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Let's get started. One announcement. And that is the reminder about the upcoming celebration Wednesday. There is the coverage. It is up here on the screen. It starts midpoint Lecture 17 starting with Bragg's Law and goes through to the end of November 8th, Lecture 24, Diffusion. And that will be the coverage. Let's get on with today's lesson. It is a continuation of what we began talking about on Wednesday. We started looking at solution chemistry, and we recognized that bonding was the key to understanding why thing mix, why things don't mix. And, along the way, we came up with some metrics, including the solubility product which was superior to simply saturation solubility because it allowed us to look at what happens when there is a plurality of solutes. And we came to know the common ion effect which in the presence of a common ion we observed repressed solubility. Today I want to talk about a subset, some specialized solution chemistry. And that t...

One announcement. There will be Quiz 9, the weekly quiz tomorrow based on the content of Homework 9 which is, I don't remember what it is, but you know what it is. I made it up, but I am already thinking about the next glorious event. Now I remember. There is chemical kinetics and glasses. That's right, chemical kinetics and amorphous solids. That's right. Last day we started talking about diffusion which is solid state mass transport by random atomic motion. And we were drawn to the paper that is up on the display which was published in 1855 by Adolf Fick which gave us the law that bears his name describing how matter diffuses through matter. Fick was a very talented individual, and I want to draw attention to something else. Remember, he was a physiologist. He actually did some work in medicine as well. In 1870, he described what survives to this day as the Fick Principle for determining cardiac output and basically equates the amount of uptake of oxygen by ...

Let's get started. One announcement. And that is that a reminder about the celebration of learning on Wednesday, October 2nd, Test 2. It will have coverage spanning lectures 7 through 17. The new material that I am going to introduce today will not be covered, but certainly this little review is worthwhile. And going back to 7 with the beginning of ionics. What I wanted to do today was just set the stage and briefly review where we were last day where we looked at the emission spectrum of a target in an x-ray tube. Here I have plotted intensity versus wavelength. Long wavelength is low energy. Energy is increasing from right to left. And what we see is a family of nested curves each taking a different plate voltage. Low voltage gives us low intensity. High voltage gives us high intensity. We see this whale-shaped background which we refer to as the continuous spectrum or "bremsstrahlung. And then once we reach a critical voltage beyond which we start to see this ...