Search found 30 matches
- Wed Dec 05, 2018 4:45 pm
- Forum: Hybridization
- Topic: Radical Placement
- Replies: 3
- Views: 438
Re: Radical Placement
The radical goes on the element that would have the formal charge closest to zero when the electron is added!
- Wed Dec 05, 2018 4:38 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Modules
- Replies: 3
- Views: 545
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 :).
- Wed Dec 05, 2018 4:37 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizing power precedence
- Replies: 1
- Views: 478
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.
- Wed Nov 28, 2018 3:09 pm
- Forum: Bronsted Acids & Bases
- Topic: Bronsted, Arrhenious, or Lewis?
- Replies: 2
- Views: 328
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?
- Wed Nov 28, 2018 3:07 pm
- Forum: Naming
- Topic: Naming Coordination Compounds
- Replies: 9
- Views: 1103
Naming Coordination Compounds
Do we just have to memorize all of the common ligand names? Or will it be provided to us?
- Wed Nov 28, 2018 3:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Identifying intermolecular forces
- Replies: 4
- Views: 604
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.
- Tue Nov 20, 2018 12:55 pm
- Forum: Hybridization
- Topic: Identifying types of bonds and hybridization in Lewis Structures
- Replies: 3
- Views: 508
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.
- Tue Nov 20, 2018 12:50 pm
- Forum: Sigma & Pi Bonds
- Topic: sigma and pi bonds
- Replies: 5
- Views: 606
sigma and pi bonds
How exactly are sigma and pi bonds different? And could someone explain the different configurations of the bonding?
- Tue Nov 20, 2018 12:46 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Memorization
- Replies: 4
- Views: 431
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.
- Thu Nov 15, 2018 2:13 pm
- Forum: Lewis Structures
- Topic: Maximum amount of bonds
- Replies: 5
- Views: 632
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.
- Thu Nov 15, 2018 2:10 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Trigonal Shapes
- Replies: 4
- Views: 621
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...
- Thu Nov 15, 2018 2:06 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge
- Replies: 10
- Views: 1697
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!
- Thu Nov 08, 2018 12:55 am
- Forum: Bond Lengths & Energies
- Topic: Lone Pairs and Bond Strengths
- Replies: 2
- Views: 363
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!
- Thu Nov 08, 2018 12:52 am
- Forum: Administrative Questions and Class Announcements
- Topic: Test during Thanksgiving Week?
- Replies: 2
- Views: 351
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
- Thu Nov 08, 2018 12:48 am
- Forum: Bond Lengths & Energies
- Topic: Special Bond Length Rules
- Replies: 3
- Views: 455
Re: Special Bond Length Rules
I do not believe so! As number of bonds increases, bond length decreases due to a stronger attraction.
- Wed Oct 31, 2018 6:27 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron removal from orbitals question
- Replies: 3
- Views: 384
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.
- Wed Oct 31, 2018 6:20 pm
- Forum: Octet Exceptions
- Topic: Max # of bonds
- Replies: 4
- Views: 467
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.
- Wed Oct 31, 2018 6:16 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions for the Building-Up principle
- Replies: 1
- Views: 275
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...
- Thu Oct 25, 2018 1:15 am
- Forum: Properties of Light
- Topic: b15
- Replies: 2
- Views: 400
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).
- Thu Oct 25, 2018 1:13 am
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 463865
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.
- Thu Oct 25, 2018 1:04 am
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy
- Replies: 6
- Views: 1750
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 ...
- Tue Oct 16, 2018 5:15 pm
- Forum: Trends in The Periodic Table
- Topic: Homework
- Replies: 10
- Views: 763
Re: Homework
Nope! You can choose any seven questions from the section for homework.
- Tue Oct 16, 2018 5:07 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Points
- Replies: 4
- Views: 459
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.
- Tue Oct 16, 2018 5:06 pm
- Forum: Properties of Electrons
- Topic: electromagnetic radiation
- Replies: 3
- Views: 410
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.
- Wed Oct 10, 2018 1:10 am
- Forum: General Science Questions
- Topic: Rydberg Equation n
- Replies: 1
- Views: 461
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,...
- Wed Oct 10, 2018 12:59 am
- Forum: Properties of Light
- Topic: Light acts as a wave or not?
- Replies: 10
- Views: 684
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...
- Wed Oct 10, 2018 12:51 am
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Periodic Table
- Replies: 3
- Views: 386
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.
- Wed Oct 03, 2018 12:17 am
- Forum: Balancing Chemical Reactions
- Topic: Mole Ratios & Stoichiometric Relations
- Replies: 2
- Views: 356
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.
- Wed Oct 03, 2018 12:14 am
- Forum: Empirical & Molecular Formulas
- Topic: MOLAR MASS
- Replies: 1
- Views: 303
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...
- Wed Oct 03, 2018 12:00 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Question G25 in 6th edition [ENDORSED]
- Replies: 2
- Views: 183
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)= # ...