## Search found 99 matches

Wed Mar 11, 2020 5:34 pm
Forum: Administrative Questions and Class Announcements
Topic: final
Replies: 14
Views: 243

### Re: final

the final will be posted on his website i think! we just have to be patient and wait for more information :)
Wed Mar 11, 2020 5:32 pm
Forum: *Enzyme Kinetics
Replies: 7
Views: 129

absorption is the process where a fluid thing is dissolved by a liquid or solid thing; adsorption is where the atoms of a substance kinda hang out on top of another thing, creating a surface tension / cover thingy
Wed Mar 11, 2020 5:29 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 3
Views: 61

### Re: Test 2

just wait for the email from your TA! if you're in Lily's discussions, the tests are ready to pick up from her mailbox in young hall. :)
Wed Mar 11, 2020 5:28 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: concentration cells
Replies: 3
Views: 36

### concentration cells

so on test two, there was the question concerning what would happen to the cell potential in a concentration cell if the mass of the cathode electrode is doubled. I figured that since the mass is going up, the molarity will be increasing, the concentration difference will be larger. with a larger co...
Sat Mar 07, 2020 8:35 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E- Chem Equations
Replies: 4
Views: 75

### Re: E- Chem Equations

the equation sheet is the same and given for every test/exam in lavelle's class!
Wed Mar 04, 2020 12:43 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Strongest Reducing Agent
Replies: 5
Views: 99

### Re: Strongest Reducing Agent

okay i just understood this like 20 mins ago so here's my rant about this: so the E is the standard reduction potential, so the higher the value is, the more reduction is going to take place. when looking for the strongest reducing agent, since the word "agent" is used, we're really lookin...
Wed Mar 04, 2020 12:40 am
Forum: Balancing Redox Reactions
Topic: hydrogen
Replies: 3
Views: 47

### Re: hydrogen

in h2o, the oxidation state of o is -2, so that makes the oxidation state of the hydrogen a +2, making it +1 for each hydrogen atom. i hope this helps a little bit :)
Wed Mar 04, 2020 12:38 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 5G.17
Replies: 1
Views: 54

### Re: 5G.17

if the gibbs free energy was positive, the book might have reversed the equation so that it was a favorable reaction
Wed Mar 04, 2020 12:36 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Units for G°
Replies: 6
Views: 57

### Re: Units for G°

i'm pretty sure that the standard gibbs free energy is in joules per mole, but i could be wrong. could someone confirm?
Wed Mar 04, 2020 12:34 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free and Direction of Reaction
Replies: 3
Views: 65

### Re: Gibbs Free and Direction of Reaction

that's a good question haha! i've just always remembered that negative delta g means the reverse reaction is spontaneous and the reactants are favored, but i've never really thought about it before. i hope someone can answer! :)
Mon Mar 02, 2020 9:19 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: gibbs free energy vs cell standard potential
Replies: 3
Views: 39

### Re: gibbs free energy vs cell standard potential

since the standard potential is an intensive property, it won't change depending on how much of a substance is reacting. I hope this helps. :)
Mon Mar 02, 2020 9:17 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: predicting is metals will dissolve
Replies: 3
Views: 45

### Re: predicting is metals will dissolve

if the reaction is spontaneous, chances are that the products will form, so the metal will dissolve into whatever products will be forming. if the reaction isn't spontaneous, then chances are that the products won't form, meaning the metal won't dissolve into any products. I hope this helps! :)
Mon Mar 02, 2020 9:15 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: deriving nernst equation
Replies: 4
Views: 61

### Re: deriving nernst equation

Christineg1G wrote:it might help to see a visual of deriving the Nernst Equation!

this really helped, thank you!!
Mon Mar 02, 2020 9:12 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics in Test 2?
Replies: 13
Views: 153

### Re: Kinetics in Test 2?

JesseAuLec1Dis1G wrote:So is test two only on the second page of outline 4 and all of outline 5?

yes! thankfully :/
Mon Mar 02, 2020 9:10 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: k
Replies: 10
Views: 122

