Search found 43 matches

by StudentD2B
Fri Mar 15, 2019 12:16 am
Forum: Dipole Moments
Topic: Polarity
Replies: 5
Views: 615

Outline Clarification

What does Dr. Lavelle mean in saying " Understand what is mean when kinetics rather than thermodynamics is controlling a reaction."
by StudentD2B
Thu Mar 14, 2019 11:06 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: given Ecell
Replies: 2
Views: 81

Re: given Ecell

Eº cell is the standard state cell potential, which means that the value was determined under standard states which include a concentration of 1 Molar (mole per liter) and an atmospheric pressure of 1. E cell is the non-standard state cell potential, which means that it is not determined under a con...
by StudentD2B
Thu Mar 14, 2019 10:56 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: k’ and A
Replies: 4
Views: 83

Re: k’ and A

technically k' is the rate of the reverse reaction. k is the rate of the forward reaction. K is the equilibrium constant. K=k/k'
by StudentD2B
Thu Mar 14, 2019 10:40 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: When to use quadratic equation
Replies: 2
Views: 182

Re: When to use quadratic equation

What exactly are you talking about? You can make an the approximation for x when the equilibrium constant is sufficiently small (10^-5) and with the 5% approximation
by StudentD2B
Thu Mar 14, 2019 10:36 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Porous Wall
Replies: 3
Views: 65

Re: Porous Wall

a concentration cell is a limited form of a galvanic cell that has two equivalent half-cells of the same composition differing only in concentrations. He might have been talking about concentration cell corrosion which occurs when two or more areas of a metal surface are in contact with different co...
by StudentD2B
Thu Mar 14, 2019 10:30 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: C in a diatomic molecule
Replies: 3
Views: 198

Re: C in a diatomic molecule

Cp is the amount of heat required to raise the temperature of a substance of 1Kg mass by one degree celsius at constant pressure . Cv is the amount of heat required to raise the temperature of a substance of 1Kg mass by one degree celsius at constant volume . So use Cp when there is constant pressur...
by StudentD2B
Thu Mar 14, 2019 10:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard cell potential and equilibrium
Replies: 3
Views: 62

Re: Standard cell potential and equilibrium

For a general reaction of the type aA + bB → cC + dD, the standard free-energy change and the equilibrium constant are related by the following equation: ΔG° = −RT lnK. Given the relationship between the standard free-energy change and the standard cell potential: ΔG° = −nFE°cell, we can write: −nFE...
by StudentD2B
Tue Mar 12, 2019 8:09 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: pre-equilibrium question
Replies: 2
Views: 66

Re: pre-equilibrium question

Find K for the first fast step, If the fast step is after the slow step, (ie. fast, slow, fast) you can ignore the second fast step completely because steps that follow the rate determining step take place as soon as the intermediate has been formed and have a negligible effect on the overall rate
by StudentD2B
Tue Mar 12, 2019 8:03 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: instantaneous and unique rate
Replies: 6
Views: 252

Re: instantaneous and unique rate

There are 4 different things you're looking at here:(1) Average Rate of Reaction, (2) Unique Average Rate of Reaction, (3) Instantaneous Rate of Reaction, (4) and Unique Instantaneous Rate of Reaction Average Rate of Reaction : The reaction rate calculated by measuring the change in concentration of...
by StudentD2B
Tue Mar 12, 2019 12:35 pm
Forum: Second Order Reactions
Topic: amounts of reactant and its affect on rate
Replies: 6
Views: 97

Re: amounts of reactant and its affect on rate

Yes! exactly.
Zeroth order - Rate =k
First Order - Rate =k[A]
Second Oder - Rate =k[A]^2
by StudentD2B
Tue Mar 12, 2019 12:31 pm
Forum: General Rate Laws
Topic: stoichiometric coeffecients
Replies: 1
Views: 51

Re: stoichiometric coeffecients

In a way they matter for elementary reactions in that the formula of a species appears as many times as that species is required (ie: O2+O2+O2 = 3O2) Since elementary reactions match their chemical expression, if a reaction is elementary, the order of a reagent will match its stoichiometric coeffici...
by StudentD2B
Sun Mar 10, 2019 11:26 pm
Forum: General Rate Laws
Topic: Integrated Rate Laws
Replies: 1
Views: 31

Integrated Rate Laws

Are we going to need to know how to get an integrated rate law from a normal rate law on the final?
by StudentD2B
Sun Dec 09, 2018 12:42 am
Forum: Balancing Chemical Reactions
Topic: How To....
Replies: 16
Views: 687

Book interpretations

In the 7th edition Focus 6C.3-4, when they reference HA, H-A, and A, what does the "A" stand for. Is it any acid or any acidic oxide or what?
by StudentD2B
Sun Dec 09, 2018 12:29 am
Forum: Balancing Chemical Reactions
Topic: How To....
Replies: 16
Views: 687

Re: How To....

