Search found 25 matches

by Amy Pai
Sun Mar 13, 2016 5:01 am
Forum: *Cycloalkenes
Topic: Winter 2012 Final Q5
Replies: 2
Views: 415

Re: Winter 2012 Final Q5

I thought you move on if there's a tie with priority (so keep going through the carbons until you hit something different)? And where are the different functional groups what we need to mark for priority? Like from the left side it's the ketone (O as priority), but from the right its just carbons un...
by Amy Pai
Sat Mar 12, 2016 1:38 pm
Forum: General Science Questions
Topic: Sig Figs
Replies: 1
Views: 659

Re: Sig Figs

Anything that isn't a calculated "given" from the question is NOT used in determining sit figs (with the exception of calculated constants on the formula sheet). So if you found those moles yourself (like, for electron transfer in redox questions), you don't use those sit figs for final an...
by Amy Pai
Sat Mar 12, 2016 1:33 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Neo- vs. Tert- and Sec- vs. Iso-
Replies: 1
Views: 1038

Re: Neo- vs. Tert- and Sec- vs. Iso-

Are you asking about priority in how to name the substitutent? If so, then it's because iso has that V at the end, while sec specifies a chain with the second C attaching to the parent. You might think there's an overlap with isopropyl and sec propyl, but sec starts only with butyl. Tert and Neo are...
by Amy Pai
Wed Feb 24, 2016 5:48 pm
Forum: *Electrophilic Addition
Topic: hydrogen versus iodine
Replies: 1
Views: 368

Re: hydrogen versus iodine

In H-I, H is partially positive (at least more so than I, which is an e- loving halogen), so H would be the one getting that e- from the organic molecule. Remember that electrons aren't exactly shared equally in a covalent bond (unless it's nonpolar covalent, so same element like H-H), so e- will sp...
by Amy Pai
Wed Feb 24, 2016 5:42 pm
Forum: *Electrophiles
Topic: Memory Tips
Replies: 8
Views: 1133

Re: Memory Tips

I just go by: Electrophile= "electron-loving" (want electron) Nucleophile= "nucleus-loving" (want positive stuff) The whole electrophiles are electron-deficient and nucleophiles are electron-rich can thus be deduced. Deducing it logically from their names (to me) is much simpler ...
by Amy Pai
Wed Feb 24, 2016 5:35 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Transition State delta G??
Replies: 1
Views: 428

Transition State delta G??

Ashely went over in her lecture the activation complex graph, and I was a bit confused as to why the delta G she drew for TS 2 went from the energy level of the reactants to the peak of TS2 (instead of maybe from the intermediate to the peak of TS2). I guess I'm just confused as to how "delta&q...
by Amy Pai
Wed Feb 24, 2016 2:21 am
Forum: *Electrophiles
Topic: How to know if reaction?
Replies: 1
Views: 279

How to know if reaction?

Is there a threshold of how negative/reactive a nucleophile is and how positive/reactive an electrophile is? Meaning, how do we know if a reaction takes place or not? Or are we generally given problems that are pretty reactive?
by Amy Pai
Thu Feb 18, 2016 11:42 am
Forum: Balancing Redox Reactions
Topic: Oxidation States
Replies: 8
Views: 999

Re: Oxidation States

For oxidation states of individual atoms in a polyatomic ion, I basically just go by H is 1+ (Alkali group +1), O is 2- (along with most halogens), and the alkaline earth metals are 2+. So basically following the trend with how many valence electrons they need. The oxidation states you need to find ...
by Amy Pai
Mon Feb 15, 2016 8:24 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Reaction Order
Replies: 1
Views: 287

Re: Reaction Order

It might be because of the exponents; meaning, when concentrations are multiplied, you add each part's powers to get the "sum" of the power. I think this also translates to if you have different reactants in your rate law, so the order is just the number of concentrations you have in your ...
by Amy Pai
Sat Feb 06, 2016 3:29 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox reactions
Replies: 3
Views: 531

Re: Balancing Redox reactions

The example Lavelle used in lecture of an intensive property was density~

I like this example because it helps with visualizing why you don't, for example, double the density of water just because your sample of water doubled in volume.
by Amy Pai
Tue Jan 26, 2016 8:12 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Question #3 winter 2014 quiz practice
Replies: 3
Views: 559

Re: Question #3 winter 2014 quiz practice

You have everything correct for the equation they gave you. But you forgot to balance it! i.e Instead of just 1 O=O, there's actually 13/2 (O=O) bonds being broken from the reactants' side. This number is from the stoichiometric coefficient after balancing the reaction above. And I'm not sure what y...
by Amy Pai
Sat Jan 23, 2016 11:58 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question 8.41
Replies: 1
Views: 214

Re: Question 8.41

This is because you set the heat gained by the ice equal to the heat lost by the surrounding water . In other words, the heat flowed into the cold ice (which melted and turned into cold water, which then cooled down the surrounding water a bit (by "taking" the heat of the hotter, surroundi...
by Amy Pai
Sun Jan 17, 2016 2:49 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Reversible Processes examples
Replies: 1
Views: 354

Reversible Processes examples

Since reversible processes maximize work and minimize energy lost to heat, what are some examples of reversible processes that are harnessed for energy production/ found in nature, etc? Or is this not feasible?
by Amy Pai
Sun Jan 10, 2016 1:10 am
Forum: Phase Changes & Related Calculations
Topic: Homework Question 8.3
Replies: 3
Views: 1918

Re: Homework Question 8.3

I'm just quoting from the solutions manual, because I think it answers your question well: "Work on the air is positive by convention as work is done on the air, it is compressed."

