Search found 103 matches

by Andrew F 2L
Wed Mar 11, 2020 1:36 pm
Forum: Administrative Questions and Class Announcements
Topic: Review Packet
Replies: 5
Views: 96

Re: Review Packet

I believe there is also another review packet going around if you type in "earthquake" into chemistry community as well that was made by students
by Andrew F 2L
Wed Mar 11, 2020 1:26 pm
Forum: Student Social/Study Group
Topic: Final Exam
Replies: 22
Views: 460

Re: Final Exam

I think that he may have us scan in our final ourselves because many people are already going home and could have access to their own devices to send it in.
by Andrew F 2L
Wed Mar 11, 2020 1:21 pm
Forum: Balancing Redox Reactions
Topic: Half Reactions
Replies: 15
Views: 92

Re: Half Reactions

I find that for basic solutions, It is easier to add H2O to the side that already has oxygen and then from there you can use OH- to balance it out from the other side.
by Andrew F 2L
Wed Mar 11, 2020 1:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E potential
Replies: 8
Views: 38

Re: E potential

If you are asked to find the standard potential after figuring out which is the cathode however, do NOT change the sign on the potential value if you are using Ecell= Ecathode- Eanode
by Andrew F 2L
Wed Mar 11, 2020 1:06 pm
Forum: Student Social/Study Group
Topic: turning in the final
Replies: 2
Views: 88

Re: turning in the final

I think we might have to scan it in ourselves because that is what is going to happen in my math class. Either way, he is going to update us as he figures things ou!
by Andrew F 2L
Sun Mar 08, 2020 10:22 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Problems
Replies: 6
Views: 43

Re: Problems

If you are referring to Kinetics vs Thermodynamics, I think it is just important to understand the concept of activation energy for kinetic reactions and how a lower activation energy will make the reaction run faster albeit with less stable products than thermodynamical controlled reactions. Also, ...
by Andrew F 2L
Sun Mar 08, 2020 10:18 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 6
Views: 43

Re: Cell Diagrams

To add on this wonderful list, Platinum as a solid metal is required on the side that has no metals because the electrode requires a solid metal to conduct the flow of e- / voltage going through it.
by Andrew F 2L
Sun Mar 08, 2020 10:16 pm
Forum: Balancing Redox Reactions
Topic: Why do we flip E for oxidation?
Replies: 13
Views: 80

Re: Why do we flip E for oxidation?

What I found was confusing was that in Youtube videos, the teachers would be adding the cell potentials while the book has us subtract the anode from the cathode. These are both the same thing it is just that, like others have said, you don't change the standard potential sign when you are using the...
by Andrew F 2L
Sun Mar 08, 2020 10:13 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Cathode and Anode K
Replies: 2
Views: 47

Re: Cathode and Anode K

I believe you are referring to the Nernst equation which takes into account the Equilibrium Constant. This example perhaps you are talking about involves a concentration cell or where they give you molarity values for each of the reactant or products and you must solve to find a something missing. U...
by Andrew F 2L
Sun Mar 08, 2020 10:10 pm
Forum: General Science Questions
Topic: Worksheets for Final Review Sessions
Replies: 2
Views: 84

Re: Worksheets for Final Review Sessions

I believe you can search up some of the TA's names as the week is coming and their discussions are taking place. Many of them post their worksheets here on Chemistry Community just like they did for the Midterm! And like you said, Lyndon will be posting his or at least announcing his worksheet to be...
by Andrew F 2L
Sun Mar 01, 2020 12:33 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Values of Standard Electrode Potentials
Replies: 4
Views: 37

Re: Values of Standard Electrode Potentials

I believe the poster above me is correct in that it relates to spontaneity of reactions but also sometimes the cell diagram is reversed and the cathode and anode are switched places so I believe the cell potential can also change its value in such a way so you would understand that the reverse react...
by Andrew F 2L
Sun Mar 01, 2020 12:26 pm
Forum: General Science Questions
Topic: Test 2
Replies: 12
Views: 227

Re: Test 2

My TA said you should expect the similar amount of problems but I would assume that the length of the problems may be different. The questions from electrochemistry seem to be longer and more complex in terms of understanding balancing redox reactions and then applying this concept to galvanic cells...
by Andrew F 2L
Sun Mar 01, 2020 12:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Reading cell diagrams
Replies: 1
Views: 50

Re: Reading cell diagrams

I believe you are correct in that we flip the sign of the cell potential value and I believe on the test it will tell you what type of cell it is so you can determine where is the anode or the cathode. Hope this helps!
by Andrew F 2L
Tue Feb 25, 2020 9:42 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: How to Order Cell Diagrams
Replies: 2
Views: 25

