## Search found 22 matches

Sat Mar 18, 2017 5:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 200
Views: 45769

### Re: Saying Thank You to Dr. Lavelle

Dr. Lavelle, When I was sitting in my Chem 14A final last quarter reviewing my answers it started to dawn on me how much chemistry I had really learned in your class (not just memorized) and how much we had covered in only ten weeks. Once again I have had similar realizations in 14B. I am not a very...
Sat Mar 18, 2017 5:01 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Quiz One Enthalpy Problem
Replies: 2
Views: 520

### Re: Quiz One Enthalpy Problem

Alright, thank you for the clarification; the most confusing part for me was seeing if the C-O single bond is broken before the double bond is formed. It makes sense now thanks!!
Fri Mar 17, 2017 11:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Calculating Work
Replies: 1
Views: 226

### Calculating Work

How do you calculate the work done if the system is isothermal and reversible? I'm trying to review one of the questions from quiz one and I'm a little lost.
Fri Mar 17, 2017 11:16 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Quiz One Enthalpy Problem
Replies: 2
Views: 520

### Quiz One Enthalpy Problem

For this problem I was wondering if we just calculate the bonds broken - the bonds formed to find the enthalpy of the reaction. Also I was wondering if the Carbon Oxygen bond breaks before the double bond is formed or if the double bond just forms? Thanks
Wed Mar 01, 2017 10:39 pm
Forum: *Cycloalkenes
Topic: Naming
Replies: 3
Views: 358

### Re: Naming

Thanks! and yeah that website seems really helpful
Wed Mar 01, 2017 8:07 pm
Forum: *Cycloalkenes
Topic: Naming
Replies: 3
Views: 358

### Naming

Can it be a cyclo _____ if it forms any closed shaped, like squares, pentagons, etc. ??? Also if there are two methyl groups you have dimethyl but when alphabetizing do you categorize it off of the M from "methyl" or the D from "Di"? Thanks!
Mon Feb 20, 2017 4:42 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Quiz 2
Replies: 1
Views: 316

### Quiz 2

Do we have access to the answers to quiz 2 from the course reader? I want to check my understanding of the activation energies and Arrhenius plots.
Sun Feb 12, 2017 10:10 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat Capacity
Replies: 2
Views: 304

### Specific Heat Capacity

There is a question from the homework that asks for the heat required to raise the temp of 400g of water and 500g of cu to 100 degrees celsius and how much of the heat (%) goes into just heating the water. How do we know the specific heat of cu ? Is this an open system? What is the best way to set t...
Thu Feb 02, 2017 10:43 pm
Forum: Balancing Redox Reactions
Topic: Balancing for E
Replies: 2
Views: 276

### Balancing for E

If E is intensive and we don't multiply the value of it by a coefficient when balancing a reaction, why do we need to balance it at all? Also in an example from lecture Copper becomes Copper(2) and its E=-0.34 . However, when we solve for Ecell we use the positive value of 0.34 instead even though t...
Thu Jan 26, 2017 10:04 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: +DeltaG
Replies: 1
Views: 240

### +DeltaG

If Delta G is positive than the process is not spontaneous, but does this mean it wants to go back to equilibrium and the reverse reaction starts or does it just stay where it is ?
Thu Jan 26, 2017 9:34 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Constant Temperature and Pressure
Replies: 2
Views: 284

### Constant Temperature and Pressure

For Gibbs free energy it says most reactions occur at constant temperature and pressure, but I don't understand how the temperature stays the same if the system is absorbing or losing heat (Delta H changes) ?
Sat Jan 14, 2017 4:41 pm
Forum: Phase Changes & Related Calculations
Topic: Water Phase Changes
Replies: 1
Views: 263

### Water Phase Changes

Is condensation water going through two phase changes one from liquid to vapor (vaporization) and then from a vapor back to a liquid on the outside of the container? Does this phase change occur because of the heat outside the environment making it endothermic?
Sat Dec 03, 2016 8:14 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Final Review Giving off H+ to form cations [ENDORSED]
Replies: 1
Views: 371

### Final Review Giving off H+ to form cations[ENDORSED]

How can we tell where the H+ ion will come from (which orbital) for the following compounds?
Al and Cu?
key says 3d and 4s respectively but why?
Sun Nov 27, 2016 2:31 pm
Forum: Conjugate Acids & Bases
Topic: Dissociation
Replies: 1
Views: 290

### Dissociation

In class Dr. Lavelle talks about how much CH3COO (-) dissociates as a product when CH3COOH reacts with water. How do we calculate this dissociation value??
Fri Nov 18, 2016 2:35 pm
Forum: Naming
Topic: Naming Coordination Compounds
Replies: 5
Views: 592

### Naming Coordination Compounds

When naming a coordination compound how can you determine the oxidation state of the metal? For example how would we tell if it is Copper(II) or Copper(III)?
Fri Nov 18, 2016 2:28 pm
Forum: Sigma & Pi Bonds
Topic: Bond Strength [ENDORSED]
Replies: 2
Views: 931

### Bond Strength[ENDORSED]

Why are sigma bonds stronger than pi bonds, if they are single bonds and pi bonds are double bonds? Shouldn't the double bond be stronger because it is shorter?
Mon Oct 31, 2016 6:52 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Anti-bonds in MO Diagram
Replies: 2
Views: 232

### Re: Anti-bonds in MO Diagram

Anti-bonding MO occurs when atoms are "out of phase" which means you subtract the wave functions, bonding MO happens when atoms are "in phase" which means you can add the wave functions.
Sat Oct 29, 2016 4:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape Review Problem
Replies: 1
Views: 207

### Molecular Shape Review Problem

yesterday at the review session we were creating a lewis structure for AlCl3 and we decided that it is a lewis acid because Al can accept a lone pair. Originally with three regions of electron density the shape was trigonal planar, however if it were to accept that extra lone pair would it become tr...
Fri Oct 21, 2016 11:25 pm
Forum: Bond Lengths & Energies
Topic: Bond Lengths
Replies: 3
Views: 454

### Re: Bond Lengths

So if we are trying to find which bond is stronger between a double bond and a single bond do we base it on the electronegativity of the elements or simply on the fact that one is a double bond so it must be stronger ?
Fri Oct 14, 2016 2:22 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Bonds of Octet Outliers
Replies: 3
Views: 425

### Ionic Bonds of Octet Outliers

I know that Hydrogen is "happy" with two electrons and it doesn't follow the octet rule, but for the other three elements mentioned that are outliers, how many electrons do they look for to be more stable when bonding ionically?
Fri Oct 07, 2016 12:49 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital Nodes
Replies: 1
Views: 239

### Orbital Nodes

How many nodes does the s orbital have ?

When using the equation:
Nodes= n - l - 1

What does the varivale l stand for ?
Fri Sep 30, 2016 2:08 pm
Forum: Student Social/Study Group
Topic: Rieber Hall Study Group
Replies: 2
Views: 632

### Rieber Hall Study Group

I am looking to start a study group for students living in Rieber Hall! Email me at wilsonlax21@gmail.com if you want me to add you to the group me so we can talk about times to meet.