Search found 46 matches
- Sat Dec 08, 2018 8:40 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: Boiling Points
- Replies: 1
- Views: 448
Re: Boiling Points
Several factors go into it. Usually, whatever has the weaker intermolecular forces will have the lower boiling point. For example, if comparing two molecules and one is capable of hydrogen bonding, that one will have the higher boiling point. If one is capable of dipole-dipole interactions and the o...
- Sat Dec 08, 2018 8:34 pm
- Forum: Naming
- Topic: Dien - polydentate
- Replies: 1
- Views: 268
Re: Dien - polydentate
dien is tridentate
- Sat Dec 08, 2018 8:32 pm
- Forum: Naming
- Topic: Shorthands
- Replies: 2
- Views: 334
Re: Shorthands
The shorthand should be used within the formulas so as not to write out the long formula for ethylenediamine, etc, not as a substitute for the name itself.
- Sat Dec 08, 2018 8:30 pm
- Forum: Ionic & Covalent Bonds
- Topic: ionic and covalent bonds
- Replies: 5
- Views: 647
Re: ionic and covalent bonds
Electronegativity and electron affinity are basically the same thing, so yes
- Sat Dec 08, 2018 8:28 pm
- Forum: Hybridization
- Topic: Hybridization of atoms other than the central atom
- Replies: 2
- Views: 554
- Sat Dec 08, 2018 8:25 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Shape - 4
- Replies: 3
- Views: 409
Re: Shape - 4
Just know it can be either. I wouldn't be surprised if you get full points for only listing one or the other, but better be safe than sorry.
- Sat Dec 08, 2018 8:23 pm
- Forum: Ionic & Covalent Bonds
- Topic: boiling point
- Replies: 3
- Views: 565
Re: boiling point
Several factors go into it. Usually, whatever has the weaker intermolecular forces will have the lower boiling point. For example, if comparing two molecules and one is capable of hydrogen bonding, that one will have the higher boiling point. If one is capable of dipole-dipole interactions and the o...
- Sat Dec 08, 2018 8:19 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: geometry
- Replies: 1
- Views: 229
Re: geometry
They can be atoms too. For example: Cl-
- Sat Dec 08, 2018 8:18 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: 6 Regions of electon density
- Replies: 1
- Views: 293
Re: 6 Regions of electon density
Square planar.
- Sat Dec 08, 2018 8:16 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Radicals
- Replies: 2
- Views: 342
Re: Radicals
Radicals are unpaired electrons that are highly reactive and exist only for short periods of time. One way something becomes a radical is if one electron in a pair is ripped away by another molecule.
- Wed Dec 05, 2018 11:02 am
- Forum: Sigma & Pi Bonds
- Topic: Identifying sigma & pi bonds
- Replies: 4
- Views: 875
Re: Identifying sigma & pi bonds
Yes, double bonds contain one sigma bond and one pi bond
- Mon Dec 03, 2018 11:08 am
- Forum: Lewis Acids & Bases
- Topic: Acid/Super Acid & Base/Super Base
- Replies: 2
- Views: 581
Re: Acid/Super Acid & Base/Super Base
A superacid is any acid stronger/ more acidic than pure sulfuric acid. Similarly, superbases are bases with extremely high basicity.
- Sat Dec 01, 2018 6:44 pm
- Forum: Lewis Acids & Bases
- Topic: Difference between Lewis and Bronsted
- Replies: 5
- Views: 591
Difference between Lewis and Bronsted
What's the difference between Lewis acids and bases and Bronsted acids and bases? Which do we work with more in this class? Is there a lot of overlap between the two, or any specific things that don't overlap?
- Sat Dec 01, 2018 6:41 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Water molecules
- Replies: 9
- Views: 923
Water molecules
Do water molecules form only one hydrogen bond with another water molecule? Or does it use both its hydrogens, forming two separate hydrogen bonds with two other water molecules?
- Sat Dec 01, 2018 6:36 pm
- Forum: Naming
- Topic: questions about 9C.3 7th edition
- Replies: 1
- Views: 265
Re: questions about 9C.3 7th edition
OH2 and H20 are interchangeable and refer to the same compound.
- Sat Dec 01, 2018 6:33 pm
- Forum: Naming
- Topic: 9C.1 7th edition alphabetical order when naming
- Replies: 2
- Views: 335
Re: 9C.1 7th edition alphabetical order when naming
The ligand names should be in alphabetical order.
- Tue Nov 27, 2018 3:57 pm
- Forum: Coordinate Covalent Bonds
- Topic: Difference between coordinate covalent and covalent bond
- Replies: 6
- Views: 9868
Re: Difference between coordinate covalent and covalent bond
All coordinate covalent bonds are covalent bonds, but not all covalent bonds are coordinate covalent, if that makes sense. Coordinate covalent bonds are a type of covalent bond where both electrons involved in forming the bond are originally from one of the interacting atoms or molecules, whereas us...
