Search found 26 matches

by Michael Lesgart 1H
Fri Mar 17, 2017 10:14 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Quiz 2 question
Replies: 3
Views: 327

Re: Quiz 2 question

So for the psuedo equilibrium constant K dagger, you would use this equation

deltaG dagger=-RT ln(K dagger) with dagger referring to the transition state

On my quiz you solved for delta G in the previous question and he temperature was given, so you would just have to solve for K
by Michael Lesgart 1H
Sat Mar 11, 2017 3:32 pm
Forum: *Electrophiles
Topic: Nucleophile vs Electrophile
Replies: 5
Views: 914

Re: Nucleophile vs Electrophile

Also, it is useful to note electronegativity in a molecule that can cause it to become an electrophile. For example, CO2 is an electrophile because of the dipole moments created by the negative charge of the O with the positive charge of the C, and the electronegativity of the Oxygens cause the Carb...
by Michael Lesgart 1H
Sat Mar 04, 2017 11:07 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow Reaction
Replies: 11
Views: 719

Re: Slow Reaction

When the question asks you to find the rate equation, what do you do when your equation requires you to know the concentration of an intermediate species? Are you supposed to replace it by looking at the fast reaction and setting the forward rate equal to the reverse rate? Or is there another method...
by Michael Lesgart 1H
Sat Feb 25, 2017 12:32 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow Reaction
Replies: 11
Views: 719

Re: Slow Reaction

I believe that the fast step is at equilibrium and the slow step is not at equilibrium. Also do you know if you use the pre-equilibrium approach if the fast step comes before the slow step or after the slow step?
by Michael Lesgart 1H
Sun Feb 19, 2017 2:13 pm
Forum: First Order Reactions
Topic: Concept of Half Life [ENDORSED]
Replies: 3
Views: 376

Re: Concept of Half Life [ENDORSED]

Is there a general trend that relates temperature and half-life? Does a higher temperature correlate to a lower half live or vice versa?
by Michael Lesgart 1H
Sat Feb 11, 2017 1:45 pm
Forum: Balancing Redox Reactions
Topic: highest possible charge [ENDORSED]
Replies: 3
Views: 334

Re: highest possible charge [ENDORSED]

How do the standard reaction potential reactions translate to oxidizing agents? Does a higher voltage mean that a reaction is a better oxidizing agent and vice versa?
by Michael Lesgart 1H
Sat Feb 04, 2017 12:45 pm
Forum: Balancing Redox Reactions
Topic: Salt bridge
Replies: 3
Views: 287

Re: Salt bridge

I have a follow up question, what allows for a current to flow: the electrons themselves or the electron movement from anode to cathode? Also, during a redox reaction, does the salt bridge allow for the reaction to occur multiple times so that a continuous charge is being generated?
by Michael Lesgart 1H
Sat Jan 28, 2017 2:29 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Reversibly & Isothermally
Replies: 3
Views: 456

Re: Reversibly & Isothermally

In reversible reactions, reactants react with other reactants to form products, and the products react with other products to form more reactants. Essentially, it is a reaction cycle. In an irreversible reaction, reactants react with other reactants to form products, and the products do not form rea...
by Michael Lesgart 1H
Sat Jan 28, 2017 2:22 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Assuming Constant Pressure?
Replies: 2
Views: 295

Re: Assuming Constant Pressure?

I would think that if the problem doesn't mention pressure change, you can assume that it is under conditions of constant pressure.
I may be wrong though
by Michael Lesgart 1H
Sat Jan 21, 2017 3:09 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Energy of the system during expansion [ENDORSED]
Replies: 2
Views: 292

Re: Energy of the system during expansion [ENDORSED]

Is it true that energy can only exist in the system or surroundings? or is it somehow lost when the piston is moved and work is done?
by Michael Lesgart 1H
Fri Jan 13, 2017 8:22 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Most Stable Form
Replies: 4
Views: 587

Re: Most Stable Form

Would it be necessary to draw out the Lewis structure with a formal charge of 0 in order to determine a molecule's most stable form? Or is there another method that can be used?
by Michael Lesgart 1H
Fri Dec 02, 2016 5:47 pm
Forum: Calculating the pH of Salt Solutions
Topic: Henderson-Hasselbalch Equation: Solving for acid
Replies: 2
Views: 1609

Re: Henderson-Hasselbalch Equation: Solving for acid

The Henderson-Hasselbach Equation is pH=pKa + log ([A-]/[HA]) [HA] is the molar concentration of the weak acid, [A⁻] is the molar concentration of this acid's conjugate base, and pKa is −log10 Ka where Ka is the acid dissociation constant. So if we are given the pH, pKa, and the concentration of [HA...
by Michael Lesgart 1H
Fri Dec 02, 2016 5:32 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Acids/Bases Proton Acceptors/Donors
Replies: 1
Views: 319

Re: Conjugate Acids/Bases Proton Acceptors/Donors

I assume its the Hydrogen furthest away from the "center of the molecule" because it can easily be transferred whereas the H in the H3 isn't easily transferred, but I may be mistaken.
by Michael Lesgart 1H
Tue Nov 22, 2016 1:49 pm
Forum: Bronsted Acids & Bases
Topic: J Section Question 1
Replies: 2
Views: 479

