Search found 40 matches

by Xin Huang 3E
Sun Mar 19, 2017 12:42 pm
Forum: Administrative Questions and Class Announcements
Topic: Naming priority
Replies: 3
Views: 440

Naming priority

In 2014 final, Q5 (D) has a naming given "prop-2-en-1-ol" as the answer. However, shouldn't the double bond be given the highest priority to have the lowest order of carbon, before all of the other substituents? I got "prop-1-en-3-ol" for this.
by Xin Huang 3E
Sat Mar 18, 2017 5:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Functional Group
Replies: 1
Views: 225

Functional Group

I know that Dr. Lavelle mentioned that in lecture, but I forgot-- Which functional groups are going to be tested on?
by Xin Huang 3E
Sat Mar 18, 2017 4:56 pm
Forum: Administrative Questions and Class Announcements
Topic: Torsional Strain
Replies: 2
Views: 406

Re: Torsional Strain

Why would this restrain also resist the rotating from higher energy to lower, namely from eclipses conformation to staggered?
by Xin Huang 3E
Fri Mar 10, 2017 12:52 am
Forum: Administrative Questions and Class Announcements
Topic: Final content
Replies: 4
Views: 535

Re: Final content

From previous finals I rarely see proofs. However, the midterm this quarter involves one proof so I cannot be sure. I feel that Dr. Lavelle's exam usually has some problems that test your understanding of certain concept (problems that do not require calculation but more like explanations). So even ...
by Xin Huang 3E
Sat Mar 04, 2017 9:47 pm
Forum: Administrative Questions and Class Announcements
Topic: Equivalent H
Replies: 1
Views: 269

Equivalent H

On p.93 in the course reader, it says that equivalent H are H with same chemical environment--are there more detailed conditions for equivalent H? It seems that the H should be attached to same amount of same atom...what else? If nothing else, then every H on an alkane should be equivalent H?
by Xin Huang 3E
Mon Feb 20, 2017 6:00 am
Forum: Administrative Questions and Class Announcements
Topic: Quiz 2 Practice Answer
Replies: 1
Views: 301

Quiz 2 Practice Answer

Will the answer key of the quiz 2 practice be posted on chemistry community? Hopefully @Chem_Mod will post it before the quiz ^ ^. Or does anyone want to share her/his answer?
by Xin Huang 3E
Tue Feb 14, 2017 9:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Half-reactions
Replies: 1
Views: 252

Half-reactions

For half-reactions, when do we leave out the water or other substances, and when do we incorporate them?
E.g. For Q7 in Winter 2013 Midterm, I notice the answer indicates:
2Mn2+(aq)+8H2O(l) --> 2MnO4-(aq)+16H++ 10e- for the anode;
Why don't we write instead: 2Mn2+(aq) --> 2Mn7+(aq)+10e- ?
by Xin Huang 3E
Sun Feb 12, 2017 10:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Rate Formuas
Replies: 1
Views: 162

Rate Formuas

For the rate of a reaction, is the order the same as the stoichiometry of a reaction?
E.g. for 2H2 + O2 => 2H2O is the rate equals to k * [H2]^2 * [O2]^2?
(wait I just realized they are gas... well...just suppose they have concentration)
by Xin Huang 3E
Tue Jan 31, 2017 9:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13687

Re: Quiz 1 Preparation Answers

If entropy is a state function, why is DeltaSurr not equal to zero when DeltaSys is? Because Entropy of surrounding is not a state function as entropy of the system does. And since deltaTotal is always > 0 (since this is the universal trend haha the world is always tending to confusion) while delta...
by Xin Huang 3E
Sun Jan 29, 2017 4:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13687

Re: Quiz 1 Preparation Answers

I am also wondering about #9, specifically about ΔS(surr), why is it not 0? Isn't it a state function, too? I know that ΔS(sys) + ΔS(surr) = ΔS(univ) > 0, but that is only for a spontaneous process? Why is #9 a spontaneous process?
by Xin Huang 3E
Wed Jan 25, 2017 10:25 pm
Forum: Administrative Questions and Class Announcements
Topic: How to Determine if Internal Energy (U) Changes?
Replies: 1
Views: 258

How to Determine if Internal Energy (U) Changes?

