October 20 - October 25

This week was a very jam-packed week for us Chemistry students. We began the week with a slight review which transitioned us to our test on Polarity and Electron/Molecular domains. After our test on our bonding unit we had a nice relaxation day in which we enjoyed Mole Day. Later in the week, we got back down to business with a pretest/practice AP test, and finished off with two POGILS on the Ionic Bond and Metals.

To review for the the test on Tuesday, we worked on a review packet (found below) we were given over the weekend and even white-boarded a few problems as a class. We also had further review materials online. Some of these included our past lectures, the answers to different POGILS, and even extra review with Hotpot quizzes. The following day, we took the test. Overall, it was not too challenging. The questions were slightly difficult and I made many stupid mistakes, but I knew most of the material pretty well overall. 

Review Packet

From there, we moved on to celebrate Mole Day (which unfortunately I was absent for :( ). From what I heard, it was a very exciting day filled with cookies and hot chocolate . This day wasn't all fun and games though. We were given an article that day on the chemistry of paintball and were assigned to write an essay about the importance of polarity and hydrogen bonding in the paintball. This article not only introduced us to polarity and hydrogen bonding, but also gave us a fun and great way to learn about it through something we could relate to. 

We then finished off the week completing two POGILS. Whatever work was not completed in class was assigned for homework. These also helped us to complete a lecture quiz on Metals due that Sunday night.

Overall, this was a week of stress and enjoyment in many forms. My participation overall was pretty good this week. I think I have a very good understanding of the few concepts we learned in this transition week. I am very interested in the chemistry of metals so I am excited to see what we move on to from here!

Hybridization, Sigma/Pi bonding, and WebMo molecules

This week was a very eventful one in Dr. J's classroom. We learned how molecules can be classified using hybridization, what sigma and pi bonding is, and then progressed to complete the VSEPR lab with its new addition of the WebMO molecular models lab. We also reviewed some concepts such as polarity and the dipole moment that weren't very clear before. These concepts were very necessary knowledge we needed to comprehend moving forward towards our test on Tuesday.

Hybridization surprised a lot of people. I had no idea what this was just going off the information from the lectures. As we worked through it in class though, Dr. J came up with a very simple and easy way for me to tell a molecule's hybridization. All we really needed to do was look at our given molecule's central atom. This atom would give us all the information we needed to know. To find the hybridization of a molecule, you need to only look at the number of electron domains in the central atom. If it had two electron domains, the hybridization would be sp.  If it had three electron domains, the hybridization would be sp2. If it had four electron domains, the hybridization would be sp3. You an only classify molecules through hybridization through four electron domains, so if a molecule had 5 domains, you could not classify it through hybridization. Examples of hybridization in molecules different types of molecules be seen below.

Sigma and Pi bonding was also another very confusing subject. The lecture also gave me absolutely no help whatsoever as to comprehending what these bonds are or how they are really formed. However, just as with hybridization, as we went over the concept of Sigma and Pi bonding in class, it became a whole lot more clear what Sigma and Pi bonds really were. Basically, a single bonded molecule would only have Sigma bonds dependent upon how many bonds you have. Take for instance, F2. F2 has one, single bond. This single bond indicates that there is one sigma bond present. A double bond however means that the molecule has one sigma bond and one pi bond. A triple bond on the other hand, indicates that the molecule has one sigma bond and two pi bonds. Take for instance the element C2H2 above. There are two single bonds and one triple bonds. The two single bonds indicate there are two sigma bonds. Add that to the one sigma and two pi bonds present in the triple bond, and you can see that C2H2 has 3 sigma bonds and two pi bonds. The powerpoint below can provide a little more assistance if needed.

Sigma and Pi bonds

The WebMO lab really cleared things up for a lot of people. This lab allowed us to create models of each of the thirteen molecules we had in our lab. Some of these included NSF, H20, and BeF2. From these models, we were able to tell a molecule's polarity, charge, dipoles, shape, and bond angles. The polarity could be seen looking at the molecule's colors when looking at the WebMO diagram. If symmetrical, the colors would indicate overall that the molecule was not polar. If not symmetrical though, the colors would indicate that the molecule is overall polar. We could tell the charge, dipoles, shape, and bond angles by just looking at the diagram and information listed below the model for most molecules.

Overall, I learned a lot about Hybridization, Sigma and Pi bonds, and gained tons of useful knowledge from the WebMO diagrams. My participation overall this week has been pretty good, especially in the WebMO lab. I would rate my understanding of the concepts this week at a 7 out of 10. I got a lot of the information, just not every single bit. I still need to work on the dipole moment of molecules because I am not quite sure how to calculate that still.

10/7-10/13: More Lewis Structures

This week was very uneventful in our AP Chemistry class. We used the first few days to finish up our calculations in our lab conducted last week and to review some important material on molecular geometries. From there we completed two more POGILs having to do with hypervalency, formal charges, resonance, and bond order. We finished up the week with a lecture quiz on Polarity and some more review on how to build some of these more complicated Lewis Structures with expanded octets.

