Search found 45 matches

by HanaAwad_4B
Mon Dec 02, 2019 12:42 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Explain VSEPR conceptually
Replies: 12
Views: 55

Re: Explain VSEPR conceptually

VSEPR gives us three-dimensional geometry. This is important because it helps us know whether a molecule is polar or nonpolar
by HanaAwad_4B
Mon Dec 02, 2019 12:40 am
Forum: Sigma & Pi Bonds
Topic: Sigma vs. Pi
Replies: 15
Views: 110

Re: Sigma vs. Pi

Because of the overlap, sigma bonds are stronger. They are also more flexible, where pi bonds are more rigid.
by HanaAwad_4B
Mon Dec 02, 2019 12:38 am
Forum: Determining Molecular Shape (VSEPR)
Topic: T-shape
Replies: 21
Views: 103

Re: T-shape

T-shape has two lone pairs and 3 bonded pairs; the geometry is trigonal bipyramidal
by HanaAwad_4B
Mon Dec 02, 2019 12:36 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Cis vs Trans
Replies: 21
Views: 145

Re: Cis vs Trans

Cis molecules are polar because the molecules are arranged in a way where the geometry does not cancel out. Trans molecules are nonpolar
by HanaAwad_4B
Mon Dec 02, 2019 12:29 am
Forum: Bronsted Acids & Bases
Topic: Final
Replies: 13
Views: 81

Re: Final

This is a cumulative final, so it includes everything from the beginning of the Quarter, including fundamentals
by HanaAwad_4B
Sat Nov 23, 2019 9:08 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: Problem 3F10 b
Replies: 6
Views: 45

Re: Problem 3F10 b

Because SiF4 is nonpolar, it has lower intermolecular forces than Si2F2 which is polar.
by HanaAwad_4B
Wed Nov 20, 2019 9:43 am
Forum: Hybridization
Topic: Ring Structure
Replies: 2
Views: 25

Re: Ring Structure

Yes, there are still lone pairs even if you can't see them. That is the organic chemistry short hand.
by HanaAwad_4B
Sat Nov 16, 2019 11:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: axial vs equitorial
Replies: 3
Views: 28

axial vs equitorial

I'm kind of confused on the difference between axial and equatorial and what we need to know about them. Thank you!
by HanaAwad_4B
Sat Nov 16, 2019 11:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 3
Views: 26

Re: Polarity

Initially, you should have a pretty good idea as to whether or not a molecule is polar based on electronegativity differences, however polar bonds can be canceled out by geometry. To be sure, I always draw the lewis structure because it helps me, but if you are confident without drawing it than that...
by HanaAwad_4B
Sat Nov 16, 2019 11:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Conceptual/Calculation Questions
Replies: 1
Views: 13

Re: Conceptual/Calculation Questions

Because there aren't many things you can calculate in this section, I'm fairly confident that the questions will be mainly conceptual. That being said, the tests are usually easier than the midterms, but I don't think it will be easier or as easy as test one. My advice is to just study your notes an...
by HanaAwad_4B
Sat Nov 16, 2019 11:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR notation
Replies: 8
Views: 60

Re: VSEPR notation

The notation would be AX3 because there are three atoms attached to Nitrogen in the Lewis structure. The amount of bonds does not really matter, but the amount of atoms surrounding the central atom is relevant. The geometry is trigonal planar.
by HanaAwad_4B
Sat Nov 16, 2019 10:59 pm
Forum: Dipole Moments
Topic: 3F15
Replies: 2
Views: 31

Re: 3F15

AsF3 is not polar because even though there are dipole moments, the geometry cancels out. Polar molecules have higher boiling points than nonpolar molecules.
by HanaAwad_4B
Sat Nov 16, 2019 10:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 4
Views: 20

