CHEMISTRY COMMUNITY

Joshua Yang 1H

total number of e- = # of dots + 2 x number of lines = 22 + 10 = 32 e-

O = 6 valence e-
Cl3 = 7 valence e- x 3 = 21e-

therefore we have 27e- accounted for.

32 - 27 = 5e-

which element in period 3 has 5 valence electrons? = phosphorus

Joshua Yang 1H

The moderators on this website have already confirmed that we will be given the actual formulas on the test. So we don't need to know how to figure out the formulas by looking at the names :)

Joshua Yang 1H

# of valence electrons - (number of dots + number of lines) = Formal charge

Joshua Yang 1H

Good news is for the tests we'll be given the actual chemical formulas so we don't have to memorize them :)

Joshua Yang 1H

Why when doing the resonance structure can we not give Cl-N a double bond? Or can we? It is technically possible, but we're looking for the lewis structure with the lowest formal charge If you calculate the formal charge of Cl, it comes out as 0, meaning that there is no need to change the electron...

Joshua Yang 1H

3.39 asks you to draw the lewis structures for (a) ammonium chloride, (b) potassium phosphide, and (c) sodium hyphoclorite My first question is will we be expected to know the empirical formula for these on our own? And secondly, for part a for example, why in the lewis structure does NH₄ have a po...

Joshua Yang 1H

In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron. I understand in this problem that hydrogen gives us n=1, but to find the other energy levels in the solution it converts the wavelength ...

Joshua Yang 1H

This is really a interesting topic actually so I decided to research and this is what I found. Gases at atmospheric pressure are not good conductors of electricity. So, to pass a current through a gas requires a gas-discharge tube, which is a glass tube with two electrodes sealed through its walls....

Joshua Yang 1H

here's the answer. All you need to do here is count how many atoms of each element you have on the molecule

Joshua Yang 1H

We're given that the wavelength of light emitted by the Na atoms = 589 x 10^-9 m a) asks for the energy emitted by an excited sodium atom when it generates a photon this deals with photons, which have no mass, therefore we use the equation E = hv and c = vλ E = hv c = vλ so v = c/λ so E = hc/λ now w...

Joshua Yang 1H

So we've encountered several problems in our chem HW where an excited atom will emit a certain light, and we would determine the energy of the photons emitted by the excited atom. Looking at this from an application point of view, do neon light signs do the same kind of thing to emit light? I'm assu...

Joshua Yang 1H

octaviahuang1f wrote:I don't think we need to record it somewhere else, just make sure to post at least three per week haha.

Haha nice :) Thank you!

Joshua Yang 1H

I've read online that motion detectors are small electronic eyes that detect infrared waves—heat waves that radiate from moving objects. When the detector senses an object moving across its field of view—especially warmer objects such as people, animals and cars—it electronically turns on the light...

Joshua Yang 1H

QuincyH1G wrote:Real question, why are you spending so much time in the bathroom?

I guess I think a lot when I do my business xD
Doesn't everybody have that moment when they have an epiphany on the toilet?

p.s. I wish I had a roof toilet
p.p.s. I have a lot of toilet ideas

Joshua Yang 1H

I understand that 30 points total are given through online discussions on chemistry community. 1 point for each topic/post and 3 points max per week. Also I understand that the "deadline" for this is Sunday midnight. My question is, do we get the credits by just posting each week? Or do we...

Joshua Yang 1H

Just writing what I have on my notes Key Concept: If EMR only had wave properties, then increasing the intensity of the EMR should theoretically eject electron However according to the experiment... Light sources with long wavelengths cannot eject electrons. BUT light sources with short wavelengths ...

Joshua Yang 1H

I'm sure we can discuss this since we already discussed test 1 in our discussion section So the calculation would be... Molar Mass of H2 : 2.01588 g/mol Molar Mass of O2 : 31.9988 g/mol Since O2 is the limiting reactant 100.00g H2 / (2 x 2.01588 g/mol) - 100.00g O2 / (31.9988 g/mol ) = mol of H2 lef...

Joshua Yang 1H

This is a little on a tangent, but related to the example Dr. Lavelle gave to us last lecture on throwing a baseball through sensors. Dr. Lavelle explained that the way these sensors work is that there is a constant stream of photons and once something passes through, the stream is broken, which cau...

Joshua Yang 1H

http://i0.kym-cdn.com/photos/images/newsfeed/000/995/634/f9f.png Pre-2012 chemistry joke bruuh :/ Explanation: Uuh (ununhexium) was officially named as Lv (livermorium) in 2012. So sadly we can't make this joke anymore bruuh https://www.nature.com/articles/nchem.2593

Joshua Yang 1H

I understand that there no longer is a course reader for this class, but I did hear that Dr. Lavelle used to have a course reader for the class. Does anybody know about this? And if anybody has it, it is useful?

Joshua Yang 1H

I didn't take AP Chem in high school and took general chemistry my sophomore year. I've noticed people on this feed saying there are night study sessions at Hedrick-when and where are those at? Thank you. They're all located in Hedrick Hall Room 125, the specific times are on the document I attache...

Joshua Yang 1H

The way I did is I just went ahead and ignored the (-) sign on F- and calculated as if I would any other problem (like part A B and D) and it gave me the answer (on the back of the textbook). the U in UF6 is Uranium on the periodic table. Figure out the molar mass of both Uranium and Fluorine, then ...

CHEMISTRY COMMUNITY

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Re: HW 3.37

Re: Chemical Formula Name

Re: Formal Charge

Re: 3.39

Re: HW problem 3.45

Re: HW 3.39

Re: Homework 1.15

Re: Question on excited atoms emitting light and Neon signs

Re: Test 1/ Question 8 [ENDORSED]

Re: Question 1.25b

Question on excited atoms emitting light and Neon signs

Re: Weekly Online Discussion Points

Re: Baseball through sensors experiment [ENDORSED]

Re: Baseball through sensors experiment [ENDORSED]

Weekly Online Discussion Points

Re: 1.21 [ENDORSED]

Re: Question from test 1 [ENDORSED]

Baseball through sensors experiment [ENDORSED]

Re: Post All Chemistry Jokes Here

Class Course Reader?

Re: Rusty on High School Chem [ENDORSED]

Re: Question Regarding Moles