Search found 36 matches

by Lucy_Balish_1I
Wed Nov 18, 2020 11:36 pm
Forum: Lewis Structures
Topic: Why is CO2 a lewis acid.
Replies: 1
Views: 16

Re: Why is CO2 a lewis acid.

Because CO2 has two double bonds, there is space for the molecule to accept electrons and shift them to the O, breaking the double bond and replacing it with a single bond. In this manner, CO2 can act as an electron acceptor and bond to an electron rich atom or molecule.
by Lucy_Balish_1I
Wed Nov 18, 2020 11:31 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 Bond
Replies: 5
Views: 34

Re: Hydrogen Bond

If two H2SeO4 molecules were to interact, hydrogen bonds would take place between the hydrogens in one molecule (which are bound to an O) and the oxygen in the other which gives rise to hydrogen bonds.
by Lucy_Balish_1I
Wed Nov 18, 2020 11:25 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing Power vs Polarizability
Replies: 4
Views: 16

Re: Polarizing Power vs Polarizability

It's fundamentally the same idea (how the charge on one atom affects the charge on another) just different terms because the atoms have opposite charges. For cations with a positive charge, their ability to distort an anion and skew the electron cloud is known as their polarization power. The tenden...
by Lucy_Balish_1I
Wed Nov 18, 2020 11:21 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration of O-
Replies: 2
Views: 14

Re: Electron Configuration of O-

The oxygen anion has a charge of 2-, not 1-, so you would add two electrons and get 2p^6. Maybe the 1- charge was a typo, because when oxygen forms an anion it carries a 2- charge.
by Lucy_Balish_1I
Wed Nov 18, 2020 11:17 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Schrodinger's Wave Function Equation
Replies: 1
Views: 9

Re: Schrodinger's Wave Function Equation

I think the main point of Schrodinger's wave function equation is how it helps describe atomic orbitals. I remember it being a double derivative but other than that I'm pretty sure there was nothing else calculation-based he went over.
by Lucy_Balish_1I
Thu Nov 12, 2020 12:09 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: Liquid or Solid molecules
Replies: 1
Views: 23

Re: Liquid or Solid molecules

Being more polarizable is tied to having more electrons, so the bigger the atom (the further down the periodic table) the more electrons it has. Consequently, it has greater interaction potential energy because the charges are greater so with more interaction attraction energy, the larger molecules ...
by Lucy_Balish_1I
Thu Nov 12, 2020 12:03 pm
Forum: Formal Charge and Oxidation Numbers
Topic: 2.A.21
Replies: 2
Views: 24

Re: 2.A.21

To determine the number of unpaired electrons, you have to draw the electron configuration for each ion (adding or subtracting electrons depending on the charge) and then filling in each subshell, spin up then spin down. If ever you are left with an subshell that is not full where there are not enou...
by Lucy_Balish_1I
Mon Nov 09, 2020 1:46 pm
Forum: Bond Lengths & Energies
Topic: Negative energies? [ENDORSED]
Replies: 7
Views: 46

Re: Negative energies? [ENDORSED]

Negative energies imply that energy is given off by what is taking place. In this case, the more negative energy forces for ion-ion attractions and hydrogen bonds are more favorable and give off more energy than dipole-dipole and dipole induced-dipole. The reverse is true that a greater energy must ...
by Lucy_Balish_1I
Mon Nov 09, 2020 1:26 pm
Forum: Electronegativity
Topic: Finding electronegativity values
Replies: 6
Views: 31

Re: Finding electronegativity values

No, we do not have to memorize electronegativity values. They will be given to us in a table when we need to perform certain calculations. However, you should familiarize yourself with the electronegativity trends and know that F, O, and Cl are highest.
by Lucy_Balish_1I
Mon Nov 09, 2020 12:32 pm
Forum: Ionic & Covalent Bonds
Topic: Dipole moments / covalent bonds
Replies: 3
Views: 18

Re: Dipole moments / covalent bonds

From my understanding, the calculation for a dipole moment involves multiplying the charge by the distance between atoms. So the longer the bond length (ie. single bond), the greater the dipole value will be. A shorted bond length (double or single bond) will have a smaller value for distance betwee...
by Lucy_Balish_1I
Fri Nov 06, 2020 9:48 pm
Forum: Lewis Structures
Topic: Lewis Bases and Lone Pair Electrons
Replies: 3
Views: 33

Re: Lewis Bases and Lone Pair Electrons

You should always put the lone pairs on the central atom when you are drawing a lewis structure. That way you can ensure that the outer electrons have filled valence shells with a low formal charge and consequently know you are finding the most stable configuration.
by Lucy_Balish_1I
Fri Nov 06, 2020 9:43 pm
Forum: Electronegativity
Topic: Shielding Effect
Replies: 6
Views: 34

