Search found 15 matches
- Fri Mar 10, 2017 10:26 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3590878
Re: Post All Chemistry Jokes Here
Quiz #3 was sodium hard :(
- Tue Feb 28, 2017 11:30 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3590878
Re: Post All Chemistry Jokes Here
- Just 14BL things
- Fri Feb 17, 2017 2:49 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3590878
Re: Post All Chemistry Jokes Here
Did you know that you can cool yourself to -273.15˚C and still be 0k?
- Fri Feb 03, 2017 2:13 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: So Much Voltage?
- Replies: 2
- Views: 534
Re: So Much Voltage?
Power is the rate at which work is done (J/second). I think that having a larger number of cells increases the lifetime of the battery, but I don't think it has an effect on the maximum amount of work that can be done at a given point in time. (I might be wrong)
- Fri Feb 03, 2017 2:07 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Gibbs Free Energy and Electrochemistry
- Replies: 2
- Views: 642
Re: Gibbs Free Energy and Electrochemistry
In order for an electrochemical reaction to occur/be useful, it has to occur spontaneously, right? Powerful batteries have a super negative deltaG, which is what allows them to do so much useful work. Electricity naturally flows from high to low electric potential (E) in a similar manner to heat flo...
- Fri Feb 03, 2017 1:57 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: What has more enthalpy?
- Replies: 1
- Views: 1519
Re: What has more enthalpy?
Enthalpy is really a measure of the energy contained within a system , not individual particles. It depends on the energies of the molecules within the system, which naturally has to take into account both the state of matter (ex. gasses inherently have more kinetic energy than solids) and the tempe...
- Fri Dec 02, 2016 4:12 pm
- Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
- Topic: HW 13.13
- Replies: 1
- Views: 862
Re: HW 13.13
Just set up an ICE table with 0.40 as the initial concentration of HF, and find out the concentration of F- (coming from NaF) by dividing the moles of F- coming from the amount of NaF you're given by the volume of the solution. Then, just plug it into the ICE table and solve for x.
- Fri Dec 02, 2016 4:09 pm
- Forum: *Titrations & Titration Calculations
- Topic: How do you know what equation to use when finding the pH?
- Replies: 2
- Views: 589
Re: How do you know what equation to use when finding the pH?
So, the question is asking you to identify which indicator you should use in a titration (which we didn't go over in lecture), but basically you're looking for the pH at the stoichiometric point, when moles of acid = moles of base. Since we are told that we're titrating CH3COOH with NaOH (weak acid ...
- Mon Nov 07, 2016 8:46 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Z
- Replies: 1
- Views: 418
Re: Z
The nuclear charge is just the number of protons, the atomic number.
- Sat Oct 29, 2016 2:29 pm
- Forum: Hybridization
- Topic: Sigma bonds
- Replies: 1
- Views: 445
Re: Sigma bonds
The hybridization theory of bonding differentiates between sigma and pi bonds based on how they overlap, which depends on their orientation in space. In a sigma bond, two orbitals pointing toward each other (along the internuclear axis) overlap end-over-end, whereas in a pi bond, two parallel orbita...
- Sun Oct 23, 2016 3:54 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Angles of molecular shapes
- Replies: 5
- Views: 1391
Re: Angles of molecular shapes
You actually could calculate that the bond angles of a tetrahedral molecule are 109.5 degrees, however, it would require thinking in three dimensions--aka multivariable calculus--to prove it. Same pythagorean theorem as before, but working in terms of xyz to maximize the distance between endpoints (...
- Sun Oct 16, 2016 4:23 pm
- Forum: Electronegativity
- Topic: Periodic Trends
- Replies: 3
- Views: 1307
Re: Periodic Trends
At my high school, I was taught that pretty much all of the periodic trends can be explained by Zeff. Zeff is the effective nuclear charge, or how tightly the nucleus holds on to its outer electrons. As you go right across a period, both protons and electrons are added. Zeff increases because the po...
- Mon Oct 10, 2016 7:07 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Emission v Absorption Lines
- Replies: 2
- Views: 1499
Re: Emission v Absorption Lines
The other response is completely correct. However, a helpful connection to make is that the absorption and emission spectra represent the same thing. The absorption spectrum of an element will appear to be a full "rainbow" with a few black stripes occurring at certain wavelengths. For the ...
- Sun Oct 02, 2016 7:46 pm
- Forum: Properties of Light
- Topic: Question about n1 and n2
- Replies: 4
- Views: 4358
Re: Question about n1 and n2
I'm not sure if this comparison is 100% accurate, but it's what I use to think of energy levels. "n" is a possible position for an electron relative to the nucleus of the atom. Since the two are attracted to each other (electrons are negatively charged and protons are positively charged), ...
- Wed Sep 28, 2016 9:42 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Peer Facilitated Learning Sessions
- Replies: 32
- Views: 13422
Re: Peer Facilitated Learning Sessions
What happens if more than twenty of us show up to a session? If this happens, can the schedule be modified to accommodate the most popular time slots?