Search found 51 matches

by Yinhan_Liu_1D
Fri Mar 17, 2017 12:18 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Z-1-chloro-2-methyl-1-butene
Replies: 2
Views: 606

Re: Z-1-chloro-2-methyl-1-butene

It is not methylene because methylene refers to a group in the middle of the carbon chain (-CH2-). The CH3 attached to one of the carbons in the double bond is a substituent by the rule that is discussed in this section, and is therefore called a methyl group. There is no "ethyl" in the n...
by Yinhan_Liu_1D
Fri Mar 17, 2017 12:15 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: (E)-But-2-en-1-ol
Replies: 1
Views: 623

(E)-But-2-en-1-ol

On our intro organ textbook, page 54, at the very top I don't understand why we need to put an "E" in front of the compound name in this molecule. Is it because the geometric isomer (the bond between the third C and the fourth C could be in the other direction)? But if we just write But-2-...
by Yinhan_Liu_1D
Thu Mar 16, 2017 9:28 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Z-1-chloro-2-methyl-1-butene
Replies: 2
Views: 606

Z-1-chloro-2-methyl-1-butene

On our textbook, page16, rule 5: the group that bounds to the second Csp2 is CH2CH3. Why is it Z-1-chloro-2-methyl-1-butene but not Z-1-chloro-2-methylene-1-butene or Z-1-chloro-2-ethyl-1-butene?? If it counts the group that directly bounds to C, it should be "methylene"; if it counts the ...
by Yinhan_Liu_1D
Wed Mar 15, 2017 9:33 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: 2,3-dimethylbutane common name
Replies: 1
Views: 615

2,3-dimethylbutane common name

I looked at one of the question posted here before, it says it's common name is diisopropyl, is that right? Is there another common name for this?

Will we be asked to name the structure that would be like this (requiring dividing the structure into multiple iso/neo groups)?
by Yinhan_Liu_1D
Wed Mar 15, 2017 8:47 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: structural formula for 2,2-Dimethylbutane
Replies: 1
Views: 934

structural formula for 2,2-Dimethylbutane

On our green textbook, page 10, the structural formula is given as (CH3)3CCH2CH3.

I am wondering, given the line structure on the side, could the structural formula also be CH3C(CH3)2CH2CH3?

If not, why?

I would appreciate your help.
by Yinhan_Liu_1D
Tue Mar 07, 2017 5:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 3 Winter 2017
Replies: 183
Views: 16409

Re: Quiz 3 Winter 2017

#2, it asks us to draw a structure, when we are drawing the line structure, do we specify (draw out) the carbon where the parent chain is branched? Or we just draw a branch?
by Yinhan_Liu_1D
Sun Mar 05, 2017 6:09 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Priority in Isomers
Replies: 1
Views: 1198

Priority in Isomers

On the organic textbook, page 156, when it is discussing the S/R isomers, it mentions the priority in drawing the structure: Nu> CH2CH3>CH3>H.

Where does this come from? Is the priority according to the number of carbon?

I would appreciate your help.
by Yinhan_Liu_1D
Tue Feb 14, 2017 4:44 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 2015 Midterm Q4/5 A
Replies: 1
Views: 257

2015 Midterm Q4/5 A

We know that in this process delU=3/2 nRdelT, isothermal, so that we could use delS=q/T=-W/T=nRln(V2/V1)

But does anybody know why we can't use delS=kB*ln (V2/V1)? It gives us a very small figure, which is not the same as that calculated in nRln(V2/V1)

I would appreciate your help.
by Yinhan_Liu_1D
Thu Feb 09, 2017 4:02 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: hw:14.107 Relation of K and H+/OH-
Replies: 1
Views: 212

hw:14.107 Relation of K and H+/OH-

I don't quite understand why we use K=[H+]/[OH-]

Are we using H2O->H+ + OH-? Then why aren't they both in the [product] part?

