Search found 32 matches
- Fri Dec 07, 2018 10:10 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Regarding the final
- Replies: 2
- Views: 380
Regarding the final
What exactly do we have to know from the acid base chapter for the final? I'm a little confused because we didn't cover some of the outline material in class.
- Fri Dec 07, 2018 9:07 pm
- Forum: Hybridization
- Topic: lone pairs of e-
- Replies: 4
- Views: 449
Re: lone pairs of e-
The hybridization of NH3 would be sp3. In hybridization you count the number of electron densities and the lone pair is an electron density.
- Fri Dec 07, 2018 9:00 pm
- Forum: Dipole Moments
- Topic: Differences in electronegativity
- Replies: 2
- Views: 537
Re: Differences in electronegativity
Between two atoms. For ex. in Li-F, F is very electronegative thus the electrons in Li are pulled heavily towards the F resulting in a dipole (positive charge on Li and negative carge on F).
- Fri Dec 07, 2018 8:50 pm
- Forum: Hybridization
- Topic: How does hybridization tell us the # of bonds?
- Replies: 1
- Views: 223
Re: How does hybridization tell us the # of bonds?
I believe the UA meant to say that hybridization tells us the number of electron densities. To my knowledge, you can't find out the number of bonds based on hybridization at least for triple bonds.. I'm not sure about this but, the only way you could find a double bond based on hybridizaton could be...
- Wed Dec 05, 2018 10:26 pm
- Forum: Naming
- Topic: Oxidation Numbers
- Replies: 3
- Views: 360
Re: Oxidation Numbers
Oxidation numbers can be negative too. It describes the number of electrons lost or gained.
- Sun Nov 25, 2018 3:17 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Trigonal Planar or Trigonal Pyramidal?
- Replies: 4
- Views: 925
Re: Trigonal Planar or Trigonal Pyramidal?
In order to find the electron - pair geometry, you need to count all electron densities including lone pairs. In order to find the molecular geometry, again you need to count all electron densities but especially be aware of how many lone pairs there are on the central atom. This is because the mole...
- Sun Nov 25, 2018 3:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Dipoles
- Replies: 2
- Views: 311
Re: Dipoles
I will give an example that will hopefully help: Consider CH3Cl. It will be in a tetraderal shape and because chlorine is so electronegative it will have a slight negative charge thus creating a dipole. Consider CH2Cl with the Cl on opposite sides. This will also be in a tertrahedral shape, but the ...
- Sun Nov 25, 2018 3:07 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sigma and Pi bonds
- Replies: 6
- Views: 666
Re: Sigma and Pi bonds
annabel 1F wrote:If there is a double bond will there always be 1 sigma and 1 pi bond?
Yes, the first bond is always a sigma bond, but bonds after that are pi bonds.
- Sun Nov 18, 2018 11:38 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: No central atom
- Replies: 7
- Views: 621
Re: No central atom
I believe the shape would be square planar. The two N atoms would be in the center with a bond between them and the H would surround them. This would result in 6 electron densities with two being lone pairs thus a square planar arrangement.
- Sun Nov 18, 2018 11:31 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Square Planar
- Replies: 5
- Views: 543
Re: Square Planar
Try to think about it logically. Square planar has 6 electron densities with 2 densities being lone pairs and the other 4 being atoms with electrons. Lone pairs have the most repulsion and electrons want to be as far away as possible, so the preferred shape would be square planar with bond angles of...
- Sun Nov 18, 2018 11:24 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular shape vs. Electron Geometry [ENDORSED]
- Replies: 2
- Views: 435
Re: Molecular shape vs. Electron Geometry [ENDORSED]
Molecular shapes include: Linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral. Note that in order to determine molecular shape you ignore the repulsion of lone pairs of electrons and only count the electron densities. Electron geometry includes: Bent, trigonal pyramid, seesaw,...
- Sun Nov 18, 2018 11:15 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 2
- Views: 264
Re: Bond Angles
It occurs due to the electron repulsions and the bond angle varies based on how the elements and their electrons interact with other elements and their electrons. If you can give a specific example of your question I can elaborate.
- Wed Nov 14, 2018 6:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Linear vs angular and trigonal planar vs trigonal pyramidal
- Replies: 2
- Views: 2290
Linear vs angular and trigonal planar vs trigonal pyramidal
When you have two electron clouds, how do you figure out if the shape is linear or angular? Same thing with trigonal; If you have 3 electron clouds how do you figure out if the shape is trigonal planar or trigonal pyramidal?
- Tue Nov 13, 2018 12:54 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Homework Week 8 [ENDORSED]
- Replies: 7
- Views: 2170
Re: Homework Week 8 [ENDORSED]
cara_cavarretta_3F wrote:Is this for all discussions or just for Thursday and Friday discussions?
All
- Sun Nov 11, 2018 8:38 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Equation
- Replies: 13
- Views: 3444
Re: Formal Charge Equation
Free valence electrons (based on periodic table ) - bonded valence electrons (based on the element given)
- Sun Nov 11, 2018 8:28 pm
- Forum: Lewis Structures
- Topic: Exceptions to Octet Rule
- Replies: 5
- Views: 1036
Re: Exceptions to Octet Rule
You should know that elements in the first and second periods can have expanded valence shells due to the empty d-orbital. You should also know that Cu and Cr have electron configuration exceptions.
- Sun Nov 11, 2018 8:19 pm
- Forum: Lewis Structures
- Topic: Ionic compound
- Replies: 4
- Views: 519
Re: Ionic compound
You don't have a line connecting two ionic compounds otherwise it would mean they have a covalent bond. To write an ionic bond, you would just put the elements in brackets and indicate their charge outside the bracket.
