Search found 22 matches
- Fri Mar 11, 2016 4:08 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Thermodynamic Stability
- Replies: 2
- Views: 581
Thermodynamic Stability
What does it mean for reactants/products to be thermodynamically stable?
- Sat Mar 05, 2016 7:33 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Video Competition
- Replies: 66
- Views: 28365
Re: Video Competition
This is the error message we are getting when we try to upload. What should we do?
- Fri Mar 04, 2016 3:31 pm
- Forum: *Cyclopropanes and Cyclobutanes
- Topic: Bond Angle Strain vs. Torsional Strain
- Replies: 8
- Views: 3414
Re: Bond Angle Strain vs. Torsional Strain
Torsional strain is caused by electron repulsion between neighboring atoms while bond angle strain is caused when bond angles disagree with the ideal orientation of the molecule. Hope this helps!
- Mon Feb 29, 2016 6:46 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: Partial Charges
- Replies: 4
- Views: 850
Re: Partial Charges
Oh ok, so then a greater difference in electronegativity would cause partial charges?
- Fri Feb 26, 2016 11:53 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: Partial Charges
- Replies: 4
- Views: 850
Re: Partial Charges
Ok, so if they are close in electronegativity, then the electrons will be more shared, giving the atoms partial rather than complete charges?
- Fri Feb 26, 2016 11:45 pm
- Forum: *Organic Reaction Mechanisms in General
- Topic: Partial Charges
- Replies: 4
- Views: 850
Partial Charges
Can someone please clarify how we know when atoms in a molecule should have partial charges? Thanks!
- Fri Feb 19, 2016 12:17 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Pre-Equilibrium Approach
- Replies: 1
- Views: 500
Re: Pre-Equilibrium Approach
The objective of step 2 is to write the rate law of the rate-determining step (slow step) in a manner that agrees with the experimentally derived rate law. To do this, you must substitute the intermediate with something else that's present in the experimental rate law. So, you're substituting the in...
- Wed Feb 10, 2016 3:56 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Midterm Winter 2014 Q. 7 and 8
- Replies: 2
- Views: 760
Re: Midterm Winter 2014 Q. 7 and 8
I believe that for this specific question, you are able to figure out which is the anode because it asks for the Ka value. Ka is the acid dissociation constant and therefore, H+ must be a product. So, it is part of the anode reaction.
- Fri Feb 05, 2016 9:34 am
- Forum: Balancing Redox Reactions
- Topic: Remember Oxidation vs. Reduction
- Replies: 1
- Views: 558
Remember Oxidation vs. Reduction
Just thought I'd share this helpful way to remember how to distinguish oxidation from reduction: OIL RIG
Oxidation
Is
Loss (of electrons)
Reduction
Is
Gain (of electrons)
:)
Oxidation
Is
Loss (of electrons)
Reduction
Is
Gain (of electrons)
:)
- Thu Jan 28, 2016 6:38 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: q and w in a reversible process
- Replies: 1
- Views: 1203
q and w in a reversible process
Does q necessarily equal -w in a reversible process?
- Thu Jan 28, 2016 6:32 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: How to draw a heating curve?
- Replies: 3
- Views: 3393
Re: How to draw a heating curve?
Also make sure the length of your horizontal line is proportional to how much heat should be supplied, and that your slopes accurately represent the different heat capacities (smaller heat capacities will have steeper slopes because less energy needs to be absorbed for the temperature to rise).
- Thu Jan 21, 2016 4:56 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Relating q, w, U, and H
- Replies: 1
- Views: 556
Relating q, w, U, and H
I would really appreciate an explanation of how q, w, U, and H are related. Some specifics I would like answered: When exactly does q = -w and why? Why does q = delta U when volume is constant? And why does q = delta H when pressure is constant?
Thank you so much!
Thank you so much!