### Re: k

this has always confused me as well, thank you for asking and thank you to those who answered!
is k the ratio of product concentration to reactant concentration at equilibrium?
Tue Feb 25, 2020 4:14 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Impact of changing chemical equation by a factor on delta G and E
Replies: 1
Views: 38

### Re: Impact of changing chemical equation by a factor on delta G and E

to my understanding, Ecell is an intensive property so it doesn't really care how much of the reaction is happening, just that it's happening. so you don't have to multiply it by anything in order for it to correspond to higher reaction coefficients. I hope this helps :)
Tue Feb 25, 2020 4:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 4
Views: 95

### Re: Test 2

I'm going to study all of them to make sure I don't get punked, but I'm pretty sure the problems from chapter 5 correspond with the second page of the thermodynamics outline. :)
Tue Feb 25, 2020 4:11 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 4
Views: 95

### Re: Test 2

I think the problems in chapter 5 onward :)
Tue Feb 25, 2020 4:10 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gas constant R
Replies: 5
Views: 56

### Re: Gas constant R

I like to look at what I need my final units to be and choose my R based off of that! so if I'm looking for J/K as my final units, I'd choose to use 8.314 for my R value because when it cancels out with the other units in the equation, J/K will be my final units. I hope this helps. :)
Tue Feb 25, 2020 4:08 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cathode vs Anode
Replies: 6
Views: 110

### Re: Cathode vs Anode

The cathode is the one being reduced and the anode is the one being oxidized. ^^ this! so this is just something else we have to memorize :/ the way that lavelle was explaining it, with the anode being on the left and the cathode being on the right, it's easier to remember because a comes before c ...
Tue Feb 25, 2020 4:05 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Self-test 4F.3A
Replies: 3
Views: 111

### Re: Self-test 4F.3A

MAC 4G wrote:Remember that pressure is inversely proportional to volume (Boyle's Law), so at a constant temperature (isothermal) V2/V1 = P1/P2.

oh! oops thank you for clearing that up for me!
Tue Feb 25, 2020 1:56 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Lecture notes
Replies: 4
Views: 66

### Re: Lecture notes

An example to look at would be Mn2+ being reduced to Mn and Al is being oxidized to Al3+. Here, Mn2+ is gaining electrons and Al is donating electrons. So, using Le Chatelier’s principle, an increase in concentration of Mn2+ causes equilibrium to shift the reaction towards the products, which would...
Tue Feb 25, 2020 1:55 pm
Forum: Balancing Redox Reactions
Topic: Acid and Bases in Redox Reaction
Replies: 4
Views: 83

### Re: Acid and Bases in Redox Reaction

The question will usually state if the reaction is taking place in a basic or acidic conditions. Usually you will need to use H2O to balance excess oxygen, when you do this you will then add either H+ or OH- to the other side of the reaction to then balance the excess hydrogen from the H2O. If it i...
Tue Feb 25, 2020 1:53 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox Reactions
Replies: 7
Views: 63

### Re: Balancing Redox Reactions

you can cancel the H+ and OH- ions when you're combining your redox half reactions and making the final full reaction equation. after you're done balancing the two, you flip one of them, most of the time you flip the oxidation half reaction, and then some things will cancel and some won't. you add H...
Tue Feb 25, 2020 1:48 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: conducting solids
Replies: 5
Views: 71

### Re: conducting solids

Transition metals are conducting metals, which is important because it allows for the transfer of electrons in the cell diagram situation. You have the salt bridge to keep the two solutions neutral, and the conducting metals to act as a carrier for the electrons, if that makes sense. I hope this hel...
Tue Feb 25, 2020 1:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 7
Views: 106

### Re: Cell Diagrams

But don't you need a solid on both sides to avoid Pt? Or does that not apply when it is the same element being oxidized and reduced? Since there's only one element, there will only be one beaker in the cell diagram if you were to draw it, if that makes sense. Everything is happening in one place, a...
Tue Feb 25, 2020 1:41 pm
Forum: Balancing Redox Reactions
Topic: Redox rxns- differences for solving?
Replies: 2
Views: 44

