Search found 22 matches

by Joshua Yang 1H
Sun May 20, 2018 10:34 pm
Forum: Lewis Structures
Topic: HW 3.37
Replies: 2
Views: 114

Re: HW 3.37

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
by Joshua Yang 1H
Sun May 20, 2018 10:26 pm
Forum: Lewis Structures
Topic: Chemical Formula Name
Replies: 3
Views: 132

Re: Chemical Formula Name

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 :)
by Joshua Yang 1H
Sun May 20, 2018 10:21 pm
Forum: Lewis Structures
Topic: Formal Charge
Replies: 4
Views: 155

Re: Formal Charge

# of valence electrons - (number of dots + number of lines) = Formal charge
by Joshua Yang 1H
Sun May 20, 2018 10:20 pm
Forum: Lewis Structures
Topic: 3.39
Replies: 5
Views: 195

Re: 3.39

Good news is for the tests we'll be given the actual chemical formulas so we don't have to memorize them :)
by Joshua Yang 1H
Sun May 20, 2018 10:08 pm
Forum: Resonance Structures
Topic: HW problem 3.45
Replies: 4
Views: 195

Re: HW problem 3.45

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...
by Joshua Yang 1H
Sun May 20, 2018 2:28 am
Forum: Lewis Structures
Topic: HW 3.39
Replies: 3
Views: 152

Re: HW 3.39

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...
by Joshua Yang 1H
Sun May 06, 2018 10:32 pm
Forum: Properties of Light
Topic: Homework 1.15
Replies: 2
Views: 221

Re: Homework 1.15

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 ...
by Joshua Yang 1H
Sun May 06, 2018 10:25 pm
Forum: Properties of Light
Topic: Question on excited atoms emitting light and Neon signs
Replies: 2
Views: 150

Re: Question on excited atoms emitting light and Neon signs

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....
by Joshua Yang 1H
Sun May 06, 2018 10:20 pm
Forum: Empirical & Molecular Formulas
Topic: Test 1/ Question 8 [ENDORSED]
Replies: 6
Views: 383

Re: Test 1/ Question 8 [ENDORSED]

here's the answer. All you need to do here is count how many atoms of each element you have on the molecule
by Joshua Yang 1H
Sun May 06, 2018 10:09 pm
Forum: Einstein Equation
Topic: Question 1.25b
Replies: 2
Views: 211

Re: Question 1.25b

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...
by Joshua Yang 1H
Sun May 06, 2018 9:54 pm
Forum: Properties of Light
Topic: Question on excited atoms emitting light and Neon signs
Replies: 2
Views: 150

Question on excited atoms emitting light and Neon signs

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...
by Joshua Yang 1H
Mon Apr 23, 2018 1:27 am
Forum: Administrative Questions and Class Announcements
Topic: Weekly Online Discussion Points
Replies: 2
Views: 171

Re: Weekly Online Discussion Points

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!
by Joshua Yang 1H
Mon Apr 23, 2018 1:05 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Baseball through sensors experiment [ENDORSED]
Replies: 5
Views: 224

Re: Baseball through sensors experiment [ENDORSED]

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...
by Joshua Yang 1H
Mon Apr 23, 2018 1:00 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Baseball through sensors experiment [ENDORSED]
Replies: 5
Views: 224

Re: Baseball through sensors experiment [ENDORSED]

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
by Joshua Yang 1H
Mon Apr 23, 2018 12:56 am
Forum: Administrative Questions and Class Announcements
Topic: Weekly Online Discussion Points
Replies: 2
Views: 171

Weekly Online Discussion Points

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...
by Joshua Yang 1H
Sat Apr 21, 2018 7:27 pm
Forum: Photoelectric Effect
Topic: 1.21 [ENDORSED]
Replies: 2
Views: 203

Re: 1.21 [ENDORSED]

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 ...
by Joshua Yang 1H
Sat Apr 21, 2018 7:19 pm
Forum: Limiting Reactant Calculations
Topic: Question from test 1 [ENDORSED]
Replies: 4
Views: 317

Re: Question from test 1 [ENDORSED]

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...
by Joshua Yang 1H
Sat Apr 21, 2018 6:36 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Baseball through sensors experiment [ENDORSED]
Replies: 5
Views: 224

Baseball through sensors experiment [ENDORSED]

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...
by Joshua Yang 1H
Sat Apr 07, 2018 7:16 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7567
Views: 1010790

Re: Post All Chemistry Jokes Here

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
by Joshua Yang 1H
Sat Apr 07, 2018 7:01 pm
Forum: Student Social/Study Group
Topic: Class Course Reader?
Replies: 1
Views: 264

Class Course Reader?

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?
by Joshua Yang 1H
Sat Apr 07, 2018 6:58 pm
Forum: General Science Questions
Topic: Rusty on High School Chem [ENDORSED]
Replies: 165
Views: 100720

Re: Rusty on High School Chem [ENDORSED]

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...
by Joshua Yang 1H
Wed Apr 04, 2018 10:06 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Question Regarding Moles
Replies: 3
Views: 282

Re: Question Regarding Moles

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 ...

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