Search found 30 matches

by Sam Kelly 1K
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: 43

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...
by Sam Kelly 1K
Tue Dec 04, 2018 11:14 am
Forum: Amphoteric Compounds
Topic: Amphoteric Structure
Replies: 2
Views: 46

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...
by Sam Kelly 1K
Tue Dec 04, 2018 10:30 am
Forum: Air Pollution & Acid Rain
Topic: Reducing Acid Rain
Replies: 4
Views: 1144

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...
by Sam Kelly 1K
Wed Nov 28, 2018 3:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand charge
Replies: 4
Views: 45

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...
by Sam Kelly 1K
Wed Nov 28, 2018 3:07 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Happy Lavelle [ENDORSED]
Replies: 5
Views: 566

Re: Happy Lavelle [ENDORSED]

Thank you for this
by Sam Kelly 1K
Wed Nov 28, 2018 2:47 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: TM charge
Replies: 4
Views: 41

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...
by Sam Kelly 1K
Wed Nov 28, 2018 2:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles of See Saw
Replies: 2
Views: 32

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
by Sam Kelly 1K
Wed Nov 28, 2018 2:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw Bond Angles
Replies: 6
Views: 4322

Re: Seesaw Bond Angles

Probably wouldn't hurt to list 180 as a bond angle
by Sam Kelly 1K
Tue Nov 27, 2018 12:18 pm
Forum: Hybridization
Topic: hybridization and radicals
Replies: 2
Views: 24

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.
by Sam Kelly 1K
Thu Nov 15, 2018 2:20 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Will we have to calculate bond angles?
Replies: 8
Views: 72

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.
by Sam Kelly 1K
Thu Nov 15, 2018 1:03 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Thanksgiving [ENDORSED]
Replies: 14
Views: 187

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?
by Sam Kelly 1K
Thu Nov 15, 2018 12:56 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Thanksgiving [ENDORSED]
Replies: 14
Views: 187

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/
by Sam Kelly 1K
Thu Nov 08, 2018 2:41 pm
Forum: Bond Lengths & Energies
Topic: MIDTERM Bond Length Question
Replies: 15
Views: 161

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 ...
by Sam Kelly 1K
Thu Nov 08, 2018 2:34 pm
Forum: Bond Lengths & Energies
Topic: bond lengths and strengths
Replies: 9
Views: 90

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...
by Sam Kelly 1K
Fri Nov 02, 2018 12:49 am
Forum: Dipole Moments
Topic: London Forces
Replies: 7
Views: 193

Re: London Forces

Are Van der Waal Forces a specific type of dispersion force or can they be used interchangeably?
by Sam Kelly 1K
Fri Nov 02, 2018 12:39 am
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bond Definition
Replies: 14
Views: 298

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?
by Sam Kelly 1K
Fri Nov 02, 2018 12:35 am
Forum: Sigma & Pi Bonds
Topic: Easy way of remembering the difference
Replies: 6
Views: 78

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?
by Sam Kelly 1K
Tue Oct 23, 2018 11:21 am
Forum: DeBroglie Equation
Topic: problem 43 6th edition
Replies: 4
Views: 88

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...
by Sam Kelly 1K
Tue Oct 23, 2018 11:15 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: What is the equation used for?
Replies: 9
Views: 97

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?
by Sam Kelly 1K
Tue Oct 23, 2018 11:03 am
Forum: Student Social/Study Group
Topic: Studying for tests/midterm
Replies: 18
Views: 760

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?
by Sam Kelly 1K
Thu Oct 18, 2018 11:12 pm
Forum: Properties of Electrons
Topic: electrons
Replies: 3
Views: 46

Re: electrons

Electrons have wavelike properties due to the diffraction patterns that they form, due in part to their extremely small size
by Sam Kelly 1K
Thu Oct 18, 2018 10:47 pm
Forum: *Black Body Radiation
Topic: Black Body
Replies: 9
Views: 171

Re: Black Body

So does the concept of black bodies explain why objects go from being red hot to being white hot?
by Sam Kelly 1K
Thu Oct 18, 2018 10:38 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 86
Views: 25199

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...
by Sam Kelly 1K
Thu Oct 11, 2018 11:40 pm
Forum: Einstein Equation
Topic: Symbol for frequency
Replies: 12
Views: 120

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.
by Sam Kelly 1K
Thu Oct 11, 2018 11:38 pm
Forum: Properties of Light
Topic: speed of light
Replies: 8
Views: 79

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?)
by Sam Kelly 1K
Thu Oct 11, 2018 11:33 pm
Forum: Properties of Electrons
Topic: Quantum World
Replies: 6
Views: 50

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.
by Sam Kelly 1K
Tue Oct 02, 2018 11:13 am
Forum: Empirical & Molecular Formulas
Topic: Formula unit
Replies: 3
Views: 72

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 ...
by Sam Kelly 1K
Tue Oct 02, 2018 10:43 am
Forum: Empirical & Molecular Formulas
Topic: Percent Composition
Replies: 5
Views: 133

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...
by Sam Kelly 1K
Mon Oct 01, 2018 11:10 am
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 86
Views: 25199

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?

Go to advanced search