## Search found 62 matches

Mon Jan 25, 2021 12:02 am
Forum: Student Social/Study Group
Topic: Comfort Movies
Replies: 128
Views: 290

### Re: Comfort Movies

Biohackers! Also I personally am very interested in CSI and Forensics so shows like Criminal Minds and Bones are go to's :)
Sun Jan 24, 2021 11:59 pm
Forum: Student Social/Study Group
Topic: Study Guide - Midterm?
Replies: 14
Views: 53

### Re: Study Guide - Midterm?

My TA recommended focusing on the textbook problems/readings!
Sun Jan 24, 2021 11:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pH
Replies: 2
Views: 10

### Re: pH

Also,s hould we memorize which of these groups in particular affect pH? Or is there a general rule we can apply?
Sun Jan 24, 2021 11:56 pm
Forum: Phase Changes & Related Calculations
Topic: when to assume x is insignificant
Replies: 24
Views: 45

### Re: when to assume x is insignificant

In addition is there a certain way we should approach every problem whether it is negligible or not? Should we always solve for it anyway?
Sun Jan 10, 2021 8:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs P
Replies: 6
Views: 43

### Re: K vs P

Also, can someone explain how the relationship Q>P means products are favored (I understand it's because the numerator is higher) but I am confused on how this tells us the direction of the reaction and what it really means regarding the stability of the reaction. If someone could explain the correl...
Sun Jan 10, 2021 8:07 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Replies: 15
Views: 75

Endothermic reactions absorb heat from the surrounding environment. So if heat is added, then there is a lower activation energy for the reaction to occur.
Sun Jan 10, 2021 8:05 pm
Forum: Student Social/Study Group
Topic: Group Me
Replies: 6
Views: 24

### Re: Group Me

This is the class groupme! https://groupme.com/join_group/62288203/dSSkobMS

I am not sure if you meant that or a specific one for your discussion..Hope it helps!
Sun Jan 10, 2021 8:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homogeneous and Heterogeneous Equilibrium
Replies: 13
Views: 62

### Re: Homogeneous and Heterogeneous Equilibrium

In addition, could someone give me an example of a heterogenous equilibrium? I am confused on how we could have one or more product/reactant in "different phases" or what that really means in the context of a reaction.
Sun Jan 10, 2021 8:01 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 2 Solutions to Quadratic Equations
Replies: 5
Views: 25

### Re: 2 Solutions to Quadratic Equations

Because the equilibrium concentrations of CO and H2O are 0.100-X (according to the ICE table), X cannot equal 0.126 or else the concentrations would be negative. For problems like these, I would look at the two solutions and see which one makes sense since one of the solutions will result in a nega...
Tue Dec 15, 2020 10:03 pm
Forum: Lewis Acids & Bases
Topic: Lewis vs Bronsted
Replies: 20
Views: 89

### Re: Lewis vs Bronsted

is finding the conjugate acids and bases different for each type of acid and base based on whether they are lewis or not? I would say yes. There are definitely patterns you can turn to, but it really depends which molecules are interacting, so it's best to look at which molecule is donating and whi...
Tue Dec 15, 2020 9:59 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation #s help
Replies: 5
Views: 33

### Re: Oxidation #s help

Ruth Rosales 3D wrote:Usually, I determine the oxidation number from the charge of the atom.

For example: MgCl2
Knowing that Cl = -1
Mg + 2Cl = 0
Mg + -2 = 0
Mg = +2

Hope this helps

Do we always assume that the oxidation for Cl is -1 because that's its more stable state?
Tue Dec 15, 2020 9:58 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of acid
Replies: 12
Views: 72

### Re: Strength of acid

Can someone explain how a more stable atom creates a molecule that is more acidic? If it has a higher electronegativity, wouldn't that mean that it holds on to the H+ atoms more strongly, therefore making it harder to release them? Thanks!
Tue Dec 15, 2020 9:56 pm
Forum: Bronsted Acids & Bases
Topic: Acids in solution
Replies: 3
Views: 24