Re: VSEPR

Approach this molecule as if there are two separate molecules. One of the Carbons is attached to another Carbon along with two Hydrogens. This makes that part of the molecule trigonal planar with a bond angle of 120 degrees. The bond angle between the two carbons is 180 degrees.
by HanaAwad_4B
Thu Nov 07, 2019 8:26 pm
Forum: Ionic & Covalent Bonds
Topic: coordinate covalent bond
Replies: 2
Views: 14

Re: coordinate covalent bond

A coordinate covalent bond is a bond formed between a Lewis Acid and a Lewis Base. A lewis acid (usually elements like Boron and Aluminum whose full shell consists of 6 not 8 electrons) accepts electrons from a lewis base. The base donates two electrons opposed to just one to form a bond. By doing s...
by HanaAwad_4B
Thu Nov 07, 2019 8:20 pm
Forum: Lewis Acids & Bases
Topic: Acid Base
Replies: 1
Views: 20

Re: Acid Base

Yes. When you have a Lewis acid and a Lewis Base you form a molecule comprised of at least one coordinate covalent compound.
by HanaAwad_4B
Thu Nov 07, 2019 8:18 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rhydberg Equations
Replies: 1
Views: 30

Re: Rhydberg Equations

They are the same thing. The first equation you listed is just a simplified version of the second equation; it is useful because you can just plug in your values and get your answer essentially in one step. Professor Lavelle said he doesn't really like the equation though because he feels as though ...
by HanaAwad_4B
Thu Nov 07, 2019 8:14 pm
Forum: Lewis Acids & Bases
Topic: lewis acid vs base
Replies: 2
Views: 22

Re: lewis acid vs base

Only some compounds have Lewis Acids and Bases. Usually elements like Boron, Aluminum etc. are lewis acids because they don't follow the octet rule and only have 6 electrons in total (opposed to 8). When this happens, another element will donate two of their electrons to the bond instead of just one...
by HanaAwad_4B
Thu Nov 07, 2019 8:05 pm
Forum: Bond Lengths & Energies
Topic: bond length rules
Replies: 2
Views: 18

Re: bond length rules

There is only one exception and that is when there is resonance. In resonance structures, though it appears as though some of the bonds are double bonds and some are single bonds, in reality, the bond lengths are all the same length and have the same strength-- the length is the average of the lengt...
by HanaAwad_4B
Sat Nov 02, 2019 9:59 pm
Forum: Ionic & Covalent Bonds
Topic: The Lewis structure for the chlorite ion ClO2- (Cl atom, 2 oxygen atoms, and one negative charge)
Replies: 1
Views: 14

Re: The Lewis structure for the chlorite ion ClO2- (Cl atom, 2 oxygen atoms, and one negative charge)

When I do Lewis structures, what works for me is not looking at what each atom is contributing, but rather looking at the total amount of valence electrons as a whole. Yes, you are right in thinking that Oxygen usually has two bonds and that results in the oxygen having a formal charge of 0. However...
by HanaAwad_4B
Sat Nov 02, 2019 9:47 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: periodic trends
Replies: 2
Views: 30

Re: periodic trends

There is, but it depends if you are analyzing the anion or the cation. When analyzing the cation, smaller atomic radius + higher charged cations have a higher polarizing power. This is because they have a stronger pull on the electrons of the anion they are bonding with. When looking at the anion, l...
by HanaAwad_4B
Sat Nov 02, 2019 9:19 pm
Forum: Resonance Structures
Topic: Drawing Resonance Structures
Replies: 3
Views: 37

Re: Drawing Resonance Structures

If a structure has resonance, you should probably draw it because the actual representation of the molecule is the average of all lewis structures. Thus, it is not correct to include only one form of the Lewis structure because it is not a completely accurate representation of the molecule. Though t...
by HanaAwad_4B
Sat Nov 02, 2019 9:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions in electronic configurations?
Replies: 3
Views: 24

Re: Exceptions in electronic configurations?

