## Search found 23 matches

Thu Mar 16, 2017 10:54 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Ring Flip
Replies: 1
Views: 348

### Re: Ring Flip

A "ring flip" is simply a transitional process that occurs for cyclohexanes when the end that is pointed down rotates and becomes the end that is pointed up, causing the other side to rotate and point down. This is usually caused by some sort of molecular collision. To draw it, one would j...
Wed Mar 15, 2017 11:00 pm
Forum: Balancing Redox Reactions
Topic: 2013 Final #4
Replies: 4
Views: 584

### Re: 2013 Final #4

Wait, How would that work? The reduction reaction isn't balanced (Fe on products but not in reactants). I also had trouble determining n for this question.
Tue Mar 14, 2017 10:11 am
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 280
Views: 134558

### Re: Saying Thank You to Dr. Lavelle

Dear Dr. Lavelle, You are truly an inspirational man and a wonderful professor. You provide so many resources to all your students so that everyone can succeed in this class, and I have found them incredibly helpful. Whenever you are lecturing you always look so excited to be explaining chemistry, a...
Sun Mar 05, 2017 8:45 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Substituents
Replies: 2
Views: 323

### Re: Substituents

The orientation of substituents does not matter for most molecules because the bonds can rotate, so any number of different orientations can be correct as long as they yield the same name. The only significant exception is in the case of geometric isomers. When choosing orientations around a double ...
Wed Feb 22, 2017 12:15 am
Forum: General Rate Laws
Topic: Units of K
Replies: 1
Views: 291

### Units of K

I was somewhat confused on the sign of k. Since the General Rate equation for RXN aA --> bB is Rate = -1/a d[A]/dt = 1/b d[B]/dt, and we know d[A]/dt = k[A]^(molecularity) would the sign of k change whether we are considering the product or reactant? Or is it always positive? Is there something I'm ...
Fri Feb 10, 2017 12:50 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: 14.35
Replies: 1
Views: 283

### Re: 14.35

The cell potential is always positive when making a battery or an electrical system that can do work. However, in some reactions, electrical work is required to drive the reaction. In these cases, Eo is negative. In this question, we are using E(cell) to determine the equilibrium constant for a reac...
Sat Feb 04, 2017 5:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Solution Manual Corrections
Replies: 1
Views: 303

### Solution Manual Corrections

Hello, I believe there may be an error in the corrections of the solution manual errors. In 14.35b) the corrected version states,

At 25 ℃, lnK = (1)(+0.12 V) ÷ 0.02569 V = +4.6
∴ K = 1 x 10^3

However it is quite clear to see that e^(4.6) = 99.5 ≈ 10^2 ≠ 10^3
Mon Jan 30, 2017 12:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: How to interpret ∆H
Replies: 2
Views: 515

### How to interpret ∆H

when ∆H is listed next to a balanced reaction, is it referring the enthalpy corresponding to the stoichiometric coefficients, or is it referring to the reaction enthalpy of 1 mol of product?
Mon Jan 30, 2017 12:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 17148

### Re: Quiz 1 Preparation Answers

Quiz 1 Preparation, pg 113
Mon Jan 30, 2017 12:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 17148

### Re: Quiz 1 Preparation Answers

Did anyone else notice that the initial conditions to Problem #3 are not consistent with PV = nRT?
(3atm)(6L) ≠ (2mol)(0.0826L-atm/mol-K)(300K)
18L-atm ≠ 49.56L-atm
Wed Jan 25, 2017 7:37 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 9.23
Replies: 1
Views: 357

### HW 9.23

Could anyone explain this problem? The Solution manual states that COF2 has greater residual entropy than BF3 because the Fluorine atoms could occupy the same location as the oxygen atom. What does that even mean? I thought that since COF2 is polar it would be more likely to line up in a particular ...
Fri Jan 20, 2017 5:29 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: temperature [ENDORSED]
Replies: 2
Views: 461

