Search found 38 matches
- Wed Jun 06, 2018 7:56 am
- Forum: Hybridization
- Topic: Hybridization
- Replies: 3
- Views: 413
Re: Hybridization
Yes, this is what Professor Lavelle said during class.
- Sat Jun 02, 2018 3:36 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs
- Replies: 2
- Views: 318
Re: Lone Pairs
That is exactly correct. The lone pairs influence the overall shape and account for a region of electron density but not directly so that four regions, including one lone pair, would not yield tetrahedral. This only occurs with 4 bonds.
- Fri Jun 01, 2018 9:05 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar and non polar
- Replies: 3
- Views: 334
Re: Polar and non polar
To determine if a molecule is polar or nonpolar it is easiest to start by drawing its dipole moment or shape. This can be done by basically just drawing the Lewis structure first, then add arrows pointing to the more electronegative atom from each individual bond. For example, in CCl4, all the arrow...
- Wed May 30, 2018 12:13 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Homework 4.11
- Replies: 1
- Views: 1724
Re: Homework 4.11
The VSEPR formula takes the form AXE with subscripts present on the X and E usually, depending on how many atoms surround the central atom (X) and how many lone pairs the central atom has (E). In some cases, if there are no lone pairs, the formula would just be AX with the appropriate subscript. In ...
- Sun May 27, 2018 5:38 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Notes Wed 5/23 and Fri 5/25
- Replies: 2
- Views: 394
Re: Notes Wed 5/23 and Fri 5/25
I could send them, I would just need an email address to do so.
- Sun May 27, 2018 5:37 pm
- Forum: Ionic & Covalent Bonds
- Topic: 6.11
- Replies: 2
- Views: 371
Re: 6.11
Hydrogen bonds are bonds that occur due to the partial positive and negative charges found on certain molecules that contain hydrogen. Specifically O-H, F-H, or N-H. Due to the differences in electronegativity, hydrogen adopts a slightly positive charge and the other atom in this bond adopts a sligh...
- Thu May 24, 2018 5:15 pm
- Forum: Resonance Structures
- Topic: XeO3 Shape
- Replies: 2
- Views: 1108
Re: XeO3 Shape
From what Professor Lavelle said during the lecture on Wednesday, lone pairs do have an impact on the shape. However, XeO3 only has one lone pair so it is actually AX3E. So it is still trigonal pyramidal. Hypothetically, a molecule with AX3E2 would have a shape called trigonal bipyramidal.
- Fri May 18, 2018 8:00 am
- Forum: Ionic & Covalent Bonds
- Topic: Melting and Boiling Points
- Replies: 3
- Views: 473
Re: Melting and Boiling Points
Since covalent bonds share electrons, they tend to have lower melting points compared to ionic bonds that lose or gain electrons. In the same line of thinking, covalent bonds also have lower boiling points compared to ionic bonds and this is due to the fact that the electrostatic attraction between ...
- Fri May 18, 2018 7:55 am
- Forum: Ionic & Covalent Bonds
- Topic: Solubility
- Replies: 3
- Views: 435
Re: Solubility
Covalent bonds are usually insoluble to my knowledge. Ionic bonds are the ones that do dissolve readily in water or other fluids.
- Fri May 18, 2018 7:53 am
- Forum: Lewis Structures
- Topic: Identifying radicals [ENDORSED]
- Replies: 4
- Views: 2465
Re: Identifying radicals [ENDORSED]
My TA told us that the easiest way to tell if a molecule is a radical is if it has an odd-numbered amount of valence electrons. If it has an even number of valence electrons then it would not be a radical. So you just have to add up how many electrons each atom has, take into consideration any charg...
- Sun May 13, 2018 6:43 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bonds
- Replies: 3
- Views: 419
Re: Covalent Bonds
In Lewis structures, sharing electrons (covalent bond) is seen via a line between two atoms. If you do not have the Lewis structure and for some reason it is not telling you what kind of bond it is, you would have to reference the general rules that Lavelle went over or which atoms tend to share ele...
