Search found 23 matches

Thu Mar 16, 2017 10:08 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Winter 2016 Final Exam Q2A [ENDORSED]
Replies: 7
Views: 759

Re: Winter 2016 Final Exam Q2A[ENDORSED]

I think this is because bar may be the standard unit for partial pressures. Whether you need the partial pressure in bar or in atm form relies on the question.
Wed Mar 08, 2017 8:11 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Describing reactions
Replies: 2
Views: 313

Re: Describing reactions

I believe it has to do with talking about Gibbs Free energy for reaction profiles.
Wed Feb 22, 2017 4:39 pm
Forum: *Electrophiles
Topic: Electrophiles and nucleophiles
Replies: 3
Views: 349

Re: Electrophiles and nucleophiles

Electrophiles are similar to a Lewis acid because they are molecules that accept a pair of electrons to make a new covalent bond. On the other hand, nucleophiles are similar to a Lewis base because they are molecules that donate a pair of electrons to make a new covalent bond.
Wed Feb 15, 2017 3:30 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Dilution and cell potential
Replies: 1
Views: 190

Re: Dilution and cell potential

cell potential is related to concentrations of reactants and products through the Nerst equation. This equation contains the reaction quotient Q, so when you dilute anode, the Q decreases turning the -(RT/nF)lnQ into a positive number.
Wed Feb 08, 2017 8:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Q=What is "i"?
Replies: 1
Views: 246

Re: Q=What is "i"?

I believe "i" is just a letter used as a place holder for taking the limit. It's the same, I would assume, as in math when you take an integral from 0 to infinity and have to use a letter to take the limit because it is improper.
Wed Feb 01, 2017 4:12 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: state functions
Replies: 2
Views: 303

Re: state functions

Delta H, Delta S (surrounding and system) and Delta G are all thermodynamic functions, therefore they are state functions that depend on current state.
Q and w are not state properties because they are path dependent.
Mon Jan 23, 2017 5:20 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Ideal Gas
Replies: 2
Views: 381

Re: Ideal Gas

My TA explained that the 2/3 coefficient stood for the internal energy units "per molecule of ideal gas" but I don't know about the 5/2 coefficient. Hope this is useful.
Thu Jan 19, 2017 1:22 pm
Forum: Calculating Work of Expansion
Topic: isothermal processes [ENDORSED]
Replies: 1
Views: 230

Re: isothermal processes[ENDORSED]

W=-nRTln(V2/V1)
I'm pretty sure this is the correct formula.
Wed Jan 11, 2017 3:18 pm
Forum: Phase Changes & Related Calculations
Topic: Systems
Replies: 2
Views: 347

Re: Systems

Thank you for that information. It was helpful seeing it written out.
Fri Dec 02, 2016 8:55 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Equilibrium Equation
Replies: 1
Views: 218

Re: Equilibrium Equation

During one of the review sessions today, the TA said that it had to do with advanced background knowledge on that molecule that we have not learned in this course. He said not to worry too much about it but if we really wanted to know, then you could look up a video on it.
Tue Nov 22, 2016 10:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between aq and l?
Replies: 1
Views: 4258

Re: Difference between aq and l?

A liquid is a pure substance so it does not change its molar concentration in a reaction. An aqueous solution is a substance that has been dissolved in a liquid so it has been dissociated into its positive and negative ions (i.e. NaCl dissociates into Na+ and Cl-). That is why the aqueous solution d...
Tue Nov 15, 2016 2:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Number for (en) [ENDORSED]
Replies: 6
Views: 878

Re: Coordination Number for (en)[ENDORSED]

The molecules outside the coordination sphere do not contribute to the compound's coordination number because they can only interact with the compound to help neutralize the charge. These molecules are not directly bound to the central atom so they do not count. Remember the coordination number is t...
Tue Nov 15, 2016 2:00 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Molecular Orbital Diagram of NO+ [ENDORSED]
Replies: 1
Views: 1572

Re: Molecular Orbital Diagram of NO+[ENDORSED]

I am not quiet sure but it seems that the book may have taken the electron off O because then it would have the same amount of electrons in the 2p orbital as Nitrogen (it looks neater). In general, I don't think it matters where you take the electron from because it has no affect which side when dra...
Mon Nov 07, 2016 7:27 pm
Forum: Hybridization
Topic: Hybridization
Replies: 1
Views: 210

Re: Hybridization

Hybridization happens between 2 covalently bonded atoms since they share electrons and thus a new orbital is formed to accommodate this sharing of electrons.
Mon Oct 31, 2016 9:03 am
Forum: Student Social/Study Group
Topic: Rieber Terrace Study Group
Replies: 12
Views: 1227

Re: Rieber Terrace Study Group

Why don't we all meet November 1st on the main floor, near the stair entrance so we leave space by the elevator, at 9 pm?? That way we can study any last minute chem stuff.
Mon Oct 24, 2016 2:51 pm
Forum: Student Social/Study Group
Topic: Rieber Terrace Study Group
Replies: 12
Views: 1227

Re: Rieber Terrace Study Group

Soooo when do you guys want to start studying for the midterm...
Fri Oct 21, 2016 2:29 pm
Forum: Student Social/Study Group
Topic: Rieber Terrace Study Group
Replies: 12
Views: 1227

Re: Rieber Terrace Study Group

Do you guys want to meet up Saturday or Sunday night on the first floor??
Fri Oct 21, 2016 2:25 pm
Forum: Student Social/Study Group
Topic: Rieber Terrace Study Group
Replies: 12
Views: 1227

Re: Rieber Terrace Study Group

I am on the 3rd floor.
Wed Oct 19, 2016 2:28 pm
Forum: Student Social/Study Group
Topic: Rieber Terrace Study Group
Replies: 12
Views: 1227

Re: Rieber Terrace Study Group

What floor do you guys live on, I have been waiting for a study group in Rieber Terrace!
Tue Oct 18, 2016 4:36 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations of Ions [ENDORSED]
Replies: 1
Views: 197

Re: Electron Configurations of Ions[ENDORSED]

The majority of the time what is seen is electrons being removed or added to make the element more stable with a full or empty shell but there are exceptions. It is possible to have an ion become a partially full shell but it is rare because it makes the element very unstable so it will want to reac...
Tue Oct 18, 2016 3:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1st orbital in He+ [ENDORSED]
Replies: 1
Views: 433

Re: 1st orbital in He+[ENDORSED]

The reason is actually because the nucleus of He+ has a 2+ charge while the H nucleus has a 1+ charge. This makes it so that the He+ nucleus attracts the electrons more strongly so structure-wise, the 1s orbital is a lot closer in He+ compared to H. I hope this helps.
Mon Oct 10, 2016 10:30 am
Forum: General Science Questions
Topic: Unit Conversions
Replies: 2
Views: 770

Re: Unit Conversions

Some that show up frequently is Mega, for example MHz.
1MHz = 10^6 Hz
Another is mili
1mL = 10^-3 L
and kilo
1Km= 10^3 m

For units, it would be helpful to realize that Joules is units of kg*m^2*s^-2 for problems that have to do with de Broglie wavelengths.
Sun Oct 02, 2016 1:38 pm
Forum: Significant Figures
Topic: Sig Figs in a problem with addition & multiplication [ENDORSED]
Replies: 5
Views: 765

Re: Sig Figs in a problem with addition & multiplication[ENDORSED]

It is best to incorporate sig figs at the end for most chemistry problems because you get a more accurate answer in the end. If you were to do it for each step, the problem would get messy and the answer in the end may not be as close to if you just round at the end.