Search found 51 matches

by Joslyn_Santana_2B
Sat Mar 18, 2017 7:18 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: pH using Nernst Equation
Replies: 2
Views: 348

pH using Nernst Equation

W2010 Q4B

1.) How do you know "the cell emf was +0.060V." means Ecell and not E*cell?

2.) How do you know n=1? I thought n=2 from Q4A, which was the redox reaction where 2 electrons were transferred.
by Joslyn_Santana_2B
Sat Mar 18, 2017 7:07 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy of Rxn
Replies: 1
Views: 326

Gibbs Free Energy of Rxn

W 2011 Q2

Why is 3H2 ignored in the 1st rxn? Why is H2 ignored in the 2nd rxn?
I thought it was because of a phase difference in the 1st one, but in the 2nd rxn there is no phase difference and it's still ignored.
by Joslyn_Santana_2B
Sat Mar 18, 2017 5:18 pm
Forum: Second Order Reactions
Topic: Quiz 2 Prep #6
Replies: 1
Views: 274

Quiz 2 Prep #6

I was wondering why it is correct, when time is supposed to be in seconds? I got to completely different answers when I converted to seconds as opposed to leaving it in minutes.
by Joslyn_Santana_2B
Sat Mar 18, 2017 3:30 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Naming Order (Iso)
Replies: 1
Views: 459

Re: Naming Order (Iso)

Yes, Iso- is included for alphabetical order, as is Neo-. Di- is not.
by Joslyn_Santana_2B
Sat Mar 18, 2017 3:29 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: 2013 Final Q8C
Replies: 1
Views: 375

Re: 2013 Final Q8C

Since they are attached, you can imagine it based on how many carbons and hydrogens there are. If that makes sense.
by Joslyn_Santana_2B
Sat Mar 18, 2017 2:38 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Priority for Trans vs. Equatorial
Replies: 1
Views: 409

Priority for Trans vs. Equatorial

Is it a rule that equatorial is prioritized over trans when choosing the most stable conformation for cyclohexanes?
I had made it trans, making the Chloro equatorial down, and the methyl axial up.
by Joslyn_Santana_2B
Sat Mar 18, 2017 2:06 pm
Forum: *Electrophilic Addition
Topic: Rxn Mechanism for Acid Catalyzed Electrophilic Addition
Replies: 1
Views: 1904

Rxn Mechanism for Acid Catalyzed Electrophilic Addition

Step 1: Where is Hydrogen that broke off from the H30? I thought the double bond was attacking it, causing it to break off.

Step 2: How are there 2 H20 molecules? How is there a product of H+/H30+?
by Joslyn_Santana_2B
Fri Mar 17, 2017 9:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 202
Views: 66459

Re: Saying Thank You to Dr. Lavelle

Dear Dr. Lavelle, Thank you for being the most organized professor I've had thus far. I remember 14A was one of my first classes here, and I was relieved to have all the topics available on your website to practice in advance. During the quarter, the abundance of resources you offered were also very...
by Joslyn_Santana_2B
Tue Mar 14, 2017 10:30 am
Forum: *Organic Reaction Mechanisms in General
Topic: Q6 Winter 2014 Final Exam
Replies: 1
Views: 404

Q6 Winter 2014 Final Exam

1.) When a TA went over this at the review session, they said this question has SN1 and SN2 reactions throughout the steps. Is a question like this one possible to appear on the Final? The whole reaction has 4 steps, which confuses me since we have only covered SN2 and Electrophilic Addition Reactio...
by Joslyn_Santana_2B
Tue Mar 14, 2017 10:11 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Equation
Replies: 2
Views: 408

Arrhenius Equation

I was wondering how the Arrhenius Equation would be changed algebraically with the given equation on the formula sheet to the one in the reader?
by Joslyn_Santana_2B
Thu Mar 09, 2017 12:34 pm
Forum: *Alkenes
Topic: Naming a Alkene with a Functional Group
Replies: 2
Views: 256

Re: Naming a Alkene with a Functional Group

Functional group gets priority over the double/triple bonds.
by Joslyn_Santana_2B
Wed Mar 08, 2017 8:09 pm
Forum: *Alkanes
Topic: Naming [ENDORSED]
Replies: 92
Views: 7775

Re: Naming [ENDORSED]

Leo_Navejas_3B wrote:For substituents do we use common or systematic naming??


