Search found 27 matches

by Raul Hernandez
Fri Mar 17, 2017 10:33 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Winter 2016 Final Exam Q2A [ENDORSED]
Replies: 7
Views: 832

Re: Winter 2016 Final Exam Q2A [ENDORSED]

Kind of unrelated question but: why is it 2X on the top? I didn't quite get that in the review session. Do you mind explaining that part?
by Raul Hernandez
Fri Mar 17, 2017 8:53 pm
Forum: Calculating Work of Expansion
Topic: Chapter 8 question 8.27
Replies: 2
Views: 413

Re: Chapter 8 question 8.27

I did see that. Also, on the formula sheet we have "W(variable pressure)= -nRTLn(V2/V1)" and from another post I saw that in a reversible pathway the pressure seems to vary so we could use this equation. However, what was in the solutions manual didn't have the "Ln" part. So, now...
by Raul Hernandez
Fri Mar 17, 2017 8:45 pm
Forum: Calculating Work of Expansion
Topic: Chapter 8 question 8.27
Replies: 2
Views: 413

Chapter 8 question 8.27

The question reads: "Calculate the work for each of the following processes beginning with a gas sample in a piston assembly with T = 305 K, P = 1.79 atm, and V = 4.29 L: (a) irreversible expansion against a constant external pressure of 1.00 atm to a final volume of 6.52 L; (b) isothermal, rev...
by Raul Hernandez
Sun Mar 12, 2017 11:59 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7774
Views: 1073241

Re: Post All Chemistry Jokes Here

What is the name of Agent 007's Eskimo cousin?

Bond. Polar Bond.
by Raul Hernandez
Tue Mar 07, 2017 9:19 pm
Forum: *Alkynes
Topic: Naming Alkyne with cycloalkane and substituents?
Replies: 1
Views: 571

Naming Alkyne with cycloalkane and substituents?

Hello. So, while doing some practice problems for molecular formulas and their names, I stumbled upon this problems and I really can't figure out why it is named the way it is. It says it has a "dimethyl" on the 7th and 8th carbon, but I don't understand how their counting the carbons or W...
by Raul Hernandez
Sun Feb 26, 2017 11:51 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7774
Views: 1073241

Re: Post All Chemistry Jokes Here

Oh, no someone dropped water on the floor...
by Raul Hernandez
Thu Feb 23, 2017 1:45 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7774
Views: 1073241

Re: Post All Chemistry Jokes Here

Correcting my friends after learning basic thermodynamics: A heated argument.
by Raul Hernandez
Wed Feb 15, 2017 4:43 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Winter 2013 Midterm, Question 3A
Replies: 2
Views: 402

Re: Winter 2013 Midterm, Question 3A

Oh. I see. I just realized my mistake. Thank you for the help!
by Raul Hernandez
Mon Feb 13, 2017 10:20 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Winter 2013 Midterm, Question 3A
Replies: 2
Views: 402

Winter 2013 Midterm, Question 3A

Hi, for this problem, when actually plugin-in the numbers, the temperature of the katana is in Celsius and the value for its specific heat capacity is in Kelvin. Now, in the answer to the problem they left it in celsius and therefore the Kelvin did not cancel out. I converted it to Kelvin and got a ...
by Raul Hernandez
Sun Feb 12, 2017 11:55 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Midterm 2013 Question 3A
Replies: 4
Views: 513

Re: Midterm 2013 Question 3A

Hi, I have an additional question to this problem: when actually plugin-in the numbers, the temperature of the katana is in Celsius and the value for its specific heat capacity is in Kelvin. Now, in the answer to the problem they left it in celsius and therefore the Kelvin did not cancel out. I conv...
by Raul Hernandez
Sun Feb 12, 2017 7:07 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Chapter 14, Problem 14.19
Replies: 3
Views: 453

Re: Chapter 14, Problem 14.19

The solutions manual uses the positive reduction value for the anode, but notice that this positive reduction potential is being subtracted from the reduction potential of the cathode. We learned to reverse the sign of the reduction potential of the anode and then add the two half-reaction potentia...
by Raul Hernandez
Sat Feb 11, 2017 10:48 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Chapter 14, Problem 14.19
Replies: 3
Views: 453

Chapter 14, Problem 14.19

Hello, I have a question regarding the answer to the problem. The problem reads: "A student was given a standard Cu(s)|Cu2(aq) halfcell and another half-cell containing an unknown metal M immersed in 1.00 m M(NO3)2(aq). When the copper was connected as the anode at 25 C, the cell potential wa...
by Raul Hernandez
Mon Jan 30, 2017 8:58 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 14142

Re: Quiz 1 Preparation Answers

For number 3, what equation do we use since there seems to be a change in pressure? I can't seem to get the answer posted here by any method I've tried.
Thanks.
by Raul Hernandez
Sat Jan 21, 2017 1:37 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Chapter 8 problem 21 [ENDORSED]
Replies: 3
Views: 499

Re: Chapter 8 problem 21 [ENDORSED]

So, I have a small question regarding the signs: how come it's negative on the side of the water and positive on the copper side? I'm just confused because wouldn't the side of the copper be negative since it's doing work on its surroundings? Everything else makes sense, though. I'm just a bit confu...
by Raul Hernandez
Sun Jan 15, 2017 9:44 pm
Forum: Phase Changes & Related Calculations
Topic: Homework Question 8.28
Replies: 1
Views: 493

