Wednesday, September 15

We began today's class by briefly looking at the blog. First, we looked at Konstantine's delayed blog from last Friday (due to technical difficulties, of course) and Katie's blog from last night. Mr. Henderson then proceeded to give us a brief lesson on how to use DropShots with the blog. This link provides the portal to the "Chemistry Classroom" account with the access password being "gbs":
http://www.dropshots.com/chemistryclassroom

While showing the class Katie's blog, Mr. M noticed that Katie had embedded an link with excellent practice into her blog. This reminded him of telling us about the Delicious assignment that we have due on Friday, September 17. He said that Katie's link was a perfect example of what we could use for our assignment. He showed us how to log into the database and how to tag and fill out the form for our links. In order to log into this website, we need a Yahoo account. Mr. H told us that it would be useful to have a Yahoo, Google, or Facebook account because those major corporations would end up taking over many of the smaller companies. Thank you for those wonderful words of wisdom, Mr. H! More thorough directions for Delicious can be found on the hand out we received in class on Monday or on the GBS Chem-Phys website:
http://gbschemphys.com/honchem/index.html

After our tech tutorial, Mr. Henderson asked us to take out our unit packets and turn to page 9. Before beginning the worksheet, he quickly reminded us of the differences between a physical (describing the substance without describing its interaction with other substances) and chemical (describing the substance by how it interacts with other substances) properties. To give us a better idea, he told us he would show us an example of a chemical property of magnesium. He showed us the sample of magnesium - a shiny metal - and turned on the methane flow. He lit the burner (from the bottom up, of course) and began to burn the magnesium. Mr. H told us that magnesium reacted very strongly with oxygen to make magnesium oxide and that we should be prepared to see a very bright light, indicating the reaction. Sure enough, when the magnesium heated up enough, we saw a very bright light. Our experience was similar to this video from Youtube:
http://www.youtube.com/watch?v=Q_LU1EASadU

Mr. H then pulled up an overhead of 4 out of the 5 pieces of evidence of a chemical change. They are: bubbling & production of gas, formation of a solid, heat or light, color changes, or temperature changes. The difference between a heat/light change and a temperature change is that the temperature change is more drastic and long term.

As soon as all the explanation was finished, we began page 9 and the "Verbal Description of Change" section. We attempted to do the section individually and went over the activity together and the answers are as followed: C, P, C, C, C, P, P, C. We had to be on the lookout for the chemical changes we learned about in each of the scenarios order to determine the type of change.

Next, we determined the "Symbolic Description of Change" as a class. If the element remained the same, it was a physical change. If the before and after differed from each other, it was a chemical change. The answers are as followed: P, C, C, P.

To finish the page, we flipped it over and determined the "Visual Depiction of Change at Microscopic Level". We had to be on the lookout for changes in the shape and arrangement of the atoms and molecules. The answers are as followed: C, P, C, P.

Abruptly, Mr. H got up and directed us to the back of the room and under the fume hood. He asked us for two pennies. He took our a large bottle of nitric acid and explained to us what a hazardous chemical it was and how we had to be careful when handling it. Mr. H was going to demo the reaction between copper and this nitric acid. He poured the acid into a flask and diluted it with some water. He dropped one of the pennies in and told us to observe. Meanwhile, he took another flask and filled it with pure nitric acid. He dropped the copper penny into the substance and told us to observe and compare it to the other flask. Immediately, we saw a change of color. The acid went from clear to a gradient green-red. Bright orange gas began spewing out of the top of the beaker. It bubbled and displayed a clear chemical change. The diluted beaker was showing the same changes (minus the color change and significantly less bubbling and gas) at a much slower rate. Mr. H ask Katie to touch the beakers carefully. She told the class they were both very warm, indicating a temperature change. It was very interesting to see the copper penny dissolving and reacting with the acid. The flask with the pure nitric acid and penny looked similar to this photo:

We concluded the class by returning to our seats. Mr. Henderson quickly read us a story about a man whose experience with nitric acid inspired him to keep experimenting with it. With little time left, we were instructed to turn to page 11 and complete the "Verbal Description of Change" and determine the Physical and Chemical properties. The answers are as followed: P, C, C, P, C, P, C, C, P.

Just as the bell was about to ring, Mr. H handed out the quizzes from last week and told us to check our answers and use it as a guide. He told us that tomorrow we could expect a lab about density and that our homework was finishing the 1.2 Webassign and our Delicious assignment.