Search found 31 matches
- Wed Jun 13, 2018 11:09 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642278
Re: Post All Chemistry Jokes Here
a s s a u l t e d b y l o v e <3
- Wed Jun 13, 2018 11:03 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642278
Re: Post All Chemistry Jokes Here
Chemistry jokes are Sodiummm funny,
I slapped my Neon that one!
(a realll knee slapper amirite?)
I slapped my Neon that one!
(a realll knee slapper amirite?)
- Wed Jun 13, 2018 11:01 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3642278
Re: Post All Chemistry Jokes Here
Why do chemists learn about ammonia first?
...because it's pretty basic stuff
...because it's pretty basic stuff
- Wed Jun 13, 2018 8:03 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Test 1, question 1 part B
- Replies: 1
- Views: 379
Test 1, question 1 part B
Part A's answer is 0.0377mol/L^-1 for Na2CO3 in 1Liter of water
Part B asks: The above solution is diluted with 1.00 L of 0.200 M sodium chloride, NaCl, solution. What is the concentration of sodium ions after the dilution?
Plz help
Part B asks: The above solution is diluted with 1.00 L of 0.200 M sodium chloride, NaCl, solution. What is the concentration of sodium ions after the dilution?
Plz help
- Sun Jun 03, 2018 6:00 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.19
- Replies: 3
- Views: 560
Re: HW 4.19
the overall compound is linear, but the 2 sub-compounds (CH3) are tetrahedral since the 3 H's and Be surround it
i hope this is somewhat clear :)
i hope this is somewhat clear :)
- Sun Jun 03, 2018 4:15 pm
- Forum: Lewis Structures
- Topic: d-block Lewis structures
- Replies: 3
- Views: 544
Re: d-block Lewis structures
Drawing out Lewis structures for the d-block would be the same as the rest of the elements in the s,p,f-blocks. I do remember there are the exceptions of Copper and Chromium, but I wouldn't know how to explain said exceptions (it was brought up in lecture several times).
- Sun Jun 03, 2018 4:10 pm
- Forum: Hybridization
- Topic: homework problem 4.35 part c
- Replies: 2
- Views: 383
homework problem 4.35 part c
could someone clarify what the lewis structure for for: BrF3 should look like? I'm having a bit of trouble arranging all the valence electrons to fit properly.
It would help to know what it looks like visually in order to come up with the hybrid orbitals.
thanks in advance!!!
It would help to know what it looks like visually in order to come up with the hybrid orbitals.
thanks in advance!!!
- Sat Jun 02, 2018 7:02 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: homework problem 4.17 [ENDORSED]
- Replies: 4
- Views: 1659
homework problem 4.17 [ENDORSED]
So #4.17 asks: Predict the bond angles at the central atom of the following molecules and ions: (a) ozone, O3; (b) azide ion, N3-; (c) cyanate ion, CNO-; (d) hydronium ion, H3O+.
Can someone please explain why N3- and NCO- can both have bond angles of about 180?
thank yyou
Can someone please explain why N3- and NCO- can both have bond angles of about 180?
thank yyou
- Tue May 29, 2018 6:44 pm
- Forum: Bond Lengths & Energies
- Topic: HW problem 6.99
- Replies: 1
- Views: 410
HW problem 6.99
this question asks: Due to its strong hydrogen bonds, in the vapor, hydrogen fluoride is found as short chains and rings. Draw the Lewis structure of an (HF)3 chain and indicate the approximate bond angles. I was able to draw the linear lewis structure chain, but How are we to find the approximate a...
- Tue May 22, 2018 11:03 pm
- Forum: Resonance Structures
- Topic: Kekulé Structures??
- Replies: 6
- Views: 882
Kekulé Structures??
Is it critical to know how to draw and add bonds to Kekule structures for the quiz?
(they're the cool hexagon looking structures..)
(they're the cool hexagon looking structures..)
- Tue May 22, 2018 5:18 pm
- Forum: Lewis Structures
- Topic: lowest energy & most stable Lewis structures
- Replies: 4
- Views: 2705
Re: lowest energy & most stable Lewis structures
By calculating the formal charges (using FC = VE - NBE - 1/2BE) for each element we can then see how close the formal charges are to zero. The closer to zero, the more probable the structure. This would be the structure with the lowest energy. the textbook also say: the formal charge on an atom in a...
- Fri May 18, 2018 1:13 am
- Forum: Resonance Structures
- Topic: HW problem 3.45
- Replies: 4
- Views: 585
HW problem 3.45
3.45 asks: Draw the Lewis structures that contribute to the resonance hybrid of nitryl chloride, ClNO2 (N is the central atom). Could someone please explain to me why N cant have a double bond with each O and a single bond with Cl? Does it have something to do with the lone pairs? Or taking away/add...
