Search found 24 matches

by Kathy Vu 3L
Sat Mar 18, 2017 2:18 am
Forum: *Cycloalkanes
Topic: 2012 Final Q6D: Naming Cycloalkane
Replies: 1
Views: 308

2012 Final Q6D: Naming Cycloalkane

Instead of having (tert-butyl), can you use isopropyl?
by Kathy Vu 3L
Fri Mar 17, 2017 11:04 pm
Forum: *Alkanes
Topic: Neo- vs. Tert-
Replies: 5
Views: 495

Re: Neo- vs. Tert-

Tert- just implies that there is a carbon attached to 3 other carbons, it does not necessarily have to be (CH3)3C-.
by Kathy Vu 3L
Fri Mar 17, 2017 10:58 pm
Forum: *Alkenes
Topic: Numbering in Naming Alkenes
Replies: 1
Views: 333

Numbering in Naming Alkenes

Can 2-pentene and pent-2-ene be used interchangeably?
by Kathy Vu 3L
Thu Mar 02, 2017 10:39 pm
Forum: *Nucleophiles
Topic: Polarization and nucleophile strength
Replies: 3
Views: 369

Re: Polarization and nucleophile strength

The more polar a molecule, the more regions of electron density. Therefore, these regions of molecules act as a nucleophile.
by Kathy Vu 3L
Mon Feb 27, 2017 5:09 pm
Forum: *Nucleophiles
Topic: Nucleophiles that are Neutral?
Replies: 2
Views: 321

Re: Nucleophiles that are Neutral?

H20 also has lone pairs, which could be attracted to the positive electrophiles.
by Kathy Vu 3L
Mon Feb 20, 2017 6:17 pm
Forum: First Order Reactions
Topic: Slope of k
Replies: 3
Views: 420

Re: Slope of k

When you derive the equation for a zero and first order reactions by integrating, it comes out to be -kt, as opposed to integrating the second order reaction and having it come out to be kt. Therefore the slope is negative for zero and first order.
by Kathy Vu 3L
Sun Feb 12, 2017 1:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond enthalpy question on quiz 1
Replies: 2
Views: 230

Re: Bond enthalpy question on quiz 1

On the quiz it helps that he put the table of bond enthalpies on the side, so you know which ones are going to be used. For me, I draw the lewis structure out and I see which one changes between both of them.
by Kathy Vu 3L
Wed Feb 01, 2017 12:35 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Free energy at equilibrium
Replies: 2
Views: 228

Re: Free energy at equilibrium

Using the equation ∆G° = – RT ln K, it assumes that the system is already in equilibrium since K is the equilibrium constant. Furthermore, ∆G° is only 0 when at equilibrium, K equals 1, which means the reactants and products are equally favored.
by Kathy Vu 3L
Sat Jan 28, 2017 12:47 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy
Replies: 7
Views: 497

Re: Entropy

Irreversible processes cause a change in entropy, whereas reversible processes have an entropy change of 0.
by Kathy Vu 3L
Wed Jan 18, 2017 10:04 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated Systems [ENDORSED]
Replies: 1
Views: 226

Re: Isolated Systems [ENDORSED]

You cannot change the energy of an isolated system, as stated in the first law of thermodynamics. This law states that the internal energy of an isolated system is constant. For example, the universe is an isolated system, therefore its energy is constant.
by Kathy Vu 3L
Thu Jan 12, 2017 10:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Workbook?
Replies: 3
Views: 387

Workbook?

When I bought my course reader, it did not come with a workbook like last quarter. Is this a new change or have others received a workbook?
by Kathy Vu 3L
Sun Dec 04, 2016 12:16 pm
Forum: Resonance Structures
Topic: Do all resonance structures need to be FC=0?
Replies: 4
Views: 556

Re: Do all resonance structures need to be FC=0?