I was told common and systematic naming are the same thing.
by Joslyn_Santana_2B
Wed Mar 08, 2017 8:08 pm
Forum: *Alkanes
Topic: Naming [ENDORSED]
Replies: 92
Views: 7775

Re: Naming [ENDORSED]

What counts when using the alphabetical reference when naming?

I thought Neo- and Iso- counted, while Tert- didn't? Or is it the opposite? Is there a reason for it?

Thanks in advance.
by Joslyn_Santana_2B
Mon Mar 06, 2017 8:06 pm
Forum: *Electrophiles
Topic: Halogens
Replies: 4
Views: 610

Re: Halogens

I wouldn't look at that as a definite rule though.
For example, Exercise 4.1 part d is F by itself, and it is an electrophile.
by Joslyn_Santana_2B
Sun Mar 05, 2017 2:16 pm
Forum: *Alkanes
Topic: Self-Test 1.4A
Replies: 1
Views: 174

Self-Test 1.4A

Is it wrong if I wrote the condensed formula with the CH3 methyl next to the CH instead of doubling the end?
by Joslyn_Santana_2B
Tue Feb 28, 2017 9:16 pm
Forum: *Organic Reaction Mechanisms in General
Topic: # of Steps
Replies: 2
Views: 241

Re: # of Steps

What is an example where the general rule does not apply?

Thank you in advance.
by Joslyn_Santana_2B
Mon Feb 27, 2017 7:27 pm
Forum: *Organic Reaction Mechanisms in General
Topic: # of Steps
Replies: 2
Views: 241

# of Steps

How do you know how many steps are going to be in the reaction mechanism? Or is it just memorizing how many for each type of mechanism?
by Joslyn_Santana_2B
Tue Feb 21, 2017 1:54 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Concentration vs. Time Graphs
Replies: 2
Views: 321

Re: Concentration vs. Time Graphs

Yes, but if there are no labels/values given then there is no other way to know? Unless you're given that information, or a rxn.
by Joslyn_Santana_2B
Tue Feb 21, 2017 10:34 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Concentration vs. Time Graphs
Replies: 2
Views: 321

Concentration vs. Time Graphs

I was wondering why the reader has that the y-intercept starts at the top for 1st Order and the y-int starts a bit below the top for 0 order, but the textbook has 1st and 0 order y-intercepts starting at the same point. The only difference is of course in the variables/values. How would we know the ...
by Joslyn_Santana_2B
Tue Feb 21, 2017 10:03 am
Forum: General Rate Laws
Topic: Units of K
Replies: 4
Views: 1368

Re: Units of K

Starting from M/s you just then divide my M continuously to get the next order units.
by Joslyn_Santana_2B
Mon Feb 13, 2017 11:29 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram Symbols
Replies: 4
Views: 434

Re: Cell Diagram Symbols

The bar indicates a separate reaction/solution. A TA said the comma means it's in the same solution.
Hope that helps.
by Joslyn_Santana_2B
Mon Jan 30, 2017 10:48 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 11.15
Replies: 2
Views: 255

11.15

1. Why does solution's manual use positive RTlnQ instead of negative? How do you know which equations to use?

2. The solution states, "Because deltaG is positive, the reaction will be spontaneous to produce I_2. I thought positive deltaG meant non-spontaneous ?
by Joslyn_Santana_2B
Mon Jan 30, 2017 4:37 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: 9.13
Replies: 1
Views: 231

9.13

Why when calculating entropy with a change in temperature are there instances where the equation used is nRln(T2/T1) and then others where we use nCpln(T2/T1)? Does the question have to explicitly say that the rxn is at constant p or v? If it doesn't say then we just assume we can use nRln(T2/T1) to...
by Joslyn_Santana_2B
Thu Jan 26, 2017 5:03 pm
Forum: Calculating Work of Expansion
Topic: 8.17
Replies: 1
Views: 176

Re: 8.17

Nvm, someone told me that it was a typo.
by Joslyn_Santana_2B
Thu Jan 26, 2017 1:33 pm
Forum: Calculating Work of Expansion
Topic: 8.17
Replies: 1
Views: 176

8.17

Hi,

For the explanation of the sign of work in this problem has me confused from the solution manual.

