Search found 21 matches

by Vivian Nguyen 2A
Sun Mar 19, 2017 11:47 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Practice Problems
Replies: 23
Views: 2336

Re: Practice Problems

Alina_Mitchell_2C wrote:What does it mean for a ring to be 8 membered?

I believe an 8 membered ring means cyclooctane. Possible larger rings include cyclononane and cyclodecane (if they're C-C single bond rings) because we are only expected to know up to the prefix for 10 members.
by Vivian Nguyen 2A
Tue Mar 14, 2017 10:49 am
Forum: Administrative Questions and Class Announcements
Topic: Final Exam Details and Review Sessions Winter 2017
Replies: 114
Views: 13620

Re: Final Exam Details and Review Sessions Winter 2017

Katrina_Domingo_3G wrote:Will the final be heavier on Organic Chemistry (because we've been tested less on it) or are all topics equally weighted?

Professor Lavelle answered above that the final will by evenly distributed based on the time we spent on the each topic. OChem is about 1/3 of the final.
by Vivian Nguyen 2A
Mon Mar 06, 2017 7:10 pm
Forum: *Cycloalkanes
Topic: Numbering of Substituents [ENDORSED]
Replies: 8
Views: 1727

Re: Numbering of Substituents [ENDORSED]

In the textbook, it states that there is no lowest sum IUPAC rule. An example of 2,7,8-trimethyldecane is given to show that even though the sum of the numbers (2+7+8=18) is larger than 3,4,9-trimethyldecane (3+4+9=16), the former is correct.
by Vivian Nguyen 2A
Fri Mar 03, 2017 11:16 pm
Forum: *Alkanes
Topic: Naming the Molecule
Replies: 1
Views: 155

Re: Naming the Molecule

The suffix -ane is used to name the main carbon chain with single C-C bonds. When the chain has double bonds, the suffix -ene is used; when there are triple bonds, -yne is used. The -yl suffix is used for substituents.
by Vivian Nguyen 2A
Fri Mar 03, 2017 8:49 pm
Forum: *Cycloalkanes
Topic: Cycloalkane with Only One substituent
Replies: 2
Views: 272

Re: Cycloalkane with Only One substituent

Yes, I believe that is correct!
by Vivian Nguyen 2A
Fri Mar 03, 2017 8:28 pm
Forum: *Cycloalkanes
Topic: More than 2 substituents on ring
Replies: 1
Views: 232

Re: More than 2 substituents on ring

When there are more than 2 substituents on a ring, we need to compare each number combination and select the one that results in the lowest numbers. Thus, the bigger substituent may not necessarily be the lower number.
by Vivian Nguyen 2A
Fri Mar 03, 2017 8:24 pm
Forum: *Cycloalkanes
Topic: Cyclo-
Replies: 7
Views: 883

Re: Cyclo-

Cycloalkanes have single C-C bonds in the parent chain, cycloalkanes have C=C double bonds, and cycloalkanes have triple bonds. To determine which to draw, we have to total the number of electrons given in the molecular formula and distribute them across the chain.
by Vivian Nguyen 2A
Thu Mar 02, 2017 9:51 pm
Forum: *Nucleophiles
Topic: H2O as a nucleophile
Replies: 3
Views: 327

Re: H2O as a nucleophile

When you draw out the Lewis structure for H2O, you see that the oxygen atom has 2 lone pairs of electrons and is therefore electron rich in this region! A nucleophile is any electron rich species, and although they are often negatively charged, they can also be neutral, like H2O.
by Vivian Nguyen 2A
Thu Mar 02, 2017 9:41 pm
Forum: *Nucleophiles
Topic: Nucleophiles and Electronegativity
Replies: 5
Views: 1176

Re: Nucleophiles and Electronegativity

The stronger nucleophile is the species that has electrons more readily available to be involved in a reaction. Thus, because Br- with its loosely bound 36 electrons, which translates to higher polarizability, is more likely to act as a source of electrons than F- with its tightly bound 10 electrons...
by Vivian Nguyen 2A
Thu Mar 02, 2017 9:37 pm
Forum: *Nucleophiles
Topic: Polarization and nucleophile strength
Replies: 3
Views: 461

Re: Polarization and nucleophile strength

I think it'd be helpful to review the first couple of chapters from Chem14A to get a refresher on the polarizability of atom! Typically, atoms will larger atomic radii (those towards the bottom of the periodic table) have more loosely bonded electrons and therefore have electrons more readily availa...
by Vivian Nguyen 2A
Thu Mar 02, 2017 9:28 pm
Forum: *Nucleophiles
Topic: nucleophiles
Replies: 2
Views: 319

