Search found 29 matches

by Erin Nash - 4G
Thu Dec 06, 2018 3:47 pm
Forum: Biological Examples
Topic: Ligands
Replies: 6
Views: 80

Re: Ligands

A ligand has to be able to form coordinate covalent bonds, so often the molecules will have a lone pair of electrons.
by Erin Nash - 4G
Thu Dec 06, 2018 3:45 pm
Forum: Calculating the pH of Salt Solutions
Topic: Ka Constant
Replies: 4
Views: 54

Re: Ka Constant

Ka is the concentrations of the products over the concentration of the reactants, but I'm not sure if we will need to know how to calculate it.
by Erin Nash - 4G
Thu Dec 06, 2018 3:42 pm
Forum: Bronsted Acids & Bases
Topic: Distinguishing bronsted acids vs bases
Replies: 3
Views: 39

Re: Distinguishing bronsted acids vs bases

A Bronsted acid is one that donates protons and a Bronsted base is one that accepts protons.
by Erin Nash - 4G
Tue Nov 27, 2018 10:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Angle Distorted
Replies: 4
Views: 67

Re: Angle Distorted

Since lone pair - lone pair electron repulsion is stronger than electrons in a bond, the angles are slightly smaller than what is experimentally observed such as for tetrahedral, the bond angles are 109.5, but if there is a lone pair, the bond angle is slightly less than 109.5.
by Erin Nash - 4G
Tue Nov 27, 2018 10:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs. Non-polar
Replies: 6
Views: 81

Re: Polar vs. Non-polar

When deciding whether a molecule is polar or nonpolar you must look at the shape to see the dipoles. If there are no dipoles, then it is nonpolar or if the dipoles cancel out then it is nonpolar. If the dipoles are uneven (large difference in electronegativity) then the molecule is polar.
by Erin Nash - 4G
Tue Nov 27, 2018 10:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma and Pi bonds
Replies: 4
Views: 73

Re: Sigma and Pi bonds

To build off of what other students have answered, sigma bonds are only for single bonds while pi bonds are double bonds and triple bonds. Pi bonds cannot rotate around the bond axis or else the bond will break. A double bonds consists of a sigma bond and a pi bond.
by Erin Nash - 4G
Tue Nov 13, 2018 9:52 am
Forum: Ionic & Covalent Bonds
Topic: London Van Der Waals Force?
Replies: 5
Views: 90

Re: London Van Der Waals Force?

Van der Waals is the force that occurs because as we know, electrons are constantly moving and sometimes their movement can create an slightly more negative charge on one side of the molecule.
by Erin Nash - 4G
Tue Nov 13, 2018 9:50 am
Forum: Lewis Structures
Topic: VSEPR Model
Replies: 6
Views: 112

Re: VSEPR Model

Before, we have just been placing the atoms equally distant from the central atom, but that is not always correct. The VESPR model emphasizes electron repulsion and thus helps us determine what the experimentally observed structure of a molecule is.
by Erin Nash - 4G
Tue Nov 13, 2018 9:49 am
Forum: Resonance Structures
Topic: Drawing resonance
Replies: 17
Views: 235

Re: Drawing resonance

You should always draw the resonance structures because the true structure of the molecule is a mixture of all of the resonance structures.
by Erin Nash - 4G
Sat Nov 10, 2018 5:55 pm
Forum: Dipole Moments
Topic: VSPER
Replies: 8
Views: 75

Re: VSPER

The VSPER model helps explain the shape of molecules that have been determined by experiments. Previously, we have just been drawing the structures without paying much attention to the distance between the atoms, but using the VSPER model we can find the exact angular distance between each atom.
by Erin Nash - 4G
Sat Nov 10, 2018 5:52 pm
Forum: Lewis Structures
Topic: Atoms with 8+ valence e-
Replies: 6
Views: 175

Re: Atoms with 8+ valence e-

Atoms that are in the 4th period and below are the ones that are able to exceed the octet rule because they have access to their 3d orbitals. The energy difference between the 3d and 4s orbital is much smaller in comparison to other orbitals.
by Erin Nash - 4G
Sat Nov 10, 2018 5:51 pm
Forum: Bond Lengths & Energies
Topic: Bond Length and Bond Strength
Replies: 5
Views: 73

Re: Bond Length and Bond Strength

Yes! This is because longer bond lengths (single bonds) are only sharing one pair of electrons and therefore the bond is weaker. Double bonds are sharing two pairs of electrons so they are stronger and the distance between them is shorter.
by Erin Nash - 4G
Sun Nov 04, 2018 4:30 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Midterm
Replies: 3
Views: 75

Re: Midterm

I believe that is all we need to know.
by Erin Nash - 4G
Sun Nov 04, 2018 4:29 pm
Forum: Sigma & Pi Bonds
Topic: What each bond refers to
Replies: 3
Views: 82

Re: What each bond refers to

We will be expected to know how to draw this for the midterm?
by Erin Nash - 4G
Sun Nov 04, 2018 4:28 pm
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bond Definition
Replies: 14
Views: 335

