Search found 29 matches
- Thu Dec 06, 2018 3:47 pm
- Forum: Biological Examples
- Topic: Ligands
- Replies: 7
- Views: 857
Re: Ligands
A ligand has to be able to form coordinate covalent bonds, so often the molecules will have a lone pair of electrons.
- Thu Dec 06, 2018 3:45 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: Ka Constant
- Replies: 4
- Views: 745
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.
- Thu Dec 06, 2018 3:42 pm
- Forum: Bronsted Acids & Bases
- Topic: Distinguishing bronsted acids vs bases
- Replies: 3
- Views: 1008
Re: Distinguishing bronsted acids vs bases
A Bronsted acid is one that donates protons and a Bronsted base is one that accepts protons.
- Tue Nov 27, 2018 10:31 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Angle Distorted
- Replies: 4
- Views: 381
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.
- Tue Nov 27, 2018 10:29 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar vs. Non-polar
- Replies: 6
- Views: 609
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.
- Tue Nov 27, 2018 10:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sigma and Pi bonds
- Replies: 4
- Views: 464
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.
- Tue Nov 13, 2018 9:52 am
- Forum: Ionic & Covalent Bonds
- Topic: London Van Der Waals Force?
- Replies: 5
- Views: 511
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.
- Tue Nov 13, 2018 9:50 am
- Forum: Lewis Structures
- Topic: VSEPR Model
- Replies: 6
- Views: 942
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.
- Tue Nov 13, 2018 9:49 am
- Forum: Resonance Structures
- Topic: Drawing resonance
- Replies: 17
- Views: 1818
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.
- Sat Nov 10, 2018 5:55 pm
- Forum: Dipole Moments
- Topic: VSPER
- Replies: 8
- Views: 909
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.
- Sat Nov 10, 2018 5:52 pm
- Forum: Lewis Structures
- Topic: Atoms with 8+ valence e-
- Replies: 6
- Views: 965
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.
- Sat Nov 10, 2018 5:51 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Length and Bond Strength
- Replies: 5
- Views: 779
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.
- Sun Nov 04, 2018 4:30 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Midterm
- Replies: 3
- Views: 368
Re: Midterm
I believe that is all we need to know.
- Sun Nov 04, 2018 4:29 pm
- Forum: Sigma & Pi Bonds
- Topic: What each bond refers to
- Replies: 3
- Views: 368
Re: What each bond refers to
We will be expected to know how to draw this for the midterm?
- Sun Nov 04, 2018 4:28 pm
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bond Definition
- Replies: 14
- Views: 1797
Re: Coordinate Covalent Bond Definition
How can you tell if it is a coordinate covalent bond?
- Sun Nov 04, 2018 4:23 pm
- Forum: Lewis Structures
- Topic: Lewis Structure for Ionic Bonds
- Replies: 2
- Views: 541
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.
- Mon Oct 22, 2018 3:14 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration
- Replies: 5
- Views: 448
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.
- 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: 550
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.
- Mon Oct 22, 2018 3:12 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Test On Tuesday
- Replies: 10
- Views: 1014
Re: Test On Tuesday
He emphasized once more during lecture today that only material we covered up until Friday will be on the test.
- Mon Oct 22, 2018 3:10 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Confused about Copper and Chromium [ENDORSED]
- Replies: 2
- Views: 1754
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...
- Mon Oct 15, 2018 3:24 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty Principle
- Replies: 5
- Views: 405
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.
- 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: 445
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.
- Mon Oct 15, 2018 3:14 pm
- Forum: DeBroglie Equation
- Topic: Rest Mass?
- Replies: 4
- Views: 381
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.
- Mon Oct 15, 2018 3:13 pm
- Forum: *Black Body Radiation
- Topic: What is a black body? [ENDORSED]
- Replies: 7
- Views: 1460
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.
- Mon Oct 15, 2018 3:10 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Incorrect Atomic Model
- Replies: 6
- Views: 453
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 ...
- Mon Oct 15, 2018 3:05 pm
- Forum: Properties of Light
- Topic: Test 2
- Replies: 17
- Views: 1209
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.
- Fri Oct 05, 2018 3:50 pm
- Forum: Properties of Light
- Topic: Behavior of small objects - clarification
- Replies: 3
- Views: 183
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.
- Fri Oct 05, 2018 3:47 pm
- Forum: Empirical & Molecular Formulas
- Topic: When to double moles
- Replies: 13
- Views: 986
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).
- Fri Oct 05, 2018 3:42 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Problem G5
- Replies: 8
- Views: 705
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?