## Search found 32 matches

Sat Dec 08, 2018 12:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Step Up Session Worksheet (Monday + Friday, Hannah) [ENDORSED]
Replies: 37
Views: 1914

### Re: Step Up Session Worksheet (Monday + Friday, Hannah)[ENDORSED]

Can you please post the solutions to Step Up Week 10?
Fri Dec 07, 2018 11:43 am
Forum: Bronsted Acids & Bases
Topic: Identifying the difference
Replies: 6
Views: 160

### Re: Identifying the difference

They way that I think of it is that with the Lewis acids and bases you are considering the transferring of electrons, while with Bronsted protons are being tranferred. Bronsted acids want to remove their H+, which removes a proton, whereas a Lewis acid accepts electrons from a lewis base.
Fri Dec 07, 2018 11:32 am
Forum: Air Pollution & Acid Rain
Topic: acid rain
Replies: 4
Views: 298

### Re: acid rain

Could someone explain the significance of acid rain?
Tue Dec 04, 2018 6:56 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Degeneracy
Replies: 4
Views: 409

### Re: Degeneracy

For an electron with quantum numbers n=3 and l=1, according to the formula (# of degenerate orbitals=2*l+1), the number of degenerate orbitals would be 2. However people have said that for a p orbital there are always 3 degenerates, so now I am confused. Is there any way to further explain this? In ...
Sat Dec 01, 2018 4:14 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelate
Replies: 6
Views: 211

### Re: Chelate

Would anyone be able to explain the relationship between a polydentate and a chelate? The textbook says that "polydentate ligands can form chelates" but I'm not very clear on what that means. This is what I found about chelates and polydentates on another post: "Polydentate refers to...
Sat Dec 01, 2018 1:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands
Replies: 2
Views: 159

### Re: Ligands

How can you easily tell if a bond is between a central atom and a ligand? Will the central atoms always be a metal or are there exceptions?
Sat Dec 01, 2018 12:58 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelate
Replies: 6
Views: 211

### Re: Chelate

In lecture, Professor Lavelle gave an example of a chelate that had only sigma bongs and could rotate, do all chelates only have sigma bonds?
Sun Nov 25, 2018 2:27 pm
Forum: Hybridization
Topic: Hybridization Orbitals
Replies: 2
Views: 140

### Hybridization Orbitals

When finding the hybrid orbitals of C2H4, why would you identify the orbitals as one C2sp^2-C2sp^2 and two H1s-C2sp^2 orbitals? I understand how to find what the hybrid orbitals are, but I am not sure how what the 1 and 2s that follow the C and H represent.
Sun Nov 25, 2018 1:41 pm
Forum: Hybridization
Topic: d orbital
Replies: 2
Views: 88

### Re: d orbital

I would start by first drawing the lewis structure that way you can easily determine the number of regions of electron density, then use the explanation above.
Sun Nov 25, 2018 1:39 pm
Forum: Hybridization
Topic: Figuring out the number of sigma and pi bonds in a molecule
Replies: 2
Views: 68

### Re: Figuring out the number of sigma and pi bonds in a molecule

For 2F3, it asks how many sigma and pi bonds are in SO2. From drawing the lewis structure I found that there are 2 sigma and 2 pi bonds. In the answer key, however it states that there is a resonance structure with 2 sigma bonds and 1 pi bond. How would these two lewis structures have resonance if o...
Sun Nov 25, 2018 1:34 pm
Forum: Hybridization
Topic: Test 3
Replies: 13
Views: 248

### Re: Test 3

I think that as long as we are able to understand how the hybridization works and know that the VSEPR model only accounts for bonded atoms then we should be okay for that part.
Thu Nov 15, 2018 3:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW Q 4.11
Replies: 4
Views: 551

### Re: HW Q 4.11

I understand that the lone pair causes the shape to be seesaw, but can we assume that the lone pairs will be on the top? Would the shape be different if the lone pair was elsewhere?
Thu Nov 15, 2018 3:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 109.5 Degrees
Replies: 4
Views: 181

### Re: 109.5 Degrees

Are tetrahedrals and molecules that are bent with four domains the only shapes that have bond angles of 109.5?
Thu Nov 15, 2018 3:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Double Bonds in VSEPR
Replies: 5
Views: 126

### Double Bonds in VSEPR

If a molecule has double bonds is there any difference in the way that we draw the VSEPR model? Would it be the same as one with only single bonds?
Thu Nov 08, 2018 3:38 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Dipole Moment
Replies: 3
Views: 124

### Dipole Moment

Can someone explain what a dipole moment is and what the arrow in the diagram of the dipole represents? Does this have anything to do with polarizability?
Thu Nov 08, 2018 3:26 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Difference between the bonds
Replies: 4
Views: 185

### Re: Difference between the bonds

Because the dipole-dipole bond is when molecules are polar on their own, and a dipole induced dipole is when there is one polar bond that causes the second non polar bond to exhibit the character of a polar bond, then both types would also have the same dissociation energy. They are two different bo...
Thu Nov 08, 2018 3:20 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrogen Bonds vs. Ion-Dipole Bonds
Replies: 5
Views: 398