- Sat Jan 16, 2016 12:03 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibbs at Constant Pressure
- Replies: 1
- Views: 802
Gibbs at Constant Pressure
Is Gibbs Free Energy at a constant pressure always 0? I figured since ΔH= q at a constant pressure and ΔS = q/t that substituting these terms into the Gibbs free equation ΔG = ΔH - TΔS would become ΔG = q-T(q/t) = q - q = 0. I am wondering if someone can explain if this is correct, why this is the c...
- Sun Jan 10, 2016 7:00 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 1
- Views: 440
Re: Hess's Law
You should be able cancel out the intermediate terms by manipulating one of the steps in the process so that the molecule you wish to cancel is present in an equal number of moles on the opposite side of the reaction equation in some other step. This way, the terms cancel out when the steps are adde...
- Fri Jan 08, 2016 11:43 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: heat and state function
- Replies: 2
- Views: 625
Re: heat and state function
A state function describes the equilibrium state of a system. In this case, enthalpy describes a thermodynamic system, irrespective of the paths each part of the system took to arrive at its current state. Heat is not a state function because it is a form of energy being transitioned as a cause of c...
- Sun Nov 22, 2015 9:54 pm
- Forum: Photoelectric Effect
- Topic: Video:Crash Course on Photoelectric Effect and Others
- Replies: 2
- Views: 763
Video:Crash Course on Photoelectric Effect and Others
Chem14A.m4v Intended to be an all-encompassing study tool, our video begins with an explanation of balancing chemical equations, followed by the basics of the photoelectric effect, Heisenberg's uncertainty principle, molecular shape and structure, molecular orbital theory, and naming coordination c...
- Tue Oct 27, 2015 11:38 am
- Forum: Lewis Structures
- Topic: ClO2 Lewis Structure
- Replies: 3
- Views: 3312
Re: ClO2 Lewis Structure
I believe this is the answer because a structure that includes a radical is not supposed to be of the lowest energy possible. But rather, that unpaired electron is there to make bonds with another atom, which is more likely to happen if Cl has only 2 single bonds and thus has not filled its octet.
- Thu Oct 22, 2015 8:39 pm
- Forum: Lewis Structures
- Topic: Bonds
- Replies: 2
- Views: 832
Re: Bonds
One of the most important things to look at when drawing Louis Structures is the formal charge of each atom. Doing this should help you figure out which bond will provide for the most stable structure. (Stability is essentially based on filling necessary octets in the most energy efficient manner.)
- Thu Oct 22, 2015 8:26 pm
- Forum: Octet Exceptions
- Topic: Expanded Octet
- Replies: 9
- Views: 3305
Re: Expanded Octet
It helps to think of it like they have d-orbitals "available" since they are in the third energy level (n=3 so l=2), but they just don't need to occupy these orbitals given the number of electrons they have.
- Sat Oct 10, 2015 9:16 pm
- Forum: Properties of Light
- Topic: Heisenberg's Equation
- Replies: 3
- Views: 919
Re: Heisenberg's Equation
Heisenberg's Indeterminacy Equation actually either allows you to calculate the uncertainty in position (delta x) or the uncertainty in momentum (delta p). The probability of finding the electron's location can be found by squaring the wavelength function.
- Sun Oct 04, 2015 4:54 pm
- Forum: *Shrodinger Equation
- Topic: Conceptual Explanation of Schrod. Equ. Pls!
- Replies: 1
- Views: 698
Conceptual Explanation of Schrod. Equ. Pls!
I'm having trouble understanding the verbal form of Schrodinger's Equation: "Operate a change on psi (x,y,z) = Energy psi (x,y,z)"
What does the operation of a change on an electron entail and why does it equal its energy?
What does the operation of a change on an electron entail and why does it equal its energy?
- Sun Oct 04, 2015 3:57 pm
- Forum: Properties of Electrons
- Topic: Speed of an Electron (hw 1.43)
- Replies: 8
- Views: 4519
Re: Speed of an Electron (hw 1.43)
So to solve this problem, you first use Heisenberg's Indeterminacy Equation, which looks like the following: Delta p x Delta x >= h/(4pi) The question gives us the uncertainty in position (Delta x) by stating the diameter of the lead atom, 350 pm. Because we want to keep our units to meters, we make...