Or there is another RXN?
by Yinhan_Liu_1D
Thu Feb 09, 2017 3:53 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: H2O->H+ + OH-
Replies: 2
Views: 706

Re: H2O->H+ + OH-

This was a response by Chemmod a couple of years ago: This reaction is the opposite of Problem 13.11d so to make the comparison easier I will flip this reaction (this does not change the chemistry). In that problem you are given the cell diagram to help in the selection and you then solve for the f...
by Yinhan_Liu_1D
Thu Feb 09, 2017 3:25 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: About Using ln or log
Replies: 1
Views: 225

About Using ln or log

Hi, dear all, I find it confusing using the equation given in ln and the equation given in log. For example in HW 14:97: If we use ln: lnK=nE/0.02569v = -12 -->K=6.14*10^-6 But if we use log as in the course reader: logK= nE/0.0592=-5.4 --> K= 3.93*10^-6 And by taking the square root of them, I get ...
by Yinhan_Liu_1D
Sat Feb 04, 2017 12:19 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: H2O->H+ + OH-
Replies: 2
Views: 706

H2O->H+ + OH-

Using O2 in the galvanic cell Can anybody tell me what's been reduced and what's being oxidized in this reaction? Since O2 does not appear in the overall reaction, how does the reduction and oxidation happen? I am really confused about this one, so I would really appreciate your help. Same with Ag+ ...
by Yinhan_Liu_1D
Fri Feb 03, 2017 5:49 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: "How does concentration affect cell potential" explanation
Replies: 1
Views: 2478

"How does concentration affect cell potential" explanation

Hi, all, We mentioned La Chatelier's Principle today. I understand that adding Mn2+ would result in the RXN going to the right (more Al3+ and Mn will be produced). And I kinda understand that adding more "positive charges" to the right means that there will be a higher difference in E. But...
by Yinhan_Liu_1D
Tue Jan 31, 2017 1:41 pm
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: hw: 9.89
Replies: 1
Views: 288

hw: 9.89

I didn't quite understand why the definition of S=0 (H+) determines that the aqueous ions has a negative entropy.

Could anyone kindly explain it?
by Yinhan_Liu_1D
Mon Jan 30, 2017 9:26 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: HW:9.47 Isothermal Irreversible Free expansion
Replies: 1
Views: 404

HW:9.47 Isothermal Irreversible Free expansion

For part (b), If the expansion is irreversible and w=0 , how could we calculate the entropy change of the system?

Why does it equal to +3.84J/K, the entropy change in the (a)isothermal reversible expansion?
by Yinhan_Liu_1D
Mon Jan 30, 2017 9:02 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: HW: 9.23 COF2 and BF3
Replies: 2
Views: 288

Re: HW: 9.23 COF2 and BF3

That could be a possible explanation, but it would best to draw out lewis structures of COF2 and BF3. By drawing out the structures, you can see that the elements can be in different positions, and whichever molecule has the most displacements, it will have higher entropy. So it is because, the mor...
by Yinhan_Liu_1D
Sun Jan 29, 2017 6:03 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: HW: 9.23 COF2 and BF3
Replies: 2
Views: 288

HW: 9.23 COF2 and BF3

COF2 will have a higher molar entropy than BF3. They would both be trigonal planar molecules. The answer says that since O and F will disorder the COF2 by occupying the same location. Is my understanding right that the molecule that has a distorted composition will have a higher entropy than the mol...
by Yinhan_Liu_1D
Thu Jan 19, 2017 1:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: What does a Standard Enthalpy with a subscript "c" mean?
Replies: 2
Views: 1011

What does a Standard Enthalpy with a subscript "c" mean?

We've learned that enthalpy with subscript f is the standard enthalpy of formation.

What does the "c" mean?

I saw it on HW:8.57.

Appreciate your help; )
by Yinhan_Liu_1D
Wed Jan 18, 2017 7:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: HW: 8.11 (b)
Replies: 1
Views: 233

HW: 8.11 (b)

Hi, dear class, I looked up the solution manual. It is using the formula involving logarithm (which is on the formula sheet too). However, we have not talked about this in class before. Should we know how it is derived? Or we just need to know and use the formula when it comes to reversible expansion.
by Yinhan_Liu_1D
Tue Jan 10, 2017 7:19 am
Forum: Student Social/Study Group
Topic: chem 14B workbook
Replies: 7
Views: 861

chem 14B workbook

Dear fellows,

Did you get the workbook when you are buying the course reader?