### Re: Hydrogen Bonds vs. Ion-Dipole Bonds

I think the reason for this is the way that the electrons are distributed within the elements. The hydrogens have a more polar bond, so their electrons are distributed in a way that causes their bond to be stronger, whereas the ion-dipole bond has a greater distance between their electrons so their ...
Tue Oct 30, 2018 7:52 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge purpose
Replies: 40
Views: 2093

### Re: Formal charge purpose

I believe that if there are multiple lewis structures that have an overall charge of 0, then it would just be a resonance right?
Tue Oct 30, 2018 6:53 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge of Ions
Replies: 9
Views: 320

### Re: Formal Charge of Ions

Why would the central charge be different from the overall charge of the molecule? I'm having a difficult time understanding this concept
Tue Oct 30, 2018 6:44 pm
Forum: Octet Exceptions
Topic: octet rule exceptions?
Replies: 5
Views: 202

### Re: octet rule exceptions?

Wait so periods 1 and 2 can both have more electrons than an octet? If so, are there any in the first 2 periods that can only reach an octet?
Sun Oct 28, 2018 2:46 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 5
Views: 210

### Re: Resonance Structures

What are some examples of resonance structures? Do they only occur in bonds between certain molecules?
Sun Oct 28, 2018 2:41 pm
Forum: Lewis Structures
Topic: Dots in Lewis Stucture
Replies: 14
Views: 368

### Re: Dots in Lewis Stucture

So for problem 2B3 part d, the diagram in the back shows that there are three bonds between Fluorine and Bromine, but there are also 2 pairs of electrons. Typically aren't there only dots in four pairs or sets of bonds?
Sun Oct 28, 2018 2:34 pm
Forum: Lewis Structures
Topic: Ground State e- Configuration
Replies: 3
Views: 91

### Ground State e- Configuration

In problem 2A21, the ground state electron configuration of Ag+ is 4d^10. Why is this the case rather than it being 4d^9 5s^1?
Wed Oct 17, 2018 2:45 pm
Forum: Photoelectric Effect
Topic: Threshold energy [ENDORSED]
Replies: 17
Views: 678

### Re: Threshold energy[ENDORSED]

From what I can tell, the threshold energy is the required energy to release an electron, but the actual energy of the photon can be more or less than the threshold energy. Correct me if I am wrong please.
So if the energy of the photon exceeds the threshold energy, will more electrons be emitted?
Wed Oct 17, 2018 2:40 pm
Forum: Properties of Light
Topic: Rydberg formula
Replies: 8
Views: 219

### Re: Rydberg formula

I think you would start by using the formula "(hc)/wavelength = change in energy" to find the change in the energy since the wavelength is given to you and h and c are constants. Then you would use Rydberg's formula.
Wed Oct 17, 2018 2:33 pm
Forum: Photoelectric Effect
Topic: Speed of Light
Replies: 5
Views: 165

### Speed of Light

I understand that if an electron's velocity is greater than the speed of light, the problem was either done wrong or it was a trick question, but I am not sure why. Does this have anything to do with balancing energy within the atomic spectra?
Thu Oct 11, 2018 4:35 pm
Forum: Photoelectric Effect
Topic: Work function
Replies: 7
Views: 185

### Re: Work function

What is the equation for the work function and the phi symbol? Is the phi a constant?
Thu Oct 11, 2018 4:23 pm
Forum: Photoelectric Effect
Topic: Empirical Equation
Replies: 4
Views: 140

### Empirical Equation

In my notes from 10-10-18, I have that "E(photon)=threshold energy +E(kinetic)"
Is threshold energy a constant that I should memorize, or will it be a value that is given in the problem/I will be asked to solve for?
Thu Oct 11, 2018 4:03 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 4
Views: 114

### Re: Photoelectric Effect

From what I understand, you are saying that a shorter wavelength (higher frequency) will eject electrons even if it is a low intensity photon. But a photon with a higher intensity will emit more electrons than a light source with a lower intensity if their frequencies were equal, correct?
Wed Oct 03, 2018 9:59 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Moles!
Replies: 7
Views: 232

### Re: Moles!

My only previous chem class was my sophomore year so even stoichiometry feels foreign. I had asked few friends who are good at chem about converting grams to moles using stoichiometry, and they have done it a few different ways but got the same answer. Does anyone have any good tips on how to set up...
Wed Oct 03, 2018 9:44 pm
Forum: Empirical & Molecular Formulas
Topic: Homework
Replies: 2
Views: 131

### Homework

Aside from having our homework assignment number, name, chapter and text book edition, are there any other things that I should include in the heading of my paper?
Wed Oct 03, 2018 9:34 pm
Forum: Empirical & Molecular Formulas
Topic: Molar Mass: E21
Replies: 3
Views: 154

### Molar Mass: E21

For question E21, it states, "Calculate the amount (in moles) and the number of molecules and formula units (or atoms if indicated) in a) 10.0g of alumni, Al[sub]2O[sub]3 b)25.92 mg of hydrogen flouride, HF; c) 1.55mg of hydrogen peroxide, H20; d) 1.25 kg of glucose, C[sub]6H[sub]12O[sub]6; e) ...