Search found 55 matches

Tue Dec 08, 2020 10:21 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: strong or weak acids and bases
Replies: 4
Views: 25

Re: strong or weak acids and bases

hello how does one decide whether a formula is a strong acid, weak acid, strong base, or weak base? for example how would i figure out what Ba(OH)2 is? thank you Strong Acid: Big size | Longer Bond Length | Weaker Bonds | Easily donates Proton -> Stronger Acid orrrrr if Resonance to stabilize acid ...
Tue Dec 08, 2020 10:09 pm
Forum: Bronsted Acids & Bases
Topic: 100% ionized
Replies: 3
Views: 13

Re: 100% ionized

Just a bit confused but what does it mean when an acid/base is completely/partially ionized in water and how does this relate to how strong/weak an acid/base is? Stronger acids; donates more protons in solution, becomes completely ionized by loosing protons. Ionized in water = disassociated Stronge...
Tue Dec 08, 2020 10:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Content
Replies: 18
Views: 156

Re: Final Content

Cumulative; the more time / focus we had on one topic, the more prevalent it'll be is what Dr. Lavelle said I believe
Tue Dec 08, 2020 9:53 pm
Forum: Student Social/Study Group
Topic: Review Session
Replies: 11
Views: 100

Re: Review Session

Friday's "lecture" I believe is a bruincast review
Tue Dec 08, 2020 9:51 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH vs. pKa
Replies: 1
Views: 13

Re: pH vs. pKa

Marylyn Makar 1D wrote:Hi! What's the difference between pH values and pKa values?

"p" = -log[]
Ka = [A-][H+] / [AH]
pKa = -log ^ number; pertains to acidity
- More acidic = higher Ka, lower pKa

H = [H30]
pH = -log[H30]
- Gives scale of concentration from acidic - alkaline-basic

Hope this helps a little!
Tue Dec 08, 2020 9:46 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: strong or weak acids and bases
Replies: 4
Views: 25

Re: strong or weak acids and bases

hello how does one decide whether a formula is a strong acid, weak acid, strong base, or weak base? for example how would i figure out what Ba(OH)2 is? thank you Strong Acid: Big size | Longer Bond Length | Weaker Bonds | Easily donates Proton -> Stronger Acid orrrrr if Resonance to stabilize acid ...
Sun Dec 06, 2020 5:52 pm
Forum: Naming
Replies: 22
Views: 107

Thank you! I'm having trouble with naming compounds so these videos are definitely going to help :D
Sun Dec 06, 2020 5:50 pm
Forum: Hybridization
Replies: 7
Views: 54

Thank you! Definitely going into my review list plan :D
Thu Dec 03, 2020 10:35 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Sapling Wk9, #3
Replies: 3
Views: 34

Sapling Wk9, #3

I understand why tetrahedral geometry is common for complexes w/ coordination number of 4.
However why is square planar geometry common and seesaw complex not?

They both have 4 "X's" or bonded atoms in naming their structure. Why is square planar favored over seesaw?
Mon Nov 30, 2020 3:51 pm
Forum: Biological Examples
Topic: Myoglobin Structure
Replies: 3
Views: 37

Re: Myoglobin Structure

When discussing the myoglobin structure in today's lecture, it was mentioned that it is a tetradentate structure. I was confused on this description because I thought that there were 6 bonds because iron likes to be in an octahedral structure, but is this not correct? Could you expand on why myoglo...
Mon Nov 30, 2020 3:32 pm
Forum: Naming
Topic: Transition Metal Roman Numeral Naming for Diff Charges
Replies: 2
Views: 37

Transition Metal Roman Numeral Naming for Diff Charges

Hi I understand(sorta) that the roman numerals are dependent on the charges (oxidation number). However, I was wondering if the direction of the charge (either positive or negative) affected the roman numeral. For example, would Iron +2 and Iron -2 both be considered Iron (II)? (assuming that both v...
Sun Nov 29, 2020 3:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Axial vs Equatorial Bonds
Replies: 11
Views: 99

Re: Axial vs Equatorial Bonds

I was having a bit of an issue understanding the differences between axial and equatorial bonds as well as how they impact the shape of molecules. Will certain atoms or lone pairs only be in one of the two positions and thus affect the shape? Axial: On the vertical axis Equatorial: On the plane Cer...
Sun Nov 29, 2020 2:01 pm
Forum: Student Social/Study Group
Topic: How have your study habits changed?
Replies: 45
Views: 294

Re: How have your study habits changed?

