## Search found 64 matches

Fri Jan 15, 2021 11:23 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Week 2 Sapling #6
Replies: 2
Views: 27

### Re: Week 2 Sapling #6

Hi, I also had this similar question so here's a link to my discussion on it and the answers were really helpful! I would suggest knowing the list of strong acids/bases to be able to work through problems like this.
Fri Jan 15, 2021 11:13 am
Forum: Ideal Gases
Topic: Thermodynamics in Equilibirum
Replies: 6
Views: 31

### Re: Thermodynamics in Equilibirum

I would think it'd be good to know a little basics of thermodynamics such as endothermic and exothermic reactions and activation energy, but for the most part he said we would be learning this later on.
Fri Jan 15, 2021 11:07 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: saplingQ. 2
Replies: 4
Views: 40

### Re: saplingQ. 2

The 0.116 in your denominator should be (0.116-x) then multiply by the K to get a quadratic equation and solve for x. I believe it is since the K is not much lower then you aren't allowed to assume that the -x will have little effect.
Fri Jan 15, 2021 11:02 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Review
Replies: 2
Views: 24

### Review

Can someone explain again how to know whether a neutral compound is more acidic or basic? I think it was if the cation came from a strong acid and the anion from a weak base it is more acidic right? Thanks in advance!
Fri Jan 15, 2021 10:56 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6D.5 part d
Replies: 3
Views: 32

### Re: 6D.5 part d

What does it mean to calculate percentage protonation of solute and how do you calculate this?
Fri Jan 08, 2021 9:46 am
Forum: Student Social/Study Group
Topic: Study Habits
Replies: 91
Views: 225

### Re: Study Habits

Hi I definitely recommend the step up or UA sessions! Also what I do is at the end of every week I go over all that we learned and make sure I know the material before we go into the next week. This typically involves doing textbook problems out of the book that help a lot.
Fri Jan 08, 2021 9:43 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Favoring
Replies: 6
Views: 38

### Favoring

Hi can someone go over the different ways either reactants or products might be favored. Such as adding more of a reactant or product, temperature, etc. Thanks in advance!
Fri Jan 08, 2021 9:40 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc
Replies: 11
Views: 38

### Re: Kc

Hi going off the Kp discussion, I believe Professor has been going over that you use partial pressure for gases and it is the same process as calculating Kc or using an ICE table.
Fri Jan 08, 2021 9:20 am
Forum: Administrative Questions and Class Announcements
Topic: Sapling Error - Did Question 10 reset?
Replies: 3
Views: 29

### Re: Sapling Error - Did Question 10 reset?

I just checked and it also did this to me for some reason. Does anyone know if this will count against us?
Fri Jan 08, 2021 9:17 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5 Multistep Eqm Constants
Replies: 3
Views: 31

### Re: Sapling #5 Multistep Eqm Constants

Hi, It took me a long time to figure this out also and a lot of people's explanations weren't making sense to me, but I found this page that goes over how to do it and under the red heading "Calculations Incorporating Two or More of These Algebraic Manipulations" where it gives an example ...
Sun Dec 13, 2020 1:23 pm
Forum: Student Social/Study Group
Topic: Final Exam
Replies: 49
Views: 289

### Re: Final Exam

brb ima go cry ;-;
Sun Dec 13, 2020 11:05 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Balmer and Lyman Series
Replies: 6
Views: 59

### Re: Balmer and Lyman Series

I just remember that Lyman is n=1 and is typically around 90-120 nm and Balmer is n=2 and typically around like 450-600nm. As long as you know these it won't be hard to discern when to use this.
Sun Dec 13, 2020 11:03 am
Forum: Student Social/Study Group
Topic: Words of encouragement
Replies: 13
Views: 101

### Re: Words of encouragement

Good luck to everyone!! Hope you all do great!
Fri Dec 11, 2020 12:20 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Sapling #5
Replies: 5
Views: 46

### Re: Sapling #5

Hi I use this for solving pH or pOH problems :) https://www.sciencegeek.net/Chemistry/t ... nit8pH.htm
Fri Dec 11, 2020 12:15 pm
Forum: Bronsted Acids & Bases
Topic: Acidic and Basic Salts
Replies: 2
Views: 28