### Re: Redox rxns- differences for solving?

I'm pretty sure we're just supposed to balance it with waters and whatever else is in the solution (hydrogen ions for acidic, hydroxide ions for basic). At least, this is what he wants us to prove that we know how to do on exams and stuff, I'm guessing. I hope this helps. :)
Tue Feb 25, 2020 1:40 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Self-test 4F.3A
Replies: 3
Views: 111

### Self-test 4F.3A

Hi I'm reviewing thermodynamics and in the book there's this problem that says "Calculate the change in entropy when the pressure of 1.5 mol Ne(g) is decreased isothermally from 20.00 barr to 5.00 barr. Assume ideal behavior." I got -17.3 J/K, but the book says the answer is supposed to be...
Mon Feb 24, 2020 3:08 pm
Forum: Balancing Redox Reactions
Topic: Platinum in cell diagram
Replies: 10
Views: 135

### Re: Platinum in cell diagram

Platinum is introduced into the cell diagram when there are no solid metals as part of the anode or cathode of the cell diagram. It serves as an inert electrode (provides a surface for the transfer of electrons, but does not affect or participate in the redox reaction). ^^ this! also when you write...
Mon Feb 24, 2020 3:06 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: cis and trans entropy
Replies: 3
Views: 125

### Re: cis and trans entropy

cis means same, so for a cis structured molecule, the alike things will be on the same side. I hope this helps :)
Mon Feb 24, 2020 3:00 pm
Forum: Balancing Redox Reactions
Topic: half reaction
Replies: 10
Views: 143

### Re: half reaction

it really helped me when my TA like, explicitly stated that you can only add what's already in the solution. so like if it says it's an acidic solution, the only thing in there except for the redox reaction is water and hydrogen ions, and if it says it's a basic solution, the only thing in there exc...
Mon Feb 24, 2020 2:57 pm
Forum: Student Social/Study Group
Topic: 2/24 lecture
Replies: 5
Views: 72

### Re: 2/24 lecture

^^ me too oops, thank you in advance! :)
Mon Feb 24, 2020 1:11 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox EQs
Replies: 10
Views: 130

### Re: Balancing Redox EQs

the biggest thing that helped me with this was like, explicitly realizing that you can only add what's in the reaction to your equations. so like in acidic solution, the only things in the solution except for your redox reaction is water and hydrogen ions and in a basic solution, the only things in ...
Mon Feb 24, 2020 1:01 pm
Forum: Administrative Questions and Class Announcements
Topic: Picking up 14A Finals in Young Hall
Replies: 3
Views: 54

### Re: Picking up 14A Finals in Young Hall

^^ me too. but I'm pretty sure we can't anymore :(
Mon Feb 24, 2020 10:38 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt bridge
Replies: 6
Views: 101

### Re: Salt bridge

The salt bridge keeps the two solutions neutral so the systems can exchange electrons. I hope this helps :)
Mon Feb 24, 2020 10:33 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 7
Views: 106

### Re: Cell Diagrams

Since you were given a solid thing in the equation, I'm not sure the Pt is needed. You just need to figure out what's being oxidized vs reduced and put them on the correct side of the "salt bridge". I hope this helps :) I'm not entirely sure if I'm correct, but I remember a problem like th...
Mon Feb 24, 2020 10:22 am
Forum: Balancing Redox Reactions
Topic: Oxidizing/Reducing Agent
Replies: 8
Views: 90

### Re: Oxidizing/Reducing Agent

to easily identify the oxidizing and reducing agents, you just remember that they're backwards! the reducing agent is the thing being oxidized, and the oxidizing agent is the thing being reduced. as long as you can determine the oxidization and reduction half-reactions, determining the oxidizing and...
Mon Feb 24, 2020 10:14 am
Forum: Balancing Redox Reactions
Topic: 6K.3 part d
Replies: 3
Views: 46

### Re: 6K.3 part d

My TA said to break it into two equations like the one reactant goes to each product in separate equations, then calculate charge and determine oxidizing/reducing agent from there. I hope this helps :)
Mon Feb 24, 2020 10:11 am
Forum: Balancing Redox Reactions
Topic: OIL RIG
Replies: 4
Views: 82