How to Order Cell Diagrams

I am confused how to order my cell diagrams because I just don't know what order to put them in. I think the solids go on the outside but I dont know the order of the reactants and products on the inside? Thank you!
by Andrew F 2L
Tue Feb 25, 2020 12:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Determining Voltage Values of Anode and Cathode
Replies: 1
Views: 15

Determining Voltage Values of Anode and Cathode

For problems like 6L.3, it asks us to determine a balanced equation but the solutions manual has voltage values attatched to the anode and cathode cell potentials and I am confused how they determined these values
by Andrew F 2L
Sun Feb 23, 2020 7:22 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cells
Replies: 3
Views: 28

Galvanic Cells

What is important to understand about galvanic cells? I am confused as to the purpose of what we are learning about electricity as it relates to energy and free energy. Could someone help me understand this? Thank you!
by Andrew F 2L
Sun Feb 23, 2020 7:20 pm
Forum: Balancing Redox Reactions
Topic: Balancing redox reactions
Replies: 5
Views: 41

Re: Balancing redox reactions

It is important to determine whether we are balancing in an acidic or basic solution. If in an acidic solution, we have the option of using H+ and H2O to add to help us balance. We should look to trying to balancing the molecules, then oxygen, then hydrogen, then charges. This applies to basic solut...
by Andrew F 2L
Sun Feb 23, 2020 7:18 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox EQs
Replies: 10
Views: 91

Re: Balancing Redox EQs

Also to note, for both acidic and basic solutions you can also add water alongside either H+ or OH- depending on the type of solution! This will help to balance Oxygen molecules first!
by Andrew F 2L
Sun Feb 23, 2020 7:15 pm
Forum: Balancing Redox Reactions
Topic: Oxidation Numbers- How to Find
Replies: 3
Views: 29

Oxidation Numbers- How to Find

I am confused about how to find the oxidation numbers of anything. Is it necessary because I am able to balance my redox reactions without understanding the numbers behind it because the rules I have looked at to try to figure it out were very confusing. Could someone please help!
by Andrew F 2L
Sun Feb 23, 2020 7:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrochemical cells
Replies: 2
Views: 39

Electrochemical cells

Can someone further explain the meaning of electrochemical cells to me? I only understand that they can bring electric currents through spontaneous rxns. What exactly does this mean? Also have we seen an example of this already?
Thank you!
by Andrew F 2L
Sun Feb 16, 2020 11:36 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff Temperature Dependence
Replies: 4
Views: 31

Van't Hoff Temperature Dependence

Can someone explain to me why we are taking the natural log of Temperature in Van't Hoff's equation? I'm confused as to what the equation also is trying to convey also because I was confused about the in class example. Thank you!
by Andrew F 2L
Sun Feb 16, 2020 10:32 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Boltzman's Entropy Equation
Replies: 4
Views: 120

Boltzman's Entropy Equation

I need help understanding the idea of microstates and why we use them in Boltzmann's equation for entropy. Is it referring to like rotational and the kinetic energy of molecules that they can occupy? Thank you!
by Andrew F 2L
Sun Feb 16, 2020 7:45 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: How to interpret reversible/irreversible graphs
Replies: 6
Views: 63

How to interpret reversible/irreversible graphs

For Gibbs free energy, what I understand is that when the value of Delta G is below 0, the reaction is reversible. How do I interpret the graph of the reversible reaction from there? Why is temperature constant along the pathway according to Dr Lavelle? Thank you
by Andrew F 2L
Sun Feb 16, 2020 7:26 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: How to incorporate 2nd Law of Thermo
Replies: 3
Views: 42

How to incorporate 2nd Law of Thermo

From my understanding, the second law of thermodynamics states that entropy for a reversible reaction can not decrease and will remain constant between the system and the surroundings. What I didn't understand for the Midterm question was how that differs for an irreversible reaction? Do we disregar...
by Andrew F 2L
Sun Feb 16, 2020 7:22 pm
Forum: Calculating Work of Expansion
Topic: Irreversible and Reversible problem
Replies: 4
Views: 92

Re: Irreversible and Reversible problem

I know that for reversible reactions, work should be the equation W=-nRTln (v2/v1) and for irreversible expansion under constant pressure aka irreversible reactions, the equation for work is -P(external)Delta V. Hope this helps because I don't exactly remember the problem but I believe it asked to c...
by Andrew F 2L
Sun Feb 09, 2020 12:44 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Internal Energy equations
Replies: 1
Views: 25

Internal Energy equations

What equations should I know for internal energy? I have only been able to determine the basic one of Delta U= q+w but There seem to be more I believe that I am not sure of which I need to solve the HW problems. Are there going to be problems that mix enthalpies and those equations with internal ene...
by Andrew F 2L
Sun Feb 09, 2020 12:40 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Entropy vs. moles
Replies: 3
Views: 28