Hi, I noticed that on course reader p.33 there are two graphs showing reversible and irreversible pathways. One of them (Path A) has constant temperature, while the other has changing T. But it seems that for both of them ΔU = 0 (since q = -w for both of them). I originally thought that ΔU = 0 for c...
by Xin Huang 3E
Thu Jan 19, 2017 7:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Ways Of Changing the Energy of A System
Replies: 1
Views: 290

Ways Of Changing the Energy of A System

For the second way of changing the energy of a system, "heat or cool the system", the course reader said only the closed system is eligible. What about open system? Why can't we change the energy of an open system by heating or cooling it?
by Xin Huang 3E
Sat Jan 14, 2017 6:00 pm
Forum: Administrative Questions and Class Announcements
Topic: ΔH Denotations
Replies: 1
Views: 286

ΔH Denotations

I have kept been confused by the different denotation of ΔH, ΔHf, ΔH(RXN), ΔH(NET), ΔHo - (o as superscript)
1. What does RXN stands for? reaction?
2. When we do homework problems or take midterm & final, is it incorrect to write just ΔH instead of those with different denotations?
by Xin Huang 3E
Wed Jan 11, 2017 7:02 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz Practice
Replies: 5
Views: 458

Quiz Practice

I notice that when I buy the course reader there is no longer a quiz practice book along with the course reader... Does that mean that there will no longer be practices for the three quizzes or any "three mock quizzes replacing the lowest quiz score" deal?
by Xin Huang 3E
Sun Dec 04, 2016 2:45 am
Forum: Administrative Questions and Class Announcements
Topic: pH for Weak Base-Strong Acid Titration
Replies: 1
Views: 400

pH for Weak Base-Strong Acid Titration

If any one has a hard time with the calculation of pH for Weak Base-Strong Acid Titration or (Weak Acid-Strong Base, which is the vice versa), check out this website: http://chem.libretexts.org/Core/Analytical_Chemistry/Lab_Techniques/Titration/Titration_of_a_Weak_Base_with_a_Strong_Acid This page i...
by Xin Huang 3E
Sat Dec 03, 2016 11:11 pm
Forum: Administrative Questions and Class Announcements
Topic: Conditions to be a Chelate Ligand
Replies: 1
Views: 333

Conditions to be a Chelate Ligand

I was solving problem 17.35 and I had a sense that only (b) can form a chelate (polydentate) ligand, but I was not completely sure why. And the answer says "Only the molecule (b) can function as a chelating ligand. The MH2 groups in (a) and (c) are arranged so that they would not be able to coo...
by Xin Huang 3E
Sun Nov 27, 2016 12:33 am
Forum: Administrative Questions and Class Announcements
Topic: About Final
Replies: 3
Views: 431

About Final

Are we going to the same room as midterm to take our final or are we going to be assigned new rooms?
by Xin Huang 3E
Fri Nov 18, 2016 12:11 am
Forum: Administrative Questions and Class Announcements
Topic: Formula for Coordination Compounds
Replies: 1
Views: 411

Formula for Coordination Compounds

Hi, can anyone kindly tell me how to determine the order of ligands when we write the formula for a given name of coordination compounds? I know that the metal should be before all the ligands, but for the ligands, do we write them in random order, or order of their charge, etc.?
Thank you!
by Xin Huang 3E
Wed Nov 16, 2016 2:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Electron configuration of molecules
Replies: 1
Views: 567

Electron configuration of molecules

Should we write detailed version of electron configuration like:(σ2s)2(σ*2s)2(π2px)2(π2py)2(σ2pz)1
Or a shorter version like: (σ2s)2(σ*2s)2(π2p)4(σ2p)1
in quiz 3?
by Xin Huang 3E
Thu Nov 10, 2016 12:21 am
Forum: Administrative Questions and Class Announcements
Topic: Equilibrium Constant
Replies: 3
Views: 483

