Search found 22 matches
- Mon Feb 29, 2016 12:50 pm
- Forum: *Alkenes
- Topic: Homework 1.12C naming
- Replies: 2
- Views: 703
Re: Homework 1.12C naming
Yup, you want to give the double bond priority in numbering. So give it the lowest number first. In numbering, the priority goes as follows: 1. functional groups like --OH or carboxylic acid 2. double or triple bonds 3. other substituent groups Try to give #1 and #2 the lowest numbers first before p...
- Sat Feb 27, 2016 3:53 pm
- Forum: *Alkanes
- Topic: Ambident Nucleophiles
- Replies: 2
- Views: 934
Re: Ambident Nucleophiles
By definition, an ambident nucleophile is a molecule that has available lone pairs of electrons on two or more of its atoms--in other words, 2 places on it where it can react with another molecule. Draw out the Lewis structures to see. (It's similar to the idea of a bidentate ligand from 14A). Refer...
- Mon Feb 08, 2016 3:56 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Answer Book Error 14.35 (b)
- Replies: 1
- Views: 487
Re: Answer Book Error 14.35 (b)
Yes, it is an error. There's some posts about it: viewtopic.php?f=140&t=11410&p=28315&hilit=solution+manual+error&
- Mon Feb 08, 2016 3:53 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Negative Cell Potential
- Replies: 1
- Views: 514
Re: Negative Cell Potential
In electrolysis the Eo value is a negative value. The reaction isn't spontaneous, and you need to use an electric current to overcome the negative voltage and force it to occur.
- Mon Feb 08, 2016 3:47 pm
- Forum: Balancing Redox Reactions
- Topic: Redox Reactions
- Replies: 1
- Views: 491
Re: Redox Reactions
It's usually given in the question. It'll specify if it's in acidic or basic solution, and you can balance the H+ and OH- as needed.
- Sun Feb 07, 2016 4:14 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Water and Cell Diagrams
- Replies: 2
- Views: 640
Re: Water and Cell Diagrams
When the reaction involves aqueous ions (like Ag+) it's assumed that the water in the solution doesn't affect the reaction. However if another phase of water is involved in the reaction then yes the liquid water (or H+ and OH- ions) should be taken into account.
- Sun Jan 24, 2016 4:58 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Standard residual entropy problem
- Replies: 2
- Views: 2102
Re: Standard residual entropy problem
To answer the question, you need to draw the lewis structure for COF2. You should get a trigonal planar shape with C in the center. You could get 3 different orientations of the molecule since the O can be in one of the three corners. Following the equation, S = k ln W (refer to pg. 32 of course rea...
- Sun Jan 24, 2016 4:46 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: 8.49
- Replies: 2
- Views: 599
Re: 8.49
I believe the +1 mol is from 2 mol reactants --> 3 mol products. So change of mols was 3-2 =1.
Other people have posted about this question before so I recommend checking those out :]
Other people have posted about this question before so I recommend checking those out :]
- Fri Jan 22, 2016 7:01 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Homework Question 8.49 - Why can you not use a mole ratio?
- Replies: 4
- Views: 1023
Re: Homework Question 8.49 - Why can you not use a mole rati
I believe that the "net production of 1 mole of gas" refers to the fact that 1 mole of OF2 (part of the 2 moles of total reactant) produces 3 moles of product. Thus, the net difference is 3-2 moles = 1 mole of gas difference between reactants and products.
- Mon Jan 11, 2016 1:07 pm
- Forum: Trends in The Periodic Table
- Topic: Lavelle's favorite periodic table
- Replies: 2
- Views: 2737
Re: Lavelle's favorite periodic table
Mine is the rice krispy periodic table :)
(this was for my birthday a while back)
https://drive.google.com/file/d/0BzeS9b9yItnNYkVYY0Z5Y2VjWEU/view?usp=sharing
(this was for my birthday a while back)
https://drive.google.com/file/d/0BzeS9b9yItnNYkVYY0Z5Y2VjWEU/view?usp=sharing
- Sat Dec 05, 2015 8:35 pm
- Forum: Lewis Structures
- Topic: Determining which element to give a formal charge
- Replies: 3
- Views: 838
Re: Determining which element to give a formal charge
Although chlorine is in period 3, it's so electronegative that it doesn't like sharing electrons, and usually won't form anything more than one single bond. Thus, it's an exception to the expanded octet rule for periods >= 3.