Re: Coordinate Covalent Bond Definition

How can you tell if it is a coordinate covalent bond?
by Erin Nash - 4G
Sun Nov 04, 2018 4:23 pm
Forum: Lewis Structures
Topic: Lewis Structure for Ionic Bonds
Replies: 2
Views: 32

Re: Lewis Structure for Ionic Bonds

For salts, you draw both of the elements separately. An example we did in a review session was (NH4)2CO3 so we drew NH4 and then next to it CO3 with no bonds connecting them.
by Erin Nash - 4G
Mon Oct 22, 2018 3:14 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 5
Views: 52

Re: Electron Configuration

Writing using the inert gases is a short cut to make it easier to write out the electron configuration, since he taught it to us I'm assuming he would accept it as an answer.
by Erin Nash - 4G
Mon Oct 22, 2018 3:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: s, p, d, f subshells in multi-electron atoms
Replies: 6
Views: 100

Re: s, p, d, f subshells in multi-electron atoms

3d always comes before 4s because it is at a lower energy level than 4s.
by Erin Nash - 4G
Mon Oct 22, 2018 3:12 pm
Forum: Administrative Questions and Class Announcements
Topic: Test On Tuesday
Replies: 10
Views: 373

Re: Test On Tuesday

He emphasized once more during lecture today that only material we covered up until Friday will be on the test.
by Erin Nash - 4G
Mon Oct 22, 2018 3:10 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Confused about Copper and Chromium [ENDORSED]
Replies: 2
Views: 58

Re: Confused about Copper and Chromium [ENDORSED]

The reason that the configuration is 3d5 4s1 and not the expected 3d4 4s2, if because in the d shell, there are 5 possible pairs of electrons. According to Hund's principle, an electron must spin parallel, until there are no free orbitals left. Thus, an atom would prefer to have all 5 orbitals fille...
by Erin Nash - 4G
Mon Oct 15, 2018 3:24 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty Principle
Replies: 5
Views: 88

Re: Uncertainty Principle

The Uncertainty Principle states the momentum (delta p) and exact location (delta x) for an electron cannot be known at the same time. Hence the delta symbols indicating a range.
by Erin Nash - 4G
Mon Oct 15, 2018 3:19 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Negative sign in front of Bohr Frequency Condition
Replies: 4
Views: 48

Re: Negative sign in front of Bohr Frequency Condition

The photon energies are always positive, but the negative signs accounts for the bound electron having a lower energy than a free electron.
by Erin Nash - 4G
Mon Oct 15, 2018 3:14 pm
Forum: DeBroglie Equation
Topic: Rest Mass?
Replies: 4
Views: 85

Re: Rest Mass?

An object that has rest mass is an object that's mass can be calculated when it is in rest. He used this in the context of light, since it is never at rest and therefore does not have rest mass.
by Erin Nash - 4G
Mon Oct 15, 2018 3:13 pm
Forum: *Black Body Radiation
Topic: What is a black body? [ENDORSED]
Replies: 7
Views: 468

Re: What is a black body? [ENDORSED]

A black body is a theoretical material that can absorb all wavelengths of light; however, Dr. Lavelle said we didn't need to worry about it.
by Erin Nash - 4G
Mon Oct 15, 2018 3:10 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Incorrect Atomic Model
Replies: 6
Views: 99

Re: Incorrect Atomic Model

We used the Heisenberg Indeterminacy Equation (delta p)(delta x) > or equal to h/4Pi to find our final answer of 3.4 x 10^10 m/s. Our delta x was 1.7 x 10^-15 m and instead of solving for the momentum right away, we had to find the velocity, since the only other information that we know is the mass ...
by Erin Nash - 4G
Mon Oct 15, 2018 3:05 pm
Forum: Properties of Light
Topic: Test 2
Replies: 17
Views: 196

Re: Test 2

I would also recommend completing the Audio-Visual Focus Topics on his website to study if you haven't done them already.
by Erin Nash - 4G
Fri Oct 05, 2018 3:50 pm
Forum: Properties of Light
Topic: Behavior of small objects - clarification
Replies: 3
Views: 48

Re: Behavior of small objects - clarification

From my understanding all that he meant by one discrete H2O was a singular molecule of H2O. However, I was confused on whether or not the flow would be continuous if a single molecule was poured out of and why.
by Erin Nash - 4G
Fri Oct 05, 2018 3:47 pm
Forum: Empirical & Molecular Formulas
Topic: When to double moles
Replies: 13
Views: 146

Re: When to double moles

You would like to get within .1 (or closer) to a whole number before you round so that the empirical formula is all integers. Many times we get answers such as 1.33 so it's easier for us to find the empirical formula (multiplying by 3).
by Erin Nash - 4G
Fri Oct 05, 2018 3:42 pm
Forum: Molarity, Solutions, Dilutions
Topic: Problem G5
Replies: 8
Views: 148

Re: Problem G5

So I understand how to use the M1V1 = M2V2 equation but for this specific problem I wasn't sure how to tell that we needed to use it. Could someone explain?

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