## Search found 22 matches

Thu Mar 16, 2017 7:28 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Gauche conformations
Replies: 2
Views: 374

### Re: Gauche conformations

Gauche is the second lowest conformation; they occur at 60 degrees and 300 degrees. The anti-conformation is the lowest configuration because it is the maximum distance away between two molecules. You can draw some examples of different newman models with different substituents so you can visualize ...
Mon Mar 13, 2017 10:18 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 2013 Final Exam #2
Replies: 3
Views: 461

### Re: 2013 Final Exam #2

Why did you switch the signs for hydrolysis of ATP form positive to negative and the formation of acetyl phosphate from negative to positive?
Wed Mar 08, 2017 2:09 pm
Forum: *Alkanes
Topic: Quiz 3 Drop -- do I show up? [ENDORSED]
Replies: 3
Views: 394

### Re: Quiz 3 Drop -- do I show up?[ENDORSED]

You need to have a score to drop before it can be replaced. So yes, you need to go to discussion and take the quiz even though you plan on dropping it.
Sun Mar 05, 2017 6:44 pm
Forum: *Alkanes
Topic: Numbers
Replies: 1
Views: 222

### Re: Numbers

If you have two substituents and they're both the same distance apart (ex; either way will result in a count of 1 and 4) then you would put the substituent in alphabetical order with the first getting the lowest number, in this case 1. If you have 2 or more substituents then the alphabetical order s...
Sat Feb 25, 2017 4:50 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre-Equilibrium Approach
Replies: 2
Views: 284

### Re: Pre-Equilibrium Approach

If the slow step is first then you can just right the rate law using concentrations in that step. However, if there is a fast step followed by a slow step then you would have to use the pre-equilibrium approach because intermediate values would be in your overall rate law, which you cannot allow. Yo...
Mon Feb 13, 2017 3:07 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert Metallic Components
Replies: 3
Views: 277

### Re: Inert Metallic Components

You would use a metal component like platinum when none of the reactants or products in a half-reaction are solids. For example, in the half-reaction H2(g) --> 2H+(aq) + 2e- , neither side of the reaction (reactants or products) includes a solid, so a platinum electrode is required. thanks for the ...
Sun Feb 12, 2017 10:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Inert Metallic Components
Replies: 3
Views: 277

### Inert Metallic Components

What is the function of inert metallic components such as platinum? How do we know when to use it? Can you give an example if possible? Thanks.
Mon Feb 06, 2017 9:39 pm
Forum: Administrative Questions and Class Announcements
Topic: Review Sessions
Replies: 1
Views: 207

### Review Sessions

Are the review sessions conducted by UAs/TAs organized in anyway? I need some help on certain topics but I don't want to go to a review session that focuses on something else.
Thu Feb 02, 2017 12:40 am
Forum: Administrative Questions and Class Announcements
Replies: 130
Views: 13525

### Re: Quiz 1 Preparation Answers

#8 on Quiz 1 Preparation says, "For reaction: 2C+2H2=C2H4, DeltaH= +52.3 kJ/mol and DeltaS= -53.07 J/K*mol at 298 K. At what temperature will this reaction be spontaneous?" Initially, I thought the formula needed to solve for the temperature was DeltaG= DeltaH - T*DeltaS but then I saw th...
Fri Jan 27, 2017 5:22 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Question 9.23
Replies: 1
Views: 194

### Re: Question 9.23

Entropy is the measure of disorder in a system. That being said, when we describe the randomness/disorder for the fluorines in BF3, it is essentially 0 because no matter how we arrange the fluorine atoms it will have the same end arrangement. COF2 however, while having a trigonal planar shape, has t...
Mon Jan 23, 2017 2:22 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Homework 8.73 a
Replies: 3
Views: 373

### Re: Homework 8.73 a

The total number for C-H bonds for both sides is six. (3mol C2H2= 6 CH). The only things breaking and forming are the C-C triple bond and C-2 double bond. If you compare the products and reactants you can see what you need to calculate to get your answer. In this case, you can ignore the carbon-hydr...
Sat Jan 14, 2017 11:37 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: question 8.57
Replies: 2
Views: 252

