Search found 20 matches

by Angela To 2B
Sat Mar 18, 2017 6:39 pm
Forum: *Alcohols
Topic: difference between hydroxy and alcohol
Replies: 2
Views: 614

Re: difference between hydroxy and alcohol

I think it's that alcohols are specifically R-OH while hydroxyl groups can be other things that aren't carbon chains. For example water (H-OH)! (Or NaOH and KOH, etc.) We didn't cover this in class, but in regards to naming, we've been adding the suffix -ol to name molecules with an alcohol function...
by Angela To 2B
Wed Mar 15, 2017 2:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Details and Review Sessions Winter 2017
Replies: 114
Views: 13646

Re: Final Exam Details and Review Sessions Winter 2017

Emma Cole 3F wrote:What equations should we know how to derive for the final exam?

There will be no derivations on the final! :)
by Angela To 2B
Wed Mar 15, 2017 2:14 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Details and Review Sessions Winter 2017
Replies: 114
Views: 13646

Re: Final Exam Details and Review Sessions Winter 2017

Melanie Martinez 1K wrote:Will questions/concepts discussed here on Chemistry Community be part of the final? If so, would the topics be those with much discussion?

Yes, Dr. Lavelle said in lecture today that topics of discussion will also be covered on the final!
by Angela To 2B
Tue Feb 21, 2017 1:24 am
Forum: Administrative Questions and Class Announcements
Topic: Quiz 2 Winter 2017
Replies: 160
Views: 15318

Re: Quiz 2 Winter 2017

Madeline Fox 2B wrote:Can someone explain why question 10 is false? I thought half-lives are always the same.

I think half-lives are the same for only 1st order reactions
by Angela To 2B
Tue Feb 14, 2017 8:45 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 2013 Midterm 8B
Replies: 4
Views: 499

Re: 2013 Midterm 8B

Is there a difference between using ln vs log in the equation? Because the solutions manual and the course reader has written it both ways.
by Angela To 2B
Wed Feb 08, 2017 6:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 3
Views: 329

Re: Cell Diagrams

To add onto what Diana said, a single line also represents that the two phases are in contact with each other, whereas the double lines represent the salt bridge!
by Angela To 2B
Wed Feb 08, 2017 6:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Mistake in equations sheet?
Replies: 1
Views: 312

Re: Mistake in equations sheet?

Yes, I think Faraday's constant is supposed to be 96,485.3 C/mol! That's what my TA used during my discussion. (Although she left off the 0.3 at the end, but I'm sure the answers are close enough)
by Angela To 2B
Tue Jan 31, 2017 4:14 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Quiz 1 Preparation
Replies: 1
Views: 320

Re: Quiz 1 Preparation

It's your R value! It should be 8.206 * 10^-2 L*atm/mol*K
by Angela To 2B
Tue Jan 31, 2017 4:11 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1018712

Re: Post All Chemistry Jokes Here

Q: What do chemists call a benzene ring with iron atoms replacing the carbon atoms?

A: A ferrous wheel.
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by Angela To 2B
Tue Jan 31, 2017 3:58 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Necessity for a Salt Bridge
Replies: 1
Views: 305

Re: Necessity for a Salt Bridge

The salt bridge is necessary for the anions (after reduction at the cathode) to go back to the anode. If there's no circuit then the reaction won't work!

I posted a topic with a link to a song that might help you understand!
by Angela To 2B
Tue Jan 31, 2017 3:55 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Electrochemistry - Voltaic Cells
Replies: 1
Views: 340

Electrochemistry - Voltaic Cells

Hi everyone! This isn't exactly a question or an answer, but I thought this could be helpful to some people who are confused about voltaic cells. My AP chemistry teacher in high school played this in class and my whole class was basically singing the chorus for the AP frq! :') https://www.youtube.co...
by Angela To 2B
Thu Jan 26, 2017 6:10 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Problem on pg 39
Replies: 2
Views: 245

Re: Gibbs Free Energy Problem on pg 39

In the example, you are trying to find the temperature at which the reaction is spontaneous. That's when delta G is negative. We set delta G to zero in order to find the temperature at which delta G is zero. In this case, that temperature was 333K. This means that for the reaction to be spontaneous,...
by Angela To 2B
Wed Jan 18, 2017 6:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Intensive vs. Extensive [ENDORSED]
Replies: 1
Views: 221

Re: Intensive vs. Extensive [ENDORSED]

An intensive property is one that doesn't depend on the amount of material present! (An intensive property doesn't change when you take away or add some of the material/sample). An example would be boiling point; the boiling point of water doesn't change when the amount of water changes.
by Angela To 2B
Wed Jan 18, 2017 6:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess' Law [ENDORSED]
Replies: 5
Views: 887

Re: Hess' Law [ENDORSED]

When deciding on which equation(s) to flip, I think it's easier to know if you look at the reactions you're originally given, balance them, and then compare it to the reaction you want to end up with. Then you can manipulate the reactions given to look like the final reaction! For example, question ...
by Angela To 2B
Wed Jan 18, 2017 6:01 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy
Replies: 8
Views: 797

Re: Enthalpy

The temperature should be in Kelvin because for the P(DELTA)V=(DELTA)nRT equation, the units of R is in J/mol*K !
by Angela To 2B
Wed Jan 11, 2017 10:35 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Reaction Enthalpy of O2
Replies: 2
Views: 327

Re: Standard Reaction Enthalpy of O2

To add onto that, it's because for standard enthalpy of formation, you want elements in their most stable phase. (which in a lot of cases is what form they come in). For the example of O2, if you want O2 in its most stable phase, it would just be O2. This would be O2(g) --> O2(g). Because it's not c...
by Angela To 2B
Wed Jan 11, 2017 10:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State Properties
Replies: 2
Views: 206

Re: State Properties

Enthalpy is considered a state function because it is NOT path dependent. Enthalpy is defined as delta H which is the change in H (which we can refer to as H final - H initial)! Therefore it's a state function because we care about the final and initial (since delta H is the difference in H), rather...
by Angela To 2B
Wed Jan 11, 2017 10:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Posts
Replies: 23
Views: 2586

Re: Posts

My TA said that we should be posting at least once a week for 1 point each! Both questions and answers count towards the point. :)
by Angela To 2B
Wed Jan 11, 2017 10:15 pm
Forum: Phase Changes & Related Calculations
Topic: Temperature of sample remaining constant?
Replies: 4
Views: 394

Re: Temperature of sample remaining constant?

If your question is what Shailyn is mentioning, then it's basically what Cliff said! During phase changes, bonds are broken which require energy (and heat is a form of energy)! If you look at a phase change graph, the areas with a horizontal line shows how much energy it can absorb before the sample...
by Angela To 2B
Tue Jan 10, 2017 3:11 pm
Forum: Administrative Questions and Class Announcements
Topic: Workbook
Replies: 2
Views: 299

Re: Workbook

I don't think so. I think it's just supposed to be the course reader and the "Introduction to Organic Chemistry" book if you bought that as well. (Or if you bought the book of past midterms/finals compilation book too). The practice problems and practice midterms are in the course reader i...

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