Re: Entropy vs. moles

I think in terms of a chemical equation, if you have a decrease in moles of the product, then entropy decreases and an increase in the moles of the product results in an increase in entropy
by Andrew F 2L
Sun Feb 09, 2020 12:37 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Irreversible and Reversible Processes
Replies: 2
Views: 32

Re: Irreversible and Reversible Processes

I know that, according to the 2nd law of thermodynamics, in a reversible reaction, the entropy of the universe is constant and for a irreversible process, the transfer of heat from a hot to a cold object causes entropy to increase in the universe because it is the transfer of energy occuring
by Andrew F 2L
Sun Feb 09, 2020 12:33 am
Forum: Administrative Questions and Class Announcements
Topic: midterm format
Replies: 8
Views: 75

Re: midterm format

I think the Midterm will be about 8 questions and I don't believe there are any true or false. Most or all of it should be free response. Also, there will be multiple parts to each question with the topics ranging from, as he told us, chemical equilibria, up to Gibb's Free energy. Hope this helps!
by Andrew F 2L
Sun Feb 09, 2020 12:32 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Confused about Heat of Combustion
Replies: 2
Views: 26

Confused about Heat of Combustion

In one of my TA's worksheet, one of her equations was q = Heat of combustion of ethane times the number of moles of ethane. Is this a formula that we should know? I am confused how she derived it
by Andrew F 2L
Wed Jan 29, 2020 7:40 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat Capacity, Molar Heat capacity, and the Third?
Replies: 3
Views: 31

Specific Heat Capacity, Molar Heat capacity, and the Third?

Can someone please explain to me in simple terms what the specific heat and molar heat capacity mean? Dr. Lavelle also mentioned a third one that I forget! I am confused what we will be doing with these values and how the problems will be structured around these concepts. I just know that the molar ...
by Andrew F 2L
Wed Jan 29, 2020 7:36 pm
Forum: Calculating Work of Expansion
Topic: Sum Equation in Lecture
Replies: 2
Views: 17

Sum Equation in Lecture

I had written down the equation from lecture which showed how to calculate the sum of an infinite number of steps by using an integral with an external pressure, but in the end Dr. Lavelle reached the equation w= -P*Delta V, so is the integral something we will be using or was it more to derive the ...
by Andrew F 2L
Wed Jan 29, 2020 7:33 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Reversible Reactions
Replies: 1
Views: 18

Reversible Reactions

Why exactly do reversible reactions produce the greatest amount of work? And I am having difficulty wrapping my head around the idea of an infinitesimally small value can reverse the process. It would seem to me that most processes should not be reversible because it would take more than a infinitel...
by Andrew F 2L
Wed Jan 29, 2020 7:31 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated Systems
Replies: 5
Views: 40

Isolated Systems

I am confused as to what exactly an isolated system is. The definition states that it can exchange neither matter nor energy with its surrounds but why is this system studied/useful if we cannot determine any changes from it? Thank you!
by Andrew F 2L
Wed Jan 29, 2020 7:27 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat, Temperature, Enthalpy
Replies: 4
Views: 29

Re: Heat, Temperature, Enthalpy

Heat is in a thermodynamical sense, is the energy transferred as the result of a temperature difference. Temperature is just a property of matter that lets us know like the quantity of energy in motion, and enthalpy tells us how much work or energy was added or removed from a substance or system
by Andrew F 2L
Sun Jan 26, 2020 8:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard enthalpy of formation of pure elements?
Replies: 1
Views: 12

Standard enthalpy of formation of pure elements?

Why is it that the standard enthalpy of formation of an element is 0? Can someone explain like the reasoning and science behind it for me? Why do we have these values for the standard enthalpy of formation for other things such as compounds? Thank you!
by Andrew F 2L
Sun Jan 26, 2020 8:26 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Method 3
Replies: 3
Views: 37

Method 3

What does Method 3 mean/ how can it be used? In lecture Professor Lavelle said to only use it when bond enthalpies aren't available but the example he used was a bit confusing for me to understand now that I look back. Can someone please explain this to me? Thank you!
by Andrew F 2L
Sun Jan 26, 2020 8:25 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Meaning of State Function
Replies: 8
Views: 61

Meaning of State Function

What exactly does it mean that Enthalpy is a state function? Does it just mean it is additive and can be combined with multiple steps? Also, can someone give a quick example of this? Thank you!
by Andrew F 2L
Sun Jan 26, 2020 8:17 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Water Phase Change
Replies: 6
Views: 41

