Search found 30 matches
- Tue Dec 04, 2018 11:33 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: KBr has Neutral pH ?
- Replies: 1
- Views: 1223
Re: KBr has Neutral pH ?
KF dissociates into K+ and F- in solution. K+ would not be a good proton acceptor, since K+ and H+ don't react at all. F- and H+ on the other hand do react, making the weak acid of HF. Since HF is a weak acid, it will only partially dissociate, with only some of it turning back into the individual c...
- Tue Dec 04, 2018 11:14 am
- Forum: Amphoteric Compounds
- Topic: Amphoteric Structure
- Replies: 2
- Views: 439
Re: Amphoteric Structure
The situation you described made me think of [SO3]-2 (sulfite), but I don't think that it's able to accept a single proton. Same goes for sulfurous acid, [H2SO3]-2 since it doesn't accept a proton to make H3SO3-. This is just one example of atoms with expanded octets, so maybe other ones can be amph...
- Tue Dec 04, 2018 10:30 am
- Forum: Air Pollution & Acid Rain
- Topic: Reducing Acid Rain
- Replies: 4
- Views: 2209
Re: Reducing Acid Rain
Another technology that can be used to reduce acid rain is the catalytic converter, which is a device for cars that transforms toxic gases into less toxic pollutants by way of a redox reactions. The combustion reactions that take place in catalytic converters are as follows: 1. 2CO + O2 -> 2CO2 2. C...
- Wed Nov 28, 2018 3:13 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligand charge
- Replies: 4
- Views: 634
Re: Ligand charge
Like Matthew said, CN- is a common polyatomic ion that we are expected to know for tests and such. (Don't feel bad if you didn't have it memorized, just try to incorporate them into hw problems to the point where they become natural.) Using the knowledge that CN has a -1 charge, you can figure out t...
- Wed Nov 28, 2018 3:07 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Happy Lavelle [ENDORSED]
- Replies: 5
- Views: 1220
Re: Happy Lavelle [ENDORSED]
Thank you for this
- Wed Nov 28, 2018 2:47 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: TM charge
- Replies: 4
- Views: 478
Re: TM charge
One way to think of it is by looking at the coordination compound, [Ni(NH3)4 Cl] Cl . 2H2O in this case, as a more complex version of something like HCl, where the H is replaced by the the [Ni(NH3)4 Cl] complex. I'm not exactly sure about the relationship between the complex and the Cl outside of th...
- Wed Nov 28, 2018 2:32 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond angles of See Saw
- Replies: 2
- Views: 2089
Re: Bond angles of See Saw
Yeah the angles would be slightly less than 90 and 120 degrees due to the lone pair, but you wouldn't have to give exact numbers on a test or anything
- Wed Nov 28, 2018 2:28 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw Bond Angles
- Replies: 6
- Views: 16111
Re: Seesaw Bond Angles
Probably wouldn't hurt to list 180 as a bond angle
- Tue Nov 27, 2018 12:18 pm
- Forum: Hybridization
- Topic: hybridization and radicals
- Replies: 2
- Views: 391
Re: hybridization and radicals
Could you give an example? It may be easier to explain using a specific case of hybridization, but in general the unpaired electron will impact the hybridization of the molecule in some way, similar to how electron pairs would.
- Thu Nov 15, 2018 2:20 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Will we have to calculate bond angles?
- Replies: 8
- Views: 745
Re: Will we have to calculate bond angles?
Yeah I think we just need to know what angles are affiliated with the different shapes, but that should be feasible through thinking about electron pair repulsion.
- Thu Nov 15, 2018 1:03 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Thanksgiving [ENDORSED]
- Replies: 14
- Views: 1589
Re: Thanksgiving [ENDORSED]
Dana Wilks 3I wrote:He still hasn't announced if next week's Wednesday lecture will be cancelled. Hopefully we'll be ahead enough!
Does anyone know exactly what point in the book we have to get to to be considered ahead?
- Thu Nov 15, 2018 12:56 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Thanksgiving [ENDORSED]
- Replies: 14
- Views: 1589
Re: Thanksgiving [ENDORSED]
Hey all, here is a fun article about some chemistry that can be applied to Thanksgiving! Hope everyone has a great break!
https://sciencebob.com/bend-a-bone-with-vinegar/
https://sciencebob.com/bend-a-bone-with-vinegar/
- Thu Nov 08, 2018 2:41 pm
- Forum: Bond Lengths & Energies
- Topic: MIDTERM Bond Length Question
- Replies: 15
- Views: 1597
Re: MIDTERM Bond Length Question
During lecture Lavelle gave us the experimental value for the average bond length in Nitrate, which turned out to be 1.24 A, maybe because when you draw the three possible structures for NO3-, there are two single bonds and one double bond. That being said, I think the correct answer on the midterm ...
- Thu Nov 08, 2018 2:38 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Difference between the bonds
- Replies: 4
- Views: 624
Re: Difference between the bonds
Elisa explained it well, but here is a graphical representation which might help:
https://www.chem.purdue.edu/gchelp/liquids/inddip.html
https://www.chem.purdue.edu/gchelp/liquids/inddip.html
- Thu Nov 08, 2018 2:34 pm
- Forum: Bond Lengths & Energies
- Topic: bond lengths and strengths
- Replies: 9
- Views: 938
Re: bond lengths and strengths
As previous posters have made clear, single bonds are typically longer and weaker, while double and triple bonds are each shorter and stronger. I think the strength of single/double/triple bonds also has to do with the lone electron pairs, however. In a single bond, for example, you will typically h...
