Weekly Blog Post 10/20 through 10/27

On Monday, we began the week by reviewing for the exam on bonding. We reviewed amongst ourselves and went over a few problems from the review worksheet with the class. This was very helpful in getting to understand the concepts. That night, Dr. J put up a chat room in which we could ask questions of other students as well as Dr. J, which was extremely helpful. Being able to ask people questions you had rather than trying to figure it out yourself is super beneficial. Plus, it's nice to answer other people's questions to boost your confidence.

The next day we took the test, which was not extremely difficult but it had it's challenges. It was mostly conceptual, and I am fairly good at picturing things in my head so I did OK on it. I definitely mastered the concepts better than I thought I would be able to. 

Wednesday was mole day!

Dr. J made some delicious cookies and we had some hot chocolate while we talked for the whole class. We were assigned an essay about paintball and the role of polarity and hydrogen bonding in the paint balls and how scientists have made the paint water soluble without using water in the paint. 

We then started to learn about ionic bonding, which was an extended review of what we began to learn last year and had some more of it over the summer. It's not very difficult, but the POGIL we did covered a lot of material. I think I have a good understanding of ionic bonding so far. It's essentially just knowing what the tendency of each atom is; to become positive or negative. Just know that metals bond with nonmetals in ionic compounds. 

Last, we began a worksheet on metallic bonding but didn't get too far. I'm still pretty unsure about the whole thing, considering I only got about three questions done on the POGIL we got. The lecture and lecture quiz will help my understanding. 

My understanding of the material this week is good besides the metallic bonding. I learned a lot over the weekend (or, rather came to understand a lot) about covalent bonding through studying and the chat room. Those are very helpful. 

Weekly Blog 10/7 through 10/13

This week was a very busy week. We started it off with learning about vsepr models and how molecules are shaped by the bonded and non-bonded pairs of electrons. The vsepr models demonstrated why water has an irregular shape and why other atoms have their shapes. It also taught us how you can figure out the shape of the molecule knowing only the mount of bonded and unbonded pairs of electrons and the number of atoms around the central one. Here is a diagram of some vsepr structures.

We also learned about formal charges, which are used in Lewis dot diagrams in order to denote the charges of atoms. The formal charges are a result of polarity in a molecule, where one atom has more pull on the shared electron than the other. This can affect the vsepr structure of the molecule because of the way bonds are formed when an atom is polar. A molecule can be non-polar even if some of the bonds are polar. If the dipole moments all add to zero, then the molecule will have a net dipole moment of zero and will be non-polar. Here is a picture of a molecule and it's dipole moments.

At first I didn't understand polarity and dipole moments at all, but after I watched the lectures several times it began to make more sense. I have a much better understanding now than I did when I first watched the lecture. I still think that I need a lot more practice with it, however. Also, whiteboarding the Lewis structures and figuring out the molecular and electron domains was extremely helpful and I now know what I'm doing with those. Overall, my understanding of the material is good, but it can definitely be better.

Weekly Blog, 9/30 through 10/6

This week, we began with Lewis structures and things such as hypervalency and electron deficiency. We also focused on bond order with a POGIL that taught us the principle that as bond order goes up, bond energy goes up. Also, as bond length goes up, bond energy goes down due to coulombs law and how far away the electron cloud is from the other nucleus of the other atom. We learned the basics of coulomb's law last year in ACIS 2 or Sustainable Green Chem, I can't remember which. Here is a good video on bond order.

After we learned the bond orders and bond lengths, we moved on to our lab. Before the lab, we had to use stoich again to calculate the amount of nitric acid we would need to complete the reaction. Stoich, once again proving to be a very useful tool in chemistry. Next, we tested to find the amount of copper in a brass screw by using nitric acid to dissolve the copper overnight, and then testing the absorbency of the nitric acid, water, and copper solution using a colorimeter. We used the same technique that we used from the previous absorbency lab to find the absorbency, then we stopped until next week to chart the data because we could not get computers.

After the lab, we did a POGIL on vespr models. Vespr models are models used to show the shape of a molecule's geometry. WE modeled the shapes with balloons because balloons, like electron clouds, are succeptable to outside pressure and will distort if there is a force acting on them. For example, if there is a balloon pushing up agaisnt another balloon, it will push away due to tension. The same is true for an orbital, but it will be pushed away by repelling negative charges rather than pressure.

My understanding of the material this week is probably not up to where I need it to be. Formal charges are still very confusing to me, I do not really know how to make a proper Lewis structure with the formal charges. Finding the formal charges is easy enough, though. This coming week I'll need to work on that a little more to iron out the wrinkles.