Is deltaE the same as deltaU, and that's why q & w switch off signs to balance the internal energy?
by Joslyn_Santana_2B
Thu Jan 26, 2017 1:05 pm
Forum: Calculating Work of Expansion
Topic: Homework 8.9 [ENDORSED]
Replies: 3
Views: 441

Re: Homework 8.9 [ENDORSED]

Will we be given the conversion factor from torr to atm on the formula sheet?
by Joslyn_Santana_2B
Thu Jan 26, 2017 12:43 pm
Forum: Calculating Work of Expansion
Topic: Problem 8.3
Replies: 3
Views: 286

Re: Problem 8.3

Hi,

I am confused, since it initially states the pump depresses the air, but for part a it says to find work if it is compressed. Are we to assume that it was compressed the same distance that it was initially depressed?

Thank you in advance.
by Joslyn_Santana_2B
Wed Jan 25, 2017 8:47 pm
Forum: Student Social/Study Group
Topic: Quiz 1 Review
Replies: 4
Views: 476

Re: Quiz 1 Review

I am interested as well! My e-mai is jospamsantana@gmail.com
by Joslyn_Santana_2B
Wed Jan 25, 2017 8:45 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Reversibly & Isothermally
Replies: 3
Views: 456

Re: Reversibly & Isothermally

I think it refers to the work, and which equation you would use in your calculations. You would use W=-nRTln(V2/V1).
It also means that deltaU is 0
by Joslyn_Santana_2B
Tue Jan 17, 2017 3:42 pm
Forum: Administrative Questions and Class Announcements
Topic: Books on Reserves
Replies: 1
Views: 263

Books on Reserves

Is there a copy of the solutions manual on reserve at any of the libraries, if so which library?

Thank you in advance.
by Joslyn_Santana_2B
Wed Jan 11, 2017 10:11 am
Forum: Calculating Work of Expansion
Topic: How to achieve maximum work from an electric battery?
Replies: 4
Views: 355

Re: How to achieve maximum work from an electric battery?

It is right after Example 8.1 under "Thinking Point:". I do not have a hard copy of the text, but it says it's page 407 of 1129, but page 265 on the pdf. Hope this helps.
by Joslyn_Santana_2B
Sun Dec 04, 2016 10:46 am
Forum: Lewis Structures
Topic: Determining Lewis structures
Replies: 4
Views: 509

Re: Determining Lewis structures

Does anyone know why the most stable lewis structure for NO2 has charges on N and one of the O's, when there is a structure where all the FC's can be 0?
by Joslyn_Santana_2B
Sat Dec 03, 2016 3:34 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Weak Acids and Bases
Replies: 2
Views: 273

Re: Weak Acids and Bases

It is actually if it's exponent is less than or EQUAL TO -4.

Ex: K_a= 3e^(-4), you can use the short cut to find x.
by Joslyn_Santana_2B
Wed Nov 23, 2016 7:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar/Nonpolar
Replies: 2
Views: 435

Re: Polar/Nonpolar

I usually look at all the dipole moments in the molecule's VESPR model, which shows visually if there are any dipole moments that cancel. If they don't cancel, then it will be polar.
by Joslyn_Santana_2B
Mon Nov 14, 2016 7:53 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Numbers [ENDORSED]
Replies: 4
Views: 481

Re: Coordination Numbers [ENDORSED]

I know that for EDTA it binds 4 times because it has 4 ends where the oxygens are bent, which makes it easier for chelating to occur.
by Joslyn_Santana_2B
Fri Nov 11, 2016 12:08 pm
Forum: Naming
Topic: naming [ENDORSED]
Replies: 2
Views: 317

Re: naming [ENDORSED]

You use Bis-, Tris-, Tetrakis-, and Pentakis- for Polydentate ligands
by Joslyn_Santana_2B
Thu Nov 03, 2016 12:40 pm
Forum: Sigma & Pi Bonds
Topic: Pi Bonds
Replies: 4
Views: 563

Re: Pi Bonds

Hi,

Here are some notes I took of a TA's explanation of visualizing the Pi bonds. Hope this helps!
by Joslyn_Santana_2B
Sun Oct 30, 2016 10:00 pm
Forum: Empirical & Molecular Formulas
Topic: Mass % Composition
Replies: 3
Views: 495

Re: Mass % Composition

On the sample midterms, it gives the solution in both versions of calculating. Also, my PLF said you can calculate it either way.
by Joslyn_Santana_2B
Wed Oct 19, 2016 11:16 pm
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 6
Views: 432

Re: Lewis Structures

Here is an example of Xe breaking the octet rule.
by Joslyn_Santana_2B
Wed Oct 19, 2016 11:02 pm
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 6
Views: 432

Re: Lewis Structures

Hi, Does anyone know why for Xenon (Xe) can break the octet guideline?

