Search found 55 matches

by Zach Richardson 2f
Mon Jan 18, 2021 12:06 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5
Replies: 8
Views: 41

Re: Sapling #5

Victoria_Sauceda_1B wrote:How do you know which parts of the equation to multiply?


You have to multiply the whole equation. When you multiply an equation, the K value will be raised to the power of the coefficient of that multiplication, if that makes sense. So if I multiply the equation by 3 I should cube the K value.
by Zach Richardson 2f
Sun Jan 17, 2021 11:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5
Replies: 8
Views: 41

Re: Sapling #5

Hi! I can try to help. You need to take the given equations and combine them in a way that is similar to the original, which is 2NH3(g)+3I2(g)↽⇀N2(g)+6HI(g). I used the following to do so: H2(g)+I2(g)↽⇀2HI(g) Ka=160 N2(g)+3H2(g)↽⇀2NH3(g) Kc=3.6×10^−2 However, you have to make sure to reverse the se...
by Zach Richardson 2f
Sun Jan 17, 2021 11:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Question Week 1 #10
Replies: 7
Views: 28

Re: Sapling Question Week 1 #10

The smaller one is the better one to use, usually the bigger one will be much too large to make sense.
by Zach Richardson 2f
Sun Jan 17, 2021 11:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5
Replies: 8
Views: 41

Sapling #5

Can someone explain sapling #5 and how we are supposed to do it? I am confused.
by Zach Richardson 2f
Sun Jan 17, 2021 10:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sampling Week 1 #2
Replies: 12
Views: 87

Re: Sampling Week 1 #2

My numbers were different, did anyone get .700 mol S)3 in a 4.000 L container with .130 mol O2
by Zach Richardson 2f
Thu Dec 17, 2020 6:35 am
Forum: General Science Questions
Topic: final timing
Replies: 24
Views: 110

Re: final timing

The final went by rather quickly, yes. Some of the questions felt like they took forever to answer.
by Zach Richardson 2f
Thu Dec 17, 2020 6:34 am
Forum: Student Social/Study Group
Topic: grade worries
Replies: 110
Views: 1171

Re: grade worries

Coming back to this after the final, yeah it is definitely a worry for a lot of us. It's important to remember that it's ok to let it go, especially now that there is nothing that can be done to change it :).
by Zach Richardson 2f
Thu Dec 17, 2020 6:33 am
Forum: Student Social/Study Group
Topic: grade calculation
Replies: 12
Views: 102

Re: grade calculation

When will we receive the grades for our finals back?
by Zach Richardson 2f
Thu Dec 17, 2020 6:32 am
Forum: Student Social/Study Group
Topic: Winter Break Plans
Replies: 32
Views: 140

Re: Winter Break Plans

What are you guys doing over winter break? Also do you have any good book or movie recommendations? I am going to be road tripping down the Pacfic Coastal Highway with my family in an RV (social distancing at its finest). I am super excited to visit a bunch of beaches and escape my house. :) That's...
by Zach Richardson 2f
Thu Dec 17, 2020 6:31 am
Forum: Student Social/Study Group
Topic: Winter Break Plans
Replies: 32
Views: 140

Re: Winter Break Plans

I'm going to stay home because of covid. :(. We will see if I can make it up to Lake Arrowhead or Big Bear or something similar.

As for chem, I might do a little review!
by Zach Richardson 2f
Sun Dec 06, 2020 10:44 pm
Forum: *Molecular Orbital Theory Applied To Transition Metals
Topic: Orbitals and coordination numbers
Replies: 2
Views: 12

Orbitals and coordination numbers

Why is the coordination number different from the number of ionic bonds a transition metal would form outside of a coordination compound?
by Zach Richardson 2f
Sun Dec 06, 2020 10:42 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination compound bonds
Replies: 1
Views: 9

Coordination compound bonds

In sapling it talks about ligands being bonded to a central atom by donating an electron pair. Is it always like this?
by Zach Richardson 2f
Sun Dec 06, 2020 10:11 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Definition of Ligand
Replies: 8
Views: 53

Re: Definition of Ligand

I think that ligands have to be donating an electron pair to be considered ligands in a coordination compound, but I believe they will always do this when interacting with a metal :)
by Zach Richardson 2f
Sun Dec 06, 2020 9:51 pm
Forum: Naming
Topic: Sapling 1
Replies: 9
Views: 56

Sapling 1

Hello, what is wrong with my answer in the linked file? It marks it as wrong.
by Zach Richardson 2f
Sun Nov 29, 2020 11:59 pm
Forum: Naming
Topic: chelating ligand
Replies: 7
Views: 80

