Search found 28 matches

by Alexis Elliott 1J
Wed Mar 15, 2017 11:58 pm
Forum: *Alcohols
Topic: Final 2015 - 9B
Replies: 2
Views: 823

Final 2015 - 9B

For the problem with the cycloheptane, why is the propane the base molecule? The heptane has a longer carbon chain so I don't quite understand why it is named that way.
by Alexis Elliott 1J
Tue Mar 14, 2017 11:10 pm
Forum: *Alkanes
Topic: Naming Practice
Replies: 7
Views: 1901

Re: Naming Practice

I am a bit confused as to where the methyl groups came from. When I named this molecule I got 4-cyclopropyldec-2-yne. I tried to go back and figure out where the methyl groups are, but I can't seem to figure it out.

Thank you!

Alexis
by Alexis Elliott 1J
Tue Mar 14, 2017 12:05 am
Forum: *Haloalkanes
Topic: Practice Problem Sets [ENDORSED]
Replies: 1
Views: 728

Practice Problem Sets [ENDORSED]

I am a bit confused as if we have to know how to name molecules with more than one double bond (or more than one triple bond). Dr. Lavelle did not go over this in class but on many of the practice work sheets that have been posted, there have been a decent amount of problems that require use to know...
by Alexis Elliott 1J
Mon Mar 13, 2017 10:47 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Final 2013 4B
Replies: 1
Views: 317

Final 2013 4B

I am really lost on how to even approach this problem. Should I be viewing this as an electrochemical problem or as a problem from chemical kinetics?

Also, I don't understand how you get Q=1/[Q2] and why the deltaQ is added.

Honestly any hint with this problem would be so helpful!

Thank you!
by Alexis Elliott 1J
Mon Mar 13, 2017 10:41 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Final 2014 - Q2B,a
Replies: 1
Views: 324

Final 2014 - Q2B,a

This question seems very similar to question we had on our midterm, I guess I am still just a bit confused as to why there is a change in entropy, when everything else (U,w,q,H) would be zero. Since there is no change in temperature, volume and pressure, would the entropy still be 0? Or is it not 0 ...
by Alexis Elliott 1J
Mon Mar 13, 2017 10:30 pm
Forum: Balancing Redox Reactions
Topic: Final Exam 2014 - Q3A
Replies: 2
Views: 393

Final Exam 2014 - Q3A

For this question we have to choose from a list of elements that we should use for a galvanic cell. I am confused as to how we would choose the correct elements and why 5 were chosen. I would think that max you would need 3.

Thank you!
by Alexis Elliott 1J
Mon Mar 06, 2017 12:14 am
Forum: Administrative Questions and Class Announcements
Topic: Quiz 3 Winter 2017
Replies: 183
Views: 19983

Re: Quiz 3 Winter 2017

Can someone help me with #3 I don't understand how both of them are nucleophiles? Are you referring to #6? Nucleophiles are species rich in electrons. For the benzene ring, this electron richness comes from its double bonds. For CH_{3}OCH_{3} the oxygen in the center of the compound can only be att...
by Alexis Elliott 1J
Thu Mar 02, 2017 10:51 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Graphs of Gibbs Free Energy vs. Energy
Replies: 2
Views: 401

Graphs of Gibbs Free Energy vs. Energy

Looking through the course reader, the graphs that depict Gibbs Free Energy vs. Reaction time and graphs that depict Energy vs. reaction time look the same. G and E are obviously not interchangeable but in what cases would we be given a graph with Gibbs Free Energy, and in what cases would we be giv...
by Alexis Elliott 1J
Wed Feb 22, 2017 3:33 pm
Forum: General Rate Laws
Topic: Half Life Equation graph
Replies: 1
Views: 265

Half Life Equation graph

I am still a bit confused as to how the half life equation for a first order reaction gives us a curved line but the integrated rate equation gives us a straight line. I do not quite understand how that can work seeing as Dr. Lavelle pointed out one of the defining characteristics of the first order...
by Alexis Elliott 1J
Sun Feb 12, 2017 10:32 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Ssurroudnings vs Ssystem
Replies: 1
Views: 273

Ssurroudnings vs Ssystem

I am a bit confused about when to use the equation deltaH/T. Sometimes there is also a negative sign included and I was also wondering when we are supposed to add in that negative sign. What can't we use the equation qrev/T?