### OIL RIG

For those of us who doesn't understand LEO GER, I'm here to offer another acronym that I learned in high school that I find easier to remember: OIL RIG. Oxidation Is Loss, Reduction Is Gain. Happy balancing! :)
Fri Feb 07, 2020 5:43 pm
Forum: Phase Changes & Related Calculations
Topic: Negative Work
Replies: 18
Views: 344

### Re: Negative Work

I had the same problem :/ but my TA explained that the problem says that the work is done BY the system so that means it will be negative. It's just really important to make sure you pay attention to everything the problem is telling you before you start it, because that's how you forget the importa...
Fri Feb 07, 2020 5:34 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy Surroundings
Replies: 4
Views: 57

### Re: Entropy Surroundings

The change in the entropy of the surroundings of a system are equal to zero when there is no pressure / the reaction is taking place in a vacuum / when it is a free expansion reaction. I hope this helps! :)
Fri Feb 07, 2020 5:32 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy + Disorder
Replies: 3
Views: 32

### Re: Entropy + Disorder

The way he sees it, entropy is representative of the spontaneity of a reaction, like, bottom line. Other people see it as like, the more chaotic it is/ the more disorder there is, the more likely it is that the reaction will occur due to the probability of the atoms hitting at just the right time an...
Fri Feb 07, 2020 5:12 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Calculating entropy using positive or negative delta H
Replies: 2
Views: 43

### Re: Calculating entropy using positive or negative delta H

It has to do with whether you're calculating the entropy of the surroundings or the system and if the reaction is endothermic/exothermic, I'm pretty sure. It'll say in the problem what you're supposed to find. I hope this helps. :)
Fri Feb 07, 2020 4:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to use Kp
Replies: 2
Views: 45

### Re: When to use Kp

You use Kp when dealing with partial pressure :) I hope this helps.
Fri Feb 07, 2020 4:51 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: First Law
Replies: 5
Views: 88

### Re: First Law

If we took that into consideration, we could never use measurements because they'd always be expanding or growing or something like that. Chem's a lot easier if you don't think super deep about it haha. :)
Fri Feb 07, 2020 4:49 pm
Forum: Phase Changes & Related Calculations
Topic: relationship between heat capacity and heating curve
Replies: 6
Views: 44

### Re: relationship between heat capacity and heating curve

Consider it the inverse of the slope, and it'll be easy to remember. The logic behind it is a little tough for me, too, so I hope someone can answer that! :)
Fri Feb 07, 2020 4:47 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: hw problem 4D 7 assuming T?
Replies: 3
Views: 44

### Re: hw problem 4D 7 assuming T?

You can only assume that the temperature is 298 K or 25*C if the question says something about ideal situations or standard temperature. I hope this helps! :)
Fri Feb 07, 2020 4:45 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: gibbs free energy of formation
Replies: 3
Views: 45

### Re: gibbs free energy of formation

Like said above, Gibbs Free Energy is more stable when negative due to the spontaneity of the reaction. If the reaction isn't favorable/ spontaneous, then forcing it to happen may not result in the most stable products. I hope this helps! :)
Sun Feb 02, 2020 4:15 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: State Property vs Function
Replies: 2
Views: 32

### Re: State Property vs Function

a state function is a property of something that depends on the current state, where a state property is a quantity independent of any states. I hope this helps. :)
Sun Feb 02, 2020 4:10 pm
Forum: Administrative Questions and Class Announcements
Topic: Extra Credit
Replies: 7
Views: 176

### Re: Extra Credit

from what I understand, you can't make up any chemistry community credits. I talked to my TA because I didn't have service the first two weekends of class so I wasn't able to submit any responses and she said there was no way to make up those missed points. she suggested I just do good on future exa...
Sun Feb 02, 2020 4:07 pm
Forum: Calculating Work of Expansion
Topic: Reversible Processes
Replies: 3
Views: 27

### Re: Reversible Processes

i think that it's implied that if the system is at equilibrium that the reaction is reversible. i hope this helps :)
Sun Feb 02, 2020 4:06 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: using mass in calorimeter
Replies: 3
Views: 49