Starting the week off right, we continued to learn about molecular geometries by white boarding and completing our VSEPR lab we started the week prior. This lab helped us really further understand the five types of electron domain geometries. These included Linear, Trigonal Planar, Tetrahedral, Trigonal  Bipyramidal, and Octahedral. In these domains were also sub-domains that can be seen in the molecular geometry pictures below. Our knowledge of these domains from this lab also really helped us complete the VSEPR lecture quiz due that night.

Linear and Trigonal Planar

Tetrahedral 

Trigonal Bipyramidal

Octahedral

We continued moving forward, finishing up our calculations from the lab we conducted a week ago. This became very confusing for me because I had not done Stoichiometry in such a long time. But then again, that's why why have lab partners! My partner and I worked through the calculations in no time to finally obtain the mass percent of Cu in that brass screw solution through both the visual method and the method using the calibration curve. From there, each class entered their final results into a google form where our entire class data was averaged and stored.

The next few days took us back to basics with two new POGILs, working on our familiarity with hypervalency, formal charges, resonance, and bond order. These POGILs focused heavily on formal charges and hypervalency in different types of molecules the most. These areas were really stressed and I understood both concepts very well. To top it off, we had another lecture quiz due that night on Polarity. Unlike formal charges and hypervalency, I really struggled with the concept of polarity. I needed to re-watch the lecture(link below) multiple times before I could grasp some of the basic concepts such as the dipole moment.

Polarity Lecture

We finally finished the week off with some more basic review as a class. We went over how to construct the Lewis structures of molecules like BSF and NSF in our table groups and came together as a class at the end to discuss the correct answer. We also found each molecule's formal charge, electron and molecular domain, and even their alternative resonance structures.

Overall, I feel a lot more confident in my knowledge of the information we went over on Lewis structures this week, but I also had quite a bit of trouble with Polarity and the calculations from the brass screw lab. I still need to work on grasping those concepts of Polarity and may need to watch the lecture over again taking notes. My participation this week was pretty good, but I think it was a little down from my participation the week prior. My ideas have really changed on the concept of hypervalency. At first, I had no idea how it worked, nor could I understand how you could just dip into the d-orbital with extra electrons. This process shocked me at first, but like much of this week's concepts, I now believe it is quite simple. 

9/30-10/6: Lewis Structures and Brass Screw Lab

          This past week was a very interesting one. We began the week with by talking about our second official lab on the amount of mass percent of copper in a brass screw. This discussion gradually took us to our next main concept which was Lewis structures. We spent the majority of the week learning about Lewis structures through various POGIL activities, while also conducting the our lab experiments on the days we were not learning about Lewis structures.

          On Monday we discussed a very difficult reaction in class that would eventually help us find the mass percent of Cu in a brass screw in our lab. We worked in our table groups and white boarded out the formula see below as a class. Coming together at the end, Dr. Finnan finally explained how to solve the reaction and how it was relevant to our next lab. 

8H⁺(aq) + 2NO₃^–(aq) + 3Cu(s) ➝ 2NO(g) + 4H₂O(l) + 3Cu²⁺(aq)

          The next day, we worked on a POGIL regarding the new topic of Lewis Structures with our table members. This POGIL taught us the basics of how to draw valence electrons for groups IA-VIIIA, how to calculate the total number of electrons and valence electrons in a model, and how to actually draw a Lewis structure. The POGIL helped tremendously with the lecture quiz due that night. One very useful resource I liked from the Lecture was the rules on how to create a Lewis structure as seen below.

          The next day, we began our lab to determine the mass percent of copper in a brass screw. We calculated the mass of the screw and the volume of nitric acid that was needed to react with the brass screw in the solution. We then measured the absorbance of the copper solution through a colorimeter to help us find the final mass percent of copper in the brass screw. Following this lab, we worked on two different POGILs on Bond Order and Bond Strength as well as a second one further explaining Lewis structures. These taught us about the different types of bonds in a Lewis structure, what a bond order is, and which bonds were the strongest. These two POGILs along with the powerpoint below helped me a lot when I tried to figure out how to do our second lecture quiz this week. Our last assignment this week was a VSEPR Theory Lab which we did not complete. Although we did not complete it, it helped us get a basic understanding of the lecture quiz due that Sunday.

Covalency Powerpoint

          Overall, I learned a lot of material this week but do not feel completely confident in my ability to make every Lewis structure. Many parts of the POGILs are confusing to me but I feel that I do have a good grasp on the material as a whole. My participation this week was pretty good but again it can always be better. I believe the only thing I need to work on is just looking over the POGILs and lectures until I can fully understand each concept. Who knew making dots and lines could be challenging?