Search found 30 matches

by Sabrina Ryu 3L
Wed Dec 05, 2018 4:45 pm
Forum: Hybridization
Topic: Radical Placement
Replies: 3
Views: 42

Re: Radical Placement

The radical goes on the element that would have the formal charge closest to zero when the electron is added!
by Sabrina Ryu 3L
Wed Dec 05, 2018 4:38 pm
Forum: Administrative Questions and Class Announcements
Topic: Modules
Replies: 3
Views: 80

Re: Modules

I couldn't find other modules, but the chemistry in person review sessions are really helpful, especially the step-up sessions! They give you worksheets with practice problems that aren't in the book, and the TA teaches everything in detail :).
by Sabrina Ryu 3L
Wed Dec 05, 2018 4:37 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing power precedence
Replies: 1
Views: 66

Re: Polarizing power precedence

I think charge is more important! However, when the elements are in very close proximity it is difficult to discern which has a greater effect, as the one with larger size and smaller charge will have similar polarizing power as the one with smaller size and larger charge.
by Sabrina Ryu 3L
Wed Nov 28, 2018 3:09 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted, Arrhenious, or Lewis?
Replies: 2
Views: 38

Bronsted, Arrhenious, or Lewis?

Which of the definitions of acids and bases (Bronsted, Arrhenious, or Lewis) will we be most commonly using within this class?
by Sabrina Ryu 3L
Wed Nov 28, 2018 3:07 pm
Forum: Naming
Topic: Naming Coordination Compounds
Replies: 9
Views: 139

Naming Coordination Compounds

Do we just have to memorize all of the common ligand names? Or will it be provided to us?
by Sabrina Ryu 3L
Wed Nov 28, 2018 3:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Identifying intermolecular forces
Replies: 4
Views: 65

Re: Identifying intermolecular forces

Intermolecular forces depend on the polarity of the molecules! Dipole-dipole forces are intermolecular forces between polar molecules, while induced-dipole-induced-dipole forces are between nonpolar molecules.
by Sabrina Ryu 3L
Tue Nov 20, 2018 12:55 pm
Forum: Hybridization
Topic: Identifying types of bonds and hybridization in Lewis Structures
Replies: 3
Views: 57

Re: Identifying types of bonds and hybridization in Lewis Structures

I think you should have awareness of sigma and pi bonds and be able to label these bonds whether it be N2sp3--H1s or otherwise.
by Sabrina Ryu 3L
Tue Nov 20, 2018 12:50 pm
Forum: Sigma & Pi Bonds
Topic: sigma and pi bonds
Replies: 5
Views: 88

sigma and pi bonds

How exactly are sigma and pi bonds different? And could someone explain the different configurations of the bonding?
by Sabrina Ryu 3L
Tue Nov 20, 2018 12:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Memorization
Replies: 4
Views: 63

Re: Memorization

Molecular shape determination can be reasoned out by first drawing the Lewis structure and then considering the repulsion of valence electrons and lone pairs. The names of molecular shapes do have to be memorized though.
by Sabrina Ryu 3L
Thu Nov 15, 2018 2:13 pm
Forum: Lewis Structures
Topic: Maximum amount of bonds
Replies: 5
Views: 92

Re: Maximum amount of bonds

An element has too many bonds when the formal charge is unreasonably high. It should be relatively close to zero.
by Sabrina Ryu 3L
Thu Nov 15, 2018 2:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Shapes
Replies: 4
Views: 45

Re: Trigonal Shapes

Trigonal planar is flat while trigonal pyramidal is bent! This is because a molecule with trigonal pyramidal shape has a lone pair that repels the other three atoms bonded to the central atom. Trigonal planar molecules have a bond angle of 120 degrees because 360/3 = 120. However, trigonal pyramidal...
by Sabrina Ryu 3L
Thu Nov 15, 2018 2:06 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 10
Views: 239

Re: Formal Charge

Formal charge is important in determining the Lewis Structure, which then allows us to determine the VSEPR model and the molecular shape!
by Sabrina Ryu 3L
Thu Nov 08, 2018 12:55 am
Forum: Bond Lengths & Energies
Topic: Lone Pairs and Bond Strengths
Replies: 2
Views: 41

Re: Lone Pairs and Bond Strengths

Lone pairs make the bond strength in a single molecule weaker as well, because the lone pairs repel each other!
by Sabrina Ryu 3L
Thu Nov 08, 2018 12:52 am
Forum: Administrative Questions and Class Announcements
Topic: Test during Thanksgiving Week?
Replies: 2
Views: 79

Test during Thanksgiving Week?

Hi, I noticed that there is a test scheduled for Thanksgiving week during discussion, but there is no class during those days. Is the syllabus right? Am I missing something
by Sabrina Ryu 3L
Thu Nov 08, 2018 12:48 am
Forum: Bond Lengths & Energies
Topic: Special Bond Length Rules
Replies: 3
Views: 71

Re: Special Bond Length Rules

I do not believe so! As number of bonds increases, bond length decreases due to a stronger attraction.
by Sabrina Ryu 3L
Wed Oct 31, 2018 6:27 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron removal from orbitals question
Replies: 3
Views: 87

Re: Electron removal from orbitals question

It is better to remove from the 4s orbital because it is the outermost shell. 3d is of higher energy, but 4s is still the outermost, or valence, shell.
by Sabrina Ryu 3L
Wed Oct 31, 2018 6:20 pm
Forum: Octet Exceptions
Topic: Max # of bonds
Replies: 4
Views: 116