Re: Water Phase Change

I think it is because gas particles have more room to move and there is more kinetic energy because the particles are hitting against each other due to the more space they have to work with
by Andrew F 2L
Sun Jan 26, 2020 8:13 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: enthalpy changes
Replies: 2
Views: 13

Re: enthalpy changes

I believe in lecture Dr. Lavelle said that one would have to research the enthalpy values online because that was how he got the values from his lecture slides online.
by Andrew F 2L
Sat Jan 18, 2020 10:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Questions and Sig Figs
Replies: 6
Views: 65

Re: Equilibrium Questions and Sig Figs

I agree with the last user's post in that it is best to round to the number of given sig figs at the very end. When dealing with pH however, the sig figs are typically calculated differently (calculated in the way of a logarithm) which I believe is 3 sig figs usually.
by Andrew F 2L
Sat Jan 18, 2020 10:27 pm
Forum: Ideal Gases
Topic: Ideal Gas meaning
Replies: 7
Views: 70

Ideal Gas meaning

What does it mean when a gas acts ideally? Is it just that the gas itself follows pv=nRT? What would a gas that didn't act ideally look like and will we be working with those gases in this course? Thank you!
by Andrew F 2L
Sat Jan 18, 2020 10:19 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatliers Principle In relation to pressure
Replies: 6
Views: 46

Le Chatliers Principle In relation to pressure

Can someone help me understand why the side with more molecules necessarily refers to more pressure? Is it just because those molecules are taking up more space? I think i am just confused with the concept of pressure in general. Thank you!
by Andrew F 2L
Sat Jan 18, 2020 10:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant Units
Replies: 4
Views: 35

Re: Equilibrium Constant Units

I think Kc is unit less because it is simply a ratio and the units don't exactly mean anything and only the number or ratio really matters. Also I think there was something said about how we are calculating activities of the reactants and products so those themselves don't have units
by Andrew F 2L
Sat Jan 18, 2020 9:49 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Why does only Temperature change K?
Replies: 2
Views: 33

Why does only Temperature change K?

Why is it that temperature can only change the equilibrium constant? Would changing concentrations also change the equilibrium constant as well?
by Andrew F 2L
Sat Jan 11, 2020 1:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5H.3
Replies: 4
Views: 40

Re: 5H.3

I have not done the problem yet, but looking at 5H2 topic of : Composition Equations, it seems to me that you can express a chemical equation as the sum of two more other chemical equations. I would split up the equation they give you into its component equations.The equilibrium constant of the over...
by Andrew F 2L
Sat Jan 11, 2020 1:33 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Change in pressure
Replies: 5
Views: 43

Re: Change in pressure

In class, I believe Dr. Lavelle mentioned Le Chatelier's principle and how if pressure is doubled then the volume must be halfed and therefore the concentrations of all the reactants and products must be doubled.
by Andrew F 2L
Thu Jan 09, 2020 6:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How to calculate Q if not given concentrations
Replies: 3
Views: 33

How to calculate Q if not given concentrations

How are we able to calculate the concentration or partial pressure, lets say, midway through a reaction if they aren't given to us to find Q? Is there a formula we can use?
by Andrew F 2L
Thu Jan 09, 2020 6:43 pm
Forum: Ideal Gases
Topic: What is the Importance of homogeneous vs heterogeneous equilibria [ENDORSED]
Replies: 12
Views: 143

What is the Importance of homogeneous vs heterogeneous equilibria [ENDORSED]

Why does it matter if a chemical reaction is a homogeneous or heterogeneous equilibrium? Is it only to differentiate what to include or not include when finding the equilibrium constant?
by Andrew F 2L
Thu Jan 09, 2020 6:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Temperature's affects on chemical equilibria
Replies: 2
Views: 27

Temperature's affects on chemical equilibria

How does changing the temperature affect chemical equilibrium? Wouldn't the reaction continue to proceed until an equilibrium is reached even if a different temperature was used in one experiment versus another?
by Andrew F 2L
Wed Dec 04, 2019 11:25 am
Forum: Administrative Questions and Class Announcements
Topic: Final Review Session
Replies: 6
Views: 111

Re: Final Review Session

Yes, Just look up "Marshmallow" in Chemistry Community's search bar and you can find it for the review session
by Andrew F 2L
Wed Dec 04, 2019 11:22 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Videos on polydentate ligands?
Replies: 2
Views: 28

Re: Videos on polydentate ligands?