### Re: Acids in solution

Also, I am a little confused on how we know whether it's 100% associated... Can we determine this based on the Lewis Structure of the molecule? In general, what does it mean for the acid to be "completely associated"?
Tue Dec 15, 2020 9:53 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: How do you determine the stronger base/acid?
Replies: 7
Views: 52

### Re: How do you determine the stronger base/acid?

In addition to this, I was wondering if the relationship pH<pKa is ALWAYS true for weak acids, or if there are certain exceptions we should remember.
Sun Dec 06, 2020 10:25 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation #
Replies: 6
Views: 44

### Re: Oxidation #

It helps me to look at the individual charges and then the sumo them! The oxidation number refers to the charge on the ion. In addition to this question, are there trends with oxidation numbers that make them easier to memorize?
Sun Dec 06, 2020 10:21 pm
Forum: Administrative Questions and Class Announcements
Topic: CCLE Lectures
Replies: 9
Views: 62

### Re: CCLE Lectures

I heard that it should be fixed by 10pm but same! :/ I had issues accessing them on CCLE when I used Safari, but it looks like Chrome did the trick! Maybe try that.
Sun Dec 06, 2020 10:17 pm
Forum: Student Social/Study Group
Topic: finals
Replies: 4
Views: 45

### Re: finals

A helpful method for me is to review the earlier material by going over practice problems for each section. If I am confused on a topic I will spend more time reviewing that. As far as practicing this week's material it is really helpful to reread your notes after each lecture to take in everything ...
Sun Dec 06, 2020 10:15 pm
Forum: Administrative Questions and Class Announcements
Topic: last day of lecture
Replies: 12
Views: 104

### Re: last day of lecture

Yeah it should be Wednesday!
Sun Dec 06, 2020 10:13 pm
Forum: Naming
Topic: naming chart
Replies: 4
Views: 42

### Re: naming chart

I got one from my discussion section that was really helpful!
Sun Dec 06, 2020 10:12 pm
Forum: Naming
Topic: naming chart
Replies: 4
Views: 42

### Re: naming chart

I got one from my discussion section that was really helpful!
Sun Nov 29, 2020 10:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Equatorial/ Axial Planes
Replies: 14
Views: 75

### Re: Equatorial/ Axial Planes

In addition to this, if a molecule is rooted, would the axial and equatorial planes be the same? In other words, are the axes consistent or are they always with regards to the vertical and horizontal planes?
Sun Nov 29, 2020 10:48 pm
Forum: Student Social/Study Group
Topic: Tips for Staying Focused
Replies: 52
Views: 527

### Re: Tips for Staying Focused

It really helps to study/work in a space where I will not get distracted. Going outside and away from distractions at home truly helps! Also, there are several study playlists on Spotify :) I find instrumental music really helps me stay focused!
Sun Nov 29, 2020 10:46 pm
Forum: Molarity, Solutions, Dilutions
Topic: Chemical Reactions
Replies: 2
Views: 45

### Re: Chemical Reactions

I don't think we need to know what specific kind of reaction each one it; it will likely be stated. But as for combustion reactions, I remember Lavelle stating that it occurs when oxygen is a reactant and water and hydrogen are products (with heat being produced).
Sun Nov 29, 2020 9:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Delocalized Bonds
Replies: 5
Views: 41

### Re: Delocalized Bonds

In addition to this question, do the formal charges change significantly when there is a delocalized bond? Or would it generally be the same?
Sun Nov 29, 2020 9:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AsO43-
Replies: 9
Views: 75

### Re: AsO43-

It helped me to draw out the dipole arrows! You will see that they point in opposite directions, which cancel out the distribution!
Mon Nov 23, 2020 12:00 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Why are hydrogen bonds so strong relative to other dipole-dipole bonds?
Replies: 11
Views: 131

### Re: Why are hydrogen bonds so strong relative to other dipole-dipole bonds?

Are hydrogen bonds ALWAYS present in N,O,F atoms? or is this just likely where they are to be found?
Sun Nov 22, 2020 11:57 pm
Forum: Dipole Moments
Topic: Dipole-dipole and london-dispersion IMF
Replies: 7
Views: 55