Thank you!
by Alexis Elliott 1J
Mon Feb 06, 2017 11:05 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Homework Problem 14.9
Replies: 1
Views: 254

Homework Problem 14.9

For this problem I understand why we have to use the equation dG = -nFE. However I am confused as to how the solutions manual gets 2 for n. I know n is the number of moles of electrons but I cannot figure out how to get 2 moles to plug into the equation.

Thanks!
by Alexis Elliott 1J
Mon Jan 30, 2017 11:37 pm
Forum: Calculating Work of Expansion
Topic: Entropy - Reversible vs Irreversible
Replies: 3
Views: 542

Re: Entropy - Reversible vs Irreversible

Thank you!!

The only other question I have is why isn't there an entropy change in reversible reactions?
by Alexis Elliott 1J
Mon Jan 30, 2017 11:36 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Molar Heat Capacity vs Molar Entropy
Replies: 1
Views: 470

Molar Heat Capacity vs Molar Entropy

I am confused as to when we use Molar Heat Capacity versus Molar Entropy because they both have the same units (J/K.mol). In problem 9.43 we have to used the molar heat capacity but since the units will cancel out to be the same even if we use molar entropy, how do we know not to use the molar entro...
by Alexis Elliott 1J
Sun Jan 29, 2017 4:24 pm
Forum: Calculating Work of Expansion
Topic: Entropy - Reversible vs Irreversible
Replies: 3
Views: 542

Entropy - Reversible vs Irreversible

During lecture I understood that if we want to calculate the enthalpy and the change is irreversible we use w=-P(V2-V1), and if it is irreversible we use w=-nRTln(V2/V1). My question is regarding entropy. Is there a different set of equations we should use based on whether the reaction is reversible...
by Alexis Elliott 1J
Thu Jan 26, 2017 2:16 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: W versus S
Replies: 2
Views: 378

W versus S

I am bit confused on the conceptual difference between the W and the S. I understand that S is a function of S, but I don't understand how they are different in terms of what they represent.

Thanks!!
by Alexis Elliott 1J
Thu Jan 26, 2017 2:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Finals from 14A
Replies: 1
Views: 311

Finals from 14A

I was wondering in what room we can get our finals from last quarter? I remember something about them being available this week, I was just forgot where we are supposed to pick them up.

Thanks!
by Alexis Elliott 1J
Sat Jan 14, 2017 4:45 pm
Forum: Administrative Questions and Class Announcements
Topic: How to change our username
Replies: 1
Views: 294

How to change our username

I was under the impression that instead of creating a new account for 14B, we could continue with our account from 14A. However, I am having trouble figuring out how to change my username to match my current discussion session. If anyone knows how to do this, advice would be much appreciated!! Thank...
by Alexis Elliott 1J
Sat Dec 03, 2016 8:10 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Problem with 2C on 2014 Final
Replies: 1
Views: 359

Problem with 2C on 2014 Final

I was wondering why the electron configuration for Br- is [Ar] 3d10, 4s2, 4p6 and not just [Kr]. I thought that since Br- and Kr are isoelectonic we could write them as having the same configurations.
by Alexis Elliott 1J
Sat Dec 03, 2016 2:18 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: When to use H-H equation
Replies: 1
Views: 941

When to use H-H equation

How do we know when to use the Henderson-Hasselback Equation? Is it for any time when the concentration of the acid equals the concentration of its conjugate base?