Polydentate ligands just refer to the different range of the number of atoms that can bind to the central atom. A good, easy video to understand I found was https://www.youtube.com/watch?v=iXWuxVaPxMk at around 4:00 Minutes
by Andrew F 2L
Wed Dec 04, 2019 11:17 am
Forum: Hybridization
Topic: Unhybridized Orbitals and pi bonds
Replies: 2
Views: 45

Re: Unhybridized Orbitals and pi bonds

I would assume so but pi or sigma bonds come from orbitals and their overlapping such as the overlapping of parallel p orbitals. I don't think that the concept of the lone pairs making pi bonds themselves will be too important however.
by Andrew F 2L
Wed Dec 04, 2019 11:11 am
Forum: Properties of Light
Topic: Light as a Wave
Replies: 8
Views: 200

Re: Light as a Wave

To clarify why Light acts as a wave, it's because Light is able to refract and it undergoes interference which are properties of waves themselves. Also simply by looking at the equation c= (Wavelength) x (Frequency) You can see that the speed of light has a wavelength and a frequency on the electrom...
by Andrew F 2L
Wed Dec 04, 2019 2:57 am
Forum: Naming
Topic: Tips on Naming
Replies: 5
Views: 64

Re: Tips on Naming

Lavelle provided a table that had the name "translations" to how you should name your coordination compounds so my tip would just be to memorize those with flashcards or something. Other than that, you name your cation first and then your anion and you start with the ligand depending on wh...
by Andrew F 2L
Tue Nov 26, 2019 12:53 pm
Forum: Hybridization
Topic: extra p orbital
Replies: 1
Views: 24

Re: extra p orbital

Hybridization is meant to move the electrons and the orbitals themselves in a way in which repulsion is at its lowest so perhaps adding an electron to the p orbital rather than the hybridized orbital is a way of minimizing the electron repulsion of the entire compound
by Andrew F 2L
Tue Nov 26, 2019 12:50 pm
Forum: Hybridization
Topic: Delocalized Hybridization
Replies: 2
Views: 15

Re: Delocalized Hybridization

I believe they could still ask you that question because technically a double bond (or any other resonance/delocalized electron pair) is considered 1 region of electronegativity.
by Andrew F 2L
Tue Nov 26, 2019 12:32 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: Test 2 7a
Replies: 6
Views: 77

Re: Test 2 7a

Yes, you coun't the number of lone pairs and hydrogens and you should get 11 bonding sites. You may get 12 but my TA said that the Hydrogen that is on the most far right that is bonded to carbon cannot form a hydrogen bond because hydrogens need to bond to N O or F (or small molecules..) and since t...
by Andrew F 2L
Tue Nov 26, 2019 12:30 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 9 Homework
Replies: 2
Views: 43

Re: Week 9 Homework

I had section today and my TA didn't send out any email postponing the homework and he still collected everyone's homework but you should try contacting your TA about it if you can't turn it in yet
by Andrew F 2L
Tue Nov 26, 2019 12:29 pm
Forum: Hybridization
Topic: when to use
Replies: 1
Views: 33

Re: when to use

I think Dr. Lavelle was just using that model to demonstrate how hybridization works because the homework problems themselves don't require you to draw any diagram
by Andrew F 2L
Sat Nov 23, 2019 10:36 pm
Forum: Biological Examples
Topic: Biological Importance
Replies: 6
Views: 55

Re: Biological Importance

I am not sure about exact molecules but I remember Dr. Lavelle said that for proteins, shape is very important so acids or any change in pH in general can be devastating towards the protein structure so perhaps any striking change in pH or temperature could be of biological importance
by Andrew F 2L
Sat Nov 23, 2019 10:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR and its relation to Hybridization
Replies: 3
Views: 38

VSEPR and its relation to Hybridization

How does a molecule's VSEPR model relate to the hybridization? Is it because the shape correlates to the orbitals overlapping like sp^2 is trigonal planar?
by Andrew F 2L
Sat Nov 23, 2019 10:26 pm
Forum: Bronsted Acids & Bases
Topic: Acid Naming
Replies: 2
Views: 44

Acid Naming

For Bronsted Acid and Base naming, is the cation still before the anion? Do they differ in any other way except that Bronsted acids donate protons instead of electrons?
Thank you!
by Andrew F 2L
Sat Nov 23, 2019 10:23 pm
Forum: Hybridization
Topic: Sigma and Pi Bonds
Replies: 7
Views: 48

Sigma and Pi Bonds

To my understanding, Sigma bonds are between single bonds and are able to rotate and Pi bonds are the bonds after the first bond of a sigma bond and cannot rotate. Do we need to know anything else for these types of bonds?
by Andrew F 2L
Sat Nov 23, 2019 10:18 pm
Forum: Hybridization
Topic: Hybridization Confusion
Replies: 3
Views: 48

Hybridization Confusion

Can someone explain what we need to know for hybridization? I am currently using the hybridization chart Lavelle game but the book goes into great detail into topics that I don't think we need to know. Can anyone clarify for me?
Thank you!
by Andrew F 2L
Sat Nov 16, 2019 4:12 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: London vs Dipole induced dipole
Replies: 2
Views: 18

