Search found 23 matches

by Fengting Liang 1F
Sat Mar 18, 2017 7:54 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 2014 Winter Final
Replies: 3
Views: 571

Re: 2014 Winter Final

Why couldn't we use solid Fe as a conductor?
by Fengting Liang 1F
Sat Mar 18, 2017 5:42 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 2014 Winter Final
Replies: 3
Views: 571

2014 Winter Final

Can someone explain for Q3 part A, why each chemical is selected to be part of the galvanic cell (or why not)?
page 182 in course reader
by Fengting Liang 1F
Fri Mar 17, 2017 8:54 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Winter 2013 Q3B
Replies: 2
Views: 304

Re: Winter 2013 Q3B

Ecell = Ecathode - Eanode is the equation you use when Ecathode and Eanode are both given as reduction potentials (meaning when both reactions are written as reduction reactions with the elections on the reactant side). However, since the second equation 2Cr3+ (aq) + 7H2O (l) --> Cr2O7 2- (aq) +14H+...
by Fengting Liang 1F
Fri Mar 17, 2017 8:48 pm
Forum: Calculating Work of Expansion
Topic: Chapter 8 question 8.27
Replies: 2
Views: 395

Re: Chapter 8 question 8.27

If you look at page 33 in the course reader, you will see that there are different equations for w given (for either reversible pathway or irreversible pathway), because in reversible, T is constant but in irreversible T changes along the pathway.
by Fengting Liang 1F
Thu Mar 16, 2017 9:55 pm
Forum: *Cyclopropanes and Cyclobutanes
Topic: Anti vs Gauche
Replies: 1
Views: 576

Anti vs Gauche

What is the difference between anti and gauche conformations?
by Fengting Liang 1F
Thu Mar 16, 2017 12:32 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Difference between cis and Z, and trans and E
Replies: 4
Views: 732

Re: Difference between cis and Z, and trans and E

Are you sure they mean the same thing? Because in class I was told that cis and trans are for identical substituents and the longest chains, while E and Z are for highest priority/highest atomic #, but I just need clarification on what "longest chain" and "highest priority" mean.
by Fengting Liang 1F
Thu Mar 16, 2017 12:10 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Difference between cis and Z, and trans and E
Replies: 4
Views: 732

Difference between cis and Z, and trans and E

What's the difference between cis- and Z-, and between trans- and E-?
by Fengting Liang 1F
Tue Mar 07, 2017 8:37 pm
Forum: *Cycloalkanes
Topic: course reader page 96 neo and tert
Replies: 3
Views: 506

Re: course reader page 96 neo and tert

I think it's because there has to be 4 C-C connections on the attached group to be able to use the prefix "neo". So if you ignore the hexane and the line connecting the butyl to the hexane, there are only 3 C-C connections (which is why you use the prefix for 3, "tert"), because ...
by Fengting Liang 1F
Tue Mar 07, 2017 5:00 pm
Forum: *Cycloalkanes
Topic: numbering the carbons
Replies: 4
Views: 701

Re: numbering the carbons

I guess what I'm trying to ask is, how do I know to start numbering the carbons at the one attached to the ethyl, and not the carbon that's attached to the fluorine?
by Fengting Liang 1F
Tue Mar 07, 2017 4:58 pm
Forum: *Cycloalkanes
Topic: numbering the carbons
Replies: 4
Views: 701

numbering the carbons

Hi I was wondering, for a molecule like 1-ethyl-4-fluorocyclohexane, why couldn't it also be written as 4-ethyl-1-fluorocyclohexane?
by Fengting Liang 1F
Mon Mar 06, 2017 9:47 pm
Forum: *Nucleophiles
Topic: Self Test 4.1B
Replies: 1
Views: 596

Self Test 4.1B

In the green organic chem textbook on pg. 147: (Since there is no answer in the book could someone explain how to get the answer to me? I just want to make sure I have the right concept) What type of reactant is cyanide? Draw its Lewis structure and comment on how it can react. What is the hybridiza...
by Fengting Liang 1F
Tue Feb 21, 2017 5:36 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: textbook #15.63
Replies: 1
Views: 271

textbook #15.63

Can someone help with this problem? I solved it a slightly different way and ended up with the right answer, but I have no idea what's going on the in solutions manual. The rate constant of the reaction between CO2 and OH- in aqueous solution to give the HCO3- ion is 1.5 x 10^10 L*mol^-1*s^-1 at 25 ...
by Fengting Liang 1F
Sat Feb 11, 2017 3:39 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Book Question 8.55
Replies: 1
Views: 219

