Safety goggle alert!11 October 2002

This Friday night chemistry class is a really good group of students. I enjoy working with them every week. Here's the back of the room. It's great having a chalkboard in the back. I can write all over the place. As you can see, a couple of these students are having so much fun that they've forgotten to wear their safety goggles!

Today we synthesized zinc iodide from metallic zinc and solid iodine. Just mix together the two solids and pour in a little methanol, then heat it up and watch. At first, the iodine dissolves in the methanol, making it look a dark brown. Eventually, the iodine gets completely consumed in the reaction and the liquid turns a lighter color, like amber-colored beer. The lighter color is due to the fact that the zinc iodide dissolves in the methanol too. Now all they have to do is pour the methanol solution off of the unreacted zinc, dry the zinc and evaporate the methanol away from the zinc iodide. Weigh both parts, and calculate the chemical formula of the zinc iodide.


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