- Tue Nov 27, 2018 3:51 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: maximizing dipole interactions
- Replies: 1
- Views: 254
Re: maximizing dipole interactions
Because dipoles with opposite charges attract each other, like a magnet. On the other hand, two dipoles with the same charge will repel each other, which would lead to weak interactions between the dipoles
- Tue Nov 27, 2018 3:48 pm
- Forum: Lewis Structures
- Topic: Complicated Lewis Structures
- Replies: 3
- Views: 337
Re: Complicated Lewis Structures
I struggle with this too, and I've found that double checking the formal charges helps me a lot.
- Tue Nov 20, 2018 6:20 pm
- Forum: Lewis Structures
- Topic: Midterm question
- Replies: 8
- Views: 663
Re: Midterm question
You could either take the average, or simply say less than 140 but more than 120 pm. Both were taken as correct answers
- Tue Nov 20, 2018 6:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 3
- Replies: 10
- Views: 962
Re: Test 3
Both outlines 3 and 4!
- Sun Nov 18, 2018 5:29 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: molecular shape and bond angles
- Replies: 3
- Views: 371
Re: molecular shape and bond angles
When there are lone pairs involved in the molecule, the resulting bond angles will usually be "less than" a specific number, and we don't have to memorize the actual values specifically.
- Thu Nov 15, 2018 10:36 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Effect of Molecular Shape on Lewis Structure
- Replies: 3
- Views: 350
Re: Effect of Molecular Shape on Lewis Structure
Not really, Lewis structures are 2-dimensional models and thus couldn't perfectly represent a 3-dimensional molecular shape.
- Thu Nov 15, 2018 10:34 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Repulsion Strength
- Replies: 5
- Views: 479
Re: Repulsion Strength
Basically the degree to which electron lone pairs or bonding pairs repel other lone pairs or bonding pairs, contributing to the overall shape of the molecule. Higher repulsion means the electrons "want to be alone," and thus repel other electrons to a greater degree, sometimes even forcing...
- Tue Nov 13, 2018 12:48 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Thanksgiving Wednesday
- Replies: 9
- Views: 850
Re: Thanksgiving Wednesday
michellebui_3L wrote:Does anybody know how we will turn in homework for Week 8 if we have discussion on Thurs/Fri?
We will turn it in week 9!
- Tue Nov 06, 2018 7:14 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Thanksgiving Wednesday
- Replies: 9
- Views: 850
Thanksgiving Wednesday
I know the Wednesday before Thanksgiving break (the day before break officially starts) a lot of professors decide to cancel lecture. Does anyone know if we will have lecture in this class on that Wednesday or if we will have it off? I need to make travel arrangements.
- Tue Nov 06, 2018 1:36 pm
- Forum: Lewis Structures
- Topic: Parenthesis for Ions' Lewis Structures
- Replies: 2
- Views: 376
Re: Parenthesis for Ions' Lewis Structures
It is a necessary step, and if on a test you were to leave off the brackets and charge in your answer you would likely be docked points. It also helps when drawing the lewis structure of a salt which contains two or more ions, since the different ions must be separated by brackets to obtain the corr...
- Tue Nov 06, 2018 1:32 pm
- Forum: Lewis Structures
- Topic: Lewis Structure for NO2
- Replies: 3
- Views: 352
Re: Lewis Structure for NO2
It's because O is more electronegative. Also, usually when there is one of one element and multiple of another, the unique element is in the center (though not always, it's just a trend).
- Wed Oct 31, 2018 7:32 am
- Forum: Formal Charge and Oxidation Numbers
- Topic: Finding the lowest energy structure
- Replies: 5
- Views: 599
Re: Finding the lowest energy structure
Calculating and comparing formal charges is the best way to determine the most stable structure!
- Wed Oct 31, 2018 7:29 am
- Forum: Lewis Structures
- Topic: Stable Lewis Structures
- Replies: 4
- Views: 368
Re: Stable Lewis Structures
Whichever structure gives the most possible atoms a formal charge of 0, or closest to 0!
- Wed Oct 31, 2018 7:26 am
- Forum: Lewis Structures
- Topic: Lewis Structures
- Replies: 2
- Views: 316
Re: Lewis Structures
Lines represent shared or bonded electrons, while dots are used when an electron is unbonded: a "lone pair"
- Tue Oct 23, 2018 12:56 pm
- Forum: Student Social/Study Group
- Topic: Studying for tests/midterm
- Replies: 18
- Views: 2670
Re: Studying for tests/midterm
I just do all the homework problems at least once, then look over them again in the days leading up to the test. Prof. Lavelle says that if you do all the homework problems you should be well-prepared for the test.