Re: Equilibrium Constant

How do we convert the pressure to concentration?
by Xin Huang 3E
Wed Nov 09, 2016 4:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Equilibrium Constant
Replies: 3
Views: 483

Equilibrium Constant

What should we do if there is a mix of gas and aqueous? do we use Ec or Ep or something else?
by Xin Huang 3E
Wed Nov 02, 2016 5:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Electron Configuration for Weird Metals
Replies: 1
Views: 676

Electron Configuration for Weird Metals

I was wondering what is the trend of electron configuration for weird metals, for example that is, consecutively, Ce is [Xe] 4f1 5d1 6s2, while Pr is 4f3 6s2. There is no half full situation, so why does the electron in 5d goes to 4f while increasing only one electron?
by Xin Huang 3E
Fri Oct 28, 2016 9:41 am
Forum: Administrative Questions and Class Announcements
Topic: Electron Configuration
Replies: 2
Views: 382

Electron Configuration

What should we write the electron configuration with noble gas abbreviation for an ion that has equal electrons in their outer shell with a noble gas? I.e. For Br- should we write [Kr] or [Ar]3d10 4s2 4p6
by Xin Huang 3E
Fri Oct 28, 2016 9:33 am
Forum: Administrative Questions and Class Announcements
Topic: Lower Energy State
Replies: 1
Views: 313

Lower Energy State

On the Course Reader p. 29, it says we write "4s" before "3d" but says that after 4s state occupied and e- enter 3d state then 3d state is lower in energy than 4s. What does that mean... Why is this?
by Xin Huang 3E
Thu Oct 27, 2016 10:25 am
Forum: Administrative Questions and Class Announcements
Topic: MidTerm Review [ENDORSED]
Replies: 4
Views: 588

MidTerm Review [ENDORSED]

Is midterm in similar form as the quizzes? (just FRQs and no MCQs) And until which point will it test on...? This Friday...or next Monday...?
by Xin Huang 3E
Thu Oct 27, 2016 10:23 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 3
Views: 329

Re: Midterm

I think the reason why he sounds so mysterious is that he wants to give us a "surprise" through, lol.
by Xin Huang 3E
Thu Oct 20, 2016 11:03 pm
Forum: Administrative Questions and Class Announcements
Topic: About the "Rough Guideline"
Replies: 4
Views: 4152

Re: About the "Rough Guideline"

Sounds logical ^ ^. Thank you so much!
by Xin Huang 3E
Wed Oct 19, 2016 9:20 pm
Forum: Administrative Questions and Class Announcements
Topic: About the "Rough Guideline"
Replies: 4
Views: 4152

About the "Rough Guideline"

About the rough guideline of differentiating the ionic bond and covalent bond, I am still a little confused about those electronegativity difference falls between 1.5 to 2, how we should figure out what types of bond there are. I was a little off on the class, so...I heard Dr. Lavelle mentioned how ...
by Xin Huang 3E
Thu Oct 13, 2016 4:07 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Date
Replies: 3
Views: 383

Re: Midterm Date

Oh! We will have a mid-term?! I thought we only had Final...Then what is the mid-Term time for those who does not have test conflicts?
by Xin Huang 3E
Thu Oct 13, 2016 4:04 pm
Forum: Administrative Questions and Class Announcements
Topic: Quizes
Replies: 21
Views: 1376

Re: Quizes

Are quizzes the form similar as self tests or are they in MCQs? And if they are FRQs, are detailed steps required, or only an answer should be OK?
by Xin Huang 3E
Thu Oct 06, 2016 12:45 am
Forum: Administrative Questions and Class Announcements
Topic: Answers to the Module Assessments
Replies: 4
Views: 519

Re: Answers to the Module Assessments

Heisenberg Uncertainty Principal:
1. C; 2. D; 3. D; 4.B; 5. C;
6. A; 7. D; 8. D; 9. A; 10. D;
11. A; 12. D; 13. A.
by Xin Huang 3E
Wed Oct 05, 2016 12:24 am
Forum: Administrative Questions and Class Announcements
Topic: Answers to the Module Assessments
Replies: 4
Views: 519

