Views: 7653
Re: LYNDON'S PORK RAMEN REVIEW
Tysm Lyndon! Can someone post the answer plss tyyy~
- Wed Mar 06, 2019 3:23 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Corrosion
- Replies: 3
- Views: 397
Re: Corrosion
Also if it is not in the syllabus, then I don’t think we need to know it.
- Wed Mar 06, 2019 3:22 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Arrhenius Equation
- Replies: 1
- Views: 336
Re: Arrhenius Equation
A represents the number of collisions multiplied by the frequency in which they are in the correct orientation, which gives us A the frequency factor.
- Wed Mar 06, 2019 3:20 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Volume and Temperature
- Replies: 2
- Views: 331
Re: Volume and Temperature
The entropy increases as the temperature increases, hope that helps.
- Thu Feb 28, 2019 11:08 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: H+ in cell diagrams
- Replies: 5
- Views: 621
H+ in cell diagrams
Can anyone explain when do we add H+ in cell diagrams?
eg.
Pt I Fe3+, Fe2+ II H+, MnO4-, Mn2+ I Pt
eg.
Pt I Fe3+, Fe2+ II H+, MnO4-, Mn2+ I Pt
- Thu Feb 28, 2019 8:14 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Organization of cell diagrams
- Replies: 9
- Views: 864
Re: Organization of cell diagrams
Aurbal Popal wrote:Also, to add on to her question, you do not need to put Pt on both sides of the cell diagram if there is a solid on the other side, right?
THAT'S RIGHT
- Wed Feb 27, 2019 3:21 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidized vs oxidizing agent
- Replies: 6
- Views: 685
Re: Oxidized vs oxidizing agent
I usually just remember one as an opposite of another. If something is being oxidized, then it is the reducing agent.
- Wed Feb 27, 2019 3:16 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Pt (s) [ENDORSED]
- Replies: 8
- Views: 972
Re: Pt (s) [ENDORSED]
I think we also add Pt when both species of the same kind are in the same solution, say Fe2+ and Fe3+
- Wed Feb 27, 2019 3:14 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell diagram
- Replies: 1
- Views: 221
Cell diagram
In some of the HW problem solutions, the cell diagram shows Fe2+, Fe3+ II ..., instead of Fe2+ I Fe3+ II...
Is there a difference between using , and I ?
Is there a difference between using , and I ?
- Thu Feb 21, 2019 1:04 pm
- Forum: Balancing Redox Reactions
- Topic: Half Reactions
- Replies: 1
- Views: 257
Re: Half Reactions
For acidic reactions, we balance out the O by adding H2O and balance out the H by adding H+.
For basic reactions, we balance out O by adding H2O and balance out H by adding OH-.
For basic reactions, we balance out O by adding H2O and balance out H by adding OH-.
- Thu Feb 21, 2019 1:00 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3890392
Re: Post All Chemistry Jokes Here
If I steal your electrons would I be legally charged?
- Thu Feb 21, 2019 12:59 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3890392
Re: Post All Chemistry Jokes Here
Did you know that you can cool yourself to -273.15˚C and still be 0 K?
- Tue Feb 12, 2019 10:19 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)
- Replies: 179
- Views: 24753
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)
Karyn Nguyen 1K wrote:For worksheet 4, is the answer for 6a wrong? I did (3/2)(31.9 mol)(8.314 J/Kmol)(311.15 K) = 124 kJ. When I didn't convert the temperature from C to K I got 15.1 kJ which is the answer given in the key.
We don’t have to convert it to kelvin as it is change in temperature (38-0)
- Tue Feb 12, 2019 10:16 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Isothermal and reversible
- Replies: 2
- Views: 380
Isothermal and reversible
Doe isothermal expansion ALWAYS mean reversible expansion?
Or is it possible to have isothermal, irreversible expansion as well?
Or is it possible to have isothermal, irreversible expansion as well?
- Tue Feb 12, 2019 9:36 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)
- Replies: 179
- Views: 24753
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sun 7-9PM (Karen)
Quick question for Worksheet 1 ques8:
When I2 is added, neither products nor reactants is favored as I2 is a solid.
What happens when I2 is removed, does the reaction not shift too?
When I2 is added, neither products nor reactants is favored as I2 is a solid.
What happens when I2 is removed, does the reaction not shift too?