Also are we responsible for table 6C.4 "Contributions to the Enthalpy of Proton Transfer of Binary Acids*"
by StudentD2B
Sun Dec 09, 2018 12:22 am
Forum: Balancing Chemical Reactions
Topic: How To....
Replies: 16
Views: 687

Entropy and Enthalpy

How much are we going to have to know about entropy and enthalpy and Gibbs Free Energy for the final. It is mentioned quite a few times in the sections in the book (7th edition Focus 6B.1 and 6C.3 - 6C.4) There are also a bunch of equations we didn't cover in class, do we need to know how to use tho...
by StudentD2B
Thu Nov 29, 2018 1:13 am
Forum: Dipole Moments
Topic: Dipole Dipole Interactions
Replies: 1
Views: 64

Dipole Dipole Interactions

How do you determine if a molecule has dipole dipole interactions? I know all atoms have London Dispersion, but I struggle with how exactly to know about dipole dipole
by StudentD2B
Sat Nov 24, 2018 12:00 am
Forum: Dipole Moments
Topic: dipole
Replies: 6
Views: 177

Re: dipole

Dipole moments can exist where polarity does not if they cancel each other out due to molecular geometry in a polyatomic molecule. For example CO2. The oxygen is more electronegative, but the C-O bonds are Both linear so they cancel each other out. If you have version 7 of the textbook there is a ch...
by StudentD2B
Fri Nov 23, 2018 11:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 3
Replies: 10
Views: 248

Re: Test 3

All of outline 4 and the end of outline three, but I would brush up on all of outline three just to be safe
by StudentD2B
Fri Nov 23, 2018 11:55 pm
Forum: Electronegativity
Topic: Nonmetals?
Replies: 1
Views: 73

Re: Nonmetals?

Yes nonmetals are more electronegative than metals and this does have to do with their placement on the periodic table in that electronegativity increases up a group and left to right across a period. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. E...
by StudentD2B
Fri Nov 23, 2018 11:49 pm
Forum: Hybridization
Topic: Hybridization of large molecules
Replies: 2
Views: 55

Re: Hybridization of large molecules

When there is more than one central atom in a molecule the hybridization of each central atom is matched to the shape at that atom predicted by VSEPR
by StudentD2B
Fri Nov 23, 2018 11:47 pm
Forum: Electronegativity
Topic: Largest Electronegativity
Replies: 4
Views: 116

Re: Largest Electronegativity

Flourine because electronegativity increases up and to the right
by StudentD2B
Fri Nov 23, 2018 11:45 pm
Forum: Hybridization
Topic: double bonds
Replies: 14
Views: 227

Re: double bonds

Not exactly. A pi bond has two electrons that lie on two lobes, one on each side of the internuclear axis, but is still only one bond. P-orbitals in a pi bond overlap in a side by side fashion. A sigma bond results from end-to end overlap (consequently because of this a sigma bond is stronger than a...
by StudentD2B
Fri Nov 23, 2018 11:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Does formal charge apply to the VSEPR Model?
Replies: 6
Views: 117

Re: Does formal charge apply to the VSEPR Model?

Part of creating a Lewis Structure is finding the structure with the lowest formal charge so I would say that yes it is fairly important to use the correct Lewis structure since the Lewis structure will affect the outcome of the VSEPR
by StudentD2B
Fri Nov 23, 2018 11:35 pm
Forum: Hybridization
Topic: Hybridization Labeling
Replies: 5
Views: 113

Re: Hybridization Labeling

As for the lone pairs on the oxygen I believe that the "Osp2" denotation is saying that the lone pairs on the oxygen are in one of the hybridized sp2 orbital. There are three: h_{1}=s + 2^{\frac{1}{2}}p_{y} h_{2}= s+(\frac{3}{2})^{\frac{1}{2}}p_{x}-(\frac{1}{2})^{\frac{1}{2...
by StudentD2B
Fri Nov 23, 2018 11:26 pm
Forum: Hybridization
Topic: Hybridization Labeling
Replies: 5
Views: 113

Re: Hybridization Labeling

I believe the labeling is specifying the different types of hybridized orbitals that are participating in the bond. (sp, sp2, sp3, sp3d, or sp3d2). For example on the top right double bond between oxygen and carbon its saying that the sigma bond is between the hybridized sp2 orbital of the carbon an...
by StudentD2B
Fri Nov 23, 2018 11:19 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 5
Views: 615

Re: Polarity

Since water is polar, it has both negative and positive regions in the molecule, the reason this is good for dissolving ionic compounds is that the water molecule and the ionic compound attract each other and thus it dissolves in water, while nonpolar molecules repel away from water and don't disso...
by StudentD2B
Fri Nov 23, 2018 11:17 pm
Forum: Dipole Moments
Topic: Nodal Planes
Replies: 2
Views: 85

