Search found 49 matches

by Rachel Wile 2D
Mon Mar 20, 2017 11:35 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14C
Replies: 3
Views: 592

Re: Chem 14C

Do you know if the Organic Chemistry Course Reader we got for Chem 14B can be used for Chem 14C? Like, are there topics in our current Organics Course Reader that are covered in chem 14C? We will be learning a lot of new topics in Chem 14C, which is why we have new materials. You could use the cour...
by Rachel Wile 2D
Sat Mar 18, 2017 5:16 am
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 209
Views: 101134

Re: Saying Thank You to Dr. Lavelle

Dr. Lavelle, I truly appreciate how you went above and beyond to provide all your students so many resources to help us succeed in the course. Whether it was taking the time to make a course reader or setting up countless hours of office hours and peer learning sessions, you have made an outstanding...
by Rachel Wile 2D
Fri Mar 17, 2017 2:26 pm
Forum: General Science Questions
Topic: Final
Replies: 9
Views: 1380

Re: Final

Do we know any of the subjects that will not be covered on the exam? Because it would be much easier to study if we knew what to focus on & the things we won't need. I would go over everything that he has talked about in class and is in the course reader. Anything that has been assigned or disc...
by Rachel Wile 2D
Tue Mar 14, 2017 6:59 pm
Forum: Administrative Questions and Class Announcements
Topic: Final content
Replies: 4
Views: 538

Re: Final content

Anything Dr. Lavelle has gone over in class is fair game for the final, so whatever proofs he has discussed or covered in class could be on the final.
by Rachel Wile 2D
Sun Mar 12, 2017 8:47 pm
Forum: *Chem3D
Topic: Shape of Organic Molecules
Replies: 2
Views: 557

Re: Shape of Organic Molecules

The stable conformation will not always be what happens in nature because of thermal collisions. As we increase the temperature, you will see the equilibrium constant between the a less stable conformation (gauche) and the most stable conformation (anti) will decrease, meaning that as the temperatur...
by Rachel Wile 2D
Thu Mar 09, 2017 8:30 pm
Forum: Student Social/Study Group
Topic: Book
Replies: 2
Views: 404

Re: Book

No, it is different.
by Rachel Wile 2D
Thu Mar 09, 2017 6:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 3
Replies: 2
Views: 306

Re: Quiz 3

Quiz 3 covers from page 74 to page 96 in the course reader.
by Rachel Wile 2D
Wed Mar 08, 2017 6:01 am
Forum: *Nucleophilic Substitution
Topic: Reaction profile for SN2 reaction
Replies: 2
Views: 864

Re: Reaction profile for SN2 reaction

They would have to specify, but exergonic is much more common than endergonic so if they do not I would draw it the exergonic way.
by Rachel Wile 2D
Wed Mar 08, 2017 5:58 am
Forum: General Science Questions
Topic: Types of energy profiles
Replies: 5
Views: 712

Re: Types of energy profiles

I believe we look at the delta G of the transition states relative to the reactants, even for the second step. However, when you are calculating activation energy of the second step you look at the the transition state relative to the intermediates. My TA said that some chemists look at delta G of t...
by Rachel Wile 2D
Fri Mar 03, 2017 11:27 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 3 Prep answers
Replies: 6
Views: 687

Re: Quiz 3 Prep answers

I'm sure he will post the answers within the next couple days, so that we have a couple days to look over the solutions before the quiz.
by Rachel Wile 2D
Fri Mar 03, 2017 6:53 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Steady State vs. Pre-Equilibrium Approach
Replies: 2
Views: 582

Re: Steady State vs. Pre-Equilibrium Approach

When the methods are done correctly, you will get the same answer with either method. Lavelle said that we are not tested on the steady-state approximation, we use the pre-equilibrium method in this class. In the pre-equilibrium method, we assume that the reactants and intermediates are in equilibri...
by Rachel Wile 2D
Wed Mar 01, 2017 6:14 am
Forum: Administrative Questions and Class Announcements
Topic: Quiz #3
Replies: 6
Views: 645

Re: Quiz #3

I believe so. Lavelle will likely make an announcement on Friday about Quiz 3 and all the topics it will cover as he normally does before an upcoming quiz.
by Rachel Wile 2D
Fri Feb 24, 2017 8:42 pm
Forum: Administrative Questions and Class Announcements
Topic: 14CL
Replies: 6
Views: 831