### Acidic and Basic Salts

How can you tell if a salt is acidic, basic or neutral? I was kind of confused on answering this for question 7 on the sapling homework.
Fri Dec 11, 2020 12:11 pm
Forum: Bronsted Acids & Bases
Topic: Determining acidic vs basic
Replies: 5
Views: 48

### Re: Determining acidic vs basic

Hi just to clear up the confusion and for the final, Professor Lavelle said we should know the list of strong acids and bases. If it is not on the list then we can assume it is a weak acid or base.
Fri Dec 11, 2020 12:07 pm
Forum: Bronsted Acids & Bases
Topic: Strong and Weak Acids/Bases
Replies: 5
Views: 43

### Strong and Weak Acids/Bases

Do we have to know a certain list of strong acids and bases for the final? If not what are some tips for helping determine the strength and weakness of an acid or base?
Fri Dec 11, 2020 12:02 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Content
Replies: 18
Views: 156

### Re: Final Content

I believe he also said we spent less time on coordination compounds so try not to stress about that topic as much as other ones.
Fri Dec 04, 2020 9:55 am
Forum: Naming
Topic: Naming
Replies: 6
Views: 65

### Naming

Hi, I don't know if this has been answered before but we were going over how to name compounds in discussion and the term 'ferrate(iii)' was used which I know refers to Iron with a third oxidation state, but why is the prefix 'ferr'? Obviously ironate sounds a little off but how would we know that i...
Fri Dec 04, 2020 9:51 am
Forum: Naming
Topic: Ligand Names Table on Final
Replies: 10
Views: 79

### Re: Ligand Names Table on Final

Hi, like everyone has been saying we won't be given that sheet. My TA discussed this in our discussion and she said that it'd be best to memorize ligands that come up frequently such as ammine, sulfato, etc.
Fri Dec 04, 2020 9:49 am
Forum: Conjugate Acids & Bases
Topic: Discussion Problem
Replies: 2
Views: 38

### Discussion Problem

Hi, In discussion we talked about conjugate acids and bases. Have we talked about this before and if so can someone explain what they are and how to write the formulas for them?
Fri Dec 04, 2020 9:46 am
Forum: Lewis Acids & Bases
Topic: lewis vs bronsted
Replies: 8
Views: 83

### Re: lewis vs bronsted

Hi, Professor Lavelle discussed that the Bronsted Acid is a proton giver while a Bronsted Acid accepts it. A Lewis acid is an electron accepter while a Lewis base is an electron provider. Here's a website that discusses the two more in depth: https://chem.libretexts.org/Bookshelves/Inorganic_Chemist...
Fri Dec 04, 2020 9:43 am
Forum: Naming
Topic: Discussion Problem
Replies: 2
Views: 33

### Discussion Problem

Hi,

We were sitting in discussion and were asked to write the formulas based on the names and one of them was:
sodium bisoxalato(diaqua)ferrate(iii)
I'm not confused how to get the formula, but isn't disaqua supposed to be before the bisoxalato?
Fri Nov 27, 2020 4:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ring Structures
Replies: 9
Views: 54

### Re: Ring Structures

Hi, going off this topic, does anyone know how to identify when a molecule might have a ring structure? Does it have to be stated or is there a way to find out?
Fri Nov 27, 2020 4:19 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape Sheet
Replies: 7
Views: 77

### Shape Sheet

Hi does anyone have any websites or worksheets that help with identifying shapes of molecules?
Fri Nov 27, 2020 4:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling Weeks 7-8 #16
Replies: 6
Views: 56

### Re: Sapling Weeks 7-8 #16

viewtopic.php?f=30&t=68588
Fri Nov 27, 2020 4:05 pm
Forum: Sigma & Pi Bonds
Topic: Main Difference between Sigma & Pi Bonds Q
Replies: 4
Views: 42

### Re: Main Difference between Sigma & Pi Bonds Q

Here is another thing to consider between these bonds: Sigma bonds are defined as having their electron density along the bond axis, while pi bonds have their electron density above and below the bond axis as seen in the above picture. What this mean is that pi bonds cannot rotate the same way as si...
Fri Nov 27, 2020 3:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling Week 7-8 #3
Replies: 2
Views: 26

### Re: Sapling Week 7-8 #3

Hi, Here is a website I found that helped me discern between shapes. It doesn't have all the shapes, but it can explain why this model is linear. https://www.chem.purdue.edu/gchelp/vsepr/structur.html
Fri Nov 20, 2020 1:33 pm
Forum: Resonance Structures
Topic: Sapling Resonance Structures
Replies: 4
Views: 66