Homework Question 8.28

The homework question reads: "A sample of gas in a cylinder of volume 3.42 L at 298 K and 2.57 atm expands to 7.39 L by two different pathways. Path A is an isothermal, reversible expansion. Path B has two steps. In the fi rst step, the gas is cooled at constant volume to 1.19 atm. In the secon...
by Raul Hernandez
Mon Nov 14, 2016 6:25 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Finding Coordination Number and Oxidation State [ENDORSED]
Replies: 7
Views: 1385

Re: Finding Coordination Number and Oxidation State [ENDORSED]

I have another question regarding the coordination number: if one of the molecules attached to the central metal is bidentate, would we count that as another bond? For example, if there's a central metal with 4 ligands and 1 of those ligands happens to be bidentate, would the coordination number be ...
by Raul Hernandez
Wed Nov 02, 2016 10:26 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Which Diagram to draw in a bond with both elements Z<8 and Z>8 [ENDORSED]
Replies: 8
Views: 911

Re: Which Diagram to draw in a bond with both elements Z<8 and Z>8 [ENDORSED]

It was an example on the 2013 Fall Midterm, and it is a heteronuclear molecule. My question was whether to use the diagram provided for the elements with z<8 or z>8 (both are similar but they differ in the placement of the sigma pz bonds). However, I think that the example given by Amy Ko (Thank you...
by Raul Hernandez
Tue Nov 01, 2016 11:40 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Which Diagram to draw in a bond with both elements Z<8 and Z>8 [ENDORSED]
Replies: 8
Views: 911

Which Diagram to draw in a bond with both elements Z<8 and Z>8 [ENDORSED]

I hope this is not trivial, but I was wondering what diagram do you choose to draw when you have two elements that are: one less than 8 protons and another with more than 8 protons. For example, how would you draw the Molecular Diagram for Fluorine and Carbon together (CF) and why? Any help will be ...
by Raul Hernandez
Tue Nov 01, 2016 11:31 pm
Forum: Photoelectric Effect
Topic: 2015 Midterm Question #3
Replies: 2
Views: 588

Re: 2015 Midterm Question #3

This is one question that you shouldn't overthink. It gives you the velocity of the electron, correct? And then it asks you about the wavelength of the same electron, right? So, you should just see that there's no need to go back and find the energy of the photon or anything like that because the qu...
by Raul Hernandez
Tue Nov 01, 2016 11:20 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Paramagnetic vs Diamagnetic
Replies: 2
Views: 441

Re: Paramagnetic vs Diamagnetic

I think the basic thing you need to know is that: if there's NO unpaired electrons in the molecule, then it is Diamagnetic and if there IS unpaired electrons it is Paramagnetic. Diamagnetic = no unpaired electrons, and it isn't attracted to magnetic fields (repelled). Paramagnetic = has unpaired ele...
by Raul Hernandez
Tue Nov 01, 2016 8:26 pm
Forum: Lewis Structures
Topic: Oxidation Number of Thallium in Tl2O3
Replies: 3
Views: 667

Re: Oxidation Number of Thallium in Tl2O3

I understand now. Thank you very much to both of you!
by Raul Hernandez
Mon Oct 31, 2016 3:36 pm
Forum: Lewis Structures
Topic: Oxidation Number of Thallium in Tl2O3
Replies: 3
Views: 667

Oxidation Number of Thallium in Tl2O3

Hello, I hope this is not too trivial, but while doing some chapter problems I came across an example that asks for the oxidation number of Thallium in Tl2O3 (Problem 3.113 in the book). The answer says the ox. no. is 3+ but I don't understand how that's the answer. I drew the Lewis dot structure an...
by Raul Hernandez
Tue Oct 11, 2016 3:29 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Quiz 1 prep #5 question [ENDORSED]
Replies: 7
Views: 946

Re: Quiz 1 prep #5 question [ENDORSED]

On the topic of Indeterminacy: do you guys know what do write in the equation for "delta x" if the position is known withing plus or minus a certain number? (let's say plus or minus 0.55). Thanks.
by Raul Hernandez
Wed Sep 28, 2016 10:53 am
Forum: Administrative Questions and Class Announcements
Topic: Peer Facilitated Learning Sessions
Replies: 32
Views: 11375

Re: Peer Facilitated Learning Sessions

For the session in Hedrick Hall, do we have to sign up or do we just show up? If so, must I be a member of AAP to sign up? Thanks.
by Raul Hernandez
Thu Jul 21, 2016 4:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: H2O Shape [ENDORSED]
Replies: 3
Views: 690

Re: H2O Shape [ENDORSED]

As explained in Chapter 4, the electrons would like to be as far away from each other as possible but they also will be repelled by the other elements and the arrangement that works best for this is to have the electrons to be on one side of the oxygen making it an angular ("bent") shape.
by Raul Hernandez
Thu Jul 21, 2016 3:56 pm
Forum: Naming
Topic: naming complex question regarding atom outside bracket [ENDORSED]
Replies: 1
Views: 274

Re: naming complex question regarding atom outside bracket [ENDORSED]

So, I saw the same question and I did a bit of research. It seems that, just like in a regular compound, you still name the last element with the ending in "ide," and this is because it is outside of the brackets so it's a whole other element bonding with the whole molecule in brackets. I ...
by Raul Hernandez
Thu Jun 23, 2016 4:51 pm
Forum: Administrative Questions and Class Announcements
Topic: When must the Preparatory Self-quizzes be turned-in?
Replies: 3
Views: 433

When must the Preparatory Self-quizzes be turned-in?

I don't recall hearing the due dates for the Preparatory Self-quizzes in either the Lectures or the discussions. Also, are they graded - since a grading percentage for them are not included in the syllabus - or are they just for the TA's to evaluate our understanding of the material as a section? An...

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