## Search found 13 matches

Fri Mar 11, 2016 2:30 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Drawing Hydrogens in Conformations
Replies: 1
Views: 285

### Drawing Hydrogens in Conformations

When we are asked to draw a conformation for cyclohexane, do we always need to include all of the hydrogens? For example in question 8B on the 2012 Final we are asked to draw a ring flip and it has all of the hydrogens drawn in but isn't it implied that they are there? We already have to draw in Bro...
Tue Mar 01, 2016 4:20 pm
Forum: *Alkanes
Topic: quiz 3 prep 1 #2
Replies: 1
Views: 272

### Re: quiz 3 prep 1 #2

Someone asked this question on another post and chem_mod said either answer would be accepted. I agree with your answer because ethyl would come first if you arrange the name in alphabetical order.
Mon Feb 08, 2016 4:03 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: 8.113 Exothermic or Endothermic
Replies: 1
Views: 315

### 8.113 Exothermic or Endothermic

Part a of 8.113 asks you to find whether the production of water gas is endothermic or exothermic. It gives you the equation C(s) + H2O(g) -> CO(g) + H2(g). If you calculate ∆H for the reaction given, you get a positive value which would indicate the reaction is endothermic but the reaction doesn't ...
Thu Feb 04, 2016 3:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.21 part b cell diagram
Replies: 1
Views: 299

### 14.21 part b cell diagram

For 14.21 part b the cell diagram is written Ag(s)|AgI(s)|I-(aq)||Cl-(aq)|AgCl(s)|Ag(s) I was wondering why there are lines in between the Ag(s) and AgI(s) as well as between the AgCl(s) and Ag(s). I was under the impression that a single line indicated a phase change but in both cases they are both...
Thu Feb 04, 2016 2:50 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.17 textbook problem
Replies: 2
Views: 405

### Re: 14.17 textbook problem

We ignore both the K+ and Cl- ions because they dissociate in solution and don't undergo any change. Therefore they are spectator ions and if you included them in a chemical equation for the overall reaction they would cancel out anyways. Then you are only left with Fe2+ and MnO4- to determine which...
Sat Jan 23, 2016 3:26 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: HW 9.55 S°m?
Replies: 1
Views: 326

### HW 9.55 S°m?

For question 9.55 it asks you to solve for ∆H, ∆S and ∆G for the formation reactions of NH3, H20, CO and NO2. In the solutions manual after you solve for everything asked it says S°m(NH3,g) = 192.45 J/molK. What is this value and what does it mean? The answer to ∆S was -99.38J/molK for NH3.
Wed Jan 20, 2016 4:28 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz #1 Topics
Replies: 4
Views: 601

### Quiz #1 Topics

I know that chapters 8 and 9 will be on quiz #1 but will all of chapter 9 be covered since we only just started it in class? If not which sections will be on the quiz and which won't?
Mon Jan 18, 2016 10:24 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Quiz #1 Workbook
Replies: 2
Views: 430

### Re: Quiz #1 Workbook

My TA said that Lavelle doesn't accept photo copies of the workbook problems but if you write them out and answer them that works. I did that last quarter.
Sun Jan 10, 2016 10:33 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat
Replies: 3
Views: 424

### Re: Specific Heat

Pressure doesn't affect specific heat because the units are J/g/degree Celsius. Also, for solids and liquids the constant-volume heat and the constant-pressure heats can be said to be equal. So you are right that the factors in the equation Q=mc∆T affect specific heat but that's it.
Sat Dec 05, 2015 4:09 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Valence e- configuration in 2011 Final
Replies: 1
Views: 287

### Valence e- configuration in 2011 Final

In question 4 of the 2011 final it asks for you to write out the valence electron configuration for F2+, F2, F2- and F2^2-. In the solutions it writes out the ∏2px and ∏2py separately. Do we need to do this or can we write ∏2p^4 for example?
Fri Dec 04, 2015 4:27 pm
Forum: *Titrations & Titration Calculations
Topic: 2010 Final Q7 Henderson-Hasselbalch Equation
Replies: 4
Views: 586

### 2010 Final Q7 Henderson-Hasselbalch Equation

For part b of question 7 on the 2010 final when you are finding the pH after the addition of 10mL of NaOH why does the solution use the Ka expression instead of the Henderson-Hasselbalch equation?
Fri Oct 16, 2015 4:34 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Chlorine and Oxidation States
Replies: 5
Views: 2315

### Re: Chlorine and Oxidation States

Basically, yes. In more technical terms you are adding or subtracting electrons to go from one subshell to another which coincides with the noble gases. For example, Chlorine can have a +7 oxidation number because its electron configuration ends with 3s^2,3p^5 so if it lost those 7 electrons in the ...
Fri Oct 16, 2015 4:27 pm
Forum: Resonance Structures
Topic: Stable Lewis Structures
Replies: 2
Views: 451

### Re: Stable Lewis Structures

You can calculate the formal charge of the resonance structures and whichever has a formal charge of zero is the most stable. However, the real structure will be a sort of combination of all the possible structures.