Search found 26 matches

by Soonwoo Chung 1D
Wed Mar 15, 2017 8:31 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: How to determine higher stability
Replies: 2
Views: 343

How to determine higher stability

Today in lecture, Dr. Lavelle gave an example with a chair conformation with a chlorine substituent and a bromine substituent, and I believe he said that the chlorine substituent had to be equatorial for it to be more stable, but how is that determined?
by Soonwoo Chung 1D
Sat Mar 11, 2017 12:53 am
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Eclipsed vs. Staggered (energy levels) [ENDORSED]
Replies: 1
Views: 2469

Eclipsed vs. Staggered (energy levels) [ENDORSED]

Can someone explain why the eclipsed conformation has a higher energy level than the staggered even though they have the same molecular formula and components?
by Soonwoo Chung 1D
Sat Mar 04, 2017 4:12 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Where to split molecule [ENDORSED]
Replies: 3
Views: 410

Re: Where to split molecule [ENDORSED]

What if there are multiple carbon double bonds? Would we have more than one split in the molecule? or does that usually not happen?
by Soonwoo Chung 1D
Sat Mar 04, 2017 1:36 am
Forum: *Calculations Using ΔG° = -RT ln K
Topic: Kinetics in organic rxns
Replies: 1
Views: 423

Re: Kinetics in organic rxns

I'm pretty sure that the kinetics of organic reactions, which refers to and takes into account the path or journey of the reaction rather than the final and initial in thermodynamics, is only about drawing the reactions (SN2 or electrophilic addition reaction) and showing the proper steps.
by Soonwoo Chung 1D
Sat Mar 04, 2017 1:22 am
Forum: *Organic Reaction Mechanisms in General
Topic: Reaction Mechanisms
Replies: 1
Views: 262

Re: Reaction Mechanisms

The two types of reactions that Dr. Lavelle went over during lecture were SN2 (Substitution Nucleophile 2) and Eletrophilic Addition Reaction, so we should only be responsible for knowing how to do those two.
by Soonwoo Chung 1D
Sat Mar 04, 2017 1:17 am
Forum: *Electrophilic Addition
Topic: nucleophile and electrophile reactions
Replies: 6
Views: 1077

Re: nucleophile and electrophile reactions

Yes, you must always show the arrows when drawing the organic reactions. The arrows represent the electron flow in proposed mechanisms and must be curved. The arrows should also start from the electron rich region, and go towards the region that is electron deficient.
by Soonwoo Chung 1D
Sat Mar 04, 2017 1:08 am
Forum: *Nucleophiles
Topic: Nucleophiles start reaction?
Replies: 2
Views: 344

Nucleophiles start reaction?

From what I have seen, it seems as if the nucleophiles are what always start the reaction, is this true in every case? or can the electrophiles be the ones to initiate the reaction?
by Soonwoo Chung 1D
Sat Mar 04, 2017 1:01 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Where to split molecule [ENDORSED]
Replies: 3
Views: 410

Where to split molecule [ENDORSED]

To identify or draw a molecule that is either cis or trans, we must look at where the substituents are located, but how do we know where to split the molecule to then see how the substituents are positioned?
by Soonwoo Chung 1D
Wed Mar 01, 2017 1:36 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Electron Repulsion
Replies: 1
Views: 214

Electron Repulsion

In a reaction mechanisms, bonds are formed and are typically favorable, but will there ever be an instant where the electron repulsion will be strong enough to prevent the bond from being formed?
by Soonwoo Chung 1D
Mon Feb 20, 2017 4:50 pm
Forum: First Order Reactions
Topic: Radioactive Decay
Replies: 1
Views: 295

Radioactive Decay

In the Radioactive Decay equation: -dN/dt=kN=kN(naught)e^-kt (pg. 64 in the course reader)
Why is there a k? and what does it represent?
by Soonwoo Chung 1D
Tue Feb 14, 2017 3:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Sig Fig Rules (Hess's Law)
Replies: 2
Views: 1038

Sig Fig Rules (Hess's Law)

When using Hess's Law, we add the enthalpies at the end, so do we use the sig fig rule in which we use the lowest amount of decimals even if we had to multiply the separate enthalpies to even out the equation?
by Soonwoo Chung 1D
Mon Feb 06, 2017 11:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Platinum
Replies: 1
Views: 204

Platinum

In a redox reaction where there is no solid metal present on one of the sides, it is replaced by Platinum, but what happens to the element that Platinum replaces? For example: Fe(3+) + Cu(s) --> Cu(2+) + Fe(2+) What happens to the Fe(2+)?
by Soonwoo Chung 1D
Wed Feb 01, 2017 1:39 am
Forum: General Science Questions
Topic: Sig Figs
Replies: 3
Views: 453

Sig Figs

In certain questions, there is no given data, but you can find it by looking at the table (for example, the enthalpies of formation). Would I just use the numbers I get from the table to determine the sig figs?
by Soonwoo Chung 1D
Thu Jan 26, 2017 5:04 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal?
Replies: 2
Views: 367

Isothermal?