I didn't get the workbook as I had when I was buying CHEM 14A course reader.

I would really appreciate your reply!

Best,
by Yinhan_Liu_1D
Sun Nov 27, 2016 10:29 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Details and Review Sessions Fall 2016
Replies: 15
Views: 8035

Re: Final Exam Details and Review Sessions Fall 2016

Professor Lavelle,

You mentioned in the Email that we will finish the syllabus on Wednesday and all material covered will be tested on.

Does it mean that we will finish buffers and titrations?
by Yinhan_Liu_1D
Sun Nov 13, 2016 6:32 pm
Forum: Naming
Topic: What is the difference between "Hydrate" and "Aqua"
Replies: 2
Views: 432

Re: What is the difference between "Hydrate" and "Aqua"

"Aqua" denotes a coordinate covalent bond between water and the central atom in the coordination sphere, while a hydrate is a water molecule outside of the coordination sphere that is attracted to a ion or polar compound via hydrogen bonds. So, you mean that the water molecule is bonded t...
by Yinhan_Liu_1D
Sat Nov 12, 2016 8:45 pm
Forum: Naming
Topic: What is the difference between "Hydrate" and "Aqua"
Replies: 2
Views: 432

What is the difference between "Hydrate" and "Aqua"

Hi, I understand that aqua is the OH2 which is within the coordination sphere (square brackets) while hydrate is not (it is written last after a dot). Does any one have an in-depth understanding of the structural or chemical difference between the two structure? Since they are both neutral and they ...
by Yinhan_Liu_1D
Sat Nov 12, 2016 8:38 pm
Forum: Naming
Topic: SO42- as OSO32-
Replies: 2
Views: 420

Re: SO42- as OSO32-

Hi, If you're looking at the anionic ligand chart, then I believe SO42- and OSO32- are the same molecule. They both indicate a sulfate molecule which is known as sulfato when it acts as a ligand. The reason why the chart writes OSO32- is to emphasize that it is the oxygen that forms a bond with the...
by Yinhan_Liu_1D
Sat Nov 12, 2016 8:17 pm
Forum: Naming
Topic: SO42- as OSO32-
Replies: 2
Views: 420

SO42- as OSO32-

Hi, all, As I was go over the naming chart in our course reader, I found that it names OSO32- as sulfato. However, as I was searching on line, all the sulfato structure I have found is centered at "S". 1) Can anyone kindly show me how center at "O" would look like? 2) Do the SO42...
by Yinhan_Liu_1D
Tue Nov 08, 2016 9:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: [J] for solute in a dilute solution
Replies: 1
Views: 207

[J] for solute in a dilute solution

I am wondering, for example, if the solute is ZnCl2, and in the chemical reaction, its phase is (aq), when we plug in the activity of this part, should we plug in [ZnCl2]^n or [Zn]^n [Cl]^2n?

In the solution, ZnCl2 appears as ions, right?

I would really appreciate your help!
by Yinhan_Liu_1D
Sat Nov 05, 2016 3:55 pm
Forum: Naming
Topic: HW 17.31 About alphabetic sequence in writing symbols and naming them
Replies: 1
Views: 228

HW 17.31 About alphabetic sequence in writing symbols and naming them

In homework 17.31 1) Why is the "aqua" in c) written as H20 not OH2? Does it matter 2) Why is it Na[Fe(OH2)2(C2O4)2] but not [Fe(C2O4)2(OH2)2]? I remember in the book, it says that the sequence of naming is different from the sequence of writing them down. (i.e. when writing them down, &qu...
by Yinhan_Liu_1D
Sat Nov 05, 2016 10:31 am
Forum: Naming
Topic: Lewis structure for Cu(OH2)6 2+ [ENDORSED]
Replies: 1
Views: 228

Lewis structure for Cu(OH2)6 2+ [ENDORSED]

I tried to figure out what the Lewis structure of this complex would look like, but I can't figure it out, especially the electron distribution and how they altogether make it to 2+.