### Re: Sapling Resonance Structures

Fri Nov 20, 2020 1:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angle of see saw and square planar
Replies: 2
Views: 33

### Re: bond angle of see saw and square planar

I'm pretty sure bond angles and whether or not they are less than 120 or 90 is determined by the amount of electron repulsion that an atom has. I don't quite know for sure so if someone else can confirm this that would help.
Fri Nov 20, 2020 1:24 pm
Forum: Ionic & Covalent Bonds
Topic: Polar Bonds
Replies: 19
Views: 109

### Polar Bonds

Hi, How are you able to determine if a molecule contains polar bonds just by looking at the structure and its atoms.
Fri Nov 20, 2020 1:15 pm
Forum: Lewis Structures
Topic: Electron Density
Replies: 14
Views: 115

### Electron Density

Can someone explain the term electron density? I understand a bond is considered one region, but is any area where an electron is considered a region of electron density?
Fri Nov 20, 2020 1:11 pm
Forum: Ionic & Covalent Bonds
Topic: Which is strongest bond
Replies: 9
Views: 97

### Re: Which is strongest bond

I'm still confused by this question as well. Isn't the bond multiplicity the same for all of those molecules do how does that have an effect on the bond strength being 'weaker'?
Sat Nov 14, 2020 3:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Midterm #2
Replies: 14
Views: 100

### Re: Midterm #2

Midterm 2 covers all material after MT1 to the end of Outline 3 (Chemical Bonds). The outlines can be found on his syllabus and they tell the specific topics of what you should know for the midterm. As well as additional textbook problems to consider.
Sat Nov 14, 2020 3:44 pm
Forum: Ionic & Covalent Bonds
Topic: Electronegativity
Replies: 18
Views: 104

### Re: Electronegativity

I think in order to calculate electronegativity you have to use the table that gives the charges and calculate the difference between the elements in the molecule. If there is another way to calculate can someone please show this.
Sat Nov 14, 2020 3:40 pm
Forum: Administrative Questions and Class Announcements
Topic: 14B Class Structure - Also Recorded Videos?
Replies: 4
Views: 51

### Re: 14B Class Structure - Also Recorded Videos?

Yes they are recorded if you look on the class planner.
Wed Nov 11, 2020 1:35 pm
Forum: Resonance Structures
Topic: Resonance Structures and Optimal Formal Charge
Replies: 2
Views: 31

### Re: Resonance Structures and Optimal Formal Charge

I believe all of a molecules resonance structures should be shown, even if it does not have optimal formal charge, but the textbook is most likely showing the ones that are most common. It might be that the molecule ClNO2 has a lot of resonance structures but they weren't as important as the ones th...
Wed Nov 11, 2020 1:29 pm
Forum: Bond Lengths & Energies
Replies: 2
Views: 22

Yes they are a thing but they are most common among the transition metals in the middle of the d-block, so we won't be exposed to these in the course.
Wed Nov 04, 2020 3:54 pm
Forum: Trends in The Periodic Table
Replies: 3
Views: 34

### Re: Van der Waals radius

I saw this too, I don't think that its a necessary topic we need to know, but if someone could let us know and explain what it is, that would be great!
Wed Nov 04, 2020 3:51 pm
Forum: Octet Exceptions
Topic: More exceptions to the Octet Guideline?
Replies: 2
Views: 17

### Re: More exceptions to the Octet Guideline?

For specific atoms he noted that hydrogen, helium, lithium and beryllium don't ever achieve the octet rule, as well as P,S,Cl can accommodate more than 8 electrons and in terms of finding out this in structures, you have to look at overall formal charge and what produces the most stable structure (B...
Wed Nov 04, 2020 3:41 pm
Forum: Lewis Acids & Bases
Topic: Octet question
Replies: 7
Views: 63

### Re: Octet question

Also going off the previous response, he mentioned today in lecture that P, S, and Cl can accommodate more than 8 valence electrons so this goes against the octet rule as well, and like was stated above, it relies on the formal charge and the more stable structure to be able to determine these types...
Wed Nov 04, 2020 3:35 pm
Forum: Lewis Structures
Topic: Coordinate Covalent Bonds & Lewis Acid-base Reactions
Replies: 6
Views: 47