### Re: Dipole-dipole and london-dispersion IMF

In the equation for the dipole moment= charge x bond length, will we be given the charge or how would we calculate it?
Sun Nov 22, 2020 11:35 pm
Forum: Octet Exceptions
Topic: Expanded Octets
Replies: 11
Views: 87

### Re: Expanded Octets

Does the number of electrons in an expanded octet depend on the block that the atom is in?
Sun Nov 22, 2020 11:15 pm
Forum: Student Social/Study Group
Topic: Molecule shape
Replies: 1
Views: 33

### Re: Molecule shape

I'm sure there are many different ways to draw molecules. Much of the information regarding this will likely come with more lectures and knowledge about molecule shape, because we just began exploring that topic!
Sun Nov 22, 2020 11:13 pm
Forum: Lewis Structures
Topic: Dot stucture
Replies: 11
Views: 66

### Re: Dot stucture

That is correct! Usually I start by drawing out each atom (its symbol) and then drawing the number of valence electrons. After that, I draw the bonds and assure that the atom has a full octet!
Fri Nov 13, 2020 10:43 pm
Forum: Administrative Questions and Class Announcements
Topic: How do I post a new topic?
Replies: 2
Views: 15958

### Re: How do I post a new topic?

In my personal experience, I post in the topic that's most related, but I saw that someone posed a question regarding the Rydberg equation in the announcement section! But if you cannot find the topic that's most related, I would just post it in a section that's faintly similar because I know some ...
Fri Nov 13, 2020 10:40 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: H-F H-F Hydrogen Bonding vs Dipole-Dipole
Replies: 11
Views: 83

### Re: H-F H-F Hydrogen Bonding vs Dipole-Dipole

In addition, when calculated a dipole moment, will |q| always be given?
Fri Nov 13, 2020 10:38 pm
Forum: Resonance Structures
Topic: lewis base or acid
Replies: 15
Views: 119

### Re: lewis base or acid

Would this make cations and anions more likely to be acids or donors? Is there a correlation?
Fri Nov 13, 2020 10:35 pm
Forum: Lewis Structures
Topic: Lewis Structure for sulfate
Replies: 2
Views: 38

### Re: Lewis Structure for sulfate

The lewis structure for SO4 should have an overall of charge of -2. Sulfur can form up to 6 bonds given that it has 6 valence electrons. Sulfur double bonds to two of the oxygen atoms (giving those oxygens a 0 formal charge) and single bonds to two other oxygen atoms (giving those oxygens a -1 form...
Fri Nov 13, 2020 10:31 pm
Forum: Formal Charge and Oxidation Numbers
Topic: When to use formal charge or octet rule?
Replies: 12
Views: 104

### Re: When to use formal charge or octet rule?

I start with the octet rule and then use formal charge to check over my work, and if there are any charges that needed to be added I will add them. It is helpful to use both, but you should start with the octet rule. I do this as well to make sure I don't leave out any electrons! However, I was uns...
Fri Nov 13, 2020 10:20 pm
Forum: Administrative Questions and Class Announcements
Topic: Lewis Structure Questions
Replies: 1
Views: 15

### Lewis Structure Questions

In questions about drawing the Lewis structure of an atom, the questions usually refer to "additional Stability"...What does this mean? Is this only with regards to resonance?
Fri Nov 13, 2020 10:13 pm
Forum: Formal Charge and Oxidation Numbers
Topic: formal charge and stability
Replies: 8
Views: 55

### Re: formal charge and stability

It is of course best for the whole structure to have a formal charge of 0, but if that doesn't happen, i think the second most stable form is when the central atom has a formal charge of 0. As you make the charges of the outer electrons zero, wouldn't this start to make the central atom's charge al...
Fri Nov 13, 2020 10:10 pm
Forum: Electronegativity
Topic: determining electronegativity
Replies: 31
Views: 255

### Re: determining electronegativity

With this being said, the closer the elements are in electronegativity, the more affinity they have, correct? I remember Lavelle saying something about this but I can't remember the exact rule..
Fri Nov 13, 2020 10:08 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence electron numbers
Replies: 6
Views: 60