Is it that because all the OH2 are neutral, but Cu has 2+ ?

I would really appreciate your help.
by Yinhan_Liu_1D
Sat Nov 05, 2016 10:07 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Question regarding "Molecular Bond of SF6"
Replies: 1
Views: 664

Question regarding "Molecular Bond of SF6"

In the textbook p140, it mentions that "the four valence orbitals provided by the sulfur atom and the six orbitals of the fluorine atoms that point toward the sulfur atom, a total of 10 atomic orbitals..." 1) Why does sulfur atom has FOUR valence orbitals? Why not 6? 2) Why is the bond ord...
by Yinhan_Liu_1D
Sun Oct 30, 2016 11:24 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Bond order of NO
Replies: 1
Views: 451

Bond order of NO

By calculation it is 2.5.

But what does this mean?

Does it mean that there's only 2 bonds? or...

I would appreciate your help.
by Yinhan_Liu_1D
Sun Oct 30, 2016 2:09 pm
Forum: Hybridization
Topic: Why would the bond angle increase when the S character of a hybrid orbital increase?
Replies: 1
Views: 215

Why would the bond angle increase when the S character of a hybrid orbital increase?

Is it due to the decreased energy level when S character increases?

I would appreciate your help.
by Yinhan_Liu_1D
Sat Oct 29, 2016 5:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles of TeCli4
Replies: 1
Views: 308

Bond angles of TeCli4

In the solution manual, it mentioned the Cl-Te-Cl bond angle could be approximately 90 degrees and 120 degrees. Since there is a bent on the original see-saw shape due to the lone pair, does the 120 refer to the original 180 degree between the axial Cl-Te bond? Does the 90 degree replace the origina...
by Yinhan_Liu_1D
Sat Oct 29, 2016 12:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Electron arrangement for ClO2-
Replies: 1
Views: 643

Electron arrangement for ClO2-

Is it similar to H2O? Since they are bothAX2E2.

Is the Electron arrangement for ClO2- trigonal pyramidal and the Shape angular?

I would really appreciate your help!

The bond angle is also less than 109.5, right?
by Yinhan_Liu_1D
Tue Oct 25, 2016 7:07 pm
Forum: Ionic & Covalent Bonds
Topic: Why does LiF have higher percentage of ionic character than KF? [ENDORSED]
Replies: 1
Views: 944

Why does LiF have higher percentage of ionic character than KF? [ENDORSED]

According to the text, the greater the difference in electronegativity, the greater the ionic character of the covalent bond.

Li has Higher Electronegativity than K.
Why does LiF have higher percentage of ionic character than KF (in the percentage graph on page 92)?

I would appreciate your help;)
by Yinhan_Liu_1D
Mon Oct 24, 2016 4:47 pm
Forum: Octet Exceptions
Topic: lewis structure for(I_3)-
Replies: 1
Views: 360

lewis structure for(I_3)-

On textbook p88 self test 3.10B

I would appreciate your help
by Yinhan_Liu_1D
Sat Oct 22, 2016 7:39 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Removing an electron from Au (problem2.47)
Replies: 2
Views: 285

Re: Removing an electron from Au (problem2.47)

When forming cations, the outermost electrons are removed. In Au the outermost electron is found in the 6s state since typically the 6s state is considered to be higher in energy and therefore farther away from the nucleus than the 5d state. This means that it is easier to remove electrons from the...
by Yinhan_Liu_1D
Sat Oct 22, 2016 7:37 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Problem2.39
Replies: 2
Views: 242

Re: Problem2.39

Gabrielle Giang 1B wrote:I'm pretty sure that b) is representing the ground state for N. The electron configuration for N is 1s^2 2s^2 2p^3, and that is what's shown. There are 3 unpaired electrons in the 2p orbital.