### Re: Coordinate Covalent Bonds & Lewis Acid-base Reactions

As described above, in the case of BF4, the B (Boron) is accepting the additional electron making it the Lewis acid and the F (Fluorine) is giving it's electron so it is the Lewis base. He said we would cover this topic in more lectures to come.
Wed Nov 04, 2020 3:32 pm
Forum: Lewis Structures
Topic: Lone Pair Electrons
Replies: 3
Views: 30

### Re: Lone Pair Electrons

I think for the sake of confusion I would just write them in because if you don't then you have to remember that they are there. This could mess you up when you are calculating formal charge, but no, this does not necessarily change the 'value' of the Lewis Structure.
Tue Oct 27, 2020 12:20 pm
Forum: Balancing Chemical Reactions
Topic: Writing Reactions
Replies: 3
Views: 47

### Re: Writing Reactions

Hi,

I think he said in one of his videos that whenever you have a combustion reaction, the products are always CO2 and H2O. So this should help you balance the equation with 4 moles of butane.
Tue Oct 27, 2020 12:16 pm
Forum: *Shrodinger Equation
Topic: Particle in a Box
Replies: 5
Views: 98

### Re: Particle in a Box

Do we need to know this for the Midterm? I don't remember him going over this in lecture.
Tue Oct 27, 2020 12:14 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Question 1.B.27
Replies: 3
Views: 40

### Re: Question 1.B.27

Hi, I haven't attempted this problem just yet, but based on what is given the change or uncertainty in velocity is 10 m/s. Then I would plug this into \Delta p = m (mass which is given, but make sure its in proper units) x \Delta v (which is 10 m/s). Then use this answer and plug into Heisenberg's I...
Tue Oct 27, 2020 12:08 pm
Forum: Administrative Questions and Class Announcements
Topic: How early should we go to our discussion sections for the midterm?
Replies: 3
Views: 70

### Re: How early should we go to our discussion sections for the midterm?

I think in this case you should probably email your TA for what they recommend. Mine said to come when discussion starts, but they would be there early if anyone wanted to show up early to get situated and you're more prepared.
Tue Oct 27, 2020 12:07 pm
Forum: Einstein Equation
Topic: E=hv vs. E=1/2mv^2
Replies: 6
Views: 71

### Re: E=hv vs. E=1/2mv^2

Hi, I just saw this on another post so I will reiterate what they said. "E=hv and c=frequency x wavelength are equations that only work for massless matter(i.e. electromagnetic radiation/photons). Anything with mass, so electrons, protons, everyday objects, abide by classical mechanics, 1/2mv^2...
Wed Oct 21, 2020 3:58 pm
Forum: Administrative Questions and Class Announcements
Topic: Webcam for Midterms [ENDORSED]
Replies: 4
Views: 75

### Re: Webcam for Midterms[ENDORSED]

I don't know exactly what the proper requirements are, but what I've heard is that people are putting zoom on their phone to show their workspace, but I don't know if it's needed on the computer. If anyone can clarify this that would be great!
Wed Oct 21, 2020 3:56 pm
Forum: Student Social/Study Group
Replies: 7
Views: 78

They are really helpful! At one I went to this week, the UA prepared content review/notes for some of the midterm concepts and practice problems she made herself that were different from the homework/textbook problems If it's too much to ask what are some topics that they brought up that were of gr...
Wed Oct 21, 2020 3:52 pm
Forum: Student Social/Study Group
Topic: Hamiltonian in Schrodinger's Wave Function
Replies: 2
Views: 66

### Hamiltonian in Schrodinger's Wave Function

Can someone explain more on exactly what a Hamiltonian is and how it relates to Schrodinger's equation. I know it is a double derivative, but I'm confused on what role it plays in the equation.
Wed Oct 21, 2020 3:47 pm
Forum: Student Social/Study Group
Replies: 7
Views: 78

For those that have been going to the Workshops or other assistance that Professor Lavelle supplied us with, what do they mostly do during that time. Is it more of just going over homework problems or do they help with overall concepts and can they help prepare for the midterm? If you have any exper...
Wed Oct 21, 2020 3:41 pm
Forum: *Shrodinger Equation
Topic: In class question
Replies: 3
Views: 50