Re: Nodal Planes

Nodal planes are areas where there is no possibility of electron density. In other words, it will be impossible to find electrons in nodal planes. Essentially for this class, I believe that all you need to know is that the p orbital has 1 nodal plane and the d orbital has 2 nodal planes. When I was...
by StudentD2B
Fri Nov 23, 2018 11:11 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 9
Views: 149

Re: Polarity

The molecule is linear, but since nitrogen is the least electronegative, it is the central atom. So the molecules are lined up N-N-O. Oxygen is much more electronegative than nitrogen making the molecule negatively charged on the oxygen side and therefore polar. Why is it lined up that way though. ...
by StudentD2B
Fri Nov 23, 2018 11:09 pm
Forum: Dipole Moments
Topic: Chemistry Community
Replies: 5
Views: 99

Re: Chemistry Community

Thank you!!!!
by StudentD2B
Thu Nov 22, 2018 11:33 pm
Forum: Dipole Moments
Topic: Nodal Planes
Replies: 2
Views: 85

Nodal Planes

Could someone clarify what exactly a nodal plane is, how to find them, and what they cause? Im a little confused on the whole subject.
by StudentD2B
Thu Nov 22, 2018 10:09 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 9
Views: 149

Polarity

Why is N20 Polar? If its a linear molecule with 2 nitrogens and 1 oxygen, shouldn't it be non-polar?
by StudentD2B
Thu Nov 22, 2018 10:01 pm
Forum: Dipole Moments
Topic: Chemistry Community
Replies: 5
Views: 99

Chemistry Community

Also to add onto the question i just posted, do my responses to other students questions count toward the total responses or is it only questions i post myself?
by StudentD2B
Thu Nov 22, 2018 10:00 pm
Forum: Dipole Moments
Topic: Chemistry Community
Replies: 2
Views: 67

Chemistry Community

How do i tell how many posts I've made on here
by StudentD2B
Thu Nov 22, 2018 9:52 pm
Forum: Dipole Moments
Topic: Bond Angles
Replies: 8
Views: 178

Bond Angles

Does anyne have like a tip or trick to remember all the specific bond angles or is repetition my best bet?
by StudentD2B
Thu Nov 22, 2018 9:51 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 5
Views: 615

Polarity

Why does the polarity of water part of the reason why it is a good solvent for ionic compounds? More generally, what role does polarity have in things dissolving?
by StudentD2B
Fri Nov 16, 2018 3:58 am
Forum: Dipole Moments
Topic: Induced-dipole
Replies: 5
Views: 157

Re: Induced-dipole

How do you know if a dipole is permanent or not. For example in the case of c5h12 from page 190 of the 7th version of the text book. (in the margins of the actual text, not a question)
by StudentD2B
Mon Nov 05, 2018 2:01 am
Forum: Administrative Questions and Class Announcements
Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Replies: 121
Views: 5517

Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]

Could someone explain why for 13D (I looked this up on the internet) the atoms have different electron configurations? I know that the electron configurations are: Neutral SC Atom: 1s2 2s2 2p6 3s2 3p6 3d1 4s2 SC2+ Ion: 1s2 2s2 2p6 3s2 3p6 3d1 Neutral K atom: 1s2 2s2 2p6 3s2 3p6 4s1 But could someone...
by StudentD2B
Mon Nov 05, 2018 12:50 am
Forum: Administrative Questions and Class Announcements
Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Replies: 121
Views: 5517

Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]

Clearly I needed to look at this earlier than I did..

For 11b, would you subtract to n=3 from the n=1 or the n=1 from the n=3
by StudentD2B
Mon Nov 05, 2018 12:23 am
Forum: Administrative Questions and Class Announcements
Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Replies: 121
Views: 5517

Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]

Jk final frequency I get 3.77 * 10^14. Why is this off
by StudentD2B
Mon Nov 05, 2018 12:19 am
Forum: Administrative Questions and Class Announcements
Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Replies: 121
Views: 5517

Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]

Could someone explain 8b to me. Please tell me where I went wrong here. I found:
wavelength: 1.10 * 10^-9m
P=7.29 * 10^-43
V=8.00 * 10^-13
Work Function= 2.50 * 10^-19 J/atom
Kinetic Energy= 7.00 * 10^-55
Final Frequency= 5.94 * 10^-10
by StudentD2B
Sun Nov 04, 2018 10:46 pm
Forum: Administrative Questions and Class Announcements
Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Replies: 121
Views: 5517

Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]

Lina Petrossian 3D wrote:How do you go about solving the first problem?


https://wps.prenhall.com/wps/media/obje ... h0305.html

See for exact solution
by StudentD2B
Sun Nov 04, 2018 10:39 pm
Forum: Administrative Questions and Class Announcements
Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Replies: 121
Views: 5517

Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]

I tried the first problem and got it very very wrong. How would I solve it correctly?
by StudentD2B
Sun Oct 21, 2018 8:13 pm
Forum: Properties of Electrons
Topic: Calculate energy required to remove an electron
Replies: 6
Views: 2105

Re: Calculate energy required to remove an electron

Why do you multiply by 10^5?

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