Thank you. Yes, I think so.
It's just the solution manual which says that it's not the ground state.
by Yinhan_Liu_1D
Sat Oct 22, 2016 1:26 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Removing an electron from Au (problem2.47)
Replies: 2
Views: 285

Removing an electron from Au (problem2.47)

When removing one electron from Au, why is it not in 5d orbitals but the only one in 6s orbitals?
Pt, the one that is directly before Au has 5d^9, right?

I would appreciate your reply.
by Yinhan_Liu_1D
Sat Oct 22, 2016 1:19 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Problem2.39
Replies: 2
Views: 242

Problem2.39

Why is the b) choice NOT representing the ground state of N?

I would appreciate your help.
;)
by Yinhan_Liu_1D
Thu Oct 20, 2016 8:16 pm
Forum: Trends in The Periodic Table
Topic: Why is the second ionization energy of an atom always higher than its first ionization energy? [ENDORSED]
Replies: 2
Views: 284

Re: Why is the second ionization energy of an atom always higher than its first ionization energy? [ENDORSED]

LOL... I think I get it.
The ionization here happens mostly within the first two groups.

In the first group, when the first ion is removed, we have to remove one ion from the core noble gas, which would be very hard, because it's already a stable formation.
by Yinhan_Liu_1D
Wed Oct 19, 2016 10:51 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Px, Py, Pz [ENDORSED]
Replies: 5
Views: 9645

Re: Px, Py, Pz [ENDORSED]

They describe the locations of electrons in a P-orbital. So instead of saying "these electron are in the front and back," we can say "their positions are on the x-axis" since they are in P-orbital, we state their location as "Px" same idea for Py and Pz Do you know how...
by Yinhan_Liu_1D
Tue Oct 18, 2016 3:35 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1st orbital in He+ [ENDORSED]
Replies: 1
Views: 480

1st orbital in He+ [ENDORSED]

In the book p37, it asks "How would you expect a 1st-orbital in He+ to differ from the sam orbital in H?"

They have the same wavefunction, right?

I can't figure it out. It would be great if you could help me.

Thanks a lot;)
by Yinhan_Liu_1D
Thu Oct 13, 2016 12:29 am
Forum: *Particle in a Box
Topic: Why can't a particle in a container have zero energy?
Replies: 2
Views: 940

Why can't a particle in a container have zero energy?

Is it because that the zero-point energy is already E1?
by Yinhan_Liu_1D
Thu Oct 13, 2016 12:12 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: What does Heisenberg Indeterminacy indicate with respect to the “randomness” of the electrons that are near nucleus
Replies: 3
Views: 446

What does Heisenberg Indeterminacy indicate with respect to the “randomness” of the electrons that are near nucleus

Are the electrons that are very close to nucleus some what "confined" to those level? When delta X is small, delta p is very big. Does it mean that those electrons are extremely "random" in their velocity (they change velocity constantly)? So that they have really high energy lev...
by Yinhan_Liu_1D
Sun Oct 09, 2016 7:28 pm
Forum: Trends in The Periodic Table
Topic: Up to which topic will the first quiz cover? [ENDORSED]
Replies: 2
Views: 295

Up to which topic will the first quiz cover? [ENDORSED]

Hey, class.

I am wondering up to which topic will the first quiz cover.

I would really appreciate your reply.
by Yinhan_Liu_1D
Tue Oct 04, 2016 8:30 pm
Forum: DeBroglie Equation
Topic: HW 1.39 Wavelength of baseball [ENDORSED]
Replies: 2
Views: 461

HW 1.39 Wavelength of baseball [ENDORSED]

Hi all.
I understand how to get the answer.
But I just have a conceptual question: what does the "wavelength of the baseball" mean in reality? Is it the trajectory? Or is it the vibration?

I hope you can help me understand that.

Thank you!
by Yinhan_Liu_1D
Wed Sep 28, 2016 3:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Peer Facilitated Learning Sessions
Replies: 32
Views: 11363

Re: Peer Facilitated Learning Sessions

Will the peer facilitators be holding any review sessions? (i.e. will the session be only in the form of Q&A?)

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