Resonant structures are used to show delocalized electrons, therefore you would have to draw all the possible bondings, even if they are not stable. As for finding out how many structures to draw, I just look at all the possible places that the double/triple bond can go.
by Kathy Vu 3L
Fri Nov 25, 2016 9:47 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Indicators of strong or weak acid/base
Replies: 3
Views: 337

Re: Indicators of strong or weak acid/base

Strong acids do have a Ka value, they are just very large since strong acids dissociate almost completely, therefore the products/reactants ratio would be very high, making the Ka value high.
by Kathy Vu 3L
Tue Nov 15, 2016 3:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reaction at equilibrium
Replies: 1
Views: 209

Re: Reaction at equilibrium

You're right the answer is C. A TRUE, definition of a chemical equilibrium B TRUE I think refers to Le Chatelier's Principle, so even if you add different combos of reactants and products, the reaction will still end up at equilibrium by shifting to one side of the reaction C FALSE there is a reacti...
by Kathy Vu 3L
Tue Nov 15, 2016 3:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Fall 2014 Quiz #8 [ENDORSED]
Replies: 2
Views: 369

Re: Fall 2014 Quiz #8 [ENDORSED]

You don't need the starting concentration because the equation for calculating K is [NH3][H2S], since NH3 and H2S have the same stoichiometric coefficients of 1, you can replace what's in the bracket as X. So 0.11=X^2, and X=0.11^(0.5), which is 0.33atm
by Kathy Vu 3L
Tue Nov 08, 2016 8:55 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: MO Diagram difference
Replies: 1
Views: 211

Re: MO Diagram difference

It has to deal with electron repulsion. For z<8, π2p MO’s are filled before the σ2p MO because there is less electron-electron repulsion between the π2p and the σ2s and the σ2s*. For z>8, σ2s and σ2s* MO’s are closer because greater nuclear charge, therefore the σ2p MO's will react less strongly wit...
by Kathy Vu 3L
Wed Oct 26, 2016 6:59 pm
Forum: Lewis Structures
Topic: Lewis Structure Octet Rule Exceptions
Replies: 3
Views: 538

Re: Lewis Structure Octet Rule Exceptions

Atoms with access to the d-block can also have an expanded octet. For example, sulfur has access to the 3d-block which is why it can take electrons from there to have an expanded octet.
by Kathy Vu 3L
Fri Oct 21, 2016 10:36 pm
Forum: Lewis Structures
Topic: Lewis Structure for CO
Replies: 1
Views: 182

Re: Lewis Structure for CO

The formal charge isn't 0 and 0, however if there were to be a double bond between the two, then carbon wouldn't have an octet.
by Kathy Vu 3L
Tue Oct 11, 2016 9:58 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 785925

Re: Post All Chemistry Jokes Here

Two chemists walk in a bar. One asks for H20, and the other says "I'll have H2O too." The second chemist dies.
by Kathy Vu 3L
Tue Oct 04, 2016 11:28 pm
Forum: DeBroglie Equation
Topic: Worked Example on page 52 in the Course Reader
Replies: 2
Views: 284

Re: Worked Example on page 52 in the Course Reader

I think that value is applicable to all object's wavelength. I would not say values less than 10^-15 don't have properties, because all objects have wave-like properties, but only those with small mass and high velocity can be measured.
by Kathy Vu 3L
Tue Oct 04, 2016 10:16 pm
Forum: DeBroglie Equation
Topic: Wavelength of Ejected Electron [ENDORSED]
Replies: 3
Views: 455

Re: Wavelength of Ejected Electron [ENDORSED]

Can I ask what questions you're referring to, because most questions I've seen, ask about the speed of the ejected electron (in which you use the photoelectric effect equation) or what wavelength you need to eject an electron.
by Kathy Vu 3L
Sun Sep 25, 2016 12:17 pm
Forum: Limiting Reactant Calculations
Topic: Mass Always Equal?
Replies: 3
Views: 411

Re: Mass Always Equal?

The limiting reactant limits the amount of product that can be formed and is completely consumed, therefore the other reactant (excess reactant) will remain when the reaction stops.
by Kathy Vu 3L
Sun Sep 25, 2016 12:12 pm
Forum: Significant Figures
Topic: Significant figures [ENDORSED]
Replies: 9
Views: 918

Re: Significant figures [ENDORSED]

Is there usually a range of answers we can put on quizzes and exams, or is there only 1 answer that is allowed?

For example what if my answer is 2.5, but others got 2.6 due to a different amount of decimals used during calculations
by Kathy Vu 3L
Sun Sep 25, 2016 12:05 pm
Forum: Significant Figures
Topic: Significant figures [ENDORSED]
Replies: 9
Views: 918

Re: Trailing zeroes [ENDORSED]

Rob_Carter_1L wrote:Just confirming, I know that 0.0100 would have 3 sigfigs due to trailing zeros, but would 1.00 have 3 as well? Is it the same after decimal points?


Yes, 1.00 would have 3 significant figures as well since the 2 zeros are trailing zeros behind a decimal point

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