Txtbook problems for days and rewatching some of his lectures to keep the information fresh before tests.
I don't know if it will be changing for finals however.
Sun Nov 29, 2020 1:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar vs non-polar for molecules
Replies: 2
Views: 10

Re: polar vs non-polar for molecules

To determine if the overall molecule is polar or non-polar it's non-polar if the bonds are non-polar but if the bonds are polar we have to know the molecule's shape and bond angles to see if the polar bonds cancel out and if they do then the molecule if non-polar, correct? Yeah you're right! If the...
Sun Nov 29, 2020 1:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 90 Degree Lone Pair Interactions
Replies: 2
Views: 21

Re: 90 Degree Lone Pair Interactions

Why does minimizing the number of 90 degree lone pair-bond interactions increase the stability of the molecule (eg in the seesaw VSEPR shape)? Is it because electron-electron repulsion is minimized in this configuration? If so, please explain in more detail. Thank you! Lone electron pairs because t...
Sun Nov 29, 2020 1:53 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Unhybridized P-orbitals as Regions of Electron Density
Replies: 1
Views: 20

Re: Unhybridized P-orbitals as Regions of Electron Density

Hello! I was a little bit confused with examples including unhybridized p-orbitals, regarding how many regions of electron density the carbon atoms have. For example, in ethene and benzene examples, Dr. Lavelle said in lecture that each carbon atom in these molecules has 3 regions of electron densi...
Sun Nov 22, 2020 2:27 pm
Forum: Lewis Structures
Topic: Guidelines on Drawing Lewis Structures
Replies: 4
Views: 46

Re: Guidelines on Drawing Lewis Structures

Also on drawing them, remember that the lowest formal charge should be the center atom.

I believe this is because the more relatively electronegative atoms (and thus the more ionization energy atoms) have a stronger hold on electrons so it'd be reflective of the true nature electron density.
Sun Nov 22, 2020 2:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2 Scores
Replies: 28
Views: 193

Re: Midterm 2 Scores

Sameer Chowdhury 1C wrote:Hi, I was wondering when we could expect to get back our scores for the second midterm.

Like last time I would assume that it'd be by Thursday at max;
You could always ask in his discussion section tomorrow; he usually tells us when there
Thu Nov 19, 2020 6:08 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability vs Polarizing Power in anions/cations & bonding
Replies: 10
Views: 64

Re: Polarizability vs Polarizing Power in anions/cations & bonding

Polarizability pertains to the anion. It is a measure of how easily their electrons can be distorted (and moved into the shared region, which is on the internuclear axis between two atoms in a bond). Larger anions have more electrons that are not as closely held to the nucleus, so they are more pol...
Wed Nov 18, 2020 9:41 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability vs Polarizing Power in anions/cations & bonding
Replies: 10
Views: 64

Polarizability vs Polarizing Power in anions/cations & bonding

What exactly is polarizability and polarizing power? I understand that polarizability has to do with an anion's ability to take away electrons (correct me if I'm wrong) But in the intermolecular energy equation, it uses the polarizability of two atoms and their polarizability which would mean that h...
Mon Nov 16, 2020 3:32 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: What exactly is a dipole? [ENDORSED]
Replies: 16
Views: 116

What exactly is a dipole?[ENDORSED]

What exactly is a dipole?

Is a dipole anything that is covalently bonded that has an imbalanced charge? Like anything that is polar?
Mon Nov 16, 2020 12:51 pm
Forum: General Science Questions
Topic: midterm 2
Replies: 6
Views: 74

Re: midterm 2

There's also Dr. Lavelle's discussion section today where you could usually ask him questions you have!
Mon Nov 16, 2020 12:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Repulsion of a Bonding-Bonding Pair
Replies: 6
Views: 47