- Sun Nov 04, 2018 2:40 pm
- Forum: Resonance Structures
- Topic: Tricks for Resonance Structures
- Replies: 5
- Views: 912
Re: Tricks for Resonance Structures
My question is, if the formal charge is 0 for all atoms in the bond, is are there resonance structures? Even though there may be a compound with a formal charge of 0, that doesn't necessarily mean the compound doesn't have any resonance structures. You need to play around with double bonds and delo...
- Sun Nov 04, 2018 2:36 pm
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 2
- Views: 331
Resonance Structures
If resonance structures are supposed to be more stable, why don't we see more molecules in a resonance form in nature?
- Sun Nov 04, 2018 2:29 pm
- Forum: Ionic & Covalent Bonds
- Topic: 3.19 (6th edition)
- Replies: 4
- Views: 386
Re: 3.19 (6th edition)
If you check the solutions manual, [Ar]3d^8 is the correct answer.
- Sun Nov 04, 2018 2:25 pm
- Forum: Lewis Structures
- Topic: Formal Charge
- Replies: 2
- Views: 232
Re: Formal Charge
I think you meant ClO-?
If that is the case then you can only draw it with a single bond; a double bond would result in either Cl or O needing to expand their valence shell in order to take in a lone electron.
If that is the case then you can only draw it with a single bond; a double bond would result in either Cl or O needing to expand their valence shell in order to take in a lone electron.
- Sat Oct 27, 2018 6:58 pm
- Forum: Photoelectric Effect
- Topic: Frequency of light
- Replies: 2
- Views: 250
Re: Frequency of light
If the visible light's energy is greater than or equal to the work function of the metal then yes, but I can't think of a metal off the top of my head.
- Sat Oct 27, 2018 6:56 pm
- Forum: Einstein Equation
- Topic: E=hv [ENDORSED]
- Replies: 52
- Views: 18468
Re: E=hv [ENDORSED]
The E in E = hv represents the energy of a photon. The E in Ek = 1/2(mv^2) represents the excess energy after an electron is removed from a metal.
- Sat Oct 27, 2018 6:49 pm
- Forum: Properties of Electrons
- Topic: Degeneracy
- Replies: 11
- Views: 1259
Re: Degeneracy
It means having orbitals that are in the same energy level. So for the s-orbital it would be 1, p would be 3 and so on.
- Sun Oct 21, 2018 8:03 pm
- Forum: Einstein Equation
- Topic: HW Problem 1.25 (6th Edition)
- Replies: 2
- Views: 360
Re: HW Problem 1.25 (6th Edition)
Convert from Mg to moles to atoms, so 0.0050g x 1mol/22g x 6.022(10^23)/1 mol. Multiply this value by the answer you got in part A.
For part C, it is the same thing. All you have to do is multiply by avogadros number then multiply that value by the answer you got in part A.
Hope that helps!
For part C, it is the same thing. All you have to do is multiply by avogadros number then multiply that value by the answer you got in part A.
Hope that helps!
- Sun Oct 21, 2018 5:29 pm
- Forum: Einstein Equation
- Topic: Chapter 1 Question 27
- Replies: 2
- Views: 526
Chapter 1 Question 27
Hi, I'm not sure how to do this problem and the solutions manual doesn't really help. Here is the problem: A lamp rated at 32 W (1 W 1 Js1) emits violet light of wavelength 420 nm. How many photons of violet light can the lamp generate in 2.0 s? How many moles of photons are emitted in that time...
- Sun Oct 14, 2018 8:57 pm
- Forum: Properties of Electrons
- Topic: Photoelectric Experiment
- Replies: 9
- Views: 554
Re: Photoelectric Experiment
Increasing the intensity is not a form of increasing energy. Increasing intensity only means more photons are present, which doesn't change the overall energy level. However, increasing the frequency increases the overall energy level.
- Sun Oct 14, 2018 8:53 pm
- Forum: Properties of Electrons
- Topic: Energy emitted by electrons
- Replies: 6
- Views: 551
Re: Energy emitted by electrons
When an electron gains energy it goes to a higher orbital (further from the nucleus). When an electron loses energy, it releases the energy as light (photons) and depending upon how much energy is released, the electron travels to a lower orbital.
- Sun Oct 14, 2018 8:49 pm
- Forum: Properties of Light
- Topic: Measurable Wavelengths
- Replies: 3
- Views: 195
Re: Measurable Wavelengths
Yes, the cutoff is at 10^-18
- Mon Oct 08, 2018 5:32 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Homework Problem in Section G
- Replies: 3
- Views: 306
Homework Problem in Section G
Can someone please explain G13? "To prepare a fertilizer solution, a florist dilutes 1.0 L of 0.20 m NH4NO3(aq) by adding 3.0 L of water. The florist then adds 100. mL of the diluted solution to each plant. How many moles of nitrogen atoms will each plant receive? Solve this exercise without us...
- Thu Oct 04, 2018 11:56 am
- Forum: Empirical & Molecular Formulas
- Topic: Empirical Formula
- Replies: 6
- Views: 611
Re: Empirical Formula
Yes, I believe you always assume that the compound has a total mass of 100g simply because it is much easier to solve with this assumption.
- Sun Sep 30, 2018 5:25 pm
- Forum: SI Units, Unit Conversions
- Topic: Fundamental Exercises E3 [ENDORSED]
- Replies: 3
- Views: 259
Fundamental Exercises E3 [ENDORSED]
Please explain problem E3 in the fundamental exercises.