SG Chem 2 Third Blog - 10/02/15

This week in Chem 2a we reviewed and finished up Unit 4 and then started learning Unit 5. On Monday and Tuesday we did a lot of white boarding, mainly consisting of two review sheets.

Review Board A

Review Board B

For many of the questions, the table groups were not able to come up with a single answer that we all understood as correct. For those questions, we decided to have class discussions to help us find and understand the right answers. For example, question three asked us to draw a mixture and a compound of CO2. The table group with board A drew the mix of CO2 as single carbon and oxygen particles (both monatomic), while the table group with board B drew the mixture as one carbon particle (monatomic) with two oxygen particles bonded together, creating a diatomic. Every other group had some variation of either board A or B. The question we had to figure out was, "Which one was correct?" This had rather a simple answer. After some discussion and help from Dr. J we found that oxygen was a diatomic and therefore board B was correct in having two oxygens combined together. 

Although this discussion was a brief one, it helped remind me that oxygen was diatomic and I was able to remember that on the test. The thing I forgot was that there was multiple elements that are diatomic so on the test I forgot to mark hydrogen as a diatomic. But now I understand what I did wrong and I'll be able to fix that mistake in the future.

Wednesday was our test day. I felt okay about it, but the hardest part for me was getting the right definitions of a mixture, compound, element, pure substance, etc. I studied them but I only memorized a definition I had written on a sheet, I didn't really understand the difference between them. This came to hurt me when taking the test because those specific definitions were not on the test and therefore I was rather confused and unsure of what was correct. 

On both Thursday and Friday we started up Unit 5. We started with a sheet called "Relative Mass" which dealt with finding the mass of different items (washers, hex nuts, and bolts) inside a container. We weighed the entire thing, box and all, then subtracted the mass of the box from each item to get the weight of the items by themselves. Then with that information we could find the mass of a single washer, hex nut, or bolt. By knowing the mass of each individual item we could then solve problems and answer questions about it, which is what we did. The main idea from this lab was that you can count the amount of items in a container (bag, box, etc.) by weighing. So far I think I'm going to like this unit better than Unit 4 mainly because the math makes sense to me.