Re: Shielding Effect

What helped me most understand shielding was the example of people standing around a fire pit. Those closest to it block you from some of the heat, but you can still feel the warmth of it even if there are people standing between you and the fire. So because s-orbital electrons are closer to the nuc...
by Lucy_Balish_1I
Mon Nov 02, 2020 1:08 pm
Forum: Lewis Structures
Topic: Two different SO4^-2 structures
Replies: 2
Views: 23

Re: Two different SO4^-2 structures

To add on to Nika's explanation, by adding two double bonds, the formal charges lowered for 4 of the 6 atoms which we learned today is much more stable. When drawing Lewis structures, the one with the lower formal charges is a better representation of the molecule.
by Lucy_Balish_1I
Mon Nov 02, 2020 12:39 pm
Forum: Lewis Structures
Topic: Delocalized Definition
Replies: 4
Views: 38

Re: Delocalized Definition

Delocalized electrons means that the electrons in a molecule are not paired to just one atom. They are able to move freely because they are shared equally between different atoms.
by Lucy_Balish_1I
Mon Nov 02, 2020 12:31 pm
Forum: Resonance Structures
Topic: Lecture 11/2
Replies: 5
Views: 38

Re: Lecture 11/2

The extra electron added at the end is due to the overall -1 charge of the nitrate ion (NO3-). Nitrate is one of the polyatomic ions and is pretty common, so I would say you should be familiar with the formula and the overall charge.
by Lucy_Balish_1I
Thu Oct 29, 2020 11:28 am
Forum: *Shrodinger Equation
Topic: Sapling week 2/3
Replies: 12
Views: 123

Re: Sapling week 2/3

You can find the molar mass of a Helium atom on the periodic table: 4.002 g/mol. Since we are using Joules with Planck's constant, convert grams to kilograms, so 4.002 x 10^-3 kg. And make sure to multiply by Avogadro's number so 6.002 x 10^23 He atoms/mol in this question so that you get the value...
by Lucy_Balish_1I
Thu Oct 29, 2020 11:25 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra
Replies: 4
Views: 38

Re: Atomic Spectra

The photons are essentially packets of light energy that help the electrons move between energy levels. To move up in energy level, an electron must absorb a specific amount of energy in the form of a photon. In the same way, to drop to a lower energy level, it must lose a specific amount of energy,...
by Lucy_Balish_1I
Thu Oct 29, 2020 11:19 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Textbook Problem 1E.13 part a
Replies: 3
Views: 20

Re: Textbook Problem 1E.13 part a

To add on to Alex's response, it is most stable to have a full electron shell and second most stable to have a half filled shell. It is least stable to have almost filled levels. Thus having a full d shell (10d) and a half full s shell (1s) is a more stable configuration for Ag (as opposed to an alm...
by Lucy_Balish_1I
Thu Oct 29, 2020 11:16 am
Forum: Einstein Equation
Topic: E=pv and E=pc
Replies: 6
Views: 71

Re: E=pv and E=pc

E=pv comes from a simple combination of units. Knowing that E is in J which is kg*m^2/s^2, you can multiply momentum (kg*m/s) by velocity (m/s) to get kg*m^2/s^2. E=pc comes from knowing the velocity for a photon is the speed of light. So you essentially input C as the velocity for a photon because ...
by Lucy_Balish_1I
Thu Oct 29, 2020 11:12 am
Forum: Empirical & Molecular Formulas
Topic: Review for Midterm
Replies: 11
Views: 110

Re: Review for Midterm

Jacquelyn Challis 1H wrote:Regarding the midterm, can I use a graphing calculator or does it need to be scientific? I can't remember if Lavelle told us this info already or not.


I believe you can use a graphing calculator. If you have a TI-84 or TI-89 you should be fine.
by Lucy_Balish_1I
Wed Oct 21, 2020 12:26 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Diagram from Lecture
Replies: 5
Views: 51

Re: Heisenberg Diagram from Lecture

It is necessary to have 2 detectors to ensure you have both final and initial values so that you can calculate the total distance travelled as well as how long it took. Distance/time = velocity.
by Lucy_Balish_1I
Wed Oct 21, 2020 12:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Sapling Homework Order
Replies: 3
Views: 30

Re: Sapling Homework Order

They are all still in order and do a good job of paralleling his lectures. As Dr. Lavelle mentioned today in his lecture, we only need to know how to solve up to question 19 for the midterm. We still have to complete the rest of the assignment but it is not due until after the midterm, so complete t...
by Lucy_Balish_1I
Mon Oct 19, 2020 12:07 pm
Forum: *Black Body Radiation
Topic: Black Body Radiation Clarification
Replies: 3
Views: 29

Re: Black Body Radiation Clarification

From what I recall, that is more of a physics concept so we really don't need to know much more besides that. I think you are all set with the knowledge that black body radiation absorbs light frequencies, so don't worry about it too much!
by Lucy_Balish_1I
Mon Oct 19, 2020 12:04 pm
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 196
Views: 829

Re: How are you studying?

