Search found 25 matches
- Sun Mar 19, 2017 9:17 am
- Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
- Topic: Winter 2013 Final 8B
- Replies: 3
- Views: 1580
Re: Winter 2013 Final 8B
the trans molecule would have one in the equatorial position and one in the axial position. Since the ethyl substituent take priority, it will be in the equatorial position.
- Thu Mar 16, 2017 5:36 pm
- Forum: *Alcohols
- Topic: Winter Final Exam 2015 9B
- Replies: 2
- Views: 1359
Re: Winter Final Exam 2015 9B
Are we just supposed to know what fructose looks like? Where were we ever taught the chemical formula of fructose in order to be able to give its IUPAC name and draw it?
- Thu Mar 16, 2017 12:15 am
- Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
- Topic: Winter 2013 Final 8B
- Replies: 3
- Views: 1580
Winter 2013 Final 8B
Why would both substiuent groups be in equatorial positions in the chair cyclohexane conformation in a cis isomer? I thought we had learned in lecture that cis isomers are always (a,e) or (e,a) meaning one is equatorial and one is axial. Please someone explain?
- Mon Mar 13, 2017 2:12 pm
- Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
- Topic: Unfavorable Interactions
- Replies: 3
- Views: 1002
Re: Unfavorable Interactions
I also found this website helpful if anyone wants to know more about torsional vs steric. http://web.chem.ucla.edu/~harding/notes/strain_01.pdf
Furthermore, I still have the same question about which carbon to rotate in the Newman projections. If anyone knows, please reply.
Furthermore, I still have the same question about which carbon to rotate in the Newman projections. If anyone knows, please reply.
- Mon Mar 13, 2017 2:08 pm
- Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
- Topic: Unfavorable Interactions
- Replies: 3
- Views: 1002
Re: Unfavorable Interactions
I have found an answer for the difference between torsional and steric strain: “torsional strain can be relieved by bond rotation whereas
steric strain cannot"
steric strain cannot"
- Mon Mar 13, 2017 1:47 am
- Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
- Topic: Unfavorable Interactions
- Replies: 3
- Views: 1002
Unfavorable Interactions
Are the only 2 unfavorable interactions we have learned so far for alkanes just the torsional and steric strains? Furthermore, what is the difference between the two, considering that both occur due to closeness of electron densities. Would one ever occur without the other? A second question I had w...
- Fri Mar 10, 2017 12:56 am
- Forum: Administrative Questions and Class Announcements
- Topic: Quiz 3 Winter 2017
- Replies: 183
- Views: 29793
Re: Quiz 3 Winter 2017
Julie Barreto 3A wrote:how would you draw out 2-butene or anything with a number in front of it ???
This is an alkene and it would be a 4-carbon molecule with a double bond between the 2nd and 3rd carbon.
- Fri Mar 10, 2017 12:47 am
- Forum: *Alkanes
- Topic: Tert vs. Neo?
- Replies: 4
- Views: 959
Re: Tert vs. Neo?
the way I learned it was that tert applied to 4 or less carbons, and neo applied to 5 or more.
- Fri Mar 03, 2017 10:28 pm
- Forum: *Alkanes
- Topic: About the Weekly Online Discussion Points...
- Replies: 3
- Views: 912
Re: About the Weekly Online Discussion Points...
I emailed my TA about this issue and he said there is nothing he can do because it is all based on the computer.
- Fri Mar 03, 2017 10:21 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Quiz 3 Winter 2017
- Replies: 183
- Views: 29793
Re: Quiz 3 Winter 2017
Will we need to know about Alkenes for quiz 3? we didn't talk about naming them or really anything about them in class but they are in section 1.3. Also section 1.4 about Geometric isomers and section 1.5 about alkynes were not covered in the course reader. Will we need to know about all of these th...
- Fri Mar 03, 2017 5:15 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: Substituent Naming
- Replies: 3
- Views: 697
Re: Substituent Naming
Da_Rhee_1O, the reason it is 2,2 in front of dimethyl is that there are two of the methyl groups attached to the same Carbon (the 2nd carbon).
- Thu Mar 02, 2017 9:22 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: Mechanisms
- Replies: 2
- Views: 646
Re: Mechanisms
I believe we only needed to read up to the end of 4.4. I don't think we need to know anything after that in chapter 4.
- Thu Mar 02, 2017 9:19 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Quiz 3 [ENDORSED]
- Replies: 14
- Views: 2019
Re: Quiz 3 [ENDORSED]
My TA mentioned that it will cover whatever we end off on in ochem on Friday as well as the last part of kinetics (i.e. Arrhenius Equation).