### Re: Valence electron numbers

Hello, I had a question regarding the electrons filling up different levels of the p-orbital.. Why can other orbitals have up to 8 electrons on their outermost energy level but the in the p-orbital they fill up x, y, and then z spaces of that orbital?
Fri Nov 13, 2020 10:00 pm
Forum: Administrative Questions and Class Announcements
Topic: How to Treat Anions and Cations
Replies: 4
Views: 47

### How to Treat Anions and Cations

With regards to cations and anions, is there a certain periodic table pattern as to where they happen to appear more frequently? What does this telling about their bonding properties and does this have anything to due with their electronegativity?
Fri Nov 13, 2020 9:41 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Importance of anions and cations
Replies: 15
Views: 89

### Re: Importance of anions and cations

With regards to cations and anions...Is it possible for them to have the same 4 quantum numbers considering they will have different properties than expected and they are altered?
Fri Nov 13, 2020 9:34 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Parallel electrons
Replies: 7
Views: 56

### Re: Parallel electrons

After reading these comments I am still confused... What does it mean for the electrons to be "parallel"? Does this change the atoms/molecules that they are likely to bond with?
Fri Nov 13, 2020 9:31 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence electron numbers
Replies: 6
Views: 60

### Re: Valence electron numbers

I may be wrong, but I remember Lavelle saying that even though the d orbital is listed before the s-orbital, it is technically last... With this being said, wouldn't that mean that it has 10 valence electrons?
Fri Nov 13, 2020 9:22 pm
Forum: Lewis Structures
Topic: Lewis Structures Method
Replies: 2
Views: 16

### Re: Lewis Structures Method

One thing that works for me is to first draw out every atom with all the electrons as dots and THEN draw the bonds so that I don't get confused :)
Fri Nov 13, 2020 9:21 pm
Forum: Ionic & Covalent Bonds
Topic: Orbitals
Replies: 3
Views: 30

### Re: Orbitals

With regards to Carbon, Lavelle mentioned that e- occupy the 2Px1 orbital and then occupy the 2Py1 orbital... Is this always the case? Or does this only happen when it comes in contact with a certain atom/molecule?
Sun Oct 25, 2020 6:37 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Minimum uncertainty problems
Replies: 3
Views: 28

### Re: Minimum uncertainty problems

You would just use the Heisenberg Uncertainty Equation! When it says "minimum uncertainty", just know you can assume the change in momentum X change in distance are EQUAL to h/4pi! In general however, you will just use the same formula (with the knowledge we have at the moment).
Sun Oct 25, 2020 6:33 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Diffraction
Replies: 4
Views: 30

### Re: Diffraction

With regards to diffraction, how can we tell when a system is constructive vs destructive? Do these properties mean something in particular? Is there certain characteristics of atoms that make the waves have one pattern over the other?
Sun Oct 25, 2020 6:31 pm
Forum: Quantum Numbers and The H-Atom
Topic: Energy Levels
Replies: 8
Views: 83

### Re: Energy Levels

With regards to energy levels in the Balmer or Lyman series, is there a specific reason why the energy is negative. For example, E4=-1/16hR and E2=-1/4hR. Is this because the light is being emitted and energy is released?
Sun Oct 25, 2020 6:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Sapling Questions
Replies: 1
Views: 27

### Re: Sapling Questions

I believe the issue has been fixed now!
Sun Oct 25, 2020 6:22 pm
Forum: Limiting Reactant Calculations
Topic: M.7
Replies: 6
Views: 78

### Re: M.7

Once you have your equation for the reaction balanced out, you need to look at the ration of one molecule to the other (if there's two i.e this case). Then, once you solve for the actual amount, whichever one limits the ratio it should have is the limiting reactant.
Sun Oct 25, 2020 6:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm scratch work
Replies: 8
Views: 49