Re: Repulsion of a Bonding-Bonding Pair

Hello! So in today's lecture, there was a statement that said: repulsion strength: lone-lone pair > lone-bonding pair > bonding-bonding pair What exactly does this mean? I think I'm confused because I don't quite understand the concept of a lone-bonding pair or a bonding-bonding pair. Is it the sam...
Fri Nov 13, 2020 2:07 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2: Lectures
Replies: 5
Views: 66

Re: Midterm 2: Lectures

Was Wednesday's lecture the last lecture that will be covered on midterm 2? Will Friday's Lecture (Nov13) be on midterm2 or is that new material for the final? According to my TA, the topics that are covered are: 1D (from quantum numbers), 1E, 1F, 2A, 2B, 2C, 2D, 3F.4, 3F.5 on the textbook So since...
Mon Nov 09, 2020 3:45 pm
Forum: Dipole Moments
Topic: Polarity
Replies: 3
Views: 32

Re: Polarity

How do you determine polarity of a molecule. Specifically what value would be considered polar or non polar? It's considered polar if there are even slight charges within the molecule. In Dr. Lavelle's discussion session, he talked about how to determine polarity / non polarity, one must know the l...
Mon Nov 09, 2020 3:37 pm
Forum: Student Social/Study Group
Topic: Discord/Group me
Replies: 3
Views: 26

Re: Discord/Group me

Mon Nov 09, 2020 3:30 pm
Forum: Ionic & Covalent Bonds
Topic: "Favorable"
Replies: 4
Views: 35

"Favorable"

What does it mean for bonds to be favorable? Are they more likely to occur when interacting? What does it mean in the context of in disassociation energy, or bond energies?
Sat Nov 07, 2020 11:03 am
Forum: Resonance Structures
Topic: Oxidation Number
Replies: 9
Views: 55

Oxidation Number

What's an oxidation number? How do you find it for a specific atom?
Sat Nov 07, 2020 11:00 am
Forum: Resonance Structures
Topic: Resonant Structures and Formal Charge
Replies: 3
Views: 24

Re: Resonant Structures and Formal Charge

When you have two resonant structures (for example two structures of perchlorate ion, ClO4-), and one only has a -1 charge on chlorine and the other only has a -1 charge on oxygen, how do you know which one would be the more preferred (plausible) resonant structure? Both structures have only one -1...
Wed Nov 04, 2020 10:14 pm
Forum: Lewis Structures
Topic: Sapling HW 5&6 #4
Replies: 2
Views: 48

Re: Sapling HW 5&6 #4

Can someone please explain to me how to do this problem? I am a little confused about the ample and overwhelming bond character part. So the C-/=O bond of the given molecule has been given as 128 pm C-/=N bond of the given molecule has been given as 136pm And you are also given the values of the ex...
Mon Nov 02, 2020 4:05 pm
Forum: Resonance Structures
Topic: Delocalization of Electrons
Replies: 2
Views: 20

Re: Delocalization of Electrons

So to my understanding, in resonance structures, electrons that form double bonds are delocalized because they exist in multiple locations (equivalent electron density). But does this mean electrons involved in single bonding and lone pairs are not delocalized? Or are they also equally shared among...
Mon Nov 02, 2020 4:01 pm
Forum: Resonance Structures
Topic: Energy and Stability in Delocalization
Replies: 3
Views: 31

Re: Energy and Stability in Delocalization

Hi! Can anyone explain why delocalization of electrons lowers energy but also increases stability? Dr. Lavelle said it in his lecture for today (11/2), but I failed to understand why this occurs. Thanks for the help! Delocalization of the electrons increases the size of the molecule which makes it ...
Mon Nov 02, 2020 3:34 pm
Forum: Resonance Structures
Topic: Energy and Stability in Delocalization
Replies: 3
Views: 31

Re: Energy and Stability in Delocalization

Hi! Can anyone explain why delocalization of electrons lowers energy but also increases stability? Dr. Lavelle said it in his lecture for today (11/2), but I failed to understand why this occurs. Thanks for the help! Delocalization of the electrons increases the size of the molecule which makes it ...
Fri Oct 30, 2020 2:50 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Vs. Covalent
Replies: 7
Views: 63

Re: Ionic Vs. Covalent

LexyDenaburg_3A wrote:Can someone explain the main difference between ionic and covalent bonds?