Re: 14CL

I believe Chem 14C and Chem 14Cl can be taken together. It is up to your own personal preference.
by Rachel Wile 2D
Wed Feb 22, 2017 6:56 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Winter 2017
Replies: 87
Views: 14432

Re: Midterm Winter 2017

I believe the average was a 74% on the Midterm.
by Rachel Wile 2D
Mon Feb 20, 2017 11:18 pm
Forum: General Rate Laws
Topic: Units of K
Replies: 4
Views: 1879

Re: Units of K

For a zero order, the units of k are M/s, or mol*L^-1*s^-1. For first order, the units are 1/s or s^-1. For second order, the units are 1/M*s or L*mol^-1*s^-1. You will notice that there is a pattern here. Every time the order is increase by one we divide by M or mols/L. So therefore, for a third or...
by Rachel Wile 2D
Fri Feb 17, 2017 6:51 am
Forum: Balancing Redox Reactions
Topic: Balancing (Acidic vs. Basic Balancing)
Replies: 3
Views: 427

Re: Balancing (Acidic vs. Basic Balancing)

The problem should always specify whether the reaction should be balanced in acidic or basic solution.
by Rachel Wile 2D
Thu Feb 16, 2017 10:41 pm
Forum: Student Social/Study Group
Topic: Peer Learning Sessions
Replies: 2
Views: 364

Re: Peer Learning Sessions

Lavelle has a list of all the office hours and the peer learning sessions on the Chem 14B website. The peer learning sessions are very helpful. I definitely recommend going to one if you can!
by Rachel Wile 2D
Mon Feb 13, 2017 9:35 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat Capacity
Replies: 2
Views: 321

Re: Specific Heat Capacity

For this problem, you would be given the heat capacity for Cu, it is in the Appendix of the textbook.
by Rachel Wile 2D
Fri Feb 10, 2017 2:38 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G vs Delta G0
Replies: 5
Views: 1642

Re: Delta G vs Delta G0

You would just solve using the first equation. To solve the second equation, you would need the reaction quotient Q.
by Rachel Wile 2D
Mon Feb 06, 2017 7:26 am
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Results
Replies: 2
Views: 396

Re: Quiz 1 Results

The quizzes are usually returned by your TA in your discussion section a week after the quiz. So, you will likely get your quiz back in this week's discussion section.
by Rachel Wile 2D
Thu Feb 02, 2017 5:51 am
Forum: Administrative Questions and Class Announcements
Topic: Fall 2016 Finals Still Available?
Replies: 5
Views: 688

Re: Fall 2016 Finals Still Available?

Won't the finals be available until Week 10 of the quarter?
by Rachel Wile 2D
Tue Jan 31, 2017 6:49 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Quiz 1 Preparation #5
Replies: 1
Views: 302

Re: Quiz 1 Preparation #5

You are trying to create the reaction that the problem is asking for. So, you have to flip and multiply some of the equations and therefore, their corresponding enthalpies in order to get the enthalpy for the equation the problem is asking for when you add all of the equations and enthalpies up. Hes...
by Rachel Wile 2D
Fri Jan 27, 2017 12:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz Topics
Replies: 10
Views: 1101

Re: Quiz Topics

I do not believe they will be posting answers for the practice quiz in the course reader in order to encourage students to work together and attend peer learning sessions or office hours, so they can figure out the correct answers.
by Rachel Wile 2D
Mon Jan 23, 2017 9:04 am
Forum: Student Social/Study Group
Topic: Quiz 1 Prep
Replies: 8
Views: 765

Re: Quiz 1 Prep

I'm interested as well. Please let me know what day and time you all are planning on meeting up!
by Rachel Wile 2D
Thu Jan 19, 2017 6:18 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated Systems [ENDORSED]
Replies: 2
Views: 380

Re: Isolated Systems [ENDORSED]

Another example of an isolated system could be an very well insulated container, such as a thermos. An isolated system is anything that cannot exchange heat or mass with its surroundings.
by Rachel Wile 2D
Tue Jan 17, 2017 3:32 am
Forum: Phase Changes & Related Calculations
Topic: Boiling Points at Altitude [ENDORSED]
Replies: 2
Views: 339

Re: Boiling Points at Altitude [ENDORSED]

Pressure drops as you gain elevation. Therefore, less heat is required to make the vapor pressure equal to the atmospheric pressure. So, the boiling point is lower at higher altitude. For example, water boils at a lower temperature in Denver than it may in Los Angeles.
by Rachel Wile 2D
Sat Jan 14, 2017 8:10 am
Forum: General Science Questions
Topic: Intro to Organic Chemistry
Replies: 9
Views: 1073