Book Question 8.55

Did the textbook misprint the intermediate reactions for this problem? I can't balance the O2s with the reactions given
by Fengting Liang 1F
Fri Jan 13, 2017 10:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpies of Formation Basics
Replies: 2
Views: 256

Re: Standard Enthalpies of Formation Basics

Usually how I think of it is if it's just the element alone, like C or Na or Ag, they're in their "standard state," unless they're diatomic gases like O2 or F2 which are also in their standard states. But a compound like CO2 isn't in a standard state and therefore you'd have to look up its...
by Fengting Liang 1F
Wed Jan 11, 2017 4:11 pm
Forum: Student Social/Study Group
Topic: Discussion Section 1I
Replies: 1
Views: 347

Discussion Section 1I

Hi!! I'm currently enrolled in discussion 1I (Thursday, 1:00-1:50pm), and would like to switch sections due to time conflicts. If anyone is in sections 1C, 1F, 1K, or 1L and is willing to switch with me please let me know! Thank you!
by Fengting Liang 1F
Sun Dec 04, 2016 12:27 am
Forum: DeBroglie Equation
Topic: 2014 Final #2A
Replies: 1
Views: 338

2014 Final #2A

Can anyone explain the conceptual part to this answer? Why can we say that "since the wavelength is less than the size (diameter), yes it makes sense."? (the wavelength comes out to be 8.11x10^-11 m. The question says: "The average speed of a helium atom at 25Celsius is 1.23x10^3 m/s....
by Fengting Liang 1F
Sat Dec 03, 2016 8:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 2012 Final #6B
Replies: 3
Views: 517

Re: 2012 Final #6B

Can someone explain how he goes from Kc=(x/1.072)^2/((0.05-x)/1.072)) and gets x=0.03059? I keep getting x=0.049 when I plug in Kc...
by Fengting Liang 1F
Sun Nov 13, 2016 2:43 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: MO diagram/bond order for C2+ [ENDORSED]
Replies: 1
Views: 1090

MO diagram/bond order for C2+ [ENDORSED]

Can anyone explain how to draw the molecular orbital diagram and get the bond order for C2+ (two carbons with one e- removed)?
by Fengting Liang 1F
Tue Nov 01, 2016 5:11 pm
Forum: Hybridization
Topic: Fall 2012 Q6A [ENDORSED]
Replies: 4
Views: 506

Re: Fall 2012 Q6A [ENDORSED]

It actually has four areas of electron density because each carbon is attached to two carbons (or one carbon and the nitrogen), as well as two hydrogens.
by Fengting Liang 1F
Sun Oct 23, 2016 4:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma and Pi Bonds
Replies: 2
Views: 402

Re: Sigma and Pi Bonds

To count the number of sigma and pi bonds you just need to know how many single, double, and triple bonds are in the molecule. single bond - one sigma bond double bond - one sigma, one pi bond triple bond - one sigma, two pi bonds As for the difference, sigma bonds overlap (interact) end to end whil...
by Fengting Liang 1F
Sun Oct 23, 2016 4:24 pm
Forum: Hybridization
Topic: Cr and Cu
Replies: 1
Views: 231

Re: Cr and Cu

If you follow the Aufbau Principle and completely fill each sublevel before moving on to the next one, you'd write the configuration for Cr like [Ar]4s^2 3d^4, and Cu like [Ar]4s^2 3d^9. But because half-filled and fully-filled sublevels are more stable than partially filled sublevels, the actual el...
by Fengting Liang 1F
Sun Oct 16, 2016 11:18 pm
Forum: Trends in The Periodic Table
Topic: Aufbau Principle [ENDORSED]
Replies: 2
Views: 411

Re: Aufbau Principle [ENDORSED]

Aufbau means that electrons fill the lowest possible energy levels first to create the most stable electron configurations (like 1s is always filled before 2s) and Hunds rule is that each orbital in each subshell is filled once before it's filled twice (and if they're filling them singly they all ha...
by Fengting Liang 1F
Sat Oct 08, 2016 7:11 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Uncertainty-Which numbers to use? Sig Figs? [ENDORSED]
Replies: 1
Views: 260

Re: Heisenberg Uncertainty-Which numbers to use? Sig Figs? [ENDORSED]

Delta x is the uncertainty in position so if it's speed (m/s) then I think your value would be delta p (uncertainty in momentum). And you're right, it would be .4+.4=.8. In regards to your sig fig question, I was taught to use the lowest amount of sig figs in my final answer. Like in your example 3....

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