I wrote out the electron configuration for it thinking it would help me see it visually, but all the d,s, and p orbitals are full. I am not seeing why it can break the octet rule.
by Joslyn_Santana_2B
Mon Oct 10, 2016 10:40 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Confusion [ENDORSED]
Replies: 3
Views: 455

Re: Elecreon Configuration Confusion [ENDORSED]

Will we have to know how to write electron configurations for Quiz 1?

I am confused on that topic, and the connections of the diagrams to the atom's structure.
by Joslyn_Santana_2B
Sun Oct 09, 2016 11:55 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Quiz 1 Preparation: Fall 2014 Question #10 [ENDORSED]
Replies: 6
Views: 729

Re: Quiz 1 Preparation: Fall 2014 Question #10 [ENDORSED]

Oh wow, this whole time i thought Rh was R with a subscript of h. Thank you!

I got how you got energy and combined the two different energy levels to get the change in energy, but I don't get how -7.5539x10^(-20) as the denominator gives you a positive # under the square root.
by Joslyn_Santana_2B
Sun Oct 09, 2016 9:48 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Quiz 1 Preparation: Fall 2014 Question #10 [ENDORSED]
Replies: 6
Views: 729

Re: Quiz 1 Preparation: Fall 2014 Question #10 [ENDORSED]

Also, how do you know which equation to use? I am confused on the solutions explanation of how they got -2.178x10^(-18) J (Z^2/n^2). At first I was using the equation set up to find frequency, but the realized that wasn't the correct one. Additionally, why is Rh (Rydberg's constant) 3.28984x10^15 on...
by Joslyn_Santana_2B
Sun Oct 09, 2016 9:12 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Quiz 1 Preparation: Fall 2014 Question #10 [ENDORSED]
Replies: 6
Views: 729

Re: Quiz 1 Preparation: Fall 2014 Question #10 [ENDORSED]

How did you get rid of the negative at the end before square rooting?
by Joslyn_Santana_2B
Wed Sep 28, 2016 10:15 am
Forum: Balancing Chemical Reactions
Topic: How familiar should we be with Naming compounds? [ENDORSED]
Replies: 8
Views: 1185

Re: How familiar should we be with Naming compounds? [ENDORSED]

For Quiz 1, then it would not be similar to all the homework questions only certain ones?

Since, in E9 it states: "Epsom salts consist of magnesium sulfate heptahydrate. Write its formula."
by Joslyn_Santana_2B
Mon Sep 26, 2016 7:07 pm
Forum: Student Social/Study Group
Topic: Off Campus/Apartments Study group
Replies: 5
Views: 665

Re: Off Campus/Apartments Study group

I'm interested!
by Joslyn_Santana_2B
Sat Sep 24, 2016 9:48 pm
Forum: Empirical & Molecular Formulas
Topic: Assessment Question #9
Replies: 2
Views: 399

Re: Assessment Question #9

Just realized this was covered in the video module.
Sorry about that, and thank you for taking your time with the explanation!
by Joslyn_Santana_2B
Sat Sep 24, 2016 7:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Repost of Assessment Question
Replies: 1
Views: 248

Repost of Assessment Question

Are we allowed to screenshot a question from the assessment to post on our question, and use for reference/clarity?
by Joslyn_Santana_2B
Sat Sep 24, 2016 7:46 pm
Forum: Empirical & Molecular Formulas
Topic: Assessment Question #9
Replies: 2
Views: 399

Assessment Question #9

For question #9 in the assessment states: "8.00g of Vitamin C is analyzed and the results are: C 3.27g, H 0.36g, O 4.37g. Using mass spectrometry its molar mass is determined to be 176.14g*mol^(-1). What is the molecular formula for Vitamin C?" I got lost after you find the ratio for the e...
by Joslyn_Santana_2B
Sat Sep 24, 2016 6:59 pm
Forum: Empirical & Molecular Formulas
Topic: Assessment Question #8
Replies: 2
Views: 336

Assessment Question #8

In the Pre-Assessment the question is #8, and states: "Xylitol, a sugar subsitute, 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? " In the answers all the Hydrogens were not multiples of 5, which was the number I...

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