~Just in case you didn't have the solutions manual. If you did, sorry this is redundant!
by Amy Pai
Thu Dec 03, 2015 5:46 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Stronger acid in acetic acid?
Replies: 1
Views: 730

Stronger acid in acetic acid?

I don't really understand the solution manual when it says nitrous acid is stronger in acetic acid because its weaker conjugate base (NO2-) will allow the presence on C2H3O2- to shift Nitrous acid's proton transfer equilibrium to products by taking up H+ ions. Can someone word this differently or ex...
by Amy Pai
Tue Dec 01, 2015 4:56 pm
Forum: *Titrations & Titration Calculations
Topic: Stoichimetric Point
Replies: 2
Views: 339

Re: Stoichimetric Point

Because the reagents are able to neutralize each other when the titrant (the opposite of the sample) is added up until a certain point (when slope gets steeper), whereas afterwards, every little increase of the titrant will affect the pH of the solution (ie. if you add a basic titrant, the pH will g...
by Amy Pai
Sat Nov 21, 2015 2:17 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Sig figs
Replies: 1
Views: 317

Sig figs

Do you truncate in calculations? Ex: textbook 12.59, b). You needed to find [OH-] for pOH, but the solution manual truncated for [OH-]: 4.2x10^-5, which affected the final pOH answer by .01. Which is more accurate, truncating throughout or just the end? I never truncated in calculations before, but ...
by Amy Pai
Thu Nov 19, 2015 5:24 pm
Forum: Lewis Acids & Bases
Topic: Ionization
Replies: 1
Views: 332

Re: Ionization

I'll use the Bronsted definition to try to explain: Being ionized in water/ solution just means that the acid lets the solvent break the H+ off of it. So like Dr. Lavelle mentioned in his lecture, if the bond (i.e. Between H+ and Cl- in HCl) is weak (longer bond length, larger radii, larger dipole, ...
by Amy Pai
Tue Nov 17, 2015 12:32 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 11.79 Partial Pressures
Replies: 1
Views: 847

Re: 11.79 Partial Pressures

First, write out the balanced equation: N2 + 3H2 <----> 2 NH3 I 3.11+1.57=4.68 1.64 23.72 C -x -3x +2x B/c reaction will shift to right (prove using le chatlier or Q<K) E 4.68-x 1.64-3x 23.72+2x Then, calculate K from the equilibrium []s from the given, and set that value equal to the new equilibriu...
by Amy Pai
Sun Nov 08, 2015 10:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 11.7c
Replies: 1
Views: 345

Re: Homework 11.7c

1). If you rearrange the ideal gas law, u get V1/V2= n1/n2, meaning that the volume ratio of two gases at the same temperature and pressure is equal to their molar ratio. 2). You do 5/12 because that's the number of X2s in equilibrium. 0.1 bar gives you the total initial pressure of the system, so I...
by Amy Pai
Sun Nov 01, 2015 12:59 pm
Forum: Octet Exceptions
Topic: SeO2 lewis strcuture
Replies: 1
Views: 4596

Re: SeO2 lewis strcuture

According to this video: https://www.youtube.com/watch?v=1ma9sY52K9U , you are right with balancing the formal charges to =0 for each atom. Where did it say that the second lewis structure was correct?
by Amy Pai
Sun Oct 25, 2015 11:17 pm
Forum: Hybridization
Topic: Question on 4.25
Replies: 2
Views: 453

Re: Question on 4.25

I also had a question on this. Is it because of the tetrahedral shape that, in 3D, the dipoles don't cancel? Meaning, even if hypothetically the chlorines were on opposing sides (of the flat lewis structure), the molecule would still be polar?
by Amy Pai
Sun Oct 18, 2015 10:27 pm
Forum: Lewis Structures
Topic: unpaired electrons for 02
Replies: 2
Views: 398

Re: unpaired electrons for 02

I haven't gotten that far in the reading yet, but I looked it up because molecular orbital theory wasn't something I learned in high school, and so I found this on youtube, which uses O2 as an example and explains the answer clearly: https://www.youtube.com/watch?v=GbzHaW0sTmQ"onclick="window.open(t...
by Amy Pai
Fri Oct 09, 2015 10:45 am
Forum: Trends in The Periodic Table
Topic: Chapter 2 Reading- Inert-Pair Effect
Replies: 1
Views: 676

Re: Chapter 2 Reading- Inert-Pair Effect

I think this is just telling you that those elements in the left area of the p-block have tendencies of either losing enough electrons to get to the lower s-orbital state or losing all their valence electrons (p and s ones) to get to the electron configuration of the closest inert gas. And since the...
by Amy Pai
Fri Oct 09, 2015 10:07 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ground state electron configuration?
Replies: 1
Views: 2271

Re: Ground state electron configuration?

I'll demonstrate using an example: Vanadium (atomic #23) Using the shorthand method, look for the noble gas with the closest number of electrons to Vanadium (without exceeding Vanadium's # of electrons), which is Argon. That gives you this: V: [Ar] Then, can count the # of electrons still needed to ...

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