### Re: temperature[ENDORSED]

It doesn't really depend on temperature. If pressure is constant, we use w = -P∆V. Alternatively when pressure is changing, we use -nRT * ln(V2/V1)
Fri Jan 13, 2017 1:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Defining Enthalpy
Replies: 1
Views: 192

### Defining Enthalpy

What exactly is enthalpy? I understand that when pressure is constant and all work is expansion work that enthalpy = heat, but what is enthalpy defined as when pressure is not constant? Furthermore, I know that heat is measured in Joules so it must be some form of energy, but what differentiates it ...
Sun Dec 04, 2016 10:08 am
Forum: Trends in The Periodic Table
Topic: Chapter 2 HW #93
Replies: 2
Views: 659

### Re: Chapter 2 HW #93

Also, it is certainly worth noting that 2.93 is one of the Solution Manual Errors, listed on Lavelle's website. The correct answer, contrary to the solution manual, is that Na > Cl, but Na+ < Cl-
Mon Nov 28, 2016 5:25 pm
Forum: Lewis Acids & Bases
Topic: HW problem 12.35
Replies: 2
Views: 454

### HW problem 12.35

Hey, so I know that the textbook mentions certain trends: For oxoacids, increasing the number of Oxygen atoms increases the relative strength of the acid. Also, for 2 oxoacids of different central atoms with the same number of Oxygen atoms, the central atom with the greater electronegativity is stro...
Tue Nov 22, 2016 1:24 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: 2007 Final Question 3B
Replies: 2
Views: 454

### Re: 2007 Final Question 3B

Right so, since Oxygen is the more electronegative atom, it would make sense for Nitrogen to lose its electron. But in the solution, Oxygen loses the electron instead. (Am I missing something?)
Mon Nov 14, 2016 11:25 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: 2007 Final Question 3B
Replies: 2
Views: 454

### 2007 Final Question 3B

Hey, this question asks for an MO diagram of NO+. In the answer to this question, Nitrogen's 2p orbitals have 3 electrons and Oxygen's 2p orbitals also have 3(as opposed to its normal 4) electrons. Why is the electron lost from the Oxygen (the more electronegative atom)?
Mon Nov 14, 2016 8:38 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8019
Views: 1403946

### Re: Post All Chemistry Jokes Here

Why did the chemist call her ex-boyfriend Dubnium when they broke up?
...
...
...
Because he was a real Db.
Wed Nov 09, 2016 12:44 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Questions 4.77
Replies: 2
Views: 344

### Re: Questions 4.77

I also did not understand this question, and would love a full explanation. Why are hydrogen's 1s electrons higher in energy than Fluorine's 2p (something that isn't the case in any of the other diagrams)? Which orbitals are bonding and which are non-bonding? And how does this all match up with the ...
Fri Oct 07, 2016 1:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Quizes
Replies: 21
Views: 1783

### Re: Quizes

Hey, so just confirming something professor Lavelle mentioned today: Quiz 1 will cover material up to page 60(Wednesday) in the course reader right?
Fri Oct 07, 2016 12:57 pm
Forum: Student Social/Study Group
Topic: Dykstra Hall Study Group (Fall 2016)
Replies: 25
Views: 2071

### Re: Dykstra Hall Study Group (Fall 2016)

Hey I got the email, but I don't think I was added to the GroupMe
Mon Oct 03, 2016 12:04 am
Forum: Student Social/Study Group
Topic: Dykstra Hall Study Group (Fall 2016)
Replies: 25
Views: 2071

### Re: Dykstra Hall Study Group (Fall 2016)

@Junghyuk_Park_3K, Yeah, sorry I missed that at first. My email is paul.wesley.adkisson@gmail.com
Wed Sep 28, 2016 9:37 am
Forum: Student Social/Study Group
Topic: Dykstra Hall Study Group (Fall 2016)
Replies: 25
Views: 2071

### Re: Dykstra Hall Study Group (Fall 2016)

Hey, I'm on Dykstra 10! When do you guys think you'll meet?

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