Re: Answers to the Module Assessments

Wave Properties of Electrons and The De Broglie Equation:
1. B; 2. A; 3. CONSTRUCTIVE; 4. CONSTRUCTIVE; 5. DESTRUCTIVE;
6. FALSE; 7. A; 8. D; 9. B; 10. A;
11. A; 12. TRUE; 13. B; 14. C; 15. B;
16. B; 17. A; 18. D; 19. B; 20. A;
21. C; 22. B; 23. A; 24. C; 25. D;
26. B; 27. C.
by Xin Huang 3E
Tue Oct 04, 2016 10:41 pm
Forum: Administrative Questions and Class Announcements
Topic: Answers to the Module Assessments
Replies: 4
Views: 519

Re: Answers to the Module Assessments

Atomic Spectra:
1. A; 2. C; 3. D; 4. C; 5. NO;
6. B; 7. A; 8. D; 9. D; 10. A;
11. D; 12. A; 13. C; 14. A; 15. D;
16. D; 17. D; 18. FALSE; 19. FALSE; 20. TRUE;
21. TRUE; 22. TRUE; 23. D; 24. C; 25. A;
26. D; 27. B; 28. B; 29. D; 30. B.
by Xin Huang 3E
Tue Oct 04, 2016 10:35 pm
Forum: Administrative Questions and Class Announcements
Topic: Answers to the Module Assessments
Replies: 4
Views: 519

Re: Answers to the Module Assessments

I am willing to share my own answers, but due to the fact that I'm so unconfident with the accuracy of these answers, please don't use my answers as model. If you see any incorrect answer, I would be so thankful if you could point out, and I will fix them on these posts. Let's make our "solutio...
by Xin Huang 3E
Tue Oct 04, 2016 10:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Answers to the Module Assessments
Replies: 4
Views: 519

Answers to the Module Assessments

Hi everyone, I wonder if all of you have completed the online assessments for the following modules (We are supposed to finish these before the end of this week right...?) Empirical and Molecular Formulas Balancing Chemical Equations Limiting Reactant Calculations Molarity and Dilution of a Solution...
by Xin Huang 3E
Thu Sep 29, 2016 12:28 am
Forum: Administrative Questions and Class Announcements
Topic: Problem 10 on Limiting Reactant [ENDORSED]
Replies: 3
Views: 419

Re: Problem 10 on Limiting Reactant [ENDORSED]

Oops, my bad. Thank you for pointing out my flaws
by Xin Huang 3E
Wed Sep 28, 2016 3:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem Workbook
Replies: 1
Views: 321

Re: Chem Workbook

Yes, I believe you can replace ONE quiz grade with BOTH of the self-quiz on the workbook, but you HAVE to hand them in before each of your real quiz for credits.
by Xin Huang 3E
Wed Sep 28, 2016 2:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Problem 10 on Limiting Reactant [ENDORSED]
Replies: 3
Views: 419

Problem 10 on Limiting Reactant [ENDORSED]

This is Problem #10 on Pre-Module Assessment: According to the following equation, 0.750 g of C6H9Cl3 is mixed with 1.000 kg of AgNO3 in a flask of water. A white solid, AgCl, completely precipitates out. What is the mass of AgCl produced? C6H9Cl3 + 3AgNO3 ---> AgCl + C6H9(NO3)3. Molar Mass: C6H9Cl3...
by Xin Huang 3E
Sun Sep 25, 2016 9:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework Assignment?
Replies: 7
Views: 785

Re: Homework Assignment?

I'm sure that those are review problems that Dr. Lavelle wants us to go through our high school materials; therefore, it might not influence the tomorrow lecture I believe... You can complete it at later time. But you'd better complete it sooner the better, cuz in your discussion sessions, your TAs ...
by Xin Huang 3E
Sun Sep 25, 2016 9:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Textbooks
Replies: 3
Views: 413

Re: Textbooks

If you want to get the 6th electronic version of the textbook, plz email me your email at helengracehuang@live.com, so that you can use this book to find the right numbers of problems ^-^

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