- Mon Feb 11, 2019 5:39 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Delta U and deltaH
- Replies: 1
- Views: 254
Delta U and deltaH
Can someone explain how is deltaU = deltaH -p* deltaV
- Mon Feb 11, 2019 5:37 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: W in adiabatic
- Replies: 1
- Views: 266
W in adiabatic
I understand that q=0 in adiabatic situations, but why does w=Cv* deltaT? ( I thought that w is suppose to be work due to expansion of gas)
- Thu Feb 07, 2019 11:50 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Reversible vs irreversible
- Replies: 3
- Views: 561
Re: Reversible vs irreversible
In thermodynamics, a reversible process is a process whose direction can be "reversed" by inducing infinitesimal changes to some property of the system via its surroundings. Throughout the entire reversible process, the system is in thermodynamic equilibrium with its surroundings. Having b...
- Thu Feb 07, 2019 11:44 am
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Degeneracy and Entropy
- Replies: 1
- Views: 255
Re: Degeneracy and Entropy
Increasing degeneracy results in an increase in entropy of the system. This is shown by the Boltzmann equation: S=kB*ln(W), where w is the degeneracy and S is entropy. Therefore, an increase in w increases the value of S, which is entropy. This also makes sense because degeneracy is the number of wa...
- Thu Feb 07, 2019 11:38 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Degeneracy
- Replies: 2
- Views: 336
Re: Degeneracy
How do we calculate degeneracy caused by heat then?
- Thu Feb 07, 2019 11:36 am
- Forum: Calculating Work of Expansion
- Topic: Ideal gas expansion
- Replies: 4
- Views: 428
Re: Ideal gas expansion
I understand that q=0 as there is no net heat change. But why isn’t W a negative value as the system has done work to expand?
- Thu Feb 07, 2019 11:32 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Difference in Entropy Due to Temperature Change
- Replies: 2
- Views: 374
Re: Difference in Entropy Due to Temperature Change
For the second equation S=Cln(T2/T1), is q constant then?
- Sat Feb 02, 2019 7:58 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Heat vs. Temp
- Replies: 9
- Views: 931
Re: Heat vs. Temp
So is it correct to say that heat is directly proportional to temperature?
- Sat Feb 02, 2019 7:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm Review
- Replies: 14
- Views: 1278
Re: Midterm Review
For last quarter there were many review sessions by both TAs and Lavelle :)
- Sat Feb 02, 2019 7:55 pm
- Forum: Student Social/Study Group
- Topic: Absent on 1/30; in need of notes
- Replies: 4
- Views: 502
Re: Absent on 1/30; in need of notes
I can send you the notes what’s your email?
- Sat Feb 02, 2019 7:53 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: bond enthalpy equations
- Replies: 6
- Views: 647
Re: bond enthalpy equations
Yes drawing out the structures really worked for me
- Tue Jan 22, 2019 8:02 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q reaction quotient
- Replies: 2
- Views: 269
Q reaction quotient
When asked for Q reaction quotient, should we give in terms of pressure or concentration when the chemical equation contains both liquid and gases?
- Sat Jan 19, 2019 9:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ka vs. Kb
- Replies: 12
- Views: 4650
Re: Ka vs. Kb
And Kp is the pressure constant?
- Sat Jan 19, 2019 9:07 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Studying for First Discussion Test
- Replies: 10
- Views: 843
Re: Studying for First Discussion Test
I will be doing all the homework problems and going through lecture notes. GOODLUCK everybody!
- Sat Jan 19, 2019 9:06 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Studying for First Discussion Test
- Replies: 10
- Views: 843
Re: Studying for First Discussion Test
Anyone knows if Karen is still giving out worksheets for this class?
- Fri Jan 11, 2019 10:49 am
- Forum: General Science Questions
- Topic: Week 1 Homework
- Replies: 5
- Views: 514
Re: Week 1 Homework
Can we submit our hw during discussion?
- Fri Jan 11, 2019 10:47 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K, Kc and Kp
- Replies: 8
- Views: 604
Re: K, Kc and Kp
The K values are only affected by the change in temperature.
- Mon Jan 07, 2019 4:44 pm
- Forum: General Science Questions
- Topic: Chem textbook
- Replies: 3
- Views: 433
Chem textbook
Hi does anyone know what book is this?
CHEMICAL PRINCIPLES (LOOSE-LEAF) & SSM (NEW COPIES W/24MO SAPLING & ETEXT ACCESS)
Cause it was listed as REQUIRED in the UCLA textbook page for Chem 14B but I don’t think it’s the textbook itself coz that was listed separately.
Tqsm!
CHEMICAL PRINCIPLES (LOOSE-LEAF) & SSM (NEW COPIES W/24MO SAPLING & ETEXT ACCESS)
Cause it was listed as REQUIRED in the UCLA textbook page for Chem 14B but I don’t think it’s the textbook itself coz that was listed separately.
