This week I read from chapter 15 on "Chemical Equilibrium" on rate of chemical reaction, activation energy, LeChatelier's principle, and (surprise!) chemical equilibrium. This chapter was pretty straightforward; it made sense right away that increasing concentration, temperature, or pressure would increase the rate of reaction. LeChatelier's principle made a heck of a lot more sense in the book than in ALEKS; I think ALEKS tends to throw more complicated stuff at you right away rather than easing you in. The discussion board on equilibrium really showed me just how important equilibrium is in our everyday lives. Without equilibrium we wouldn't be able to function; in fact, I think our body systems would shut down pretty quickly. The world would be a very unstable place.
This week I read chapter 7, " Chemical Recreations," in Uncle Tungsten. Sacks starts off fairly generally, talking about the fun he had making crystals and "chemical gardens." After a bit he starts talking about acids and bases, and describes the experiments his uncle showed him. I particularly enjoyed the very end of the chapter where Sacks talks about how he collected bus tickets that had a chemical symbol with the corresponding atomic weight on them. I've saved the tickets for almost all of the movies, shows, and operas I've seen, so it sounds like something I would do. I was also struck by how Sacks said he had a new respect for salt after watching the violent reactions that produced it. Salt is such a basic ingredient in the cupboard that I've always taken it for granted; I think I have a bit more respect for it now too.
This week also showed me that there are acids and bases all around me every day. We have a lemon tree outside, so we have plenty of access to acidic lemon juice. We use vinegar on a fairly regular basis, and that's also an acid. I wash my hands every day using soap, and I wash my hair with shampoo; both of those are basic. It seems like acids are a good choice when you need to break down substances (for example, we use vinegar to help get rid of calcium deposits on dishes); on the other hand, drain cleaner is strongly basic, and that also dissolves things like hair and grease in clogged drains. When you're cleaning you'll probably want to reach for an acid-based cleaner to clean metals, and if you're dealing with other, more organic substances, you'll probably need something that's basic.
The videos this week were pretty straightforward overall. The redox playlist gave me some good tips; I liked how the math was set up in "Oxidation States - Ions" and "Oxidation States - Compounds." "Activity Series Application 2" was a helpful companion to the material in the book. I also appreciated the help with "Calculating pH of hydronium concentration" and "Calculating pH." One thing that has been tripping me up is identifying whether acids and bases are strong or weak, so I was happy to see the video on that. I'm still a little unclear about how exactly it works; I think I may have missed where we talked about monoprotic and diotic and comparing it to the oxygen. I also couldn't remember where the piece was on strong bases. I got an idea of how it worked from the video but I'm going to have to study it a bit more.
Thinking back over the last 7 weeks, overall I have been pretty happy with how this class has been. It definitely started out overwhelming. I wish there was some way for the setup to be a bit more condensed; I got the hang of it after a couple of weeks, but for the new student it was kind of like "Whaaaaa??? Where do I go for this? How about this? Oh... these are in here... then where am I supposed to upload this?" I also was not expecting to spend quite so much time on it each day. I thought I would be working 3-4 hours a day total (max!), so when I was spending closer to 5 or 6 depending on what was going on I got a bit frazzled. I'm glad we were warned in advance that this class would take a lot of work; I think it might be worth it to really emphasize that in the future and tell students that they can expect to spend an average of anywhere from x to y hours per day on class-related work (not just homework). I'm torn about the idea of students' critiquing each others' lab reports. I've worked as a tutor before and I have done plenty of paper grading and critiquing, so it wasn't difficult for me. However, it did take up a fair bit of time and was another thing I had to remember to do on top of everything else. On the other hand, I did appreciate the critiques; people picked up on typos or showed me where I needed to be clearer. I think perhaps this might be a good idea for a semester-based class where things are a bit more spread out. I have really enjoyed the discussion board assignments. I think the topics have been good ones and I like that they all have related to chemistry in everyday life. It's easy to forget that chemistry is fundamental to our existence and start seeing it as a bunch of symbols and numbers and mathematical formulas. The discussion boards bring it back to earth and show how diverse it is. They also are a way to help me get to know the other students at some level. I always have fun going and reading everyone else's posts and seeing what examples they've come up with. I think some of the "response questions" have kind of been cop outs... for example, "Isn't it fascinating that such-and-such that you just clearly showed has such an effect?" (I've had a couple of those myself, so I'm not pointing a finger at anyone.) However, a lot of the questions have really sparked some interesting responses, so that aspect of it is a bit of a mixed bag. The labs have been pretty enjoyable as a whole. I appreciate that they require (for the most part) such basic ingredients. It goes to show that you don't need a fancy shmancy lab with high tech equipment to demonstrate the principles of chemistry. Also, even though the oral report was a bit of a pain to put together, I think it is a good requirement. It was fun seeing how everyone approached assembling their videos and adapting the experiment so it would work well on camera. I've noticed that many of the aspects of this class have made me more familiar with basic computer programs like Google Docs, Blogger, and YouTube. It's a nice bonus to have some experience with these programs under my belt.
I'm a bit nervous about the final exam. I need to take it a day early because the testing center isn't open on Fridays, so that only really leaves me Wednesday to study. I've done it before (flashbacks to my up-til-2-AM-night-before-final experiences), so I'll cram it all in. Any final is nervewracking though, and since I'm really trying to keep my grade in the range it's in right now I need to do well!
Lab this week was another one of this unexpected surprises. The first part of experiment 12, where I dissolved the aspirin tablets, went off without a hitch. I ran into some snags in part two. The cabbage pH indicator fluid I'd made wasn't even close to being strong enough, so the paper strips were not changing color. At all. Of course I didn't have any more cabbage, so after some "What do I do???" texts to the instructor she suggested I make blueberry pH liquid. I had never thought of such a thing, and I had to laugh as I was prepping the strips: "Well, I can check stirring paper strips in a bowl of warm blueberry liquid off my bucket list." But lo and behold, it worked! I think I'll be using blueberry pH liquid instead of cabbage in my next experiment because the results were so much better. Experiment 13 went a little smoother. I was a bit surprised by the results with the glowstick; why did it get so much dimmer in a glass of ice water than in a freezer when a freezer is at 0 degrees and the water's in the low 30s? I kept the glow stick in the freezer as long as I could but it wasn't for 24 hours, so maybe that was a part of it. The iodine and calcium C part of the experiment was fun; the color change is pretty spectacular.
A follow up from last week: I made rock candy. Or rather, I attempted to make rock candy. I've had a wooden skewer (which, I was told, was a perfectly acceptable substitute for string) in sugar water for about 6 days now and nary a crystal in sight. The weather has still been fairly humid until recently, and thinking about it I believe the extra moisture in the air could have been keeping the sugar more saturated. The only other thing I can think of is I added a splash of vanilla (which I was also told should work just fine, according to the recipe I used)... maybe the alcohol affected it somehow? Anyway, here's what 4 cups of sugar got me. (I'm trying not to think about how many brownies I could've made with 4 cups of sugar.) I had moistened the stick and rolled it in sugar before putting it in the sugar water solution (again, something that was supposed to guarantee bigger crystals), so that's the sugar you'll see towards the top.
I can't believe I just have one more blog entry left after this! Less than a week left!
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