Re: Intro to Organic Chemistry

I believe we will be using it later in the quarter when we begin learning about Organic Chemistry. It is a replacement for the organic chemistry textbook, but it is not a replacement for the actual textbook that we need to have for the rest of the class.
by Rachel Wile 2D
Wed Jan 11, 2017 9:11 am
Forum: Administrative Questions and Class Announcements
Topic: Random Enrollment Checks
Replies: 9
Views: 1252

Re: Random Enrollment Checks

Yes, I also believe the enrollment checks are just to ensure that there are not people from other lectures attending a different lecture and taking up seats. I do not think you could be penalized for not coming to class because the class does not give points for attendance, as it is more of an expec...
by Rachel Wile 2D
Tue Jan 10, 2017 11:40 am
Forum: Student Social/Study Group
Topic: chem 14B workbook
Replies: 7
Views: 820

Re: chem 14B workbook

Yes, the only books I got from the course reader store was the actual course reader and the introduction to organic chemistry booklet.
by Rachel Wile 2D
Fri Dec 02, 2016 4:33 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Difference between pka and Ka
Replies: 1
Views: 248

Re: Difference between pka and Ka

pKa is the -log(Ka). The smaller the value of Ka, the larger the value of pKa. The larger the value of pKa, the weaker the acid.
by Rachel Wile 2D
Wed Nov 30, 2016 7:29 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: finding final pH
Replies: 2
Views: 411

Re: finding final pH

We do this because pOH+pH=14. So, if the the question is asking us to find the pH and we have found the pOH we can just subtract the number we have found (pOH) from 14 in order to find pH.
by Rachel Wile 2D
Wed Nov 23, 2016 7:48 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: d-block electron configurations
Replies: 2
Views: 549

Re: d-block electron configurations

You only need to memorize the elements that have 4 or 9 valence electrons in the d-orbital. Since they are one away from a half-filled or filled shell, they will take 1 away from the 4s shell because it is lower energy to have a half-filled or filled d-orbital. The other d-block elements have a &quo...
by Rachel Wile 2D
Tue Nov 22, 2016 10:16 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Higher/lower energy in a MO diagram?
Replies: 4
Views: 608

Re: Higher/lower energy in a MO diagram?

I believe the amount of distance you draw between them is due to the difference is electronegativity. So if one of the atoms is much less electronegative, it will be much higher than the one that is much more electronegative. On the other hand, if the difference in electronegativity between the two ...
by Rachel Wile 2D
Sat Nov 19, 2016 9:46 am
Forum: Sigma & Pi Bonds
Topic: Bond Strength [ENDORSED]
Replies: 2
Views: 960

Re: Bond Strength [ENDORSED]

It isn't saying that a double bond is weaker than a single bond, because it is not. Think of it like the pi bond within the double is weaker than the sigma bond. You are not looking at a pi bond + a sigma bond (a double bond) vs. just a sigma bond (single bond). I hope that is more clear.
by Rachel Wile 2D
Wed Nov 16, 2016 9:57 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Heteronuclear Diatomic Molecules: Electronegativity
Replies: 1
Views: 255

Re: Heteronuclear Diatomic Molecules: Electronegativity

I believe this is due to lone pairs of electrons being more stable on more electronegative elements leading them to be lower in energy.
by Rachel Wile 2D
Fri Nov 11, 2016 10:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14B and 14BL [ENDORSED]
Replies: 11
Views: 2935

Re: Chem 14B and 14BL [ENDORSED]

I'm planning on taking Chem 14B next quarter and then taking 14BL the next quarter after that. Would you recommend doing this or waiting until the end of the 14 series to take the labs?
by Rachel Wile 2D
Thu Nov 10, 2016 5:40 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: HOMO to LUMO Concept
Replies: 3
Views: 443

Re: HOMO to LUMO Concept

When you draw your molecular orbital diagram, your lowest molecular orbital that has no electrons in it is the LUMO. Your highest molecular orbital that is occupied by electrons is your HOMO. The HOMO and LUMO orbitals are the most important orbitals for reactivity.
by Rachel Wile 2D
Thu Nov 03, 2016 9:17 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration for Fe 3+
Replies: 6
Views: 32662