Tqsm!
- Sat Dec 08, 2018 3:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
- Replies: 118
- Views: 21745
Re: FINAL PRACTICE - Lyndon's Churro Review Session [ENDORSED]
Thank you! Does anyone know which other TAs or UAs post worksheets as well (besides Lyndon and Karen)?
- Sat Dec 08, 2018 3:53 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 39575
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Thanks Karen for the helpful worksheets!
- Thu Nov 29, 2018 2:15 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular orientation
- Replies: 2
- Views: 296
Re: Molecular orientation
Thanks! That was really helpful! But what about COOH though... is it one of the few exemptions?
- Wed Nov 28, 2018 8:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular orientation
- Replies: 2
- Views: 296
Molecular orientation
Is it safe to assume that the sequence of the chemical formula is a correct representation of the molecular structure itself?
Example: the molecular structure of CNO- is in the sequence C-N-O since the formula is CNO-
Example: the molecular structure of CNO- is in the sequence C-N-O since the formula is CNO-
- Wed Nov 28, 2018 8:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Electron Geometry and Molecular Geometry
- Replies: 2
- Views: 409
Electron Geometry and Molecular Geometry
When the question asks for the shape, can I just give the molecular geometry, or do I have to give both electron and molecular geometry?
- Wed Nov 28, 2018 8:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Shape and Lewis Structure
- Replies: 1
- Views: 225
Shape and Lewis Structure
When the question asks for the Lewis Structure, would I be penalized if I draw out the shape instead (as the shape is just a more “advanced” version of Lewis Structure?
- Fri Nov 16, 2018 1:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Distance from Central Atom
- Replies: 8
- Views: 590
Re: Distance from Central Atom
Then does a non-wedge bond indicate that the bond goes sideways?
- Fri Nov 16, 2018 1:03 pm
- Forum: Student Social/Study Group
- Topic: curve?
- Replies: 20
- Views: 3056
Re: curve?
Is it true that he will curve if the class finals average is too low?
- Fri Nov 16, 2018 1:02 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: CH 4 HW 4.41 6TH EDITION
- Replies: 3
- Views: 275
Re: CH 4 HW 4.41 6TH EDITION
Is the CN bond usually a triple bond?
- Thu Nov 08, 2018 9:23 pm
- Forum: Lewis Structures
- Topic: Placement of Elements?
- Replies: 5
- Views: 608
Re: Placement of Elements?
I don't think it matters.
- Thu Nov 08, 2018 9:21 pm
- Forum: Sigma & Pi Bonds
- Topic: Easy way of remembering the difference
- Replies: 6
- Views: 731
Re: Easy way of remembering the difference
I believe that they only happen in covalent bonds as ionic bonds are a complete transfer of electrons without any sharing.
- Thu Nov 08, 2018 9:19 pm
- Forum: Student Social/Study Group
- Topic: Homework 6
- Replies: 5
- Views: 648
Re: Homework 6
Yes I did some from the past sections and some on the newer topics too.
- Thu Nov 08, 2018 9:18 pm
- Forum: Electronegativity
- Topic: Covalent Bonds
- Replies: 2
- Views: 276
Re: Covalent Bonds
Yes, for the reasons above AlCl3 is actually ionic with covalent character.
- Thu Nov 08, 2018 9:16 pm
- Forum: Octet Exceptions
- Topic: Octet vs formal charge
- Replies: 16
- Views: 3152
Re: Octet vs formal charge
Also make sure that for elements that do not have expanded d orbitals (Period 2 and above) do not exceed their octet shell.
- Thu Nov 08, 2018 9:08 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3890392
Re: Post All Chemistry Jokes Here
Not quite chem related but..
Why do many pre-med students want to donate their bodies to research after they die?
Because that is the only way for them to get into med school.
Why do many pre-med students want to donate their bodies to research after they die?
Because that is the only way for them to get into med school.
- Sun Nov 04, 2018 8:51 pm
- Forum: Ionic & Covalent Bonds
- Topic: Chem Midterm
- Replies: 13
- Views: 1191
Re: Chem Midterm
Do we need a blue book for the test?
- Sat Nov 03, 2018 2:35 pm
- Forum: Bond Lengths & Energies
- Topic: Lengths of Bonds
- Replies: 9
- Views: 667
Re: Lengths of Bonds
Thank you!