I'm having trouble understanding some concepts so can someone please explain exactly what isothermal means?
Also, I am unsure about what R (the gas constant) is.
by Soonwoo Chung 1D
Wed Jan 18, 2017 7:43 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Calorimeter questions
Replies: 2
Views: 229

Calorimeter questions

Question from the course reader (pg. 20): In a constant p calorimeter at 25 degrees Celsius, mix 50.0ml each of 1.0 M HCL and 1.0 M NaOH. After mixing, T=31.9 degrees Celsius. How much heat released? Why is the problem solved using density and specific heat capacity of just water? I don't understand...
by Soonwoo Chung 1D
Mon Jan 09, 2017 9:50 pm
Forum: Administrative Questions and Class Announcements
Topic: No more quiz workbook?
Replies: 4
Views: 503

No more quiz workbook?

I bought the course reader today and noticed that an introduction to organic chemistry book was given instead of the quiz workbook like from 14A. Does that mean we are going to be handed out quizzes instead of having it on us?
by Soonwoo Chung 1D
Thu Dec 01, 2016 1:00 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem 14B [ENDORSED]
Replies: 3
Views: 434

Re: Chem 14B [ENDORSED]

Will the course reader be available before break, or will we have to wait until we come back? I would like to review it during break if possible.
by Soonwoo Chung 1D
Sun Nov 27, 2016 3:03 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Strong or weak? [ENDORSED]
Replies: 3
Views: 552

Strong or weak? [ENDORSED]

Is there a way to tell if a base is strong or weak? Or should we just have them memorized?
by Soonwoo Chung 1D
Mon Nov 14, 2016 10:50 pm
Forum: Naming
Topic: Ions?
Replies: 1
Views: 178

Ions?

When naming a coordinate complex, do we always have to add "ion" at the end? And if not, how do we know when to not?
by Soonwoo Chung 1D
Sat Nov 12, 2016 7:35 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Drawing Molecular Orbitals [ENDORSED]
Replies: 1
Views: 237

Drawing Molecular Orbitals [ENDORSED]

How do we determine at what level we draw the s and p orbitals for each atom? For example, for NO+, we draw the s and p orbitals for O lower than for N, but why do we do that?
by Soonwoo Chung 1D
Mon Oct 31, 2016 7:55 pm
Forum: Lewis Structures
Topic: Line structures
Replies: 1
Views: 264

Line structures

Will the midterm include line structures instead of Lewis structures and require us to know how to read them ?
by Soonwoo Chung 1D
Tue Oct 25, 2016 3:10 pm
Forum: Lewis Structures
Topic: Lewis Structure (Octet Rule)
Replies: 2
Views: 368

Lewis Structure (Octet Rule)

Why can some elements like Phosphorus bond with more than four atoms resulting in more than eight valence electrons?
by Soonwoo Chung 1D
Wed Oct 19, 2016 2:39 pm
Forum: Lewis Structures
Topic: Group 13 Elements [ENDORSED]
Replies: 1
Views: 224

Group 13 Elements [ENDORSED]

When creating a lewis structure involving group 13 elements like boron, it is okay for it to not have a complete octet? Can it have any number of electrons as long as the other atoms are satisfied?
by Soonwoo Chung 1D
Mon Oct 10, 2016 2:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Material Covered on Quiz 1
Replies: 4
Views: 638

Re: Material Covered on Quiz 1

From what I know is that the quiz will include the topics from the online modules we did over the summer (molecular formula , balancing equations, etc.) up to right before the orbitals (so the last thing we did was schrodingers equation). Can someone confirm?
by Soonwoo Chung 1D
Wed Oct 05, 2016 12:13 am
Forum: DeBroglie Equation
Topic: Measurable Wavelength (baseball) [ENDORSED]
Replies: 1
Views: 331

Measurable Wavelength (baseball) [ENDORSED]

When a baseball is thrown, there are obviously no measurable wavelike properties, but is there any way or are there any conditions that would possibly make it so that the baseball's movement does show wavelike properties?
by Soonwoo Chung 1D
Thu Sep 29, 2016 9:02 pm
Forum: Properties of Light
Topic: Kinetic Energy
Replies: 4
Views: 706

Re: Kinetic Energy

So when there is excess energy, which causes the light to bounce off, is the excess energy all kinetic energy? or is it an addition to the electrons and only intensifies the light? So what I'm asking is whether the kinetic energy itself is what is creating the light or just making it stronger.

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