Re: London vs Dipole induced dipole

London Forces is another way of saying Induced-dipole-induced dipole because if you look in the name, it tells you that the dipoles are induced by another induced dipole from the moving regions of electrons with fleeting partial charges. Dipole-induced dipole refers to when a dipole (polar molecule)...
by Andrew F 2L
Sat Nov 16, 2019 4:10 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: Ion-Dipole
Replies: 2
Views: 22

Re: Ion-Dipole

Ion-Dipole interactions are the interactions between ions and a polar molecule with dipoles for example water. If you look at water and salt for example, the negative partial charge of oxygen is drawn to the cation Na+ and the opposite goes for Cl-. Ion-dipole interactions are significant only when ...
by Andrew F 2L
Sat Nov 16, 2019 3:54 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-dipole interactions
Replies: 2
Views: 27

Re: Dipole-dipole interactions

Dipole-Dipole interactions come from when there are two polar molecules with their dipoles and their partial charges come close to each other and attract. You would need to look through the molecules given to determine if they have dipoles or are polar in the first place
by Andrew F 2L
Sat Nov 16, 2019 3:53 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: biological examples?
Replies: 3
Views: 37

Re: biological examples?

I also remember in the textbook that it talked about the delicate nature of proteins and how hydrogen bonds have a great impact on the structure of proteins. If the hydrogen bonds are broken, the entire overall shape of the protein molecule becomes misshaped and becomes unusable.
by Andrew F 2L
Sat Nov 16, 2019 3:35 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: Bond Strengths in order?
Replies: 2
Views: 33

Bond Strengths in order?

I am confused about the strengths of the bonds in order from weakest to strongest. I know Hydrogen Bonding is the strongest and London Forces are the weakest but what about dipole-dipole interactions, ion-dipole interactions, and dipole induced dipole interactions?
by Andrew F 2L
Sun Nov 10, 2019 1:43 am
Forum: Dipole Moments
Topic: Ionic vs Covalent Solubility
Replies: 3
Views: 25

Re: Ionic vs Covalent Solubility

Water is a really polar solvent and interact really strongly with ions. The hydrogens are partially positively charged and oxygens negatively charged so the water pulls apart the Sodium and Chlorine
by Andrew F 2L
Sun Nov 10, 2019 1:36 am
Forum: Dipole Moments
Topic: Boiling Point
Replies: 11
Views: 126

Re: Boiling Point

Lavelle was trying to make a point about how the shape of the molecule has a big impact in physical properties like boiling points even though molecules will have the same bond types
by Andrew F 2L
Sun Nov 10, 2019 1:28 am
Forum: Dipole Moments
Topic: Polarizing Power
Replies: 3
Views: 37

Re: Polarizing Power

According to the book, polarizing power arises from when atoms and ions have the impact of large distortions. Cations are typically high in polarizing power due to a smaller radius and being highly charged. Polarizing power of cations increases from left to right across a period
by Andrew F 2L
Sun Nov 10, 2019 1:24 am
Forum: Dipole Moments
Topic: Dispersion Forces
Replies: 1
Views: 25

Re: Dispersion Forces

I believe the interaction occurs when electrons approach a molecule with a dipole, electrons in the atom respond and so the atom develops a dipole. This is basically meaning that a polar molecule induces a dipole in a nonpolar atom or molecule by disrupting the electrons
by Andrew F 2L
Sun Nov 10, 2019 1:13 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Interaction Potential Energy
Replies: 2
Views: 33

Re: Interaction Potential Energy

I think it is because as the atomic radius gets smaller, it gets harder to remove an electron that is closer to a more positively charged nucleus probably from electron shielding. Hope this helped
by Andrew F 2L
Fri Nov 08, 2019 12:26 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: Interaction energy
Replies: 3
Views: 24

Re: Interaction energy

The formula for interaction energy is Ep = ∝ - (α1-α2)/(r^6) This describes the potential energy for atoms to interact with each other I believe so in the equation, we are looking at the distance between the atoms as well which contributes to the potential energy required for the atoms to interact w...
by Andrew F 2L
Sun Nov 03, 2019 8:43 am
Forum: Ionic & Covalent Bonds
Topic: Copper ions
Replies: 2
Views: 23

Re: Copper ions

Hi, So copper is one of those exceptions to the electron configuration rule because a completely full or half full d orbital is more stable than when the orbital is only slightly full so that is why the e- fills into the 3d orbital. And so the configuration is [Ar]3d10 4s1 and if you wanted to see y...
by Andrew F 2L
Sun Nov 03, 2019 8:43 am
Forum: Ionic & Covalent Bonds
Topic: Copper ions
Replies: 2
Views: 23

