Week 4 - Finishing up Chapter One; Starting Chapter Two
Updated September 10, 2021 For those of you who have already had me, you know that this is the page to come to to get assignments, labs, weekly announcements and summaries. Past weeks announcements will be placed in the Quarter 1 Archives drop-down menu.
Do make sure you have printed out both the O-Chem Syllabus and Weekly Pacing Guide.
This week we dedicated some time studying resonance structures, and the need for them. You should have read from Section 1.10 Resonance Theory, six rules concerning such structures:
Rule 1 - Resonance occurs in species for which there are two or more valid Lewis structures.
Rule 2 - Resonance structures are imaginary; the one, true species is represented by the resonance hybrid.
Rule 3 - The resonance hybrid looks most like the lowest energy (most stable) resonance structure.
Rule 4 - Resonance provides stabilization.
Rule 5 - Resonance stabilization is usually large when resonance structures are equivalent.
Rule 6 - All else being equal, the greater the number of resonance structures, the greater the resonance stabilization.
The stabilization of resonance structures results from the delocalization of electrons; when electrons are less confined, and are free to move about a molecule, they have less energy. The molecule exhibiting resonance is more stable also, since the negative charge of the delocalized electrons can be distributed across many atoms, as opposed to concentrating that charge on only one.
As a reminder, the two videos below address Resonance Theory - please watch as you need to!
We did not really get the opportunity to discuss Functional Groups and Biological Molecules this week, so make sure you read about these in the textbook. There will be a quiz on Thursday asking you to "recognize" these molecules, and the following week you will need to actually draw these out.
You should know this about functional groups: within a given molecule, such as a pharmaceutical, not all the atoms on the molecule are reactive - only those with areas of electron density (negative charge) or having an electron deficit (positive charge). Functional groups represent many such arrangements of atoms within molecules that are reactive due to charge separations.
The Section 1.13 video below will assist you greatly in understanding these functional groups, and the Section 1.15 video will show you how these find themselves in biological molecules.
Chapter 1 Test - Open Book I emailed you the pdf file for the Chapter 1 Test Saturday morning. When taking, keep this in mind:
This is to be an open book exam - please use only the resources provided by your textbook, and not from the internet
You might want to allot about ninety minutes to two hours to take this exam
Since this particular one is open book, it does not need to be proctored by a parent, but future exams may need to be
Due Tuesday, September 21st, along with the Chapter 1 Homework
What to Expect in Week 4
On Tuesday we will introduce Chapter 2 - Three-Dimensional Geometry, Intermolecular Interactions and Physical Properties. I have linked a video from Section 2.1 - VSEPR Theory, and Section 2.2 - Dash-Wedge Notation. So that we can do the modeling lab for VSEPR, please watch these in advance of that lab (linked right).
Make certain also that you print out the Chapter 2 Homework so you can answer problems as we encounter them in class! Below are the videos covering material from Sections 2.4 and 2.5. I don't anticipate we will get that far, but they are below for your review.
Check-off List of Things to Do:
In order to be adequately prepared for classes next week, please make sure you do the following by: Tuesday, September 14th, 2021
Watch the Section 2.1 video on VSEPR Theory
Watch the Section 2.2 video on Dash-Wedge Notation
Print out and bring to class the VSEPR Theory Modeling Lab, I will give each of you a kit
Thursday, September 16th, 2021
Print out and bring to class: Chapter 2 Homework
Watch videos for Sections 2.4, and 2.5
Prepare for Quiz #4, covering functional groups, you will need to recognize the 17 functional groups