- Sun May 13, 2018 5:10 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bonds
- Replies: 4
- Views: 666
Re: Covalent Bonds
I believe this is due to the fact that atoms with lower ionization energies are prone to have more open spaces that need to be filled with electrons, or less of a complete octet. So putting that as the central atom makes the Lewis structure easier since this atom would have more access to forming mu...
- Fri May 11, 2018 7:55 am
- Forum: Lewis Structures
- Topic: Ionic vs Covalent
- Replies: 5
- Views: 724
Re: Ionic vs Covalent
When a Lewis structure is depicting an ionic bond, the final result will show the relative charges of each atom based on whether it has gained or lost an electron. So there will either be a (+) or (-) sign next to the atom. While in covalent bonds, there are no charges (usually, but there could be p...
- Fri May 11, 2018 7:50 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Px, Py, Pz orbitals
- Replies: 2
- Views: 2582
Re: Px, Py, Pz orbitals
As you know, one of the four angular quantum numbers (l) is 1 which corresponds to P. Since the angular quantum number is 1, the possible values for the magnetic quantum number (ml) are 1,0,-1. Each orbital has a certain type of shape that is described by the angular quantum number and in the case o...
- Sat May 05, 2018 6:51 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: D and S oribitals
- Replies: 3
- Views: 378
Re: D and S oribitals
I believe in most cases the S orbital is filled up before the D orbital at least for the first few periods. Once you reach the fourth period, the electrons fill up the first two spaces in the 4s orbital but then go back to start filling up the D orbitals of the 3rd shell. So to my understanding, the...
- Sat May 05, 2018 2:51 pm
- Forum: Limiting Reactant Calculations
- Topic: Homework M12
- Replies: 3
- Views: 549
Re: Homework M12
I have not done this problem but having done others of the same nature I think I should be able to clarify. Once you find the limiting reactant, you multiply the amount you have of that reactant (in moles) by the molar ratio you would need of the other reactant in order to find how much you would ac...
- Fri May 04, 2018 9:00 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Pauli Exclusion Principle
- Replies: 1
- Views: 272
Re: Pauli Exclusion Principle
I believe that the Pauli Exclusion Principle is based on the fact that electrons repel each other and cannot occupy the exact same space so therefore they cannot have the same four quantum numbers. Each orbital, denoted by the quantum number (ml), can have two different values for (ms) +1/2 or -1/2 ...
- Thu May 03, 2018 6:44 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Question 1.19 Help
- Replies: 2
- Views: 370
Re: Question 1.19 Help
For this problem you just need to look at the value of (l) since (ml) is dependent on (l). The value of (l) is given by the letter s,p,d, or f. They each correspond to 0,1,2,3 respectively if you remember from the notes. For b) if the value of (l) is 2, then based on the rules given by Lavelle, (ml)...
- Sun Apr 29, 2018 7:57 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: In regards to ml
- Replies: 2
- Views: 282
Re: In regards to ml
Ml is it's own independent value but the values it can be are based off of whatever (l) is just like the values of (l) are dependent on (n). I'm not sure if this is why (ml) has the subscript (l) but I do know that (ml) cannot be just any random number and is dependent on (l).
- Sun Apr 29, 2018 7:52 pm
- Forum: Photoelectric Effect
- Topic: h.w. 1.65 [ENDORSED]
- Replies: 2
- Views: 452
Re: h.w. 1.65 [ENDORSED]
This value should be the work function because it states that it is the value of energy needed to break the bond, but you could also just use this value as the energy of the photon because it doesn't mention any kinetic energy so that value could be 0 which would make the work function and the energ...