- Fri May 11, 2018 8:54 pm
- Forum: Ionic & Covalent Bonds
- Topic: HW problem 3.21
- Replies: 4
- Views: 1366
HW problem 3.21
Part D.) This question asks to find the ground state electron configuration and number of unpaired electrons for : Ag+ The answer key says its configuration is : [Kr]4d^10, and has no unpaired electrons, but how? I got :[Kr]4d^9 5s^1, which should be just one unpaired electron.... someone please exp...
- Tue May 08, 2018 3:21 am
- Forum: Trends in The Periodic Table
- Topic: Last Lecture with Midterm Material
- Replies: 1
- Views: 305
Last Lecture with Midterm Material
Just to confirm, the last lecture that covers material for the midterm is the last lecture of week 4? Or is it up until week 5, 2nd lecture?
I just know for sure chemical bonds is part of chapter 3, and that was at the end of week 5.
sorry if this question has been asked before
I just know for sure chemical bonds is part of chapter 3, and that was at the end of week 5.
sorry if this question has been asked before
- Tue May 08, 2018 3:02 am
- Forum: DeBroglie Equation
- Topic: test 2, question5
- Replies: 5
- Views: 830
Re: test 2, question5
hahaha sorry to all, I think i figured out my error because that number seemed wayyy too small. I was multiplying everything out together on my calculator and I think that caused it to give me the wrong numbers and had some cancellation errors. If someone could please confirm if my answer is correct...
- Tue May 08, 2018 12:03 am
- Forum: DeBroglie Equation
- Topic: test 2, question5
- Replies: 5
- Views: 830
test 2, question5
During a reflex signal, the local velocity of a sodium ion is assumed to be 112m/s. What is the de Broglie wavelength of one ion of sodium? So ive set up my equation: (6.626x10^-34J.s) / (22.989g/mol^-1)(112m/s)(6.022x10^23mol^-1)(1000g/1kg) multiplied out to: (6.626x10^-34J.s) / (1.55x10^30m.s.kg)=...
- Sun May 06, 2018 10:38 pm
- Forum: General Science Questions
- Topic: Solutions for tests
- Replies: 3
- Views: 557
Re: Solutions for tests
I asked the same question and people told me that the answer keys are not to be released, you can go to your TA's office hours and look online in chemistry community, (a lot of the test questions have been posted! :)
- Sun May 06, 2018 9:44 pm
- Forum: Empirical & Molecular Formulas
- Topic: test 1, question 7
- Replies: 2
- Views: 579
test 1, question 7
Determine the empirical formula for an organic compound that, when burned in the presence of oxygen, formed 69.4g of CO2 and 17.05g of H2O. What is the mass percentage of carbon and hydrogen in the sample? So, I was able to figure out the percentages, but how am i supposed to figure out the empirica...
- Fri May 04, 2018 12:21 pm
- Forum: Properties of Light
- Topic: test 2 solutions
- Replies: 2
- Views: 418
test 2 solutions
Hi,
I was wondering if the solutions to either test 2 or test 1 are released? Where can I find them? If they are/have been, I can't find them anywhere...
thanks :)
I was wondering if the solutions to either test 2 or test 1 are released? Where can I find them? If they are/have been, I can't find them anywhere...
thanks :)
- Sun Apr 29, 2018 10:17 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: orbitals/lobes
- Replies: 3
- Views: 410
orbitals/lobes
Are we supposed to know how to draw/or identify what different orbitals look like? I remember briefly drawing them in lecture in week 3 or first lecture of week 4, but don't remember what was said about them? Just curious...
- Sun Apr 29, 2018 12:41 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: HW question 2.17 [ENDORSED]
- Replies: 2
- Views: 354
HW question 2.17 [ENDORSED]
2.17 How many orbitals are in subshells with l equal to (a) 0; (b) 2; (c) 1; (d) 3?
Hi, I'm not sure how to figure out the number of orbitals using the information given of l. I couldn't attend lecture on wednesday so I am a bit behind with the new chapter
Hi, I'm not sure how to figure out the number of orbitals using the information given of l. I couldn't attend lecture on wednesday so I am a bit behind with the new chapter
- Fri Apr 27, 2018 12:18 pm
- Forum: Einstein Equation
- Topic: Hw problem 1.59 [ENDORSED]
- Replies: 3
- Views: 618
Hw problem 1.59 [ENDORSED]
I know for this problem I have to use E=hc/(lambda), but after that I'm not really sure how to proceed with the information given about the photons... please help 1.59 Each second a certain lamp produces 9.8 x 10^20 photons with a wavelength of 434 nm. How much energy (in joules) is produced as radi...
