Search found 20 matches

by Tiffany_Hoang_3C
Tue Mar 14, 2017 3:26 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Axial and Equatorial Bonds
Replies: 1
Views: 290

Axial and Equatorial Bonds

How do I identify which bond is the axial bond and which is the equatorial bond? And how do I know in which direction to draw them?
by Tiffany_Hoang_3C
Tue Mar 07, 2017 5:28 pm
Forum: *Cycloalkanes
Topic: numbering the carbons
Replies: 4
Views: 699

Re: numbering the carbons

When the numbers are the same (1 and 4), the substituent that is named first (ethyl) should get the lower number (1).
by Tiffany_Hoang_3C
Mon Feb 27, 2017 10:14 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics vs. Thermodynamics
Replies: 3
Views: 419

Re: Kinetics vs. Thermodynamics

Thermodynamic analysis tells us if the forward or reverse process if favored (but does not tell us how fast the reaction is). Kinetic analysis tells us the speed or rate of a reaction.
by Tiffany_Hoang_3C
Tue Feb 21, 2017 3:26 am
Forum: First Order Reactions
Topic: Rate 1st Order Rxn
Replies: 3
Views: 459

Re: Rate 1st Order Rxn

Yes, k is the rate constant so they are both the same. k[A] = k[A]oe-kt is not meant to be seen as an equation, but rather as two different ways to express the rate of a 1st order reaction.
by Tiffany_Hoang_3C
Mon Feb 13, 2017 4:54 pm
Forum: First Order Reactions
Topic: Reaction Order Graphs
Replies: 1
Views: 286

Reaction Order Graphs

What would the graphs of a first-order reaction and a second-order reaction look like if we plotted time vs. [A] (instead of time vs. ln[A] and time vs. 1/[A], respectively)?
by Tiffany_Hoang_3C
Wed Feb 08, 2017 9:53 pm
Forum: General Rate Laws
Topic: Orders
Replies: 1
Views: 246

Orders

What does the order (first, second, zero) indicate about a reaction?
by Tiffany_Hoang_3C
Mon Jan 30, 2017 10:27 pm
Forum: Phase Changes & Related Calculations
Topic: Quiz 1
Replies: 11
Views: 943

Re: Quiz 1

The solutions are posted under the topic "Administrative Questions and Class Announcements".
by Tiffany_Hoang_3C
Wed Jan 25, 2017 10:23 am
Forum: Administrative Questions and Class Announcements
Topic: Fall Quarter Finals
Replies: 2
Views: 373

Re: Fall Quarter Finals

Finals are already available for pick-up in Young Hall 3034.
by Tiffany_Hoang_3C
Sat Jan 21, 2017 11:27 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Examples of Isolated systems [ENDORSED]
Replies: 3
Views: 894

Re: Examples of Isolated systems [ENDORSED]

An isolated system is one in which both matter and energy cannot exchange with the surroundings. Not sure if these were shared in your discussion, but some examples of isolated systems include a (very high quality) thermos bottle, a bomb calorimeter, and the universe.
by Tiffany_Hoang_3C
Mon Jan 16, 2017 11:33 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard State [ENDORSED]
Replies: 1
Views: 313

Standard State [ENDORSED]

Can someone please clarify what the standard state for a pure liquid or solid is? Also, the standard state of an element?
by Tiffany_Hoang_3C
Tue Nov 29, 2016 6:43 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7580
Views: 1012701

Re: Post All Chemistry Jokes Here

Q: Why do chemists enjoy working with ammonia?
A: Because it's pretty basic stuff.
by Tiffany_Hoang_3C
Mon Nov 21, 2016 6:40 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: pKa and pKb
Replies: 2
Views: 301

Re: pKa and pKb

Yes, you are correct! pKA and pKB are measured on a scale of 0 to 14 since pKA=-logKA and pKB=-logKB.

A smaller pKB does indicate a stronger base and a smaller pKA does indicate a stronger acid.
by Tiffany_Hoang_3C
Thu Nov 17, 2016 4:57 pm
Forum: Naming
Topic: Quizlet for the names of Common Ligands
Replies: 10
Views: 1127

Re: Quizlet for the names of Common Ligands

We use prefixes like bis-, tris-, etc when the ligand is a polydentate and we need to indicate the number of ligands. For example, (en) 2 would be bisethylenediamine because en is a bidentate (it binds at two sites and donates two electron pairs) and there are two of that ligand (which is why it is ...
by Tiffany_Hoang_3C
Thu Nov 10, 2016 1:19 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: MO diagram [ENDORSED]
Replies: 2
Views: 286

Re: MO diagram [ENDORSED]

For Z < 8, because the nuclear charge is less, the energy difference between filled s-orbitals and p-orbitals is less. The e- density from filled sigma and sigma* orbitals is concentrated along the bond axis, resulting in electron-electron repulsion and thus, a higher energy sigma orbital.
by Tiffany_Hoang_3C
Mon Oct 31, 2016 2:00 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: D-block exceptions for midterm and f-block
Replies: 4
Views: 635

Re: D-block exceptions for midterm and f-block

In the course reader on page 66, it says we only need to know the s-block, the p-block, and the first row of d-block. So I think chromium and copper are the only exceptions we need to know.
by Tiffany_Hoang_3C
Wed Oct 26, 2016 12:15 am
Forum: Lewis Structures
Topic: Central Atom
Replies: 5
Views: 605

Re: Central Atom

The least electronegative atom means not a lot of energy is needed to remove an electron from the atom. This means that it is more likely to share electrons and create bonds, making it a good central atom.
by Tiffany_Hoang_3C
Tue Oct 18, 2016 9:46 pm
Forum: Resonance Structures
Topic: Formal Charge [ENDORSED]
Replies: 3
Views: 451

Re: Formal Charge [ENDORSED]

For the second question, the formal charge of an atom indicates either a gain or loss of electrons when forming a covalent bond. The equation for formal charge is FC = V - (L + S/2) where V is the number of valence electrons, L is the number of lone pair electrons, and S is the number of shared elec...
by Tiffany_Hoang_3C
Mon Oct 10, 2016 2:03 pm
Forum: Einstein Equation
Topic: What is the difference between deltaE=hv and E=hv?
Replies: 5
Views: 3005

Re: What is the difference between deltaE=hv and E=hv?

ΔE is the change in energy (which can be positive or negative and can be found if given the frequency/wavelength of a light emitted/absorbed when an electron moves to a different energy level) while E is simply the energy of a given wavelength/frequency. In #10, we subtract the E of the energy level...
by Tiffany_Hoang_3C
Mon Oct 03, 2016 1:35 pm
Forum: Properties of Light
Topic: C=λV units question
Replies: 3
Views: 1108

Re: C=λV units question

The wavelength will be in meters. Rearranging the equation for wavelength, λ=c/v. Since c is in m/s and the frequency is in Hz (which is s^-1 or 1/s), the s will cancel out, leaving you with m.
by Tiffany_Hoang_3C
Fri Sep 30, 2016 12:21 am
Forum: Limiting Reactant Calculations
Topic: Steps for Limiting Reactant Problems
Replies: 4
Views: 846

Re: Steps for Limiting Reactant Problems

Can a rxn have two limiting reactants? And is it possible that a rxn has no limiting reactants at all? A reaction cannot have two limiting reactants. The limiting reactant is the reactant that limits (the most) the amount of product that can be formed. There will be at most one limiting reactant. H...

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