- Sat Dec 05, 2015 1:33 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: (Br2)2+ Paramagnetic or Diamagnetic
- Replies: 3
- Views: 3029
Re: (Br2)2+ Paramagnetic or Diamagnetic
It's a mistake. It's paramagnetic. Lavelle replied here: viewtopic.php?f=43&t=8834&p=22074&hilit=br2&
- Mon Nov 30, 2015 10:11 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3916777
Re: Chemistry Jokes
Q: Why should you never give up studying chemistry even if you feel like you're going to fail the final?
A: Because chem-is-try! <3
A: Because chem-is-try! <3
- Wed Nov 18, 2015 8:43 pm
- Forum: Naming
- Topic: Using prefixes bis-, tris-, etc.
- Replies: 3
- Views: 1027
Re: Using prefixes bis-, tris-, etc.
Why does that problem put diaqua before bixoxalato? Isn't it supposed to be according to alphabetical order?
so sodium diaqua bisoxalato ferrate (III)
so sodium diaqua bisoxalato ferrate (III)
- Mon Nov 16, 2015 7:37 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Enrolling in 14BL
- Replies: 1
- Views: 914
Re: Enrolling in 14BL
The UCLA registrar site says that CHEM14B is an enforced corequisite to CHEM14BL, so I assume they won't let you enroll in the lab until you're in the lecture first...can anyone confirm? I have the same problem. Link: http://www.registrar.ucla.edu/schedule/subdet.aspx?srs=142117200&term=16W&...
- Sun Nov 01, 2015 3:50 pm
- Forum: Empirical & Molecular Formulas
- Topic: Which methods to use when finding empirical formulas
- Replies: 2
- Views: 897
Re: Which methods to use when finding empirical formulas
I use the same methods as you do for those types of problems, and it wasn't marked incorrect or anything on the first quiz (after all, we arrive at the same answer). So, I assume it's okay to do so.
- Sun Nov 01, 2015 3:35 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: MO diagrams
- Replies: 2
- Views: 518
Re: MO diagrams
No. One element would have lower orbitals than the other only if it has a larger electronegativity.
- Sun Nov 01, 2015 3:33 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Valence e- Configuration
- Replies: 1
- Views: 449
Re: Valence e- Configuration
I'm not quite sure what you're asking, but yes, whenever you want to find the electronic configuration of a diatomic molecule you should draw out the MO diagram. I find, however, that drawing only the middle portion of the diagram (the combined orbitals) is often sufficient to answer questions about...
- Wed Oct 21, 2015 11:40 am
- Forum: Electronegativity
- Topic: Electronegativity and Bond Strength
- Replies: 4
- Views: 3790
Re: Electronegativity and Bond Strength
I think the reason for this is that when the electronegativity difference is high, the electrostatic attraction between the positive and negative charges will also be high, causing a shorter bond length. The bond also takes on an increasingly ionic character. I'm not sure, however, if ionic compound...
- Wed Oct 21, 2015 11:21 am
- Forum: Electronegativity
- Topic: Which element is more electronegative?
- Replies: 1
- Views: 1754
Re: Which element is more electronegative?
Oxygen is more electronegative than chlorine. It has an electronegativity unit of 3.5 while chlorine is 3.0. But I'm fairly certain we only need to know the general trend and not specific details like this. http://butane.chem.uiuc.edu/cyerkes/chem102ae_fa08/homepage/Chem102AEFa07/Lecture_Notes_102/L...
- Fri Oct 09, 2015 11:59 am
- Forum: Administrative Questions and Class Announcements
- Topic: Differences between 5th Edition and 6th Edition textbook
- Replies: 1
- Views: 2131
Differences between 5th Edition and 6th Edition textbook
I have the 5th edition textbook instead of the 6th. I've realize that some of the homework problems assigned may not correspond to the ones in the 5th edition. For instance, there was a question assigned on black body radiation which we obviously did not cover. I believe that chapter 1 might have be...
- Fri Oct 02, 2015 4:40 pm
- Forum: Significant Figures
- Topic: All students read this sig fig post [ENDORSED]
- Replies: 170
- Views: 36699
Re: All students read this sig fig post [ENDORSED]
If we are calculating values using only constants, such as the wavelength of light emitted when an electron jumps from energy level n=4 to n=2, how many sig-figs should we use? Will we be using a sheet for constants and equations during exams (and thus should we follow the amount of sig-figs given t...