Re: J Section Question 1

I guess you can use this as a strategy:
A Bronsted acid donates protons, A Lewis acid accepts electrons
A Bronsted base accepts protons, A Lewis base donates electrons
Also, you can visualize the potential reaction and see if protons are donated or accepted.
Hope this helped!
by Michael Lesgart 1H
Fri Nov 18, 2016 11:56 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Neglecting solids and liquids
Replies: 1
Views: 2628

Re: Neglecting solids and liquids

You ignore the concentration of solids and liquids because they have a constant concentration. Liquids and solids cannot be compressed because the molecules are very close together; without compression there is no change is concentration (like there is when gasses are compressed.) For these reasons,...
by Michael Lesgart 1H
Mon Nov 14, 2016 12:08 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Quiz #3 [ENDORSED]
Replies: 7
Views: 764

Re: Quiz #3 [ENDORSED]

Yes. I'm pretty sure that MO theory will be on the exam. We covered it in class and it wasn't on the midterm so its safe to say that its going to be on there
by Michael Lesgart 1H
Sun Nov 06, 2016 5:49 pm
Forum: Hybridization
Topic: Hybridizaton Textbook equation
Replies: 2
Views: 314

Re: Hybridizaton Textbook equation

I assume that the equations must mean that the first hybridization for the atom has one s orbital and 3 p orbitals (hence px, py, pz). Therefore, you can conclude that the hybridization is sp3. You can also determine the hybridization of an atom by finding how many regions of electron density there ...
by Michael Lesgart 1H
Sun Oct 30, 2016 4:46 pm
Forum: Quantum Numbers and The H-Atom
Topic: Midterm 2007 review question [ENDORSED]
Replies: 1
Views: 356

Re: Midterm 2007 review question [ENDORSED]

When n=5, l can equal 0,1,2,3,4 which corresponds to the s,p,d,f, and (theoretically) g subshells. 5s has one orbital (maximum of 2 electrons), 5p has three orbitals (maximum of 6 electrons), 5d has five orbitals (maximum of 10 electrons), 5f has 7 orbitals (maximum of 14 electrons), and 5g would th...
by Michael Lesgart 1H
Sun Oct 23, 2016 7:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Unpaired Electrons
Replies: 1
Views: 204

Re: Unpaired Electrons

Whether or not an element has an unpaired electron depends on the total number of electrons in the molecule. So you would first need to find the total number of valence electrons and then you would draw a lewis structure (try to follow the octet rule). You would then figure out how many electrons wo...
by Michael Lesgart 1H
Mon Oct 10, 2016 6:14 pm
Forum: Balancing Chemical Reactions
Topic: Naming Chemical Formula and Balancing Chemical Equations [ENDORSED]
Replies: 5
Views: 1157

Re: Naming Chemical Formula and Balancing Chemical Equations [ENDORSED]

When writing out the chemical equation, should we include the state that the chemical is in? so would it be N2(g) + O2(g) ==> 2NO(g)
by Michael Lesgart 1H
Sun Oct 09, 2016 9:03 pm
Forum: Significant Figures
Topic: All students read this sig fig post [ENDORSED]
Replies: 91
Views: 8948

Re: All students read this sig fig post [ENDORSED]

For testing purposes, is there a difference between writing 1.8 x 10^-2 and 0.018? I know they're synonymous, but I've seen both used in the textbook and workbook so I was wondering if there is a preference for either when it comes to giving a final answer. I would use 1.8 x 10^-2 because it is in ...
by Michael Lesgart 1H
Sun Oct 02, 2016 11:40 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra AV post assessment #31 [ENDORSED]
Replies: 8
Views: 583

Re: Atomic Spectra AV post assessment #31 [ENDORSED]

Oh ok thank you very much for the clarification
by Michael Lesgart 1H
Sun Oct 02, 2016 11:20 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra AV post assessment #31 [ENDORSED]
Replies: 8
Views: 583

Re: Atomic Spectra AV post assessment #31 [ENDORSED]

Wouldnt you get a different answer if you use a different constant?
by Michael Lesgart 1H
Sat Oct 01, 2016 4:18 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra AV post assessment #31 [ENDORSED]
Replies: 8
Views: 583

Re: Atomic Spectra AV post assessment #31 [ENDORSED]

Why do you use 1.097 x 10^7 instead of 3.29 x 10^15 for R?
by Michael Lesgart 1H
Fri Sep 30, 2016 2:18 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra AV post assessment #24
Replies: 3
Views: 311

Re: Atomic Spectra AV post assessment #24

I noticed in your work that you equated frequency (v) to 1/ but actually, frequency (v) is equal to /
by Michael Lesgart 1H
Fri Sep 30, 2016 1:43 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectroscopy Experiment Setup
Replies: 1
Views: 202

Atomic Spectroscopy Experiment Setup

In an atomic spectroscopy experiment, what exactly is detected? Is it all light or just emitted light?

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