## Search found 20 matches

Tue Mar 14, 2017 3:26 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Axial and Equatorial Bonds
Replies: 1
Views: 315

### 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?
Tue Mar 07, 2017 5:28 pm
Forum: *Cycloalkanes
Topic: numbering the carbons
Replies: 4
Views: 782

### 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).
Mon Feb 27, 2017 10:14 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics vs. Thermodynamics
Replies: 3
Views: 461

### 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.
Tue Feb 21, 2017 3:26 am
Forum: First Order Reactions
Topic: Rate 1st Order Rxn
Replies: 3
Views: 527

### 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.
Mon Feb 13, 2017 4:54 pm
Forum: First Order Reactions
Topic: Reaction Order Graphs
Replies: 1
Views: 315

### 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)?
Wed Feb 08, 2017 9:53 pm
Forum: General Rate Laws
Topic: Orders
Replies: 1
Views: 267

### Orders

What does the order (first, second, zero) indicate about a reaction?
Mon Jan 30, 2017 10:27 pm
Forum: Phase Changes & Related Calculations
Topic: Quiz 1
Replies: 11
Views: 1050

### Re: Quiz 1

The solutions are posted under the topic "Administrative Questions and Class Announcements".
Wed Jan 25, 2017 10:23 am
Forum: Administrative Questions and Class Announcements
Topic: Fall Quarter Finals
Replies: 2
Views: 408

### Re: Fall Quarter Finals

Finals are already available for pick-up in Young Hall 3034.
Sat Jan 21, 2017 11:27 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Examples of Isolated systems [ENDORSED]
Replies: 3
Views: 1290

### 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.
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: 336

### 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?
Tue Nov 29, 2016 6:43 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7951
Views: 1123498

### Re: Post All Chemistry Jokes Here

Q: Why do chemists enjoy working with ammonia?
A: Because it's pretty basic stuff.
Mon Nov 21, 2016 6:40 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: pKa and pKb
Replies: 2
Views: 336

### 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.
Thu Nov 17, 2016 4:57 pm
Forum: Naming
Topic: Quizlet for the names of Common Ligands
Replies: 10
Views: 1245

### 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 ...
Thu Nov 10, 2016 1:19 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: MO diagram [ENDORSED]
Replies: 2
Views: 321

### 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.
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: 702

### 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.
Wed Oct 26, 2016 12:15 am
Forum: Lewis Structures
Topic: Central Atom
Replies: 5
Views: 668

### 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.
Tue Oct 18, 2016 9:46 pm
Forum: Resonance Structures
Topic: Formal Charge [ENDORSED]
Replies: 3
Views: 505

### 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...
Mon Oct 10, 2016 2:03 pm
Forum: Einstein Equation
Topic: What is the difference between deltaE=hv and E=hv?
Replies: 5
Views: 3479

### 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...
Mon Oct 03, 2016 1:35 pm
Forum: Properties of Light
Topic: C=λV units question
Replies: 3
Views: 1193

### 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.
Fri Sep 30, 2016 12:21 am
Forum: Limiting Reactant Calculations
Topic: Steps for Limiting Reactant Problems
Replies: 4
Views: 937

### 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...