Re: Max # of bonds

Theoretically you could form 9 bonds, but I do not know how likely it would be, especially because atoms in molecules like to maintain a formal charge closest to zero.
by Sabrina Ryu 3L
Wed Oct 31, 2018 6:16 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions for the Building-Up principle
Replies: 1
Views: 52

Re: Exceptions for the Building-Up principle

The exceptions to the building up principle have to do with the d block. For elements that would have "_d4 _s2" become "_d5 _s2" according to whatever period it is in. This is because five electrons, one in each sub shell for d orbital is more stable and has lower energy than 2 e...
by Sabrina Ryu 3L
Thu Oct 25, 2018 1:15 am
Forum: Properties of Light
Topic: b15
Replies: 2
Views: 104

Re: b15

Hi, 1.66x106^-17J is the work function! So it is following the equation (1/2)mv^2 = hv - (work function). It is just rearranged so you can find the energy (hv).
by Sabrina Ryu 3L
Thu Oct 25, 2018 1:13 am
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 96
Views: 30425

Re: Advice from a Medical Student [ENDORSED]

Hi! I wanted to know which of the review/Q&A sessions helped the most? Was it office hours? step up sessions? I wanted to go to multiple but it was overwhelming to even decide which to go to.
by Sabrina Ryu 3L
Thu Oct 25, 2018 1:04 am
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 6
Views: 124

Re: Ionization Energy

I think you mean nitrogen and oxygen? That is one of the exceptions to the ionization energies increasing from left to right, because oxygen is in group 16 and nitrogen is in group 15. This is because the electron configuration of nitrogen is more stable, because all of the p orbitals only have one ...
by Sabrina Ryu 3L
Tue Oct 16, 2018 5:15 pm
Forum: Trends in The Periodic Table
Topic: Homework
Replies: 10
Views: 162

Re: Homework

Nope! You can choose any seven questions from the section for homework.
by Sabrina Ryu 3L
Tue Oct 16, 2018 5:07 pm
Forum: Administrative Questions and Class Announcements
Topic: Points
Replies: 4
Views: 80

Re: Points

Posting three times during a day is the same amount of points as posting throughout the week! You just need to have three by the end of the week.
by Sabrina Ryu 3L
Tue Oct 16, 2018 5:06 pm
Forum: Properties of Electrons
Topic: electromagnetic radiation
Replies: 3
Views: 56

Re: electromagnetic radiation

The photoelectric effect supports the idea that electromagnetic radiation has particle-like qualities, because a certain packet of energy (photons) is necessary to eject electrons of an atom, meaning EM radiation is quantized. If electrons were only wavelike, it would be a continuous spectrum.
by Sabrina Ryu 3L
Wed Oct 10, 2018 1:10 am
Forum: General Science Questions
Topic: Rydberg Equation n
Replies: 1
Views: 180

Re: Rydberg Equation n

The differing energy levels depends on which series of the electromagnetic spectrum you are using! When the question asks about the visible light spectrum, you are using the Balmer series, where n1 = 2. Otherwise, when asked about the ultraviolet part of the spectrum, you are using the Lyman series,...
by Sabrina Ryu 3L
Wed Oct 10, 2018 12:59 am
Forum: Properties of Light
Topic: Light acts as a wave or not?
Replies: 10
Views: 113

Re: Light acts as a wave or not?

Light does act as both a wave and a particle! On Monday's lecture we focused on the particle aspect while talking about the photoelectric effect, black bodies, and atomic spectra. However, if you read the book there are more details about the wave aspect of light, including diffraction and the Schro...
by Sabrina Ryu 3L
Wed Oct 10, 2018 12:51 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Periodic Table
Replies: 3
Views: 132

Re: Periodic Table

I also heard that you should use the full number given to you on the periodic table. During lecture, Lavelle also said that you shouldn't round until the very end, so you should use the full values that you calculate whether it be grams, moles, etc.
by Sabrina Ryu 3L
Wed Oct 03, 2018 12:17 am
Forum: Balancing Chemical Reactions
Topic: Mole Ratios & Stoichiometric Relations
Replies: 2
Views: 84

Re: Mole Ratios & Stoichiometric Relations

I believe that molar ratios and stoichiometric ratios are synonymous. They describe the ratio between the number of moles of compounds in a chemical equation.
by Sabrina Ryu 3L
Wed Oct 03, 2018 12:14 am
Forum: Empirical & Molecular Formulas
Topic: MOLAR MASS
Replies: 1
Views: 74

Re: MOLAR MASS

In this problem, "M" is an unknown metal, but we know that M(OH)2 has a molar mass of 74.10 g/mol. Thus, we can subtract the molar mass of the OH portions of the molecule (17.01*2 g/mol) to get 40.08 g/mol of metal "M." We know that "M" has a charge of +2, because it bo...
by Sabrina Ryu 3L
Wed Oct 03, 2018 12:00 am
Forum: Molarity, Solutions, Dilutions
Topic: Question G25 in 6th edition [ENDORSED]
Replies: 2
Views: 80

Re: Question G25 in 6th edition [ENDORSED]

In order to find how many molecules remain after 90 doublings, you first have to calculate how many molecules are in the 10mL of solution: .010 mL x (0.10 mol/L) x (6.022*10^23 molecules/1mol) = 6.0 x 10^20 molecules. Then, you could set up an exponential formula: 6.0 x 10^22 molecules x (0.5^n)= # ...

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