Also, can we use this equation in titrations or only for buffers?
by Alexis Elliott 1J
Sun Nov 27, 2016 9:30 pm
Forum: Identifying Acidic & Basic Salts
Topic: Identifying a salt
Replies: 4
Views: 797

Identifying a salt

I was wondering what exactly qualifies as a salt. I am confused because so many things are referred to as a salt and I am not quite sure what they all have in common.

Thanks!
by Alexis Elliott 1J
Mon Nov 14, 2016 7:34 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Numbers [ENDORSED]
Replies: 4
Views: 666

Coordination Numbers [ENDORSED]

So coordination numbers are the number of places a ligand can mind to a metal cation I think. Dr. Lavelle said in lecture that ethylenediamine can bind in 2 places and diethylenetriammine can bind in 3. However, I am having difficulty figuring out how many places nitrito, carbonato, oxalate,sulfato ...
by Alexis Elliott 1J
Sun Nov 13, 2016 9:30 am
Forum: Naming
Topic: Naming Vanadium
Replies: 1
Views: 459

Naming Vanadium

I am a bit confused on how to convert the name Vanadium into the "ate" for because it has a negative charge. Would it be "Vanadiumate"? This really doesn't sound right to me. But I can't think of many more options besides "Vanadate" and that doesn't sound right either. ...
by Alexis Elliott 1J
Sun Nov 13, 2016 9:25 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Prep for Quiz 3
Replies: 1
Views: 289

Prep for Quiz 3

There are quite a lot of notes not gone over in lecture, but in the course reader (i.e. the information about how Pressure and Temperature and Volume are related). I was wondering if we need to memorize all of those equations or if that was just extra information in the course reader?

Thanks!
by Alexis Elliott 1J
Sun Nov 13, 2016 9:22 am
Forum: Ideal Gases
Topic: Concept of Ideal Gas
Replies: 1
Views: 351

Concept of Ideal Gas

I am just a bit confused on the actual concept of what an Ideal Gas is. Does an ideal gas have no friction at all? Or is it simply something we use in theory but that is not actually in the real world?

Thank you!
by Alexis Elliott 1J
Thu Oct 27, 2016 8:38 pm
Forum: Sigma & Pi Bonds
Topic: Sigma and Pi bonds vs Covalent [ENDORSED]
Replies: 1
Views: 340

Sigma and Pi bonds vs Covalent [ENDORSED]

I am just a bit confused about the difference between Sigma and Pi bonds and Covalent bonds. Are Sigma and Pi bonds just types of covalent bonds or are they different? If they are different, how so?

Thank you!
by Alexis Elliott 1J
Sun Oct 23, 2016 8:16 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Lewis Structures and Formal Charge
Replies: 7
Views: 862

Lewis Structures and Formal Charge

Hi guys, I was wondering if for every Lewis Structure we draw if we have to calculate the formal charge to figure out how many bonds to put in. Do you always have to calculate the formal charge to see if your number of bonds is correct? Or if you have the right number of electrons in your structure ...
by Alexis Elliott 1J
Tue Oct 04, 2016 11:54 am
Forum: Properties of Electrons
Topic: Difficulty with Problem 1.55 [ENDORSED]
Replies: 1
Views: 327

Difficulty with Problem 1.55 [ENDORSED]

For problem 1.55, the wavelength given is in cm^-1. When I attempted to solve this problem I converted the cm to m, but when I checked the solutions manual, the meters where converted to cm, and I got a completely different answer. I am wondering why the meters in this case where converted to cm and...
by Alexis Elliott 1J
Wed Sep 28, 2016 9:05 pm
Forum: Properties of Light
Topic: Unique Frequencies with atoms/molecules
Replies: 3
Views: 543

Unique Frequencies with atoms/molecules

Can someone please review why each atom/ molecule can have a unique frequency? I do not quite understand how an atom or a group of atoms can emit light or why each atom emits a different frequency of light.
Thank you!

Go to advanced search