### Re: using mass in calorimeter

I'm also kind of confused on this, but I think that it has something to do with open, closed, and isolated systems? maybe?
Sun Feb 02, 2020 4:02 pm
Forum: Calculating Work of Expansion
Topic: Work positive or negative
Replies: 5
Views: 58

### Re: Work positive or negative

the way I think about it is to imagine yourself as the system. if you're doing work, you're doing to be using energy (negative value) and if work is being done on you, that's energy saved (positive value). I hope this helps :)
Sat Dec 07, 2019 5:01 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Ka, Kb, pKa, etc. on Final
Replies: 2
Views: 74

### Re: Ka, Kb, pKa, etc. on Final

I think that we'll go over Ka and Kb more in depth in 14B, but that we should know what they are conceptually for the final. So like, we won't be doing calculations right now but we might have to use the conceptual understandings to specify which acids/bases will be strong/weak. I hope this helps. :)
Sat Dec 07, 2019 3:29 pm
Forum: Administrative Questions and Class Announcements
Topic: Main focus
Replies: 3
Views: 63

### Re: Main focus

My TA told us that there will be one question per outline, but two for quantum and the other question is free game from the homework. :) I hope this helps.
Sat Dec 07, 2019 1:56 pm
Forum: Bronsted Acids & Bases
Topic: CHOOH
Replies: 1
Views: 52

### Re: CHOOH

It's just how the structure is (one O has a double bond, the other is a single bond with an attached hydrogen). I think it might have something to do with its functions, but I could be wrong. I hope this helps a little. :)
Sat Dec 07, 2019 1:54 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Electron Configuration
Replies: 10
Views: 181

### Re: Electron Configuration

When you write the configuration, you write it in the order of lowest to highest energy level. :) I hope this helps, this is what Lavelle said during lecture.
Sat Dec 07, 2019 1:52 pm
Forum: Hybridization
Topic: Ammonia
Replies: 4
Views: 130

### Re: Ammonia

Since there are 5 valence electrons, when you hybridize the orbitals to get sp3, there will be one valence with a lone pair and three orbitals with one electron in it (that's the five valence electrons you're asking about). I hope this answers your question! :)
Sat Nov 30, 2019 6:32 pm
Forum: Bronsted Acids & Bases
Topic: Acid and Base
Replies: 1
Views: 37

### Re: Acid and Base

They normally form acids. :)
Sat Nov 30, 2019 6:24 pm
Forum: Hybridization
Topic: Hybridization and the Octet Rule
Replies: 3
Views: 73

### Re: Hybridization and the Octet Rule

Keep in mind that Br is in the group that has 7 valence electrons, so it really only wants one more electron, so if there's more than one atom bonded to it, the octet rule is gonna be a lil wonky. Just always count the areas of electron density and you should be okay. :) I hope this helps.
Sat Nov 30, 2019 6:20 pm
Forum: Lewis Acids & Bases
Topic: Identifying lewis acids and bases
Replies: 4
Views: 43

### Re: Identifying lewis acids and bases

Lewis acids end up with a new H+ ion, while the Lewis base ends up with a more basic ion. :) Basically acids accept electrons while bases donate them. I hope this helps!
Sat Nov 30, 2019 6:18 pm
Forum: Dipole Moments
Topic: Polar or nonpolar?
Replies: 4
Views: 2908

### Re: Polar or nonpolar?

My TA told me that generally if there is at least one atom that is not the same (amongst the outside 4 atoms of a tetrahedral) then the molecule as a whole is polar. This! If the atoms on the tetrahedral aren't all the same, chances are that there will be a dipole moment that doesn't cancel out, ca...
Sat Nov 30, 2019 6:12 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong acid/weak base interaction
Replies: 1
Views: 26

### Re: Strong acid/weak base interaction

I'm not sure, but I think we do need to know that the pH is the negative log base 10 of the concentration of H+ ions and the same for pOH and OH-. I hope this helps! :)
Sat Nov 23, 2019 11:48 pm
Forum: Naming
Topic: Greek Prefixes
Replies: 2
Views: 46

### Re: Greek Prefixes

So if there's two di-methyl ethane or something like that and they're bonding together, then you'd say bismethyl ethane or whatever molecule it is. I hope this helps! :)
Sat Nov 23, 2019 7:22 pm
Forum: Sigma & Pi Bonds
Topic: How to Find Sigma Bonds and Pi Bonds
Replies: 15
Views: 435