- Tue Oct 23, 2018 12:54 pm
- Forum: Administrative Questions and Class Announcements
- Topic: test 2
- Replies: 5
- Views: 681
Re: test 2
Prof. Lavelle also has the outline for the test on his website so you can see everything that will be covered in test 2.
- Tue Oct 23, 2018 12:52 pm
- Forum: Properties of Light
- Topic: Power calculations
- Replies: 6
- Views: 827
Re: Power calculations
I sometimes have this same problem, and for me I've discovered it usually has to do with not converting everything to the right units before calculating. For instance leaving something as grams when it should be kilograms can lead to the right number answer except with the wrong power.
- Fri Oct 12, 2018 11:28 pm
- Forum: Properties of Electrons
- Topic: Wave Particles Duality of Matter
- Replies: 4
- Views: 311
Re: Wave Particles Duality of Matter
Constructive inference is when two waves interact "in phase," or when their peaks line up together and their troughs line up together. this results in a combined wave of greater amplitude. Think of an ocean wave, if two little waves combine they make a bigger wave. Conversely, destructive ...
- Fri Oct 12, 2018 6:12 pm
- Forum: Properties of Light
- Topic: Electromagnetic Spectrum: Colors
- Replies: 3
- Views: 262
Re: Electromagnetic Spectrum: Colors
There aren't clear-cut boundaries between specific colors; but rather, they overlap and blend together. So, 500 nm would be blue-green, or a sort of teal color. Other colors on the spectrum might be mostly blue but a little green, or mostly green but a little blue. And people might classify colors d...
- Fri Oct 12, 2018 6:06 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect
- Replies: 2
- Views: 297
Re: Photoelectric Effect
If 1 million high energy photons hit a metal surface, the maximum amount of electrons that could be ejected would be 1 million electrons, not .5 million. This is because the ratio of incoming photons to ejected electrons is 1:1, provided that each of the photons has a high enough energy to cause the...
- Fri Oct 12, 2018 6:01 pm
- Forum: DeBroglie Equation
- Topic: "Wave-like Properties" of Matter
- Replies: 6
- Views: 242
Re: "Wave-like Properties" of Matter
In lecture he said that the cutoff for wavelength isn't really an exact number, though the wavelength value he suggested as the cutoff was about 10^-18 or greater. He also said that he wouldn't test us on questions that are close to the cut off value; if the wavelength is too small it will be by a l...
- Mon Oct 08, 2018 12:19 am
- Forum: SI Units, Unit Conversions
- Topic: Fahrenheit, Celsius, Kelvin
- Replies: 3
- Views: 516
Re: Fahrenheit, Celsius, Kelvin
Basically, the US (as well as Myanmar and Liberia) are the only countries that still use the imperial system for measurements, including Fahrenheit. Fahrenheit started as a British colonial measurement hundreds of years ago, but by now both the UK and all of its former colonies (except the US) have ...
- Mon Oct 08, 2018 12:03 am
- Forum: Significant Figures
- Topic: Formula sheet?
- Replies: 5
- Views: 605
Re: Formula sheet?
I think we just get a periodic table and the scientific constants, not formulas.
- Sun Oct 07, 2018 11:33 pm
- Forum: Limiting Reactant Calculations
- Topic: Question M3
- Replies: 3
- Views: 318
Re: Question M3
If only one reactant mass is given, you can assume that that is the limiting reactant. Otherwise, you will need to test to see which reactant is limiting :)
- Thu Oct 04, 2018 8:27 pm
- Forum: Significant Figures
- Topic: Decimal point
- Replies: 14
- Views: 831
Re: Decimal point
Yukta Italia 3I wrote:Does that mean 120. has 3 sig figs and 120 has two sig figs?
Yes!
- Thu Oct 04, 2018 12:04 pm
- Forum: Empirical & Molecular Formulas
- Topic: Polyatomic Ions
- Replies: 1
- Views: 193
Polyatomic Ions
Should we have all the common polyatomic ions memorized? Or will we be given that information when needed? If we do need it memorized, does anyone have any tricks to remember them more easily?
- Thu Oct 04, 2018 12:00 am
- Forum: Significant Figures
- Topic: Decimal point
- Replies: 14
- Views: 831
Re: Decimal point
If it had been 120 instead of 125, for example, 120 is only two significant figures while 120. is three. It has to do with zeroes at the end of numbers
- Sun Sep 30, 2018 9:45 pm
- Forum: SI Units, Unit Conversions
- Topic: Grams/mole
- Replies: 12
- Views: 1117
Grams/mole
In some places I see grams per mole written as (g/mol) and other places as (g.mol^-1). I'm pretty sure they mean the same thing but I just want to confirm? Also is there a reason to use one notation rather than the other?
- Sun Sep 30, 2018 2:15 pm
- Forum: General Science Questions
- Topic: First Homework
- Replies: 3
- Views: 284
Re: First Homework
During Friday's Lecture (Week 1)