- Fri Nov 02, 2018 1:49 am
- Forum: Dipole Moments
- Topic: London Forces
- Replies: 7
- Views: 948
Re: London Forces
Are Van der Waal Forces a specific type of dispersion force or can they be used interchangeably?
- Fri Nov 02, 2018 1:39 am
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bond Definition
- Replies: 14
- Views: 1864
Re: Coordinate Covalent Bond Definition
What properties (e.g. bond energy, melting point) does a coordinate covalent bond that differ from a normal covalent bond?
- Fri Nov 02, 2018 1:35 am
- Forum: Sigma & Pi Bonds
- Topic: Easy way of remembering the difference
- Replies: 6
- Views: 723
Re: Easy way of remembering the difference
Albert Duong 1B wrote:Generally, single bonds are always sigma bonds, but multiple bonds will have both sigma and pi bonds.
In what situations would single bonds not be sigma bonds?
- Tue Oct 23, 2018 12:21 pm
- Forum: DeBroglie Equation
- Topic: problem 43 6th edition
- Replies: 4
- Views: 433
Re: problem 43 6th edition
To solve for this, we would use the equation ∆x∆p = h/4π. For an electron, ∆p = m∆v, and therefore, m∆x∆v = h/4π. The uncertainty on position of an electron would be the diameter of the atom so ∆x = 350 pm. "m" is the mass of the electron which is 9.109*10^-31 kg and h=6.626*10^-34 J.s Ho...
- Tue Oct 23, 2018 12:15 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: What is the equation used for?
- Replies: 9
- Views: 870
Re: What is the equation used for?
So should we expect to have to use this equation on the test/midterm/final? Or more just understand the concept?
- Tue Oct 23, 2018 12:03 pm
- Forum: Student Social/Study Group
- Topic: Studying for tests/midterm
- Replies: 18
- Views: 2787
Studying for tests/midterm
How do you guys usually study for our tests? Typically I just review the chapter/notes and do some practice problems. Is there another good way to review?
- Fri Oct 19, 2018 12:12 am
- Forum: Properties of Electrons
- Topic: electrons
- Replies: 3
- Views: 467
Re: electrons
Electrons have wavelike properties due to the diffraction patterns that they form, due in part to their extremely small size
- Thu Oct 18, 2018 11:47 pm
- Forum: *Black Body Radiation
- Topic: Black Body
- Replies: 10
- Views: 1347
Re: Black Body
So does the concept of black bodies explain why objects go from being red hot to being white hot?
- Thu Oct 18, 2018 11:38 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 409209
Re: Advice from a Medical Student [ENDORSED]
Thanks for the advice! Would you say the same thing applies for students planning on going to graduate/professional school in a STEM field, but not necessarily med school? Absolutely! Dr. Lavelle's Chem14A and 14B courses are imperative for laying down the foundation for any science classes you tak...
- Fri Oct 12, 2018 12:40 am
- Forum: Einstein Equation
- Topic: Symbol for frequency
- Replies: 12
- Views: 2289
Re: Symbol for frequency
I imagine we should stick to v (nu) since that's what Lavelle has used in lectures and will likely look for on exams.
- Fri Oct 12, 2018 12:38 am
- Forum: Properties of Light
- Topic: speed of light
- Replies: 8
- Views: 672
Re: speed of light
Sort of unrelated, but since we are working solely with the speed of light in a vacuum, I'm wondering what the speed of light is when not in a vacuum (if that even makes sense?)
- Fri Oct 12, 2018 12:33 am
- Forum: Properties of Electrons
- Topic: Quantum World
- Replies: 6
- Views: 554
Re: Quantum World
On a related note, is there any connection between the velocity of an electron and frequency? 1B.15 asks for wavelength of an ejected electron using a given velocity, so I am unsure of how to approach the problem.
- Tue Oct 02, 2018 12:13 pm
- Forum: Empirical & Molecular Formulas
- Topic: Formula unit
- Replies: 3
- Views: 508
Re: Formula unit
Yeah as Rosemary said, formula unit refers to the empirical formula of a compound, or the lowest ratio of ions in an ionic compound. For example, NaCl is the formula unit of table salt/sodium chloride. Other compounds like NH4NO2 are a little more complicated, since one might think it could just be ...
- Tue Oct 02, 2018 11:43 am
- Forum: Empirical & Molecular Formulas
- Topic: Percent Composition
- Replies: 5
- Views: 638
Re: Percent Composition
I agree with Andie on this one, in that just comparing the number of atoms in a compound is an unreliable way of determining mass composition. Rather, you can estimate the percent mass by comparing rounded values of the 3 elements in nitric acid (H ~ 1g, N ~ 14g, O3 ~ 48g), and see that oxygen has t...
- Mon Oct 01, 2018 12:10 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 409209
Re: Advice from a Medical Student [ENDORSED]
Thanks for the advice! Would you say the same thing applies for students planning on going to graduate/professional school in a STEM field, but not necessarily med school?