- Sun Apr 29, 2018 7:47 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Question 2.41
- Replies: 3
- Views: 377
Re: Question 2.41
C is definitely false because as Professor Lavelle said during lecture, the angular quantum number (l) can only have values up to one value less than the principle quantum number (n) so there is no way the first number (n) and the second number (l) could be the same.
- Sat Apr 28, 2018 7:02 pm
- Forum: *Shrodinger Equation
- Topic: Shrodinger Equation [ENDORSED]
- Replies: 2
- Views: 510
Re: Shrodinger Equation [ENDORSED]
For the Schrodinger equation, I think the setup is actually Ψ(x,y,z) = energyΨ(x,y,z) or HΨ = EΨ. The values x,y,z are referred to as a position when I wrote about it in my notes from lecture so I am assuming the three values determine a location for the wave function. The letters you used are for t...
- Sat Apr 28, 2018 6:18 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Four Different Quantum Numbers
- Replies: 7
- Views: 752
Re: Four Different Quantum Numbers
I believe this has to do partially with the negative charge of electrons. They repel each other if in close proximity and if two electrons were to have the same four quantum numbers, they would theoretically be found in the same place with the same energy, same angular motion, and same spin directio...
- Fri Apr 27, 2018 9:17 am
- Forum: Limiting Reactant Calculations
- Topic: limiting reactant
- Replies: 2
- Views: 365
Re: limiting reactant
The first step in these problems that I like to take is converting the values of each reactant from grams to moles This is done by dividing each amount of reactant in grams by its molar mass so that would be (100g CO/28.01g.mol) and (100g O2/32 g.mol). This should give you 3.57 mol of CO and 3.125 m...
- Sun Apr 22, 2018 5:42 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Which Equation Do We Never Use for Light? [ENDORSED]
- Replies: 3
- Views: 545
Re: Which Equation Do We Never Use for Light? [ENDORSED]
The equation he said to never use for light was wavelength (lambda) = h(planck's constant)/p(momentum). This is Debroglie's equation and it should be used with any other particles, including atoms, molecules, etc. Just not with light. It basically is meant to suggest that other substances besides li...
- Sat Apr 21, 2018 3:38 pm
- Forum: Properties of Light
- Topic: Speed of Light which is more accurate? [ENDORSED]
- Replies: 6
- Views: 2201
Re: Speed of Light which is more accurate? [ENDORSED]
I do not believe it makes much of a difference. Someone asked this question in my discussion and my TA said that it does not matter but if we are taking a test and they give us the constant of speed on the page with all the formulas and constant, we should use whatever value they provided us, whethe...
- Fri Apr 20, 2018 8:09 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Equation & Test 2
- Replies: 4
- Views: 474
Re: Heisenberg Equation & Test 2
I do not believe that we will be tested on this material since we have not gone over this in lecture and we were told that this test covered material up to section 1.5. They do not discuss the Heisenberg equation in the first five sections of chapter 1 and it is also not listed as one of the topics ...
- Thu Apr 19, 2018 6:35 pm
- Forum: Properties of Light
- Topic: Homework Problem 1.5
- Replies: 2
- Views: 281
Re: Homework Problem 1.5
That is the correct order and that is because wavelength is inversely related to energy. So microwaves have the largest wavelength and thus the least energy while gamma rays have the smallest wavelength and therefore the greatest energy. It is important to remember that unlike wavelength, frequency ...
- Thu Apr 19, 2018 11:30 am
- Forum: Photoelectric Effect
- Topic: Lyman vs. Balmer vs. Paschen vs. Brackett?
- Replies: 3
- Views: 1345
Re: Lyman vs. Balmer vs. Paschen vs. Brackett?
The difference between these series is the initial energy level that they begin with. For the Lyman series, the lower energy level is always n = 1, Balmar series is n = 2, Paschen series is n = 3, and Brackett series is n = 4. The final energy level can vary but the initial will always determine wha...
