CHEMISTRY COMMUNITY

Rosamari Orduna 1D

a s s a u l t e d b y l o v e <3

Rosamari Orduna 1D

Chemistry jokes are Sodiummm funny,
I slapped my Neon that one!

(a realll knee slapper amirite?)

Rosamari Orduna 1D

Why do chemists learn about ammonia first?

...because it's pretty basic stuff

Rosamari Orduna 1D

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

Rosamari Orduna 1D

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 :)

Rosamari Orduna 1D

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).

Rosamari Orduna 1D

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!!!

Rosamari Orduna 1D

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

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

Is it critical to know how to draw and add bonds to Kekule structures for the quiz?

(they're the cool hexagon looking structures..)

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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)=...

Rosamari Orduna 1D

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! :)

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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 :)

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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 :)

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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.

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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 ...

Rosamari Orduna 1D

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...

Rosamari Orduna 1D

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?

CHEMISTRY COMMUNITY

Search found 31 matches

Re: Post All Chemistry Jokes Here

Re: Post All Chemistry Jokes Here

Re: Post All Chemistry Jokes Here

Test 1, question 1 part B

Re: HW 4.19

Re: d-block Lewis structures

homework problem 4.35 part c

homework problem 4.17 [ENDORSED]

HW problem 6.99

Kekulé Structures??

Re: lowest energy & most stable Lewis structures

HW problem 3.45

HW problem 3.21

Last Lecture with Midterm Material

Re: test 2, question5

test 2, question5

Re: Solutions for tests

test 1, question 7

test 2 solutions

orbitals/lobes

HW question 2.17 [ENDORSED]

Hw problem 1.59 [ENDORSED]

Re: Wavelength= (h/p) [ENDORSED]

Re: HW 1.37 [ENDORSED]

1.33 HW Confusion (part a)

Re: Wavelength

Re: Help on 1.9 [ENDORSED]

Chapter 1, Question 1.13 [ENDORSED]

Problem 1.11 -Atomic Spectra [ENDORSED]

Units for Wavelengths [ENDORSED]

SI Units- Bond Length [ENDORSED]