- Thu Nov 01, 2018 7:08 pm
- Forum: Bond Lengths & Energies
- Topic: Lengths of Bonds
- Replies: 9
- Views: 667
Re: Lengths of Bonds
Btw does anyone know why is that when calculating the bond length of say BiF4, we only sum up the bond length of Bi and F, instead of summing the lengths of Bi and 4Fs?
- Thu Nov 01, 2018 7:06 pm
- Forum: Bond Lengths & Energies
- Topic: Lengths of Bonds
- Replies: 9
- Views: 667
Re: Lengths of Bonds
Cause the electron density is higher?
- Thu Oct 25, 2018 1:42 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Homework Ch.2 Question 15, 6th Edition
- Replies: 6
- Views: 475
Re: Homework Ch.2 Question 15, 6th Edition
605122791 wrote:But the textbook says that
Number of radial nodes
= n-1-l
Which should give us
=3-1-1
=1
Can someone explain why is the answer 2 instead of 1 please?
For b) the number of radial nodes
- Thu Oct 25, 2018 1:41 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Homework Ch.2 Question 15, 6th Edition
- Replies: 6
- Views: 475
Re: Homework Ch.2 Question 15, 6th Edition
But the textbook says that
Number of radial nodes
= n-1-l
Which should give us
=3-1-1
=1
Can someone explain why is the answer 2 instead of 1 please?
Number of radial nodes
= n-1-l
Which should give us
=3-1-1
=1
Can someone explain why is the answer 2 instead of 1 please?
- Thu Oct 25, 2018 1:39 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Homework Ch.2 Question 15, 6th Edition
- Replies: 6
- Views: 475
Re: Homework Ch.2 Question 15, 6th Edition
The answer given in the solution manual is
a) 1 nodal plane
b) 2 radial nodes
a) 1 nodal plane
b) 2 radial nodes
- Thu Oct 18, 2018 12:00 am
- Forum: SI Units, Unit Conversions
- Topic: formula units [ENDORSED]
- Replies: 69
- Views: 33034
Re: formula units [ENDORSED]
Yes, which is the Avogadro Number.
- Wed Oct 17, 2018 11:59 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Using different letters for variables
- Replies: 1
- Views: 87
Using different letters for variables
Hi, I was wondering if I am allowed to use different letters when writing down a formula.. eg.for c = v x lamda can I write v = f x lamda instead? I find it confusing as some of the letters in the new equations, means a totally different thing form what I have used to learn. So, would I get penalize...
- Wed Oct 17, 2018 11:51 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 452687
Re: Advice from a Medical Student [ENDORSED]
Thank you for the advice!
- Wed Oct 10, 2018 11:13 pm
- Forum: SI Units, Unit Conversions
- Topic: Ways to remember prefixes
- Replies: 7
- Views: 4892
Re: Ways to remember prefixes
I used the Tune of Happy Birthday song!
Tera Giga Mega
Kilo Hecto Deca
Deci Centi Milli Micro
Nano Pico Hepto
Tera Giga Mega
Kilo Hecto Deca
Deci Centi Milli Micro
Nano Pico Hepto
- Wed Oct 10, 2018 11:12 pm
- Forum: SI Units, Unit Conversions
- Topic: How does grading for discussion posts work?
- Replies: 80
- Views: 9180
Re: How does grading for discussion posts work?
My TA said it’s dued by Friday midnight
- Wed Oct 10, 2018 11:11 pm
- Forum: Properties of Light
- Topic: Telling color by wavelength
- Replies: 3
- Views: 271
Re: Telling color by wavelength
Thanks so much for the chart!
- Fri Oct 05, 2018 4:00 pm
- Forum: SI Units, Unit Conversions
- Topic: How does grading for discussion posts work?
- Replies: 80
- Views: 9180
Re: How does grading for discussion posts work?
Hi guys. May I know what’s included in our test next week?
Is it the whole of the Fundamental section, or just the sections mentioned in Outline 1?
Thanks!
Is it the whole of the Fundamental section, or just the sections mentioned in Outline 1?
Thanks!
- Fri Oct 05, 2018 3:55 pm
- Forum: SI Units, Unit Conversions
- Topic: SI Units on tests
- Replies: 5
- Views: 566
Re: SI Units on tests
Is the conversion between US units and SI units given in the tests?
Thanks!
Thanks!
- Fri Oct 05, 2018 3:48 pm
- Forum: Significant Figures
- Topic: All students read this sig fig post [ENDORSED]
- Replies: 170
- Views: 36394
Re: All students read this sig fig post [ENDORSED]
Hi is it ok to not bother about significant figures in the beginning of calculations (by writing down more than the required sf.), and only round it to the correct number of sf. in the last equation?