Simply put

Ionic: give / take of electrons
Covalent: sharing of electron pairs

If you wanna know a bit more I'm happy to do so lmk
Thu Oct 29, 2020 9:55 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Textbook Problem 1B27
Replies: 6
Views: 79

Re: Textbook Problem 1B27

1B.27 A bowling ball of mass 8.00 kg is rolled down a bowling alley lane at 5.00±5.0m⋅s−1. What is the minimum uncertainty in its position? Could someone explain why we don't convert 8.00kg to grams in this problem Thank you! I'm also confused in the uncertainty in position. I thought Dr. Lavelle e...
Thu Oct 29, 2020 9:52 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Textbook Problem 1B27
Replies: 6
Views: 79

Re: Textbook Problem 1B27

1B.27 A bowling ball of mass 8.00 kg is rolled down a bowling alley lane at 5.00±5.0m⋅s−1. What is the minimum uncertainty in its position? Could someone explain why we don't convert 8.00kg to grams in this problem Thank you! I'm also confused in the uncertainty in position. I thought Dr. Lavelle e...
Tue Oct 27, 2020 10:44 am
Forum: Properties of Light
Topic: Wavelength
Replies: 26
Views: 183

Re: Wavelength

Is wavelength always converted into m or are there any instance where wavelength must be in nm? If the final answer is in nm then it should be in nanometers. The primary reason we convert it to m is to use formulas with constants which are oftentimes given in terms of m, kg, s... etc. Otherwise you...
Tue Oct 27, 2020 10:42 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: General Heisenberg Question
Replies: 7
Views: 88

Re: General Heisenberg Question

Hi everyone! In Heisenberg problems, will there be instances where we're given a +/- with a percentage? For example, can the problem give us an uncertainty for position as 5.00 +- 1%, or would there always be an actual number after the +- sign? I understand that in theory, we would have to double i...
Tue Oct 27, 2020 10:39 am
Forum: Properties of Electrons
Topic: Wave Properties of Electrons Post-Assessment #34
Replies: 2
Views: 33

Re: Wave Properties of Electrons Post-Assessment #34

This question asked: If an electron (mass 9.11 x 10-31 kg) has an associated wavelength of 7.28 x 10-9 m, what is its speed? Is your answer reasonable, why? I calculated the speed to be 1.00x10^5 m/s, and I said this was not reasonable because the calculated speed is much slower than the speed of l...
Fri Oct 23, 2020 6:05 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electrostatic potential
Replies: 2
Views: 47

Re: Electrostatic potential

Is the the Electrostatic potential equation (q1)(q2)/r solve anything beyond being a conceptual point Hi! Currently Dr. Lavelle has not yet used it for actual empirical calculations. And yes, currently it's a conceptual point to show how electrostatic potential is proportional to the magnitude of c...
Fri Oct 23, 2020 3:12 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electrons in Orbitals
Replies: 5
Views: 58

Re: Electrons in Orbitals

I don't know why the first electron in an orbital is specifically spin-up, but I'm pretty sure they occupy different orbitals before filling them up because of the repulsion forces between them, so they'd want to be as far away as possible and thus occupy different orbitals. Also spin-up / spin-dow...
Fri Oct 23, 2020 3:07 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamental G25
Replies: 2
Views: 46

Re: Fundamental G25

I am reviewing and am having a little trouble with this question. Practitioners of the branch of alternative medicine known as homeopathy claim that very dilute solutions of substances can have an effect. Is the claim plausible? To explore this question, suppose that you prepare a solution of a sup...
Fri Oct 23, 2020 11:56 am
Forum: *Shrodinger Equation
Topic: Sapling week 2/3
Replies: 12
Views: 148

Re: Sapling week 2/3

Should we be able to answer this question already? If so does anyone know the steps to solve it? Any help would be great. Thanks! What is the minimum uncertainty in an electron's velocity (Δvmin) if the position is known within 15 Å. What is the minimum uncertainty in a helium atom's velocity (Δvmi...
Thu Oct 22, 2020 6:20 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: "Math Function"
Replies: 2
Views: 79

Re: "Math Function"

The Scrhodingers equation showed how to find the probability of an electron by squaring the sin graph. Where the sin graph peaked, the square of the sin graph will peak higher, meaning that there is a high probability of an electron being there. This connects to orbitals because you can predict whe...
Wed Oct 21, 2020 1:21 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: "Math Function"
Replies: 2
Views: 79

