Search found 18 matches

by Angela_Park_1F
Wed Mar 15, 2017 2:39 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Cyclohexane conformation
Replies: 1
Views: 312

Cyclohexane conformation

when a cyclohexane goes from one stable conformation to another (so from chair to chair), it goes through the boat conformation. This means the carbon hydrogen bonds go through an eclipsed state. This means that the molecule becomes less stable and higher in energy. Why would the conformation change...
by Angela_Park_1F
Wed Mar 08, 2017 12:52 pm
Forum: *Alkanes
Topic: Common Names on Page 94 of course reader
Replies: 2
Views: 398

Common Names on Page 94 of course reader

On page 94, it lists "common names (often used non IUPAC names)"

Are we expected to know all these specifically? Or are they interchangeable with IUPAC names?
Also, I know some of these names overlap with IUPAC names. Which are the same in IUPAC naming?
by Angela_Park_1F
Wed Mar 08, 2017 12:42 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Electron pair transfer in a stable molecule
Replies: 1
Views: 380

Electron pair transfer in a stable molecule

Hi, I know that electrons pairs will move towards electron deficient molecules, or electrophiles. But in the case where a molecule is stable on its own, without addition or subtraction of electrons, why do NU and E reactions still occur? For example in CH3CH=CHCH3, the molecule has a neutral charge,...
by Angela_Park_1F
Tue Feb 28, 2017 12:04 am
Forum: *Organic Reaction Mechanisms in General
Topic: Graph of first and zero order reactions
Replies: 2
Views: 633

Graph of first and zero order reactions

Hi, Looking at the tangent graphs of the first order and zero order reactions, we see that both slopes are -k. So it looks like a straight line going down. Would we be able to tell if it is a first or zero order reaction just by looking at the graphs? If not, what other information do we need?
by Angela_Park_1F
Sun Feb 19, 2017 10:14 pm
Forum: General Rate Laws
Topic: RXN rate graph question
Replies: 1
Views: 250

RXN rate graph question

I read somewhere and in the coursereader that in the "Time vs. Concentrations (mol/L)" graph, we draw a line tangent to the curve to determine the rate rather than taking the average of the whole line divided by the time. Why/how is this method a more accurate representation of the concent...
by Angela_Park_1F
Fri Feb 10, 2017 12:46 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question on q=nC(change in)T
Replies: 2
Views: 552

Question on q=nC(change in)T

I know that the equation wants the change in temperature, but are the units for T supposed to be in Kelvins or Celsius?
Do units matter for this equation or would the change in temperature end up canceling the units?
by Angela_Park_1F
Sun Feb 05, 2017 8:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: What is the function of a porous disk?
Replies: 1
Views: 195

What is the function of a porous disk?

Hi I think Dr. Lavelle mentioned it in class but I did not catch all of it.
In the experiment to calculate E(cell), a porous disk is placed between the anode and cathode. What is the function of the disk? Is it just there to separate the two concentrations?
by Angela_Park_1F
Tue Jan 31, 2017 11:39 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 17039

Re: Quiz 1 Preparation Answers

Alyssa_Hsu_2K wrote:Hi, I was wondering why the sig figs for number 10 is 3 instead of 2? Doesn't the 20 degrees celsius mentioned in the problem only have 2 sig figs?


I had the same question..!
by Angela_Park_1F
Sun Jan 29, 2017 1:49 pm
Forum: Calculating Work of Expansion
Topic: Work Equation Derivation
Replies: 1
Views: 261

Work Equation Derivation

I understand that there are two equations for work depending on whether they represent reversible or irreversible processes: w=-P(external) x \Delta V w=-nRT x ln (Vfinal/Vinitial) But I was wondering how to differentiate between the two? How do we know whether a process is reversible or irreversibl...
by Angela_Park_1F
Sun Jan 22, 2017 9:27 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Understanding experiments with beakers
Replies: 1
Views: 239

Understanding experiments with beakers

I wanted to see if I understood the experiments like they were explained in lecture. What is the process of the experiments like for the 3 ways of changing the energy of a system? How would the experiment differ if they were closed, open, or isolated systems?
by Angela_Park_1F
Sat Jan 14, 2017 2:38 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Titrations & Enthalpy Change
Replies: 1
Views: 348

Titrations & Enthalpy Change

Just conceptually, what is the relationship between titrations, which we learned about in 14A, and enthalpy change? I know we have been learning about thermometric titration, but how does the actual titration like you would conduct in a lab, relate to what we are learning (how to calculate enthalpie...
by Angela_Park_1F
Fri Jul 22, 2016 6:40 pm
Forum: *Titrations & Titration Calculations
Topic: Titration Problem involving CH3NH2 and HCl [ENDORSED]
Replies: 1
Views: 971

Titration Problem involving CH3NH2 and HCl [ENDORSED]

This problem was from Ashley's Review today. I do not understand how/where we got the 5.3 x 10-3 mol / 0.065 L because the 5.3 x 10-3 mol is the moles of HCl, not CH3NH3+.

Please help! Thanks :)
by Angela_Park_1F
Fri Jul 22, 2016 1:07 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: x,y,z spots in 2P orbitals [ENDORSED]
Replies: 2
Views: 602

x,y,z spots in 2P orbitals [ENDORSED]

I was wondering how to differentiate which orbital spots in 2P (X,Y,Z) go first when drawing molecular orbital diagrams in ascending order. If we are drawing diagrams for elements of atomic larger than 8 I know the diagram changes. And so would the order of 2P (X,Y,Z) orbitals change as well? Also, ...
by Angela_Park_1F
Mon Jul 18, 2016 12:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles of CH4O
Replies: 2
Views: 2429

Bond angles of CH4O

In a CH4O molecule, the textbook said the angles around Oxygen will be less than 109.5 degrees while the angles around the hydrogens will be 109.5 degrees. I am confused because I thought it would be the other way around where bond angles were less than 109.5 degrees around the hydrogens and more th...
by Angela_Park_1F
Fri Jul 15, 2016 12:51 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Energy Levels of 2 different atoms
Replies: 1
Views: 221

Energy Levels of 2 different atoms

I know that for molecular orbital diagrams with 2 of the same atoms like O2 you draw the 2s and 2p levels parallel to each other (equal in distance from the top or bottom), and I know that for a molecule like NO you would place the 2s and 2p levels above or below each other depending on 'energy leve...
by Angela_Park_1F
Thu Jul 07, 2016 8:24 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration [ENDORSED]
Replies: 4
Views: 528

Electron Configuration [ENDORSED]

What is the difference between electron configuration, ground state electron configuration, and full ground state electron configuration?
by Angela_Park_1F
Wed Jun 29, 2016 8:00 pm
Forum: Resonance Structures
Topic: Resonance and Energy [ENDORSED]
Replies: 1
Views: 260

Resonance and Energy [ENDORSED]

I was wondering if someone could explain how when resonance happens, the energy of the molecule lowers? I understand that some electrons blend to each bond but isn't the total number of electrons and thus the energy level stay the same?
by Angela_Park_1F
Fri Jun 24, 2016 2:36 pm
Forum: Empirical & Molecular Formulas
Topic: Question from online forum: The Molecular Formula of Xylitol
Replies: 2
Views: 1137

Question from online forum: The Molecular Formula of Xylitol

Xylitol, a sugar substitute, has a mass composition of C 39.43%, O 52.58%, H 7.88%, and a molar mass of 152.15 g.mol-1 . What is its molecular formula?

I tried to solve this multiple times but I just do not get any of the multiple choice responses. :(

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