The exceptions to electron configurations are Chromium and Copper. Basically, in these two elements, you do not fill up the 4s shell first. Instead, you put one electron into the 4s shell and then move on to the 3d shell. So Cr's electron configuration is [Ar] 3d5 4s1 and Cu is [Ar] 3d10 4s1. The wa...
by HanaAwad_4B
Sat Nov 02, 2019 9:01 pm
Forum: Octet Exceptions
Topic: 2a9d???
Replies: 2
Views: 21

Re: 2a9d???

Exceptions to the octet include: H, He, Li, Be, B, and anything after the first two rows of the periodic table. The octet rule does not really apply to the majority of the periodic table. Because Br is after the second row of the periodic table, it usually has more than 8 electrons when it is the ce...
by HanaAwad_4B
Sun Oct 27, 2019 3:56 pm
Forum: Ionic & Covalent Bonds
Topic: 2A.5
Replies: 2
Views: 19

2A.5

When I was trying to write the electron configuration for Bi^3+ I did not know why the answer key included 14f in this configuration. How would I find out what the correct configuration is for Bi^3+?
by HanaAwad_4B
Sun Oct 27, 2019 3:46 pm
Forum: Lewis Structures
Topic: Central Atom
Replies: 2
Views: 31

Re: Central Atom

Lowest Ionization energy means that the atomic radius is larger, thus it is easier to pull the electrons away from the nucleus. For this reason, they are better at bonding with other atoms.
by HanaAwad_4B
Sun Oct 27, 2019 3:43 pm
Forum: Lewis Structures
Topic: Multiple Central Atoms
Replies: 2
Views: 25

Re: Multiple Central Atoms

In molecules like that, the Carbon is almost always going to be the central atom due to how many bonds it can hold (this is also what organic chemistry mainly focuses on-- Carbon molecules). Carbon Molecules can have 4 bonds as it has 4 valence electrons. Oxygen has 6 valence electrons and only need...
by HanaAwad_4B
Sun Oct 27, 2019 3:37 pm
Forum: Ionic & Covalent Bonds
Topic: Resonance
Replies: 10
Views: 72

Re: Resonance

Basically, Lewis structures are an oversimplification of what the molecule actually looks like. There can be multiple ways to draw the same structure (doesn't just have to be three ways, but can be 2+) because the molecule is constantly switching which bonds are double and single. This also explains...
by HanaAwad_4B
Sun Oct 27, 2019 3:28 pm
Forum: Ionic & Covalent Bonds
Topic: Double and single bond lengths
Replies: 6
Views: 35

Re: Double and single bond lengths

Double bonds are stronger and shorter because they share more electrons than single bonds, thus there is a stronger pull between the two atoms that are bonded. A good way to think about this is holding on to a ball with one hand vs with two hands. If you are only holding onto the ball with one hand,...
by HanaAwad_4B
Mon Oct 21, 2019 12:00 am
Forum: Balancing Chemical Reactions
Topic: Combustion
Replies: 17
Views: 219

Re: Combustion

Combustion always results in CO2 and H2O.
by HanaAwad_4B
Sun Oct 20, 2019 11:58 pm
Forum: Balancing Chemical Reactions
Topic: Balancing equations.
Replies: 12
Views: 158

Re: Balancing equations.

Balance what there is less of first. Also, keeping continuous track of what each side has and being organized helps a lot.
by HanaAwad_4B
Sun Oct 20, 2019 11:57 pm
Forum: SI Units, Unit Conversions
Topic: Accuracy vs Precision
Replies: 11
Views: 119

Re: Accuracy vs Precision

Accuracy is how close you are to the actual desired amount. Precision describes more the consistency of your work ethic. You can be precise but still not be accurate as a result of malfunctioning lab equipment.
by HanaAwad_4B
Sun Oct 20, 2019 11:55 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Nodal Planes
Replies: 2
Views: 24

Re: Nodal Planes

Nodal planes are where the probability of finding an electron is 0. You find these areas by using Schrödinger's equation.
by HanaAwad_4B
Sun Oct 20, 2019 11:51 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions in Electron Configurations
Replies: 5
Views: 38

