Search found 17 matches

by Davis Chong 4H
Mon Feb 27, 2017 11:22 pm
Forum: *Alkanes
Topic: Equivalent numbering - meaning?
Replies: 2
Views: 369

Re: Equivalent numbering - meaning?

bless u
by Davis Chong 4H
Mon Feb 27, 2017 10:22 pm
Forum: *Alkanes
Topic: Equivalent numbering - meaning?
Replies: 2
Views: 369

Equivalent numbering - meaning?

Hey y'all, On page 6 of the organic chem book given out (green) it says: When equivalent numbering is possible (here is is 3,5 or 5,3 {the example was 3-ethyl-5-methylheptane}) then the first substituent in the name is assigned the lower number. What does it mean by equivalent numbering? If the numb...
by Davis Chong 4H
Sun Feb 26, 2017 4:26 pm
Forum: *Organic Reaction Mechanisms in General
Topic: "No charge separation" meaning? [ENDORSED]
Replies: 3
Views: 5623

"No charge separation" meaning? [ENDORSED]

Hey y'all, On pg 166 on the Intro to Organic Chemistry book, it says "The bonding in ethanamide is very similar to nitroethane, but its two resonance contributors are not equal in energy. The resonance structure on the left is more stable as there is no charge separation . What exactly does thi...
by Davis Chong 4H
Sun Feb 05, 2017 8:06 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram commas vs |
Replies: 1
Views: 300

Cell Diagram commas vs |

Hiya, When do you determine whether to separate elements by | or by commas? I'm having trouble figuring out why the answer book uses commas in some cases, or even includes some elements. In addition, while I understand why Pt is used, I'm not sure when to determine to use Pt as the electrode. A spec...
by Davis Chong 4H
Tue Jan 24, 2017 8:55 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Question 31(b
Replies: 1
Views: 353

Question 31(b

31 is basically - Which has higher standard molar entropy @ 298 K? b) asks to compare liquid cyclopentene and 1 pentene, given their shapes which I don't think I can draw here, but cyclopentene is a pentagon (C5H10) and 1-pentene is just a squiggly line. The answer says 1-pentene has more "flex...
by Davis Chong 4H
Mon Jan 16, 2017 10:55 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question about R value
Replies: 1
Views: 361

Question about R value

The R value can be variable. But what determine what the R value is for a specific question/equation/context?

Cheers
by Davis Chong 4H
Thu Jan 12, 2017 10:23 pm
Forum: Calculating Work of Expansion
Topic: 8.93 Substituting PdeltaV=nRT into w=PdeltaV
Replies: 1
Views: 418

8.93 Substituting PdeltaV=nRT into w=PdeltaV

The substitution in this question is straightforward enough, but I don't quite understand how the deltaV almost transfers its delta onto n(moles) as well, resulting in delta(n) * R * T. As in here: w = -P*deltaV w = -P( [delta(n) * R * T]/P) w = -delta(n) * R * T I guess it makes sense that a change...
by Davis Chong 4H
Tue Nov 29, 2016 12:13 am
Forum: Polyprotic Acids & Bases
Topic: HW question 12.77, a different sort of polyprotic Acids and Bases question [ENDORSED]
Replies: 1
Views: 627

HW question 12.77, a different sort of polyprotic Acids and Bases question [ENDORSED]

There's a homework problem in Chapter 12 #77 that says: A 3.38-g sample of the sodium salt of alanine, NaCH3CH(NH2)CO2, is dissolved in water, and then the solution is diluted to 50.0 mL. For alanine, Ka1=4.57 X 10^-3. Ka2=1.30 x 10^-10. What is the pH of the resulting solutions? I looked in the sol...
by Davis Chong 4H
Mon Nov 28, 2016 9:08 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: -CH3 electron donating property
Replies: 1
Views: 364

-CH3 electron donating property

Why do we say that -CH3 (in CH3COOH) has electron donating property and less electron withdrawing than -H (in HCOOH)? From the answer book for question 53, aceti acid is a little less stronger than formic acid due to this property of the CH3 on the acetic acid vs the single H on formic acid.
by Davis Chong 4H
Mon Nov 28, 2016 8:16 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Adding salt and no shift in equilibrium?
Replies: 2
Views: 562

Adding salt and no shift in equilibrium?

I believe a similar question was asked in class but I still didn't understand.
Using the example in the course reader pg 170
Acidic bufer Ch3COONa
When adding the CH3COO from the salt, wouldn't the equilibrium just shift the CH3COO- in accordance with its equilibruim constant to maintain the ratio?
by Davis Chong 4H
Sun Nov 27, 2016 9:58 pm
Forum: Lewis Acids & Bases
Topic: Embarrassing question about BF3
Replies: 1
Views: 416

Embarrassing question about BF3

Why exactly is BF3 a Lewis acid? I understand that the Lewis dot diagram gives it 6 out of 8 electrons on the valence shell so thus it'd want another electron pair, making it an electron pair acceptor - but then wouldn't the formal charges be thrown off and not be optimal? Is there a hierarchy in co...
by Davis Chong 4H
Mon Nov 14, 2016 7:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Having multiple possible concentrations [ENDORSED]
Replies: 1
Views: 330

Having multiple possible concentrations [ENDORSED]

In lecture today when he used the quadratic eq. to solve for the concentrations, Dr. Lavelle said that we could disregard the negative answer, which resolved the issue of having 2 possible concentrations. What if both of the answers from the EQ were positive? How would we chose then? Apologies if we...
by Davis Chong 4H
Tue Oct 18, 2016 7:35 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Typo in the book? 3.13:Correcting the Ionic Model
Replies: 1
Views: 420

Typo in the book? 3.13:Correcting the Ionic Model

On page 93, its says "compounds composed of a small, highly charged cation and a large, polarizable anion tend to have bonds with considerable covalent character."

Shouldn't they have considerable IONIC character?
by Davis Chong 4H
Tue Oct 18, 2016 6:47 pm
Forum: Lewis Structures
Topic: Expanded Valence Shell Tendencies
Replies: 1
Views: 340

Expanded Valence Shell Tendencies

For atoms that have their d-orbital available and expand past the octet rule such as P, does the atom tend to try and fill up whatever shell it is on? So P would try and get 10 electrons?
by Davis Chong 4H
Sat Oct 15, 2016 3:10 pm
Forum: Lewis Structures
Topic: Which comprise the valence electrons for Sc + other transition metals?
Replies: 1
Views: 290

Which comprise the valence electrons for Sc + other transition metals?

Is it the 4s e- that are removed first as the valence electons or the 3d? Wouldn't shielding cause the 4s to penetrate to the nucleus and then the 3d e- would count as valence? Or is shielding not even a part of it?
by Davis Chong 4H
Mon Sep 26, 2016 10:57 pm
Forum: Properties of Light
Topic: Balmer, Lyman, and Paschen series HW question 1.11
Replies: 4
Views: 2620

Balmer, Lyman, and Paschen series HW question 1.11

Hello, I was wondering how the soln. manual arrived at the answer that it did. 1.11 In the spectrum of atomic hydrogen, several lines are generally classified together as belong to a series (for example, Balmer series, Lyman series, Paschen series), as shown in Figs. 1.10 and 2.1. What is common to ...

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