### Re: How to Find Sigma Bonds and Pi Bonds

After drawing the lewis structure, the answers are drawn! sigma bonds are single bonds, I remember it with the alliteration "sigma single". pi bonds are double bonds, and I remember that one with the two lines down when you draw a pi symbol. :) I hope this helps.
Sat Nov 23, 2019 7:22 pm
Forum: Sigma & Pi Bonds
Topic: How to Find Sigma Bonds and Pi Bonds
Replies: 15
Views: 435

### Re: How to Find Sigma Bonds and Pi Bonds

After drawing the lewis structure, the answers are drawn! sigma bonds are single bonds, I remember it with the alliteration "sigma single". pi bonds are double bonds, and I remember that one with the two lines down when you draw a pi symbol. :) I hope this helps.
Sat Nov 23, 2019 7:11 pm
Forum: Biological Examples
Topic: Structure of Heme Complex with Sickle Cell Disorder
Replies: 1
Views: 29

### Re: Structure of Heme Complex with Sickle Cell Disorder

From what I remember from high school biomedical classes, sickle cell anemia is caused by a point mutation in DNA, that when translated into RNA and then coded for proteins, accidentally makes a different protein that causes the structure to change and make the weird banana shape. I may be wrong, bu...
Sat Nov 23, 2019 7:07 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand
Replies: 4
Views: 61

### Re: Ligand

Google says that a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex, but in actual english, a ligand is just like, a smaller atom that binds to a larger atom or molecule.
Sat Nov 23, 2019 7:02 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: Vapor Pressure/Boiling Point/Melting Point
Replies: 2
Views: 87

### Re: Vapor Pressure/Boiling Point/Melting Point

Something starts boiling when the external pressure is the same as the internal pressure, but something melts when the energy is being absorbed by the solid from to become the melted, liquid form of the substance (the temperature which solid's vapor pressure is equal to the liquid form's vapor press...
Sat Nov 16, 2019 8:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E 1 b)
Replies: 2
Views: 36

### Re: 2E 1 b)

A linear molecule can have no lone pairs or it can have lone pairs. Since the angle remains at 180 degrees, these lone pairs must be oriented in such a way that they cancel out, permitting the bond angle to remain at 180. This often found on central atoms possessing three or four lone pairs of elec...
Sat Nov 16, 2019 8:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Tool to Memorize VSEPR
Replies: 3
Views: 46

### Re: Tool to Memorize VSEPR

Thank you for this! I've been struggling to recite my flashcards, but this helped a lot haha. :)
Sat Nov 16, 2019 7:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.11 hw prob
Replies: 1
Views: 27

### Re: 2E.11 hw prob

To be considered T-shaped, the VSEPR label thing (whatever it's called) is AX3E2. It has to have a lone pair on both the top and the bottom of the "T-shape" in order to take that form. With just the one lone pair, the bonds will be repelling from the lone pair, rather than getting caught i...
Sat Nov 16, 2019 7:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 6
Views: 161

### Re: Lone Pairs

The geometry is based purely on electron dense areas, but the VSEPR model only uses the bonded parts, as the repulsion will cause all electron-dense areas to move as far away from each other. :) I hope this helps.
Sat Nov 16, 2019 7:50 pm
Forum: General Science Questions
Topic: Test 2
Replies: 5
Views: 73

### Re: Test 2

Test 2 is going to cover everything that we started learning after the midterm, so like. Outline 3 and 4 on the website. Basically just chemical bonds and VSEPR. :) Hope this helps.
Fri Nov 08, 2019 3:23 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
Replies: 6
Views: 120

### Re: Test 2

It's during week 8 and it'll only cover the material after the midterm to week 8! :) I hope this helps.
Fri Nov 08, 2019 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: DNA
Replies: 3
Views: 60

