Thursday, November 11, 2010

Lecture #22, Wednesday, November 10th

Today we started the last unit of the quarter, which will cover alternate energy. This topic has gained considerable interest in both the scientific and political communities and is a nice topic to end on as we can combine several topics throughout all of general chemistry to better understand the principles behind alternate energy.

The first look at alternate energy comes in chapter 12 of the text titled modern materials. Many of the technologically relevant materials our society craves come from materials. While it is nice to study the ideal gas laws and properties of solutions, it is materials research that will allow us to argue whether the iPhone 4 is better than the HTC Evo.

Next week in lab you will begin constructing your own solar cell. The idea for this laboratory experiment came from the following youtube video, which you will need to watch in order to complete your pre-lab assignment. Solar Cells are contained in Chapter 12 of the text and we will include it in our alternate energy unit.

Before we dive into the content in Chapter 12, it is relevant to review the material from the transition metal chapter regarding molecular orbital diagrams. The properties of materials are highly dependent upon the energy difference between the energy levels of the molecular obitals containing electrons and the molecular orbitals that are empty.

In molecules this is called the HOMO-LUMO gap and in materials we refer to this energy difference as the band gap. To manipulate these orbital energies changing the transition metal center or the ligand.

We also reviewed the molecular orbital diagram of a hypothetical octahedral complex with titanium at its center containing six oxygen ligands. Next lecture we will see how these orbital energies change as we go from a discrete molecule to an extended solid.

Songs Played Before Class:
Jay Z feat. Rihanna and Kanye West: Run This Town
Michael Jackson-The Way You Make Me Feel

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