Search found 31 matches

by Anna_Kim_2E
Sun Mar 19, 2017 9:00 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Midterm 2016 Q3C
Replies: 2
Views: 361

Re: Midterm 2016 Q3C

viewtopic.php?f=140&t=20850&p=59021&hilit=cell+diagram&sid=62cad8228751744d5735abc415246b2e#p59021

I was stuck on this too, but its due to counter ions that's coming back into half cell with Ag+.
by Anna_Kim_2E
Sun Mar 19, 2017 3:51 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Winter 2016 Q3C (p.207)
Replies: 3
Views: 416

Re: Winter 2016 Q3C (p.207)

First the conventional way of writing the cell diagram is Reactant, Product, Reactant, Product etc. The reason AgBr(s) is in the diagram is because it is solid and Ag+ has been oxidized and that is why it is to included in the diagram. It is actually supposed to be the whole solid rather than the d...
by Anna_Kim_2E
Thu Mar 16, 2017 6:19 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: staggered vs eclipsed stability
Replies: 3
Views: 421

Re: staggered vs eclipsed stability

180 degrees - anti staggered would be the lowest energy conformation.
by Anna_Kim_2E
Fri Mar 10, 2017 2:36 pm
Forum: *Alkanes
Topic: Iso / Neo when to use
Replies: 3
Views: 416

Re: Iso / Neo when to use

iso on a substituent is used when it is not attached in a linear structure.
by Anna_Kim_2E
Fri Mar 03, 2017 11:25 pm
Forum: *Alkanes
Topic: About the Weekly Online Discussion Points...
Replies: 3
Views: 478

Re: About the Weekly Online Discussion Points...

Do we then get extra points for posting more than one each week?

I thought I heard somewhere we get like 2% extra credit??
Can anybody confirm this?


Thank you
by Anna_Kim_2E
Wed Feb 22, 2017 1:39 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: assuming order from units of k
Replies: 1
Views: 244

Re: assuming order from units of k

Yes you can figure out the order of reaction by looking at the units of k. Because the unit of rate is M/s, if you plug the unit of rate in 0 order, 1st order, and 2nd order rate law, you will be able to get the unit of k for different orders. For example rate=k[A]^0 for 0 order. Since you know that...
by Anna_Kim_2E
Wed Feb 22, 2017 1:25 pm
Forum: General Rate Laws
Topic: Units for Reaction Rate and the Rate Constant
Replies: 3
Views: 452

Re: Units for Reaction Rate and the Rate Constant

The units of rate constant is varies for the different depending on the order of reaction.
by Anna_Kim_2E
Tue Feb 21, 2017 10:42 pm
Forum: Second Order Reactions
Topic: 15.35
Replies: 1
Views: 284

Re: 15.35

For second order, -d[A]/dt = k[A]^2 . Integration of both sides results in an equation 1/[A] = kt + 1/[A]0. Hence, in order to find out for the half life, we use this equation when it is in second order.
by Anna_Kim_2E
Tue Feb 21, 2017 10:38 pm
Forum: Zero Order Reactions
Topic: 15.99
Replies: 2
Views: 419

Re: 15.99

For second order, half life is t = 1/k[A]initial . Therefore, t (half life) and concentration have 1/[A] relationship.
Whereas, for zero order, half life t = [A]initial/2k , which shows that t(half life) and initial concentration direct linear relationship.
by Anna_Kim_2E
Tue Feb 14, 2017 7:13 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: midterm 2014 Q2D
Replies: 2
Views: 271

Re: midterm 2014 Q2D

I am still having a bit of confusion.

So on the problem, on the attached picture, how is the sig fig of the answer determined? Do we just disregard the value that ln becomes? ln(12.90/7.60)
by Anna_Kim_2E
Mon Feb 13, 2017 11:56 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 2014 Midterm
Replies: 5
Views: 567

Re: 2014 Midterm

Ka = [H+][F-]/[HF] and K = [H+]^2[F-]^2]/[HF]^2

therefore, when comparing Ka to K, K is exactly Ka square. Therefore you square root the value K in order to achieve Ka.
by Anna_Kim_2E
Mon Feb 13, 2017 9:55 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: midterm 2014 Q2D
Replies: 2
Views: 271

midterm 2014 Q2D

I am having a bit of confusion for sig figs when ln, e, or log is involved. I am aware that for ln(X), if X has 3 signifiant digits then the value for ln(X) should have 3 decimal places. But in midterm 2014 Q2D, e^4.63 = 102, which also means that ln(102) = 4.63. 4.63 has 2 decimal places. Then, Sho...
by Anna_Kim_2E
Mon Feb 13, 2017 12:33 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy unit
Replies: 1
Views: 231