Re: Electron Configuration for Fe 3+

You take electrons out of the 4s orbital, before you take them out of the 3d orbital, because it is lower energy to have them in the 3d orbital in comparison to the 4s.
by Rachel Wile 2D
Fri Oct 28, 2016 1:30 pm
Forum: Trends in The Periodic Table
Topic: Periods 15 and 14 relationship
Replies: 2
Views: 374

Re: Periods 15 and 14 relationship

If you draw the electron configuration for each and specifically look at the 2p orbital you will see that Nitrogen has a half-filled p-shell, which is more stable than Carbon which is one away from a half filled p-shell. Carbon wants the electron more than Nitrogen to attain the stability.
by Rachel Wile 2D
Thu Oct 27, 2016 6:49 am
Forum: Formal Charge and Oxidation Numbers
Topic: How to figure out formal charge? [ENDORSED]
Replies: 6
Views: 803

Re: How to figure out formal charge? [ENDORSED]

When calculating formal charge it is easiest just to take the number of valence electrons and subtract the number of bonds (same thing as the number of bonded electrons/2) and subtract the number of lone pair electrons. The resulting number is your formal charge. Do this for each of the atoms of you...
by Rachel Wile 2D
Fri Oct 21, 2016 6:38 am
Forum: Student Social/Study Group
Topic: Hedrick Summit Study Group Chem 14A
Replies: 29
Views: 2569

Re: Hedrick Summit Study Group Chem 14A

I would like to join this study group if it is still active!
by Rachel Wile 2D
Fri Oct 21, 2016 5:57 am
Forum: Empirical & Molecular Formulas
Topic: Writing Formulas
Replies: 6
Views: 759

Re: Writing Formulas

To remember polyatomic ions, I have always used this mnemonic: Nick the Camel ate a Clam Supper in Pheonix with Ale. Nick = N for Nitrogen, the word has 3 consonants so there are 3 oxygens, and 1 vowel so a charge of -1. Therefore, Nitrate = NO3-1 Camel = C for Carbon, 3 consonants and 2 vowels, so ...
by Rachel Wile 2D
Sat Oct 15, 2016 11:07 pm
Forum: Hybridization
Topic: Memorization Tricks
Replies: 9
Views: 1548

Re: Memorization Tricks

Another good acronym is Kings Hate Dragons Because Dragons Can't Make Money for Kilo, Hecto, Deca, Base, Deci, Centi, Milli, and Micro.
by Rachel Wile 2D
Wed Oct 12, 2016 10:05 pm
Forum: Balancing Chemical Reactions
Topic: Diatomic Molecules
Replies: 4
Views: 1070

Re: Diatomic Molecules

The mnemonic device I use for diatomic molecules is HOBr FINCl (pronounced hobber finkle). It has helped me remember that the diatomic elements are Hydrogen, Oxygen, Bromine, Fluorine, Iodine, Nitrogen, and Chlorine. Diatomic elements have to be memorized, so it is a good idea to find memorization s...
by Rachel Wile 2D
Fri Oct 07, 2016 10:03 pm
Forum: Empirical & Molecular Formulas
Topic: empirical formulas [ENDORSED]
Replies: 1
Views: 325

Re: empirical formulas [ENDORSED]

The empirical formula gives you the proportions of the elements present in a compound. The empirical formula can be used to calculate the percent composition of a compound. When working out reactions of a compound, its proportions are important to know.
by Rachel Wile 2D
Wed Oct 05, 2016 12:50 pm
Forum: *Black Body Radiation
Topic: Black body [ENDORSED]
Replies: 3
Views: 621

Re: Black body [ENDORSED]

A black body is something that absorbs all of the electromagnetic radiation incident upon it. It is an idealized emitter and absorber of energy. It is good concept to know because it may help you understand how other objects absorb/emit electromagnetic radiation better.
by Rachel Wile 2D
Thu Sep 29, 2016 3:59 pm
Forum: Student Social/Study Group
Topic: Chemistry Joke
Replies: 13
Views: 1363

Re: Chemistry Joke

You would think that atoms bonding with other atoms would mean they're being friendly, but really they steal each other's electrons.
How ionic!
by Rachel Wile 2D
Wed Sep 28, 2016 10:27 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Calculations
Replies: 1
Views: 559

Re: Limiting Reactant Calculations

For this problem, I believe you can just ignore the physical conditions since they are not extreme. The only reason 1 atm and 25 degrees C are given in the problem is so the reader knows that the reaction is not put under extreme conditions, such as extremely high temperatures, which could cause H2S...

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