Re: chelating ligand

Nina Tartibi 1F wrote:You can identify a chelate if the structure of the molecule has more than one lone pair on the atoms in the structure. If it only has one lone pair, it is a monodentate.

what is the functional difference between a chelate and a monodentate?
by Zach Richardson 2f
Sun Nov 29, 2020 11:56 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: Overall Review of Intermolecular Forces
Replies: 4
Views: 38

Re: Overall Review of Intermolecular Forces

Well in very large complex proteins for example, hydrogen bonds and Van der Waals interactions play a very important role in tertiary and quaternary structures. The permanent dipole of water is the reason why things dissolve in water and thus why it is necessary for life. A lot of these interactions...
by Zach Richardson 2f
Sun Nov 29, 2020 11:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Type of Bond from Shape
Replies: 12
Views: 49

Re: Determining Type of Bond from Shape

The lewis structure will show you the kind of bond because the shape will not tell you if a bond is single or double or triple.
by Zach Richardson 2f
Sun Nov 29, 2020 11:38 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Polarity
Replies: 14
Views: 85

Re: Polarity

Forgive me if I am wrong, but I cannot think of an example with one lone pair that is not polar. I think that if the lone pairs are opposite each other they will cancel out. If I am wrong I would appreciate it if someone corrected me.
by Zach Richardson 2f
Sun Nov 29, 2020 11:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling #18
Replies: 2
Views: 32

Sapling #18

Can someone explain to me why an odd number of carbons will cause the end hydrogen atoms to be on perpendicular planes? I understand that it has something to do with the pi-bonds, but why exactly?
by Zach Richardson 2f
Sun Nov 29, 2020 11:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: finding the shape of a molecule
Replies: 6
Views: 33

Re: finding the shape of a molecule

Well, each lewis structure that is possible will have a distinct shape. The question is if that shape would really occur. If you are looking for the shape that will exist, find the lewis structures that will exist.
by Zach Richardson 2f
Sun Nov 29, 2020 11:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Remembering Bond Degrees
Replies: 7
Views: 75

Re: Remembering Bond Degrees

Well a lot of the shapes do have "parents" so to speak. For example trigonal pyramidal and bent are based on the tetrahedral shape, and they have very similar bond angles. See saw is based on a trigonal bipyramidal shape and thus has very similar bond angles. So you really only have to rem...
by Zach Richardson 2f
Sun Nov 29, 2020 11:27 pm
Forum: Hybridization
Topic: How to simply determine hybridization
Replies: 27
Views: 185

Re: How to simply determine hybridization

Hi, first determine the lewis structure of the molecule you want to look at, then look at the number of regions of electron density (bonding pairs + lone pairs) attached to the atom in question. That will tell you how many orbitals you need.
by Zach Richardson 2f
Sun Nov 29, 2020 9:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: sigma vs pi bonds
Replies: 33
Views: 185

Re: sigma vs pi bonds

I know that a souble bond has to be a pi-bond, but I am slightly confused as to why. In lecture Dr. Lavelle explained it as if it should make sense that because a pi-bond forms side-by-side that it would be the double bond but I didn't understand :(. Why is this true?
by Zach Richardson 2f
Sun Nov 29, 2020 9:53 pm
Forum: Hybridization
Topic: Orbital hybridization nomenclature
Replies: 2
Views: 23

Orbital hybridization nomenclature

I do not completely understand why the number is what it is on a hybridized orbital. For example, why is an sp3 hybridized orbital called an sp3 when it is made up of the 2s and 2p orbitals?
by Zach Richardson 2f
Sun Nov 29, 2020 9:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angles
Replies: 8
Views: 71

Re: Bond angles

I believe that the bond angles are experimentally determined, and aren't calculated from VSEPR. The only way we know of to determine them is experimentally.
by Zach Richardson 2f
Sun Nov 15, 2020 11:49 pm
Forum: Resonance Structures
Topic: resonance structures
Replies: 10
Views: 45

Re: resonance structures

Everyone is saying that it would be the one with formal charges closest to 0, but as we see in sapling #4 this is just a guideline! The only real way (that we know of so far) is to observe the bond lengths experimentally.
by Zach Richardson 2f
Sun Nov 15, 2020 11:46 pm
Forum: Resonance Structures
Topic: Total Number of Resonance Structures
Replies: 3
Views: 39

Total Number of Resonance Structures

Hello, is there a way to know the total number of resonance structures offhand? For example in sapling #4 I can see why the resonance structures can form between the carbon and the oxygen molecules, but between the carbon and nitrogen is a little less clear for me.
by Zach Richardson 2f
Sun Nov 15, 2020 11:33 pm
Forum: Lewis Structures
Topic: Lewis acids and bases
Replies: 23
Views: 105