- Fri Apr 13, 2018 8:25 pm
- Forum: Properties of Electrons
- Topic: History of experiments on the model of atom
- Replies: 7
- Views: 793
Re: History of experiments on the model of atom
I have not heard the professor mention anything about this during lecture and I have not seen this listed as something we should know in the outlines on his website. I think knowing how to solve different problems related to what we are learning is what we are expected to focus on but I am not compl...
- Fri Apr 13, 2018 1:32 pm
- Forum: Photoelectric Effect
- Topic: Kinetic Energy
- Replies: 2
- Views: 195
Re: Kinetic Energy
So the equation for this is E(photon) - E(energy to remove electron) = Ek (kinetic energy or excess energy). Electrons are only removed if E(photon) is greater than or equal to E(energy to remove electron). In this case, if the photon's energy is equal to the energy needed to remove the electron, th...
- Fri Apr 13, 2018 9:06 am
- Forum: Properties of Light
- Topic: Frequency and wavelength [ENDORSED]
- Replies: 4
- Views: 511
Re: Frequency and wavelength [ENDORSED]
I know that in general, they do have an inverse relationship, waves with higher frequency tend to have shorter wavelengths and vice versa but I am not aware of the reasoning behind it.
- Fri Apr 13, 2018 9:03 am
- Forum: Properties of Light
- Topic: Speed in vacuum
- Replies: 3
- Views: 767
Re: Speed in vacuum
That value is for the speed of light from what I wrote down during my notes. I do not remember him saying it was the speed in a vacuum or if it means the same thing but that might be my mistake. I believe it is a value he just gave to us and we might use it later on but I do remember it was one of t...
- Fri Apr 13, 2018 8:47 am
- Forum: Limiting Reactant Calculations
- Topic: Q.22 on Audio-Visual Focus-Topic [ENDORSED]
- Replies: 2
- Views: 284
Re: Q.22 on Audio-Visual Focus-Topic [ENDORSED]
Once you have found which reactant is limiting, you would follow by finding how much of the product can be made given the mass of the reactant. You would use the molar ratios of the reactant and the product so make sure you convert the mass of the reactant from grams to mols. Once that part is solve...
- Thu Apr 12, 2018 9:13 pm
- Forum: Properties of Light
- Topic: Units of speed of light [ENDORSED]
- Replies: 2
- Views: 367
Re: Units of speed of light [ENDORSED]
From what I read in the textbook, it seems that although frequency is measured as cycles per second or Hz, it is also set equal to s^-1 as was written during lecture. So 1 Hz is equivalent to 1 s^-1. Wavelengths are measured in nanometers typically but that can easily be converted to meters so the s...
- Thu Apr 12, 2018 5:58 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Finding the molarity concentration of one type of atom from a molecule
- Replies: 3
- Views: 233
Finding the molarity concentration of one type of atom from a molecule
Hi, I have seen a handful of questions where we are asked to find molarity given a volume and grams of a solute but sometimes the question asks for the concentration of a particular portion of the molecule like just the Na ions from a solute that is NaCl. In order to find the concentration of Na ion...
- Thu Apr 12, 2018 5:41 pm
- Forum: SI Units, Unit Conversions
- Topic: Clarification on unit conversions
- Replies: 4
- Views: 287
Re: Clarification on unit conversions
Yes, but just make sure that the initial unit is meters because if it is something different like say centimeters then the conversion would be off. You could also technically just move the decimal over 9 times or 12 times to get the correct conversion value but that seems like more of a hassle compa...
- Thu Apr 12, 2018 5:38 pm
- Forum: Photoelectric Effect
- Topic: Why do shorter wavelengths have more energy than longer wavelengths?
- Replies: 4
- Views: 6672
Re: Why do shorter wavelengths have more energy than longer wavelengths?
I believe it is because shorter wavelengths have higher frequencies. I like to think about it in the perspective of how shorter wavelengths can travel faster or more of them can occur in a shorter time frame so it makes sense they would have more energy if they occur more consistently. When you comp...