### Re: Midterm scratch work

You can use a blank piece of paper to do your work, but my TA said you do not have to submit it! And yes, the exam will be multiple choice, likely with no partial credit.
Sun Oct 18, 2020 11:57 pm
Forum: Photoelectric Effect
Topic: Photoelectric experiment vs atomic spectra
Replies: 5
Views: 57

### Re: Photoelectric experiment vs atomic spectra

In the experiment, was there a specific reason why they used metals (mainly copper) to reflect the e-. In addition, can an experiment like this one be both classical & Quantum mechanics by changing a few variables of the experiment.
Sun Oct 18, 2020 11:53 pm
Forum: Quantum Numbers and The H-Atom
Topic: Balmer and Lyman series
Replies: 4
Views: 30

### Re: Balmer and Lyman series

Why is it that the Balmer series only goes to n=2? Is this just what is visible to the naked eye? In that case, wouldn't everyone see a different portrayal
Sun Oct 18, 2020 11:49 pm
Forum: Properties of Light
Topic: energy level transfer
Replies: 7
Views: 36

### Re: energy level transfer

In lecture, Lavelle mentioned once the energy of e- on the second energy level matches that of the first, the electron is excited. However, I was under the impression that one energy level had to be completely full before e- proceeded to the next energy level. Can someone explain what he meant by th...
Sun Oct 18, 2020 11:46 pm
Forum: Balancing Chemical Reactions
Topic: Writing chemical formulas based on compound names
Replies: 3
Views: 45

### Re: Writing chemical formulas based on compound names

In one of his first lectures, Lavelle mentioned that the chemical formulas will be provided for us in tests.
Sun Oct 18, 2020 11:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations that dont follow the pattern
Replies: 3
Views: 24

### Re: Electron Configurations that dont follow the pattern

Can you explain what you mean by "the pattern"?
Thu Oct 08, 2020 11:53 pm
Forum: Administrative Questions and Class Announcements
Topic: Posting on Chemistry Community
Replies: 7
Views: 69

### Re: Posting on Chemistry Community

Britney Tran IJ wrote:so the chemistry community posts are due on Sunday at midnight instead of Friday right?

Yes! the Chem Community and HW are both due on Sunday night
Thu Oct 08, 2020 11:52 pm
Forum: Student Social/Study Group
Replies: 5
Views: 53

Hi guys! There is a groupie me for discussion 2L.. and not many have joined. Thought I would share the link on here!

https://groupme.com/join_group/63062393/OTZeg2L7
Thu Oct 08, 2020 11:47 pm
Forum: Molarity, Solutions, Dilutions
Topic: Module: Molarity and Dilution of a solution
Replies: 5
Views: 130

### Re: Module: Molarity and Dilution of a solution

Just a general question about the conversion of grams to moles and mL to L... I know we usually have to change the grams to moles as a first step to proceed with he problem, and with regards to molarity, we will likely be dealing with Liters.. However, I keep getting different answers due to the fac...
Thu Oct 08, 2020 11:42 pm
Forum: Molarity, Solutions, Dilutions
Topic: Module: Molarity and Dilution of a solution
Replies: 5
Views: 130

### Re: Module: Molarity and Dilution of a solution

A solution is prepared by dissolving 55.1 g of KCl in approximately 75 mL of water and then adding water to a final volume of 125 mL. What is the molarity of KCl(aq) in this solution? A. 0.169 mol.L-1 B. 10.8 mol.L-1 C. 0.0923 mol.L-1 D. 5.91 mol.L-1 I'm a bit confused in the wording of this questio...
Thu Oct 08, 2020 11:34 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical and Molecular Formula
Replies: 17
Views: 124

### Re: Empirical and Molecular Formula

In lecture, Lavelle explained that we will not know if the formula we have concluded is the empirical or molecular formula until we are given the molar mass of the molecule. Will we always be given the molar mass? If not, should we just assume that the formula is the empirical formula?
Thu Oct 08, 2020 11:31 pm
Forum: Balancing Chemical Reactions
Topic: Combustion
Replies: 14
Views: 189

### Re: Combustion

In a combustion reaction, when C burns in the presence of O, why is CO2 always a product? And same with H20? Is there a specific reason why this occurs?