Entropy unit

So last week in the review session, the TA said that entropy should always be written in Joules and when in kJ we should convert it to J. Is there a specific reason why it has to be in J/Kmol and not kJ/Kmol?
by Anna_Kim_2E
Fri Feb 10, 2017 2:14 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 2016 WINTER MIDTERM Q8A
Replies: 1
Views: 330

Re: 2016 WINTER MIDTERM Q8A

You use subtraction Ecathode-Eanode when they are both in their reduction state. Hence, since the two half reactions are already in oxidation and reduction states, you can add their E° of the both equations. 0.8V+0.4V=1.2V
by Anna_Kim_2E
Fri Feb 10, 2017 2:05 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1017402

Re: Post All Chemistry Jokes Here

Image
by Anna_Kim_2E
Wed Feb 08, 2017 7:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 3
Views: 329

Re: Cell Diagrams

Also to add on, anode, reaction losing electron, goes on the left side of the double bar, and cathode, the reaction gaining electrons, goes on the right side of the double bar.
by Anna_Kim_2E
Tue Jan 31, 2017 1:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13715

Re: Quiz 1 Preparation Answers

Can someone explain why in #11 does q go from -23.8 to 23.8? Because -23.8kJ is negative because it was released from converting PbO to Pb. Then, that amount of heat is transferred into the system, which is water. When heat is put into an system, it is an endothermic process and the sign should be ...
by Anna_Kim_2E
Mon Jan 30, 2017 12:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13715

Re: Quiz 1 Preparation Answers

Where do you find the prep quiz?
I only see the midterms from past years.

Do I have to buy a separate booklet or is it in the course reader? Then what page is it in?
by Anna_Kim_2E
Wed Jan 25, 2017 12:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz Topics
Replies: 10
Views: 1100

Re: Quiz Topics

Just for a clear confirmation, then there is nothing due at our discussion sections before our quiz because we are not doing the turn-in quizzes. Is that right?
by Anna_Kim_2E
Mon Jan 16, 2017 3:35 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1017402

Re: Post All Chemistry Jokes Here

I asked the guy sitting next to me if he had any Sodium Hypobromite…

He said NaBrO
by Anna_Kim_2E
Fri Dec 02, 2016 2:25 pm
Forum: Significant Figures
Topic: Sig Figs for pH
Replies: 3
Views: 1080

Re: Sig Figs for pH

The previous thread says that we should,
"When working with pH, use the number of sig figs as the number of decimal places in the pH. For example, if the pH=-log(1.8 x 10^-5) then pH = 4.74 (two sig figs in 1.8 x 10^-5, and two after the decimal in 4.74)."
by Anna_Kim_2E
Thu Nov 17, 2016 12:08 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1017402

Re: Post All Chemistry Jokes Here

Q:Did you hear about the man who got cooled to absolute zero?

A: He's 0K now
by Anna_Kim_2E
Sun Nov 13, 2016 11:03 pm
Forum: Naming
Topic: Naming
Replies: 2
Views: 405

Re: Naming

I think so because anything we learned last week is fair game.
by Anna_Kim_2E
Fri Nov 04, 2016 8:35 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1017402

Re: Post All Chemistry Jokes Here

Haha
by Anna_Kim_2E
Thu Oct 27, 2016 9:00 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations Stability
Replies: 1
Views: 218

Re: Electron Configurations Stability

Having a half full d5 or full d10 subshell has lower energy, therefore, where there is d4 or d9 subshell, it is better to move one electron from the 4s and fill the d subshell.
by Anna_Kim_2E
Thu Oct 20, 2016 4:14 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radius [ENDORSED]
Replies: 1
Views: 334

Re: Atomic Radius [ENDORSED]

The different energy levels of the orbitals affect the overall size of the atomic radii. When the elements have the same energy level and orbital, the electrons have affect in the different electrostatic attractions that pertain to each element.
by Anna_Kim_2E
Fri Oct 14, 2016 11:30 am
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 5
Views: 634

Re: Photoelectric Effect

I think it is nanometer that has been converted to meters.
When you want to convert, for example, 900nm into meters, because there are 1x10^9nm in 1 meter, or 1x10^-9m in 1nm , it would 900nm would be multiplied by 10^-9 to convert into meters.
by Anna_Kim_2E
Fri Oct 07, 2016 7:42 am
Forum: Phase Changes & Related Calculations
Topic: Chemistry Humor
Replies: 26
Views: 2585

Re: Chemistry Humor

geek-chemistry.jpg
by Anna_Kim_2E
Mon Sep 26, 2016 5:34 pm
Forum: Student Social/Study Group
Topic: Off Campus/Apartments Study group
Replies: 5
Views: 683

Re: Off Campus/Apartments Study group

I am definitely interested. I can do any day of the week and preferably during the day than the evening.

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