For me, I start by watching the lectures and making sure to attend them around the time when we normally would if they were live. This helps me stay on top of watching the videos and also feel like I have to still "go to class" and be accountable for my participation. During lecture I take...
by Lucy_Balish_1I
Mon Oct 19, 2020 11:59 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectroscopy Post-Assessment Question
Replies: 6
Views: 49

Re: Atomic Spectroscopy Post-Assessment Question

Once atoms form molecules, they have a specific energy transitions and wavelengths that it absorbs which lets it have a unique spectral fingerprint as well. Hope this helps! Just like what Sophie said, both atoms and molecules have a unique "fingerprint" which can be depicted through spec...
by Lucy_Balish_1I
Wed Oct 14, 2020 2:55 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Lyman Series, Balmer Series, and Infrared
Replies: 4
Views: 47

Re: Lyman Series, Balmer Series, and Infrared

The Paschen series is what you are asking about. This series includes transitions from n >= 4 to n = 3 state.
by Lucy_Balish_1I
Wed Oct 14, 2020 2:06 pm
Forum: Einstein Equation
Topic: Wave Model Question
Replies: 5
Views: 66

Re: Wave Model Question

The wave model predicts that the amplitude of the wave (the intensity) determines how much energy the wave carries. But this classical model does not apply to light. It can explain its wavelike appearance properties but does not accurately explain its energy properties. This is because the photoelec...
by Lucy_Balish_1I
Wed Oct 14, 2020 1:55 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: atomic spectroscopy question
Replies: 2
Views: 48

Re: atomic spectroscopy question

A good way to think about this is that the energy levels have to match up. If there is not enough energy, it will not match the energy needed to jump the gap, so it will pass through because it is not useful to the atom. But when the energy is enough and matches what is required, the atom will absor...
by Lucy_Balish_1I
Mon Oct 12, 2020 1:34 pm
Forum: Quantum Numbers and The H-Atom
Topic: high intensity light
Replies: 3
Views: 52

Re: high intensity light

We learned today that increasing the intensity/amplitude of a light (making it brighter) does not have any effect on the electrons emitted. This is because the energy required to emit an electron has not been met. To meet this required energy, a specific photon with a high frequency is necessary. To...
by Lucy_Balish_1I
Mon Oct 12, 2020 12:24 pm
Forum: Properties of Light
Topic: Quanta and Photons
Replies: 19
Views: 158

Re: Quanta and Photons

I once heard someone describe quanta as pennies of the quantum world. If you want to transfer energy, quanta are the smallest units that you can do so in. This analogy is super helpful! Thank you for sharing because it makes something so abstract seem as tangible as everyday coins. Definitely incre...
by Lucy_Balish_1I
Mon Oct 05, 2020 10:54 am
Forum: Molarity, Solutions, Dilutions
Topic: Dilutions
Replies: 10
Views: 108

Re: Dilutions

When doing a dilution, you usually pour more water in or pour a more concentrated solution in. You don't usually pour more solute in. For instance, if I had a bowl with 10 blueberries and 10 strawberries, I could reduce the ratio of blueberries by putting more strawberries. I didn't change the amou...
by Lucy_Balish_1I
Mon Oct 05, 2020 10:48 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Accuracy vs Precision
Replies: 20
Views: 202

Re: Accuracy vs Precision

Yes, I agree. That was super helpful!! For me the way I try to remember is "precision means consistent" and "accuracy means correct".
by Lucy_Balish_1I
Mon Oct 05, 2020 10:42 am
Forum: Empirical & Molecular Formulas
Topic: Emprical Formulas Ever Larger than Molecular? [ENDORSED]
Replies: 26
Views: 437

Re: Emprical Formulas Ever Larger than Molecular? [ENDORSED]

The empirical formula is always the most basic, simplified ratio. Thus, the molecular formula will either be the same or a multiple of that base ratio depending on the molar mass.
by Lucy_Balish_1I
Mon Oct 05, 2020 10:34 am
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 221
Views: 116095

Re: Advice from a Medical Student [ENDORSED]

Thank you so much for your encouraging advice. I appreciate you taking your time to post this, and now I am even more motivated to take notes during lectures and discussions. Best of luck in Med School!!
by Lucy_Balish_1I
Mon Oct 05, 2020 10:31 am
Forum: Molarity, Solutions, Dilutions
Topic: Diluting a Solution
Replies: 9
Views: 97

Re: Diluting a Solution

Yes, that statement applies to a solution when you keep diluting it and it remains in the same container - the moles remain constant and the volume increases so the molarity decreases. But when you remove some of this solution and add it to another container, you are making a NEW solution. And if yo...
by Lucy_Balish_1I
Thu Oct 01, 2020 3:51 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Reactions [ENDORSED]
Replies: 6
Views: 317

Re: Balancing Chemical Reactions [ENDORSED]

You can balance this equation by putting a 4 in front of CO and CO2 and a 3 in front of Fe.
That way you end up with Fe3O4 + 4CO = 3Fe + 4CO2 which is balanced.

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