Search found 31 matches

by Rosamari Orduna 1D
Wed Jun 13, 2018 11:09 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 918766

Re: Post All Chemistry Jokes Here

a s s a u l t e d b y l o v e <3
by Rosamari Orduna 1D
Wed Jun 13, 2018 11:03 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 918766

Re: Post All Chemistry Jokes Here

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

(a realll knee slapper amirite?)
by Rosamari Orduna 1D
Wed Jun 13, 2018 11:01 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 918766

Re: Post All Chemistry Jokes Here

Why do chemists learn about ammonia first?

...because it's pretty basic stuff
by Rosamari Orduna 1D
Wed Jun 13, 2018 8:03 pm
Forum: Molarity, Solutions, Dilutions
Topic: Test 1, question 1 part B
Replies: 1
Views: 173

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
by Rosamari Orduna 1D
Sun Jun 03, 2018 6:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW 4.19
Replies: 3
Views: 225

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 :)
by Rosamari Orduna 1D
Sun Jun 03, 2018 4:15 pm
Forum: Lewis Structures
Topic: d-block Lewis structures
Replies: 3
Views: 178

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).
by Rosamari Orduna 1D
Sun Jun 03, 2018 4:10 pm
Forum: Hybridization
Topic: homework problem 4.35 part c
Replies: 2
Views: 99

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!!!
by Rosamari Orduna 1D
Sat Jun 02, 2018 7:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: homework problem 4.17 [ENDORSED]
Replies: 4
Views: 201

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
by Rosamari Orduna 1D
Tue May 29, 2018 6:44 pm
Forum: Bond Lengths & Energies
Topic: HW problem 6.99
Replies: 1
Views: 152

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...
by Rosamari Orduna 1D
Tue May 22, 2018 11:03 pm
Forum: Resonance Structures
Topic: Kekulé Structures??
Replies: 6
Views: 297

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..)
by Rosamari Orduna 1D
Tue May 22, 2018 5:18 pm
Forum: Lewis Structures
Topic: lowest energy & most stable Lewis structures
Replies: 4
Views: 360

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...
by Rosamari Orduna 1D
Fri May 18, 2018 1:13 am
Forum: Resonance Structures
Topic: HW problem 3.45
Replies: 4
Views: 177

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...
by Rosamari Orduna 1D
Fri May 11, 2018 8:54 pm
Forum: Ionic & Covalent Bonds
Topic: HW problem 3.21
Replies: 4
Views: 169

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...
by Rosamari Orduna 1D
Tue May 08, 2018 3:21 am
Forum: Trends in The Periodic Table
Topic: Last Lecture with Midterm Material
Replies: 1
Views: 121

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
by Rosamari Orduna 1D
Tue May 08, 2018 3:02 am
Forum: DeBroglie Equation
Topic: test 2, question5
Replies: 5
Views: 319

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...
by Rosamari Orduna 1D
Tue May 08, 2018 12:03 am
Forum: DeBroglie Equation
Topic: test 2, question5
Replies: 5
Views: 319

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)=...
by Rosamari Orduna 1D
Sun May 06, 2018 10:38 pm
Forum: General Science Questions
Topic: Solutions for tests
Replies: 3
Views: 256

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! :)
by Rosamari Orduna 1D
Sun May 06, 2018 9:44 pm
Forum: Empirical & Molecular Formulas
Topic: test 1, question 7
Replies: 2
Views: 246

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...
by Rosamari Orduna 1D
Fri May 04, 2018 12:21 pm
Forum: Properties of Light
Topic: test 2 solutions
Replies: 2
Views: 146

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 :)
by Rosamari Orduna 1D
Sun Apr 29, 2018 10:17 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: orbitals/lobes
Replies: 3
Views: 145

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...
by Rosamari Orduna 1D
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: 101

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
by Rosamari Orduna 1D
Fri Apr 27, 2018 12:18 pm
Forum: Einstein Equation
Topic: Hw problem 1.59 [ENDORSED]
Replies: 3
Views: 242

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...
by Rosamari Orduna 1D
Sun Apr 22, 2018 11:44 pm
Forum: DeBroglie Equation
Topic: Wavelength= (h/p) [ENDORSED]
Replies: 7
Views: 336

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 :)
by Rosamari Orduna 1D
Sun Apr 22, 2018 8:05 pm
Forum: DeBroglie Equation
Topic: HW 1.37 [ENDORSED]
Replies: 6
Views: 278

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...
by Rosamari Orduna 1D
Sun Apr 22, 2018 6:48 pm
Forum: Photoelectric Effect
Topic: 1.33 HW Confusion (part a)
Replies: 2
Views: 128

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...
by Rosamari Orduna 1D
Sun Apr 15, 2018 11:02 pm
Forum: Properties of Light
Topic: Wavelength
Replies: 3
Views: 127

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.
by Rosamari Orduna 1D
Sat Apr 14, 2018 5:23 pm
Forum: Properties of Light
Topic: Help on 1.9 [ENDORSED]
Replies: 4
Views: 167

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...
by Rosamari Orduna 1D
Sat Apr 14, 2018 5:12 pm
Forum: Photoelectric Effect
Topic: Chapter 1, Question 1.13 [ENDORSED]
Replies: 1
Views: 160

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...
by Rosamari Orduna 1D
Sat Apr 14, 2018 4:46 pm
Forum: Photoelectric Effect
Topic: Problem 1.11 -Atomic Spectra [ENDORSED]
Replies: 1
Views: 80

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 ...
by Rosamari Orduna 1D
Sat Apr 14, 2018 11:25 am
Forum: Properties of Light
Topic: Units for Wavelengths [ENDORSED]
Replies: 4
Views: 112

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...
by Rosamari Orduna 1D
Sat Apr 14, 2018 9:40 am
Forum: SI Units, Unit Conversions
Topic: SI Units- Bond Length [ENDORSED]
Replies: 1
Views: 255

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?

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