"Math Function"

I'm still kind of confused on this whole topic of scrhodingers as a base of orbital formation. Dr. Lavelle keeps talking about math functions and its relation to creating orbitals. Does the math function refer to psi? psi^2? the Hamiltonian (double derivative?)? Wave function (psi?) And what is plot...
Sat Oct 17, 2020 5:43 pm
Forum: Photoelectric Effect
Topic: Textbook Problem 1A9
Replies: 4
Views: 35

Re: Textbook Problem 1A9

A college student recently had a busy day. Each of the student’s activities on that day (reading, getting a dental x-ray, making popcorn in a microwave oven, and acquiring a suntan) involved radiation from a different part of the electromagnetic spectrum. Complete the following table and match each...
Sat Oct 17, 2020 5:37 pm
Forum: Administrative Questions and Class Announcements
Topic: Calculator?
Replies: 9
Views: 104

Re: Calculator?

If I remember correctly, according to my TA and other folks, TI 84's can be used during exams.
Mon Oct 12, 2020 11:11 pm
Forum: Photoelectric Effect
Topic: Post Module Assessment PhotoElectric Effect #29 & 30
Replies: 1
Views: 21

Post Module Assessment PhotoElectric Effect #29 & 30

This is a 3 part question from 28-30 28: light hitting sodium metal surface, velocity of ejected electron = 6.61*10^5 m/s In 28 you're given that the work function for sodium is 150.6kJ/mol 29 asks what is the energy reqruied to remove an electron from one sodium atom If the work function is also th...
Mon Oct 12, 2020 11:03 pm
Forum: Properties of Light
Topic: Photoelectric Effect Post Assessment #34
Replies: 2
Views: 40

Re: Photoelectric Effect Post Assessment #34

KE = E(in) - E(threshold) Frequency = c/ wavelength v = (3*10^ m/s) / (194*10^-9m) v = 1.55*10^15 s^-1 E = vh E = 1.024*10^-18 J E(in) = 1.024*10^-18 J E(threshold) = 7.22*10^-19 J E(in) - E(threshold) = 3.03*10^-19J Probably loss of some sig figs here and there so -> 3.05*10^-19J Hopefully this hel...
Mon Oct 12, 2020 10:23 pm
Forum: Photoelectric Effect
Replies: 1
Views: 30

So the syllabus states
for the Quantum World Unit that the problems are from 1A, B, D, E, & F. Just making sure, is it recommended that we still read over C or is it going to be material that is not needed/covered in class?
Mon Oct 05, 2020 4:22 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity Equations
Replies: 3
Views: 43

Re: Molarity Equations

I would assume it'd be helpful to know the different equations but if you can derive the different equations from the MV(i) = MV (f) I don't see a particular need to memorize them directly
Mon Oct 05, 2020 4:21 pm
Forum: Empirical & Molecular Formulas
Topic: Sapling HW 9
Replies: 21
Views: 223

Re: Sapling HW 9

Yes; because empirical formula is a ratio of moles
Mon Oct 05, 2020 4:15 pm
Forum: Molarity, Solutions, Dilutions
Topic: I learned the difference between pH paper and chromatographs.
Replies: 3
Views: 71

Re: I learned the difference between pH paper and chromatographs.

You could also do your own chromatography at home! There's a type of paper called chromatography paper which you can use and see the different chemical components of a given marker / pen! I think it's called paper(ink)chromatography if you wanna search it up Basically, it's separating the black mark...
Mon Oct 05, 2020 3:38 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Fundamentals HW E.1
Replies: 7
Views: 126

Re: Fundamentals HW E.1

I was wondering which equation is supposed to be used to solve exercise E1? How would it result in an answer in the pm length unit. if a "." was 1 ag atom and 1 mole of Ag atoms has 6.0221*10^23 atoms and they're all lined up it would be ............... etc And if each of them has a radius...
Mon Oct 05, 2020 3:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Submitting HW on Sapling
Replies: 5
Views: 60

Re: Submitting HW on Sapling

I don't believe that there is a submit button; if you did the hw and it has checkmarks in the quetions it should be fine