- Sun Apr 22, 2018 11:44 pm
- Forum: DeBroglie Equation
- Topic: Wavelength= (h/p) [ENDORSED]
- Replies: 7
- Views: 1230
Re: Wavelength= (h/p) [ENDORSED]
Hi, I'm not 100% sure but, photons do not have mass per se. De Broglie's is not the appropriate equation to used for photons at rest, however if they have a "non zero" momentum, then I think we do use his equation. Again, don't quote me. I tried :)
- Sun Apr 22, 2018 8:05 pm
- Forum: DeBroglie Equation
- Topic: HW 1.37 [ENDORSED]
- Replies: 6
- Views: 865
Re: HW 1.37 [ENDORSED]
the answer given by the book is 1.44pm, but if we want a difference in percentage, which is a second thing they are asking for, do we use exact numbers to get that? Or should we not worry about it since, the answer key states they are "identical"? I got a 0.01% difference but I used 6 sigf...
- Sun Apr 22, 2018 6:48 pm
- Forum: Photoelectric Effect
- Topic: 1.33 HW Confusion (part a)
- Replies: 2
- Views: 306
1.33 HW Confusion (part a)
1.33 The velocity of an electron that is emitted from a metallic surface by a photon is 3.6 * 10^3 km*s-1. (a) What is the wavelength of the ejected electron? (b) No electrons are emitted from the surface of the metal until the frequency of the radiation reaches 2.50 * 10^16 Hz. How much energy is r...
- Sun Apr 15, 2018 11:02 pm
- Forum: Properties of Light
- Topic: Wavelength
- Replies: 3
- Views: 302
Re: Wavelength
Yes, the length of a wave (wavelength) is the equivalent of a period seen on a graph in trigonometry (cos/ or sin graph). We measure the distance or period of both from "peak to peak" as Dr. Lavelle put it during lecture to determine the one cycle of a wave.
- Sat Apr 14, 2018 5:23 pm
- Forum: Properties of Light
- Topic: Help on 1.9 [ENDORSED]
- Replies: 4
- Views: 479
Re: Help on 1.9 [ENDORSED]
I had difficulty with this problem myself, but I think I figured it out! so it tells us to find the wavelengths of all the thingies given, so we have to use the the lambda=c/v for the values 8.7x10^18Hz and 300 MHz which is the same as 300x10^6Hz. The wavelength is given for one of them 2.5nm, so no...
- Sat Apr 14, 2018 5:12 pm
- Forum: Photoelectric Effect
- Topic: Chapter 1, Question 1.13 [ENDORSED]
- Replies: 1
- Views: 1310
Chapter 1, Question 1.13 [ENDORSED]
Use the Rydberg formula for atomic hydrogen to calculate the wavelength of radiation generated by the transition from n = 4 to n = 2. (b) What is the name given to the spectroscopic series to which this transition belongs? (c) Use Table 1.1 to determine the region of the spectrum in which the transi...
- Sat Apr 14, 2018 4:46 pm
- Forum: Photoelectric Effect
- Topic: Problem 1.11 -Atomic Spectra [ENDORSED]
- Replies: 1
- Views: 235
Problem 1.11 -Atomic Spectra [ENDORSED]
1.11 In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series (for example, Balmer series, Lyman series, Paschen series), as shown in Figs. 1.10 and 2.1. What is common to the lines within a series that makes grouping them together logical? In the ...
- Sat Apr 14, 2018 11:25 am
- Forum: Properties of Light
- Topic: Units for Wavelengths [ENDORSED]
- Replies: 4
- Views: 373
Units for Wavelengths [ENDORSED]
I'm doing practice problems from the text book and I notice that when calculating the wavelengths using the equation: lambda= c/v, the units are are m.s^-1/ s, so the s cancels. Once I've divided the numbers on my calculator i get an extremely small number like (i.e. 0.000000522) how do I know how m...
- Sat Apr 14, 2018 9:40 am
- Forum: SI Units, Unit Conversions
- Topic: SI Units- Bond Length [ENDORSED]
- Replies: 1
- Views: 1041
SI Units- Bond Length [ENDORSED]
Could someone remind me of the units Professor Lavelle briefly talked about in lecture concerning bond length, I know we're not there yet in terms of using them but yeahh..
What are the units?
Why?
What are the units?
Why?