Search found 15 matches

by Helen_Onuffer_1A
Tue Mar 14, 2017 10:28 pm
Forum: *Electrophilic Addition
Topic: Attachment of Atoms
Replies: 5
Views: 1021

Re: Attachment of Atoms

I believe so, since a carbon with fewer H atoms bonded to it (or fewer bonds in general) would have a greater negative partial charge (since carbon wants 4 bonds to be most stable).
by Helen_Onuffer_1A
Tue Mar 14, 2017 10:21 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework 8.11
Replies: 3
Views: 1598

Re: Homework 8.11

I believe reversible does more work in this problem because the system is doing work on its surroundings. When a process is doing work on its surroundings, if it is done slowly, you get the most work. Since a reversible process is infinitely slow (hence the summation/integral in the reversible work ...
by Helen_Onuffer_1A
Sun Mar 12, 2017 10:48 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Winter 2016 final 4B
Replies: 4
Views: 637

Re: Winter 2016 final 4B

Isn't O an intermediate?
by Helen_Onuffer_1A
Sat Mar 04, 2017 12:20 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow Reaction
Replies: 11
Views: 963

Re: Slow Reaction

When the question asks you to find the rate equation, what do you do when your equation requires you to know the concentration of an intermediate species? Are you supposed to replace it by looking at the fast reaction and setting the forward rate equal to the reverse rate? Or is there another metho...
by Helen_Onuffer_1A
Sun Feb 26, 2017 11:42 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 2 Winter 2017
Replies: 160
Views: 17378

Re: Quiz 2 Winter 2017

chris2E wrote:Is there a reason why number six's answer has three significant figures despite the given concentration 0.35M having two significant figures? Do we not bother with sig figs when ln is involved?

0.30 is only two sig figs.
by Helen_Onuffer_1A
Sun Feb 19, 2017 2:50 pm
Forum: General Science Questions
Topic: Sig Figs
Replies: 5
Views: 1138

Re: Sig Figs

It is important to keep track of the number of sig figs throughout the problem, but I usually save rounding off numbers used in calculations until the end for more precision. You need to be careful with addition/subtraction vs. multiplication/division because they have different rules when determini...
by Helen_Onuffer_1A
Sun Feb 05, 2017 10:25 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Quiz 1
Replies: 4
Views: 760

Re: Quiz 1

Each quiz and exam are worth a certain amount of points (I think altogether you can get up to ~400 points total throughout the quarter), but the quizzes/tests/grades are not curved until the end of the quarter. I believe it is explained in syllabus/front of the course reader.
by Helen_Onuffer_1A
Sun Jan 29, 2017 2:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: HWQ 8.67
Replies: 1
Views: 313

Re: HWQ 8.67

I think that because carbon is given as graphite, which has a crystalline structure, you have to atomize it to use it to form CH3OH.
by Helen_Onuffer_1A
Sat Jan 14, 2017 4:16 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8201
Views: 1432213

Re: Post All Chemistry Jokes Here

Why do chemists like nitrates so much?
They're cheaper than day rates.
by Helen_Onuffer_1A
Thu Nov 17, 2016 10:44 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8201
Views: 1432213

Re: Post All Chemistry Jokes Here

Q: What do you do with a sick chemist?
A. First you try to helium, then you try to curium, but if this fails then you have to barium.
by Helen_Onuffer_1A
Wed Nov 09, 2016 9:21 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: MO diagram [ENDORSED]
Replies: 2
Views: 345

Re: MO diagram [ENDORSED]

When Z < 8, the 2p pi bonds have a lower energy than the 2p sigma bonds so those get filled first since we fill the lowest energy levels first.
by Helen_Onuffer_1A
Fri Nov 04, 2016 11:32 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration for Fe 3+
Replies: 6
Views: 38033

Re: Electron Configuration for Fe 3+

I think that once you start filling the 3d orbital, it becomes lower energy than the 4s orbital. It's probably more complicated than that, but we haven't really learned all the details yet.
by Helen_Onuffer_1A
Thu Oct 20, 2016 10:38 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodes [ENDORSED]
Replies: 3
Views: 741

Re: Nodes [ENDORSED]

The p orbital has 1 nodal plane since l = 1. It looks like an hourglass, with the nodal plane through the center.
by Helen_Onuffer_1A
Fri Oct 07, 2016 11:47 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework Problems #11 and #15 [ENDORSED]
Replies: 4
Views: 676

Re: Homework Problems #11 and #15 [ENDORSED]

When it says that the Lyman series goes to n=1 and the Balmer series goes to n=2, the book means that the final n/energy level for electrons in the two series are 1 and 2, respectively. (So say you're trying to calculate the initial and final energy levels of an electron that emitted a line in the L...
by Helen_Onuffer_1A
Fri Sep 30, 2016 10:38 am
Forum: Significant Figures
Topic: All students read this sig fig post [ENDORSED]
Replies: 133
Views: 17388

Re: All students read this sig fig post [ENDORSED]

Does it matter how many significant figures there are after the decimal while adding, multiplying, dividing, etc. ? (or does the number of significant figures of the result matter only?) Like the post above, a general rule I've always followed is to only round/determine sig figs for the answer beca...

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