### Re: In class question

He also said we wouldn't spend too much time on this topic so if the details are too intricate, I wouldn't sweat trying to memorize much of it. He said it wouldn't be covered on the midterm either.
Wed Oct 21, 2020 3:37 pm
Forum: Student Social/Study Group
Topic: Heisenberg's Indeterminacy Equation
Replies: 1
Views: 25

### Heisenberg's Indeterminacy Equation

Hi, I know Professor Lavelle said that we wouldn't break down how to formulate the Heisenberg's Indeterminacy Equation, but I was just wondering if anyone knew where the (h/4pi) came from? How did he come to this conclusion in his equation? Again, this is just for my own knowledge because I was curi...
Wed Oct 14, 2020 12:18 pm
Forum: Properties of Electrons
Topic: Lyman vs. Balmer series
Replies: 20
Views: 164

### Re: Lyman vs. Balmer series

Are we going to have to memorize the difference between the Lyman and Balmer series?
Wed Oct 14, 2020 12:14 pm
Forum: Student Social/Study Group
Replies: 4
Views: 53

What is Respondus for? I would post this as a new topic, but I don't see where to do that lol.
Wed Oct 14, 2020 12:10 pm
Forum: Photoelectric Effect
Topic: Sapling #4
Replies: 2
Views: 26

### Re: Sapling #4

Hi, I just went over this with my TA. So, when you get the threshold energy from part 1, you use that to calculate the number of electrons emitted using this equation (threshold energy)(number of electrons)=(total energy). The total energy is given and the threshold energy is what you got from part ...
Tue Oct 13, 2020 4:14 pm
Forum: Properties of Light
Topic: Sapling Week 2/3 Homework
Replies: 3
Views: 24

### Re: Sapling Week 2/3 Homework

Yes, the above answer is correct, the wavelength and frequency of the photons don't change; however, by adding more photons (in this case 100 photons) the energy increases by that amount because 1 photon has 1 energy corresponded with it. I put this answer into sapling and I got it correct as well. ...
Tue Oct 13, 2020 4:07 pm
Forum: Photoelectric Effect
Topic: Work Function
Replies: 4
Views: 28

### Re: Work Function

I don't know if I am reading your question right, but just in case this helps, the threshold energy and work function are the same thing. They are both the energy needed/required to eject an electron so if the work function is given, then so is the threshold energy. If someone else can confirm this ...
Tue Oct 06, 2020 11:20 am
Forum: Limiting Reactant Calculations
Topic: Sapling Homework #10
Replies: 7
Views: 74

### Re: Sapling Homework #10

I don’t think we are supposed to be able to determine molecular formula based off given structures so I’m sure if you look it up, which is what I did, that it would be fine until we learn how to determine formulas from structures given!
Tue Oct 06, 2020 11:17 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Reactants vs. Reagents
Replies: 5
Views: 50

### Re: Reactants vs. Reagents

Hi! As the two previously stated a reactant and reagent are used interchangeably, but a reagent is what first comes in the lab setting that then becomes a reactant which is used up in the chemical reaction. In terms of this course I think that if you see the two then there’s no reason to think there...
Mon Oct 05, 2020 8:35 pm
Forum: SI Units, Unit Conversions
Topic: Memorizing Conversions
Replies: 25
Views: 592

### Re: Memorizing Conversions

Hi,

There is a conversion sheet given, but it would save you so much time to learn basic conversions such as L to mL, mass to moles, kilograms to grams and many frequent ones that mostly appear in fundamental problems or coursework!
Mon Oct 05, 2020 8:31 pm
Forum: Significant Figures
Topic: Sig Figs
Replies: 11
Views: 118

### Re: Sig Figs

Hi,

When trying to solve for significant figures, it is best to put it in scientific notation like someone mentioned above. So 3.204 x 10^(-3) shows there are 4 significant figures. Dr. Lavelle posted a significant figures review on his website if you need to brush up on those concepts.
Mon Oct 05, 2020 8:25 pm
Forum: Balancing Chemical Reactions
Topic: Periodic Table
Replies: 50
Views: 482

### Re: Periodic Table

Hi, I believe Dr. Lavelle said in his first lecture that we won't have to memorize the periodic table or any equations this quarter because they will be given. He said the class is mainly to understand concepts, not simply memorize equations or other material similar to that. If you want to know som...