Re: Copper ions

Hi, So copper is one of those exceptions to the electron configuration rule because a completely full or half full d orbital is more stable than when the orbital is only slightly full so that is why the e- fills into the 3d orbital. And so the configuration is [Ar]3d10 4s1 and if you wanted to see y...
by Andrew F 2L
Sun Nov 03, 2019 8:38 am
Forum: Resonance Structures
Topic: Defining Resonance Structures
Replies: 3
Views: 33

Re: Defining Resonance Structures

Resonance is when there are multiple correct ways to draw the Lewis Structure for a molecule because the bonds are movable and stable in either position, either from rotating the molecule or just simply changing the bonds around for usually every other bond pair. An example of this can be the ion Ni...
by Andrew F 2L
Sun Nov 03, 2019 8:34 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm Format
Replies: 4
Views: 67

Re: Midterm Format

I had thought that it was going to be a scantron with multiple choice but I don't remember Dr. Lavelle explicitly commenting the format. I assume it will be, like you said, many free answer questions but I don't necessarily believe it is going to have True/False or matching or anything like that. Al...
by Andrew F 2L
Sun Nov 03, 2019 8:30 am
Forum: Properties of Light
Topic: Wavelength and Type of Light
Replies: 3
Views: 74

Re: Wavelength and Type of Light

Hi,
Yes you should know the cutoff for visible light and perhaps UV light but when I went to the TA review session he said don't worry too much about this as most problems are going to ask you to solve and knowing all the ranges of light is a little too specific
by Andrew F 2L
Fri Nov 01, 2019 5:41 pm
Forum: Dipole Moments
Topic: induced dipole
Replies: 4
Views: 48

Re: induced dipole

To add on, the instantaneous dipole moment which is the momentary charge separation of charge, gives rise to the attractive force from the induced dipole moments which acts on all molecules and atoms and is the only interaction between nonpolar molecules and monatomic gases.
by Andrew F 2L
Sat Oct 26, 2019 4:11 pm
Forum: Lewis Structures
Topic: Steps to drawing a structure
Replies: 5
Views: 57

Re: Steps to drawing a structure

Adding on to what others have said about having the least electronegative atom in the middle, I believe I heard Lavelle saying that many of the compounds that are created from the bonds have Hydrogen in them and Hydrogen atoms are nearly always at the very ends of the Lewis structure.
by Andrew F 2L
Sat Oct 26, 2019 4:07 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Shortcut
Replies: 3
Views: 49

Electron Configuration Shortcut

I am on the electron configuration section of the textbook but I am still having trouble understanding how the orbitals get filled and I am confused about the order of the orbitals sometimes. Also, did Dr. Lavelle tell us that we were allowed to use the shortcut of the noble gases to write out the e...
by Andrew F 2L
Sat Oct 26, 2019 4:03 pm
Forum: Lewis Structures
Topic: Sulfate Lewis Structure (From class)
Replies: 1
Views: 31

Sulfate Lewis Structure (From class)

Can someone explain to me how Dr. Lavelle was able to draw the Lewis Structure for Sulfate because I am confused on how he knew when to stop adding double bonds- I also was confused how he factored in the 2- charge of the ion into the lewis structure; are these two connected?
Thank you!
by Andrew F 2L
Sat Oct 26, 2019 3:57 pm
Forum: Trends in The Periodic Table
Topic: Trend Problems on Midterm
Replies: 1
Views: 35

Trend Problems on Midterm

How are the Trend problems going to be presented in the questions on the midterm? Would they follow the ones from the textbook or be a little simpler where Dr. Lavelle asks which element has a larger radius for example?
by Andrew F 2L
Sat Oct 26, 2019 3:21 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Radial Distribution Function
Replies: 4
Views: 50

Radial Distribution Function

Are we expected to understand how to use the Radial Distribution Function in its entirety to calculate the probability of finding an e-? It seems like a confusing equation and I can't remember if Dr. Lavelle wanted us to completely remember it
by Andrew F 2L
Sat Oct 19, 2019 8:18 pm
Forum: Properties of Electrons
Topic: Conceptual vs. problem
Replies: 2
Views: 46

Re: Conceptual vs. problem

I don't think you need to worry too much about how scientists proved the laws, but it doesn't hurt to skim through their experiments because it could help you understand the laws and what they mean in terms of how to solve problems, but in general I think being able to apply the equations is most im...
by Andrew F 2L
Sat Oct 19, 2019 8:04 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electron Configuration Model Confusion
Replies: 3
Views: 40