### Re: DNA

There's a hydrogen between an oxygen on thymine and a hydrogen on adenine, and a hydrogen on thymine and a nitrogen on adenine. it just has to do with the lone pairs on the oxygen and nitrogen. :) I hope this helps.
Fri Nov 08, 2019 3:18 pm
Forum: Student Social/Study Group
Topic: Dipole Moment
Replies: 5
Views: 87

### Re: Dipole Moment

Basically, in really broad terms, a dipole moment is found between two atoms who are sharing an electron. Due to one's higher electron affinity, it might hold the electron closer to it than its partner. The increase in negativity as the electron is closer to an atom is what the dipole moment is, if ...
Fri Nov 08, 2019 3:14 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 bonding
Replies: 4
Views: 45

### Re: Hydrogen bonding

I'm not sure what you mean, but the H in H2O has hydrogen boding with the oxygen atoms within the molecule, if that helps answer at all. :/ For there to be hydrogen bonding, there needs to be either a nitrogen, oxygen, or fluorine atom with at least one lone pair bonding to a hydrogen. I hope that h...
Fri Nov 08, 2019 3:11 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical formula
Replies: 3
Views: 158

### Re: Empirical formula

I had this question, too! Thank you everyone for posting the explanations :))
Sun Oct 27, 2019 3:01 pm
Forum: Resonance Structures
Topic: Resonance Structures in relation to Formal Charge
Replies: 3
Views: 52

### Re: Resonance Structures in relation to Formal Charge

No :) The formal charge on each element helps determine which lewis structure is "more accurate", as when the formal charge on each element is zero, the structure is more stable. So the formal charges will always be different depending on how many lone pairs, bonding electrons, and valence...
Sun Oct 27, 2019 2:57 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 2A.13. p-orbital electron removal
Replies: 1
Views: 36

### Re: 2A.13. p-orbital electron removal

To answer 2A13, you only need to name the orbital that the electron would be removed from, which you got correct. :) However, on your other question, there is only one electron removed to form an ion. It is rare for Cl to lose electrons in general, as it normally gains one to form Cl-. I hope this h...
Sun Oct 27, 2019 2:49 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1E.17
Replies: 2
Views: 55

### Re: 1E.17

Okay, so when the 3d shell starts to gain electrons, its energy level drops and it ends up having less energy than the 4s energy level. Since the electrons are removed from the orbitals that are farthest away from the nucleus (and that encounter the most shielding), the electron would be removed fro...
Sun Oct 27, 2019 2:45 pm
Forum: Ionic & Covalent Bonds
Topic: Valence Electrons 2A.1
Replies: 2
Views: 54

### Re: Valence Electrons 2A.1

From what I understand, you always count the subshells when finding ground-state configurations. Even when finding an ionic configuration, you still count the subshells, just some of the electrons have moved to other energy levels so it may seem as if you "aren't counting" them. For Mn in ...
Sun Oct 27, 2019 2:33 pm
Forum: Ionic & Covalent Bonds
Topic: He
Replies: 3
Views: 54

### Re: He

In the ground state configuration, the number of protons matches the number of electrons. Helium has two protons, so it will have two electrons in its ground state! :) I hope this helps.
Sun Oct 20, 2019 9:07 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Neon- electron configuration
Replies: 3
Views: 40

### Re: Neon- electron configuration

Elements like neon have a full valence shell and meet the octet rule! They don't really have a need for more electrons, so they're less likely to form bonds. :) I hope this helps!
Sun Oct 20, 2019 9:06 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Why is 4s before 3d?
Replies: 9
Views: 152

### Re: Why is 4s before 3d?

This would be an important topic to know for the midterm! So when you look at the periodic table, electrons fill orbitals in that order. So since the elements that have 4s orbitals are in front of those that have valence electrons in the 3d state, they fill the 4s first. :) Over all, it's important ...
Sun Oct 20, 2019 9:03 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Memorizing Wavelengths and Frequencies?
Replies: 2
Views: 37

### Re: Memorizing Wavelengths and Frequencies?

I would memorize which series starts at n=0 vs n=1 and like, the scale of wavelengths (?, I'm talking about like, gamma rays having higher wavelengths than ultraviolet rays), but other than that, I don't think there's much of a use to memorize all these things that you most likely won't use. :) Hope...
Sun Oct 20, 2019 9:00 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: When do you use a negative sign in the Bohr equation?
Replies: 7
Views: 94