Re: Lewis acids and bases

I get the general rule, but how can we tell if a molecule can accept or donate electrons just by looking at the chemical formula?
by Zach Richardson 2f
Sun Nov 15, 2020 11:32 pm
Forum: Lewis Structures
Topic: Coordinate Covalent Bond vs Lewis Acid/Base
Replies: 2
Views: 13

Coordinate Covalent Bond vs Lewis Acid/Base

Hello,

Is there a difference between a coordinate covalent bond and a lewis acid/base interaction? It seems to me like both involve the donation of a pair of electrons to another atom.
by Zach Richardson 2f
Sun Nov 15, 2020 11:15 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: Sapling #13
Replies: 1
Views: 28

Sapling #13

Hello,

Can someone explain how many hydrogen bonds can form for sapling #13? What qualifies as a "highly electronegative" atom in the structure?
by Zach Richardson 2f
Thu Nov 12, 2020 11:05 pm
Forum: Ionic & Covalent Bonds
Topic: Difference between ionic bonding and ion-ion interactions?
Replies: 4
Views: 58

Re: Difference between ionic bonding and ion-ion interactions?

I am also confused about this because in the lecture on Monday, Dr. Lavelle listed the Na+ Cl- reaction under ion-ion interionic attractive forces, when I thought these two formed an intraionic ionic bond.
by Zach Richardson 2f
Sun Nov 08, 2020 11:29 pm
Forum: Ionic & Covalent Bonds
Topic: Metals vs Cations
Replies: 1
Views: 20

Metals vs Cations

Can ionic bonds only be formed between a metal cation and an anion? Or can it be a larger, molecular ion as a cation (like NH4+)?
by Zach Richardson 2f
Sun Nov 08, 2020 11:25 pm
Forum: Resonance Structures
Topic: Delocalized
Replies: 5
Views: 45

Re: Delocalized

Lewis structures are highly simplified and therefore things like resonance structures are drawn as a model having multiple possibilities instead of showing that there are electrons not bound to any particular atom or two atoms.
by Zach Richardson 2f
Sun Nov 08, 2020 11:23 pm
Forum: Resonance Structures
Topic: Bond lengths
Replies: 20
Views: 143

Re: Bond lengths

No it is not necessary because Lewis structures are simplified models and do not actually represent the molecule in physical space.
by Zach Richardson 2f
Sun Nov 08, 2020 11:20 pm
Forum: Octet Exceptions
Topic: SO42- Octet Rule Exception Orbitals
Replies: 4
Views: 29

SO42- Octet Rule Exception Orbitals

I am moderately confused on the So4(2-) Octet rule exception that Dr. Lavelle explained when he was talking about formal charge. I understand that because s has quantum number n=3 it can have s, p or d orbitals. However, I thought that the 4s would fill before the 3d and I'm not sure how that works ...
by Zach Richardson 2f
Wed Nov 04, 2020 1:26 pm
Forum: Quantum Numbers and The H-Atom
Topic: l numbers bigger than 3
Replies: 5
Views: 39

l numbers bigger than 3

What do l numbers bigger than 3 mean? I thought there were just s,p,d,f; but one of the problems is "what l numbers are possible for n=7" and the correct answer is anything 6 or less. What would an l number of 6 look like?
by Zach Richardson 2f
Sun Nov 01, 2020 11:49 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: N,L,mL
Replies: 3
Views: 34

Re: N,L,mL

Also spin to determine which electron in the orbital we are talking about.
by Zach Richardson 2f
Sun Nov 01, 2020 11:47 pm
Forum: Ionic & Covalent Bonds
Topic: Electron spin in bonds
Replies: 8
Views: 76

Re: Electron spin in bonds

Forgive me if I am wrong, but isn't spin a constant property of the electron or am I completely missing something.
by Zach Richardson 2f
Sun Nov 01, 2020 11:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Scores
Replies: 28
Views: 269

Re: Midterm Scores

I thought that scoring would be automatic but I think that it might take longer to be released, maybe some students still have to take the test?
by Zach Richardson 2f
Sun Nov 01, 2020 11:45 pm
Forum: Trends in The Periodic Table
Topic: studying
Replies: 12
Views: 61

Re: studying

I love re reading the parts in the textbook, especially because they will give you will get different parts before and after a lecture.
by Zach Richardson 2f
Sun Nov 01, 2020 11:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Config. Refresher
Replies: 3
Views: 50