Electron Configuration Model Confusion

In class, Lavelle had kept using a diagram with up and down arrows and then he simply followed the periodic table and kept adding spin states I believe. Can someone explain what model that was and what he was doing like, was he filling up all the orbitals?
by Andrew F 2L
Sat Oct 19, 2019 6:45 pm
Forum: Limiting Reactant Calculations
Topic: Missed this Question on Test1
Replies: 5
Views: 204

Re: Missed this Question on Test1

Hey! So I started by converting Carbon Dioxide and Water into moles from the 10 grams of Carbon Dioxide and 20 grams of water that they tell us is given. Because the balanced reaction calls for 6 moles of each, I divided the number of moles we calculated in both carbon dioxide and water by 6 and the...
by Andrew F 2L
Fri Oct 18, 2019 8:55 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital Order
Replies: 2
Views: 55

Re: Orbital Order

I think Lavelle meant that the 3d orbital is a higher energy state than the 4s state so the electrons fill it out first and then start to fill the 4s state.
by Andrew F 2L
Fri Oct 18, 2019 8:46 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Hund's rule and Pauli Exclusion Principle
Replies: 14
Views: 153

Re: Hund's rule and Pauli Exclusion Principle

I think in class he just meant that due to e- repulsion, e- in same sub-shell occupy diff orbitals with parallel spin so they have the same spin i believe. And for the Pauli exclusion principle rule He said that there can be no more than 2 e- per orbital and if there are 2e- in the same orbital, the...
by Andrew F 2L
Sun Oct 13, 2019 7:06 pm
Forum: Properties of Electrons
Topic: Stefan–Boltzmann law meaning and relevance
Replies: 1
Views: 7

Stefan–Boltzmann law meaning and relevance

Hi, I was confused about the Stefan–Boltzmann law and what it meant and if we need to truly understand it because I don't remember Lavelle talking about it. Does it mean that when the scientists were doing the experiment, they were able to find a value that they could heat the total intensity to? Al...
by Andrew F 2L
Sat Oct 12, 2019 6:54 pm
Forum: Properties of Light
Topic: Textbook numbering
Replies: 2
Views: 35

Re: Textbook numbering

I had a confusing time with the online textbook but I figured out that after the Fundamental section, everything is titled after Focuses so for the Quantum World we're on Focus 1 and within those Focuses there are the letters like A, B, C, etc.. as Topics. So for the first homework it is under Topic...
by Andrew F 2L
Fri Oct 11, 2019 6:20 pm
Forum: Properties of Electrons
Topic: Wave Properties of Electrons
Replies: 4
Views: 69

Re: Wave Properties of Electrons

Hey! So Electrons have something called a Wave-Particle duality where they exhibit characteristics of both. There's an experiment where if electrons pass through a double slit and hit a screen behind the slits, they create a pattern of bright and dark bands which shows that they act like waves and h...
by Andrew F 2L
Thu Oct 10, 2019 1:08 am
Forum: Properties of Light
Topic: Hydrogen Atoms for White Light
Replies: 3
Views: 28

Hydrogen Atoms for White Light

What is the significance of using hydrogen atoms when using white light to determine the absorption spectrum? Is it the simplest element to analyze? Also Lavelle had said that we were able to substitute practically any element for it but I am confused because he said something about having to change...
by Andrew F 2L
Thu Oct 10, 2019 12:29 am
Forum: Properties of Electrons
Topic: Rydberg formula clarification
Replies: 3
Views: 48

Rydberg formula clarification

In class today Lavelle was talking about how he would not like us to use the Rydberg formula I believe? He said something about how it didn't help us understand physically what was happening. Can someone elaborate what he meant by that and what formula he wan'ts us to use instead? Thank you so much.
by Andrew F 2L
Sun Oct 06, 2019 10:49 am
Forum: Balancing Chemical Reactions
Topic: Advice for Test 1
Replies: 7
Views: 110

Re: Advice for Test 1

I think you should focus on the fundamentals he posted up and just do practice problems. I would also go through the textbook and at least skim through the book and its examples so you can get a feel for the questions
by Andrew F 2L
Thu Oct 03, 2019 11:54 pm
Forum: Molarity, Solutions, Dilutions
Topic: G25 Homework Question Medical Reasoning
Replies: 1
Views: 39

G25 Homework Question Medical Reasoning

I have completed the problem but I am confused as to how there could be possible health benefits? Why would more or less molecules be helpful? Is it so that there is more concentrated medicine going in?
by Andrew F 2L
Thu Oct 03, 2019 7:55 pm
Forum: Molarity, Solutions, Dilutions
Topic: Homework Problem G17 Part B
Replies: 2
Views: 46

Homework Problem G17 Part B

I am confused as to why the process is nearly identical even though there is the 5H2O in part b compared to part a. Is it because it is a new solute so we are simply calculating its molar mass and changing only that?

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