### Re: When do you use a negative sign in the Bohr equation?

The negative sign is always present in the equation! :) Sometimes people don't use it when calculating because it makes sense that the final answer would end up being negative in any case. Hope this helps!
Sun Oct 20, 2019 8:59 pm
Forum: Properties of Electrons
Topic: Spin
Replies: 5
Views: 109

### Re: Spin

The way I learned it (and I know this isn't very representative of how it actually works, but it's easy to understand like this), some electrons spin clockwise, and others spin counter-clockwise. In order to "have a full set," or "see all angles of the clock," you would need one ...
Sun Oct 13, 2019 6:31 pm
Forum: Properties of Light
Topic: 1A. 15 homework question
Replies: 1
Views: 21

### Re: 1A. 15 homework question

My TA did this problem in discussion. He used v = R ( (1/n1^2) - (1/n2^2) to get n2. To get n1, just determine whether to use the Lyman series (for ultraviolet, starts n1 = 1) or the Balmer series (for visible, starts n1 = 2), as each starts on a different energy level. R is Ryderberg's constant. I ...
Sun Oct 13, 2019 6:26 pm
Forum: Properties of Light
Topic: Next test
Replies: 23
Views: 402

### Re: Next test

Lavelle said that we'd get all equations and constants on every test, I'm pretty sure. :) He most likely won't provide all of the derivations, but those should be easy to get from the original.
Sun Oct 13, 2019 6:25 pm
Forum: Properties of Light
Topic: Manipulation of Equations
Replies: 6
Views: 70

### Re: Manipulation of Equations

E= h (c(lambda^-1) and E = (hc) / (lamda) are the same equation. :) A negative exponent, in the simplest terms, just means that it's supposed to be in a denominator. I hope this helps.
Sun Oct 13, 2019 6:21 pm
Forum: Properties of Light
Topic: Photoelectric Effect
Replies: 7
Views: 72

### Re: Photoelectric Effect

In a vacuum, there is less of a possibility of interference, so the data from the experiment is more accurate. :)
Sun Oct 13, 2019 4:51 pm
Forum: Properties of Light
Topic: P.E Experiment
Replies: 2
Views: 31

### Re: P.E Experiment

When a photon is emitted, light is produced. When a photon is absorbed, the electron gets excited and moves up an energy level. I hope this helps!
Thu Oct 03, 2019 10:18 pm
Forum: Balancing Chemical Reactions
Topic: Diatomic elements?
Replies: 8
Views: 126

### Re: Diatomic elements?

I'm pretty positive it's because they're unstable in singularity and/or they naturally occur in nature as diatomic. :)
Thu Oct 03, 2019 10:14 pm
Forum: SI Units, Unit Conversions
Topic: Homework
Replies: 9
Views: 213

### Re: Homework

My AP Chemistry teacher told me to always do chem work in pen, so it's kind of a habit for me. I'm sure it'll be accepted either way, since it's the first assignment due and all. I wouldn't worry too much. :)
Thu Oct 03, 2019 10:11 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Replies: 9
Views: 188

Avogadro's number represents the amount of things inside one mole! Fun fact: it's dimensionless, as it represents different things. I say things because Avogadro's number can represent the amount of particles, formula units, atoms, etc. in one mole. :)
Thu Oct 03, 2019 10:09 pm
Forum: SI Units, Unit Conversions
Topic: When to use what units
Replies: 5
Views: 128

### Re: When to use what units

When calculating molarity, you should convert it into the units given in the standard equation (moles and liters). From experience though, if you have a method to keeping track of your units, just go for it. Either way, you're still calculating the concentration of a solute in a solution. :)
Thu Oct 03, 2019 10:06 pm
Forum: SI Units, Unit Conversions
Topic: 2.Mass Percentage and Decimal Rounding:
Replies: 10
Views: 145

### Re: 2.Mass Percentage and Decimal Rounding:

I've been basing my significant figures off of the molar masses indicated on the periodic table. If there is a given mass in the problem, match your percentages to that amount of sig figs. :)