- Mon Feb 20, 2017 7:11 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Quiz 2 #9 and #10
- Replies: 3
- Views: 666
Re: Quiz 2 #9 and #10
The reason that in #9 D is the answer is that not all proteins are enzymes. A is correct because an enzyme binds with a substrate in order to help catalyze the reaction. Therefore, when the amount of substrate is low, there aren't very many substrates for enzymes to bind with. When the concentration...
- Mon Feb 20, 2017 12:58 am
- Forum: Administrative Questions and Class Announcements
- Topic: Quiz 2 Winter 2017
- Replies: 160
- Views: 24932
Re: Quiz 2 Winter 2017
Chem_Mod wrote:nlc_lec1 wrote:Do we need to know how to do #9 and #11 from Quiz 2 Prep?
9 yes
11 no
could you please explain #9? It has to do with enzymes and I don't really know anything about them.
- Sun Feb 19, 2017 1:03 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Quiz 2 Winter 2017
- Replies: 160
- Views: 24932
Re: Quiz 2 Winter 2017
Do we need to know how to do #9 and #11 from Quiz 2 Prep?
- Sun Feb 19, 2017 1:01 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: QUIZ 2 #11
- Replies: 3
- Views: 781
Re: QUIZ 2 #11
Do we need to know how to do this for the quiz? I thought the material covered only up until page 73. Will we also need to know how to do #9?
- Sun Feb 19, 2017 12:32 pm
- Forum: First Order Reactions
- Topic: Half Life
- Replies: 1
- Views: 537
Re: Half Life
When you look at the 1st order integrated rate law, you see that ln[A]=-kt+ln[A]o. At the half life, [A]=1/2 of [A]o. When you plug this value into the equation, you will get ln(1/2([A]o/[A]o)). The [A]o values cancel so you are left with simply ln 1/2. This is why the half life is independent of [A...
- Sat Feb 11, 2017 1:35 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: 14.27 [ENDORSED]
- Replies: 2
- Views: 682
Re: 14.27 [ENDORSED]
For this reaction, you will not get a situation in which the 2 half reactions will have electrons which cancel to give you that exact net reaction. When this happens, you need to use the Gibbs Free Energy instead of trying to add the potentials together. Using this method, you can solve for E^o of t...
- Sat Feb 11, 2017 1:32 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Reducing agents [ENDORSED]
- Replies: 2
- Views: 772
Re: Reducing agents [ENDORSED]
To determine the strength of the reducing agent, you have to look at the reduction potentials for each one. The more negative the reduction potential, the higher chance the metal will want to be oxidized, therefore making it the best reducing agent. What this means is that a species that wants to be...
- Sat Feb 04, 2017 4:11 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Different Versions of the Nernst Equation
- Replies: 2
- Views: 804
Different Versions of the Nernst Equation
I know that there are three different versions of the Nernst Equation, and I understand the derivations for each one. I was wondering, though, when you would use the one with ln vs when you would use the one with log. I also was wondering why in the example on page 53 of the course reader (the Conce...
- Fri Feb 03, 2017 12:15 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Internal Energy
- Replies: 2
- Views: 512
Re: Internal Energy
This is correct. You can see from the equation U=3/2*(nRT) therefore delta U= 3/2*(nR(deltaT)). In an isothermal reaction the change in temperature is zero since temperature is constant.
- Thu Jan 26, 2017 6:11 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs Free Energy Problem on pg 39
- Replies: 2
- Views: 501
Re: Gibbs Free Energy Problem on pg 39
In this example, (delta)G would equal zero because that is the temperature at which (delta)H=T*(delta)S. The reason we want this exact value is that any temperature above this value will be just enough to make the latter half of the equation (the T*deltaS part) a higher number than the deltaH value....
- Sun Jan 22, 2017 4:36 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: HW 8.47
- Replies: 2
- Views: 618
Re: HW 8.47
My book stated that the work done by the system was 22 kJ, so I simply used the formula Δu=q+w, and made the work negative since the work is done BY the system, and therefore the system is losing energy. Also, since the equation is at constant pressure, q is really q sub p, and i used Δu=15+(-22) to...
- Sun Jan 22, 2017 4:31 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Clarification regarding reversible, isothermal expansion [ENDORSED]
- Replies: 1
- Views: 620
Re: Clarification regarding reversible, isothermal expansion [ENDORSED]
In a reversible, isothermal reaction, the system is at equilibrium. Because of this, the heat put into the system will cancel out the work done by the system, or vice versa. Therefore the change in temperature would be zero and that is why it should be isothermal. As for why we use the integral equa...