Re: Electron Config. Refresher

The schrodinger wave equation will return a different energy value for electrons in different orbitals with the same n value because the wave function is different.
by Zach Richardson 2f
Sun Nov 01, 2020 11:41 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework Question 23
Replies: 1
Views: 19

Homework Question 23

Can someone explain how this fits in with the explanation of electron affinity in the lesson?
by Zach Richardson 2f
Sun Oct 25, 2020 10:18 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: dz^2 orbital difference
Replies: 2
Views: 36

dz^2 orbital difference

Why is dz^2 known as a d-orbital? How were they classified by orbital in the first place, because the dz^2 function seems very different from the other d orbital wave functions. It seems like its own thing to me.
by Zach Richardson 2f
Wed Oct 21, 2020 11:51 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: delta v
Replies: 6
Views: 77

delta v

When the electron becomes entangled with the photon, is there actually an uncertainty about its velocity or merely the time it takes to cover a certain distance? Meaning, could different entanglements with the same photon with the same initial speed of the electron result in different actual velocit...
by Zach Richardson 2f
Wed Oct 21, 2020 1:46 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Equation
Replies: 11
Views: 129

Re: Rydberg Equation

Darren1e wrote:So I remember him saying R= 3.29x10^15hz, but when I look it up online it says it is 1.0874x10^-7 m^-1. Are they the same in different units?

I was wondering this as well. Why are there two different answers for this?
by Zach Richardson 2f
Sun Oct 18, 2020 11:33 pm
Forum: Photoelectric Effect
Topic: EM radiation neither absorbed nor emitted by atom
Replies: 7
Views: 37

Re: EM radiation neither absorbed nor emitted by atom

I'm hoping that this gets seen by a moderator to clear this up, but what I think he meant is particles that are not absorbed and don't bounce off can pass through, however I am not entirely sure of this.
by Zach Richardson 2f
Sun Oct 18, 2020 11:21 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Advice for studying
Replies: 92
Views: 2080

Re: Advice for studying

Find people to study with! It's better to study together :)
by Zach Richardson 2f
Sun Oct 18, 2020 11:18 pm
Forum: DeBroglie Equation
Topic: Question about post-module assessment
Replies: 5
Views: 95

Re: Question about post-module assessment

Everyday objects do not have wave properties and thus do not have diffraction patterns.
by Zach Richardson 2f
Sun Oct 18, 2020 11:17 pm
Forum: DeBroglie Equation
Topic: Natural Frequency?
Replies: 2
Views: 8

Natural Frequency?

This is a silly question but I was wondering if the Debroglie equation has anything to do with the phenomenon of natural frequencies from physics, like how a singer can break a glass using a specific frequency of sound.
by Zach Richardson 2f
Sun Oct 18, 2020 10:57 pm
Forum: Einstein Equation
Topic: Question about Perception of Photons
Replies: 2
Views: 49

Re: Question about Perception of Photons

I was equally confused about this, and in general the concept of a particle having a frequency in the De broglie model/equation.
by Zach Richardson 2f
Sun Oct 18, 2020 10:56 pm
Forum: Einstein Equation
Topic: Particles with mass
Replies: 5
Views: 25

Particles with mass

I see this mentioned a lot in here, talking about particles with mass vs. photons, and I wanted to ask how do photons not have mass? If they can impart energy to something by heating it up or exciting electrons as in the Photoelectric effect, how can that be accomplished without mass?
by Zach Richardson 2f
Tue Oct 13, 2020 11:40 pm
Forum: Photoelectric Effect
Topic: E(photon) greater than or less than energy required to remove electron
Replies: 2
Views: 23

Re: E(photon) greater than or less than energy required to remove electron

Nevermind, I understand. There are two ways to take that sentence and I chose the wrong one, but it makes sense.
by Zach Richardson 2f
Tue Oct 13, 2020 10:43 pm
Forum: Photoelectric Effect
Topic: E(photon) greater than or less than energy required to remove electron
Replies: 2
Views: 23

E(photon) greater than or less than energy required to remove electron

At about 38:25 into Lecture 5, Dr. Lavelle makes a statement that electrons will not be removed from the metal if the energy of the photons is greater than or equal to the energy (screenshot attached). This does not make sense to me. If the energy is greater than what is required, then there should ...
by Zach Richardson 2f
Sun Oct 11, 2020 8:55 pm
Forum: Properties of Light
Topic: Light oscillations
Replies: 2
Views: 40

Re: Light oscillations

Using the wave model of light, I believe light would be a wave that oscillates at a rate that is inversely proportional to its wavelength, so yes it is oscillating.

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