### Re: question 8.57

Because this is a combustion reaction (subscript of C), C2H2, C2H6, and H2 will be ignited with O2 to form H20 and CO2. You should have three different reactions that show this. Since your final equation is show as C2H2+2H2 ---> C2H6, you have to rearrange and balance equations in a way that will eq...
Sat Dec 03, 2016 12:02 pm
Forum: *Titrations & Titration Calculations
Topic: 2007 Final Q5
Replies: 2
Views: 568

### 2007 Final Q5

Do we need to memorize compounds of acids and bases for the final? Knowing what methylamine for this question was worth four points alone.
Fri Nov 25, 2016 2:23 pm
Forum: Bronsted Acids & Bases
Topic: Strong vs. weak
Replies: 3
Views: 475

### Re: Strong vs. weak

You can determine the strength of an acid or a base by looking at the atomic radius. For acids, the larger the atomic radius, the more susceptible it will be to losing a hydrogen making it a stronger acid.

In other cases you will need to mathematically find the values for pH.
Sun Nov 13, 2016 9:57 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Sigma and Pi order in MO
Replies: 1
Views: 169

### Sigma and Pi order in MO

What order are you supposed to put the sigma and pi bonds when doing the molecular orbital theory? In some cases in the 2p orbitals, the sigma bond is lower in energy than the pi bonds and the opposite in other cases. I think there was a rule about switching between the two once you hit the 8th char...
Sat Nov 12, 2016 11:24 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Naming NH4[PtCl3(NH3)]
Replies: 2
Views: 1502

### Re: Naming NH4[PtCl3(NH3)]

Determine if the entire compound is neutral, negatively, or positively charged. After adding up the charges of different molecules in the compound, you can then determine what charge/roman numeral to put on the metal. In this case you would need to write Platinum (II) to make the compound neutral.
Sun Oct 30, 2016 11:44 pm
Forum: Hybridization
Topic: Hybridization [ENDORSED]
Replies: 3
Views: 393

### Re: Hybridization[ENDORSED]

Megan M 1L wrote:How do you figure out out the hybridization from the number of regions of electron density? How does 3 regions correlate to sp2?

Look on page 103 in the course reader. Different numbers of electron densities correlates with a specific hybrid orbital.
Sat Oct 29, 2016 10:52 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent and Ionic Character
Replies: 3
Views: 522

### Covalent and Ionic Character

Hey everyone. I've reread the book over and over again about the sections dealing with ionic and covalent characteristics. What exactly are the differences between the two and how do you order each one from largest to smallest or smallest to largest? I had trouble with this on my second quiz and i s...
Mon Oct 24, 2016 6:28 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Characters
Replies: 5
Views: 640

### Ionic Characters

When subtracting electronegativities of a molecule, do you take into account a subscript of an element?
For example, H2S. Would I need to multiply the electronegativity of hydrogen by two before subtracting it from sulfur, or do I just subtract the two without multiplying them.
Sat Oct 15, 2016 10:28 pm
Forum: Student Social/Study Group
Topic: Evergreen Study Group
Replies: 5
Views: 660

### Re: Evergreen Study Group

it won't let me post a question as an independent thread but hopefully you guys can help me out with this question. can I go to different discussion sessions for quizzes? Im on a team and might miss an upcoming quiz.
Sun Oct 09, 2016 12:00 am
Forum: Properties of Light
Topic: Properties of Light [ENDORSED]
Replies: 1
Views: 214

### Properties of Light[ENDORSED]

Hey everyone. I just wanted some people to clarify if light had properties relating to waves. In the video module about the photoelectric effect, Prof. Lavelle said that light did not increase in energy whenever the frequency increased, therefore saying that light does not have wave properties. But ...
Sat Oct 01, 2016 1:26 pm
Forum: Student Social/Study Group
Topic: Hedrick Summit Study Group Chem 14A
Replies: 29
Views: 2532

### Re: Hedrick Summit Study Group Chem 14A

I'm on the 8th floor of Summit! Add me to the study group!