Re: Exceptions in Electron Configurations

The only reason why these configurations do not follow the original rules is that if they did, the energy would not be distributed symmetrically. The d subshell has 5 orbitals that hold 2 electrons each. It helps to think about it visually. Draw out the 5 orbitals for the d shell and fill it in and ...
by HanaAwad_4B
Sun Oct 13, 2019 7:36 pm
Forum: DeBroglie Equation
Topic: Constructive vs. Destructive Interference
Replies: 5
Views: 37

Re: Constructive vs. Destructive Interference

Constructive is when the peaks of two of the waves do not clash, combine, and then result in a larger wavelength. Destructive is when the peaks of two wavelengths do not line up, combine, and result in a smaller wavelength. If the trophs are the same size, they will cancel out completely. I recommen...
by HanaAwad_4B
Sun Oct 13, 2019 7:30 pm
Forum: Administrative Questions and Class Announcements
Topic: Modules
Replies: 3
Views: 23

Modules

I was looking over modules and reached the last one. Will he post more modules or is that it?
by HanaAwad_4B
Sun Oct 13, 2019 7:30 pm
Forum: General Science Questions
Topic: THe mole
Replies: 5
Views: 46

THe mole

Why is the quantity of the mole based on a Carbon atom instead of elements like Oxygen or Nitrogen?
by HanaAwad_4B
Sun Oct 13, 2019 7:27 pm
Forum: Administrative Questions and Class Announcements
Topic: test 1 grades
Replies: 2
Views: 34

test 1 grades

Hi! Does anyone know if and when we will get our first test back? Also, someone told me that he will not put in those grades until the very end of the Quarter. Is that true?
by HanaAwad_4B
Sun Oct 13, 2019 7:26 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1A. 15
Replies: 1
Views: 36

1A. 15

In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line.
Is it possible for me to solve this without using the Rydberg equation?
by HanaAwad_4B
Sat Oct 05, 2019 10:10 pm
Forum: Empirical & Molecular Formulas
Topic: Homework Problem L39
Replies: 2
Views: 60

Re: Homework Problem L39

Just remember that something becomes- ide when it is gaining or losing electrons (when it's an ion).
by HanaAwad_4B
Sat Oct 05, 2019 10:00 pm
Forum: Balancing Chemical Reactions
Topic: Strategies for Balancing Chemical Equations
Replies: 12
Views: 89

Re: Strategies for Balancing Chemical Equations

Something that really helps is staying organized. When I balance my equations, I list every atom that the equation has and how many of each atom there is. For example, if the equation you have to balance is N2 + O2 yields NO I will write down N and O in a vertical line. I will then put the number 2 ...
by HanaAwad_4B
Sat Oct 05, 2019 9:56 pm
Forum: Administrative Questions and Class Announcements
Topic: Week 2 Homework Problems [ENDORSED]
Replies: 67
Views: 1707

Re: Week 2 Homework Problems [ENDORSED]

You can do whatever is relevant to the class. Because we have a test on Tuesday over general chem, we can still submit homework in the fundamentals section.
by HanaAwad_4B
Sat Oct 05, 2019 9:47 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Atoms, Molecules, and Formula Units
Replies: 4
Views: 77

Re: Atoms, Molecules, and Formula Units

You have to think of each of these terms as a unit. Even though molecules have more atoms, they are still joined, thus they are one unit. The same thing applies to formula units. This is why Avogadro's number applies to all of it. An easy way to think of Avogadro's number is the same way to think ab...
by HanaAwad_4B
Wed Oct 02, 2019 11:35 am
Forum: Empirical & Molecular Formulas
Topic: Homework Problem L.39
Replies: 2
Views: 48

Homework Problem L.39

The Question is: a 1.50-gram sample of metallic tin was placed in a 26.45 g crucible and heated until all the tin had reacted with the oxygen in the air to form an oxide. The product weighs 1.9g. a) What is the empirical formula of the oxide? b) Write the name of the oxide. ---- I don't really know ...

Go to advanced search