Re: nucleophiles

It's just important to remember that although there are some correlations between basicity and nucleophilic strength, we cannot say that the stronger the base, the stronger the nucleophile! Any species that has electrons readily available to be involved in a reaction is a nucleophile.
by Vivian Nguyen 2A
Thu Mar 02, 2017 9:20 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius [ENDORSED]
Replies: 4
Views: 626

Re: Arrhenius [ENDORSED]

From what I understand, the Arrhenius equation will be on the upcoming quiz along with all the ochem that we have been learning. Quiz topics include the arrhenius equation, naming, constitutional isomers, energy profiles, and Sn2 mechanisms.
by Vivian Nguyen 2A
Thu Mar 02, 2017 12:53 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Quiz 3 [ENDORSED]
Replies: 14
Views: 988

Re: Quiz 3 [ENDORSED]

My TA said that the following topics will be covered on the quiz: Arrhenius equation, naming, constitutional isomers, energy profiles, and Sn2 mechanisms.
by Vivian Nguyen 2A
Sun Feb 26, 2017 3:35 pm
Forum: *Electrophiles
Topic: Activation Energy
Replies: 1
Views: 232

Re: Activation Energy

Activation energy, Ea, is the energy barrier. It is the amount of energy that must be added to start a reaction, which is recovered as the reaction proceeds. The standard free energy of activation, deltaG is the free energy difference between reactants and products.
by Vivian Nguyen 2A
Fri Feb 17, 2017 10:03 pm
Forum: General Rate Laws
Topic: Kinetics
Replies: 1
Views: 223

Re: Kinetics

k prime is the pseudo rate constant. It is used when we have a reaction with more than one reactant; when one reactant concentration is small and the others are large, the reaction rate is dependent only on the small concentration reactant. When the other reactants are in large excess, they are esse...
by Vivian Nguyen 2A
Sun Feb 12, 2017 9:38 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Identifying the Anode vs. Cathode in an Equation
Replies: 1
Views: 199

Re: Identifying the Anode vs. Cathode in an Equation

The anode (found on the left) is the oxidation half-reaction, and the cathode (located on the right) is the reduction half-reaction. It is quite easy to determine which one is the anode and which is the cathode by looking at the given Enaught values. We want to reverse the half-reaction that will re...
by Vivian Nguyen 2A
Sun Feb 05, 2017 10:09 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert metallic conductors in electrode reactions
Replies: 1
Views: 121

Inert metallic conductors in electrode reactions

The book states that platinum (Pt) is customarily used as the electrode for hydrogen (when 2H+ + 2e- --> H2) since the reaction requires an unreactive metal or graphite to carry electrons in and out of the electrode compartment. For other reactions that do not include a conducting solid as a reactan...
by Vivian Nguyen 2A
Mon Jan 30, 2017 11:05 am
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13715

Re: Quiz 1 Preparation Answers

Can anyone explain how they calculated q in #3? I was able to calculate w, and I know how to calculate deltaU if I can determine q. Do we assume that deltaU = 0, which would make q=-w? Thank you! We can assume that deltaU = 0 because we are looking at an ideal gas that expands isothermally and reve...
by Vivian Nguyen 2A
Sun Jan 29, 2017 11:07 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: difference between free energy and standard free energy
Replies: 1
Views: 1768

Re: difference between free energy and standard free energy

At equilibrium, G(reactants)=G(products, and thus the free energy (G) is equal to 0. According to the course reader, "G for a spontaneous process represents the energy that is free to do useful work".
Standard free energy (G°) is measured by -RTlnK
by Vivian Nguyen 2A
Sun Jan 22, 2017 7:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy Formula
Replies: 2
Views: 264

Re: Enthalpy Formula

We also use the formula above to show that a change in the enthalpy of a system is equal to the heat release or absorbed at constant pressure. Since at constant pressure H = U + PV and U = q + w, we see that H = q + w + PV. If the system can only do expansion work, w = -PexV; thus, H= q - PexV + PV,...
by Vivian Nguyen 2A
Sat Jan 14, 2017 9:11 am
Forum: Phase Changes & Related Calculations
Topic: Thermochemistry
Replies: 1
Views: 184

Re: Thermochemistry

According to the textbook, state properties depend only on the current state of the system. Therefore, if the system is changed from one state to another, the change in a state property is independent of how that change was brought about. We looked at the mountain example in class that highlighted a...

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