the moth

The last few days were so uneventful and boring that i didn't even bother writing. Oh my dear audience. That's if i have any audience...I haven't thought of that. I don't know how many people will read this and i really don't care. Ok, I care enought to try to make the blog entertaining wit sarcastic remarks and funny anecdotes, but not enought to do anything to get people to read this... but then again i don't know how to do that so let's leave it at that.

On tuesday I prepared 2 chemistry experiments for the 10th grade chemistry class of physics guy. One was mole-mass relationships and the other was or moles and chemical coefficients. Both simple experiments yet both require copious amounts of materials.

Mole-Mass relatioships:

This I think is the most hazardous experiment 10th graders will ever do, mostly because it involves fire and 6M HCl. I like HCl as much as I like stepping on dog shit, and 6M is nothing to laugh about. Essentially, the experiment reacts hydrochloric acid with sodium hydrogen carbonate (a.k.a. sodium bicarbonate, baking soda). The result? NaCl, sodium chloride, plain table salt.

NaHCO3 + HCl -> NaCl + CO2 + H2O

The whole point is to determine how the equation balances out by how many moles reacted with what, and by weighing the resulting NaCl once all the water is evaporated.

First you weigh a flame dried evaporating dish. Then grab about 2.5g of NaHCO3, put it on the evaporation plate, add about 5mL of HCl and let it react. The reaction can be fast and violent, so it's best to add the acid slowly and constantly, using a dropper, this is also so that once the bicarbonate is reacted (i.e. stopped bubbling) you can stop in time to avoid excess. It would also be good to cover the evap plate while reacting with a watchglass, so it doesn't spatter around.
Then you evaporate the resulting NaCl solution in the evaporation plate, carefully, moving the flame back and forth, you don't want spills from the boiling of the liquid. Once the stuff is dry, weigh it and find the mass of the NaCl formed.

So you calculate from the amount of moles of bicarbonate added and the final mass of NaCl and extrapolate the amount of moles reacted in total from the reaction... simple enough eh? This will give you an idea of how many atoms of what reacted with how many atoms of what else.



Moles - chemical equation coefficients relationships:

This one's similar but far simpler. This one's also done to determine the ratio of moles reacted in an equation. The whole point is to react a sulfate of one metal with another metal.

CuSO4 + Fe -> FeSO4 + Cu

What sucks about this experiment is that it's better to use an analytical balance, as amounts need to be exact to get good results. And students are known to break everything they touch (not all of them but most), so they have to do it with the shitty balance, no way i'm letting them use my nice balance.

Here's how. Grab a beaker, put 50mL of distilled water in it. Then dissolve 8g of CuSO4 (copper sulfate) in it. Stir. Add 2.2400g of powdered iron metal yo the blue juice. Stir for 5 minutes, then let settle for 2 minutes. Transfer by either decanting or filtering (i'd rather filter, it's quicker, and drying is a snap, but you'd have to weigh the filter paper circle first). Rinse the beaker with distilled water and pour whatever's left through the filter. Put the paper in a 40 degrees centigrade oven for an hour and weigh the resulting dry copper metal on the paper, substracting the weight of the paper of course.

From the weight of the Cu and its atomic weight, you can see how much Cu reacted out of the Sulfate (in theory all of it) and establish a ratio of Fe-Cu reacted in the whole shenannigan. Fun eh?


After about 2 hours of getting everything together i took a break. A break that lasted until 17:30... which is when i leave work. I found this game on shockwave called death from above, it's about world war I airplane dogfights. Quite fun, but too easy, won it in 1 afternoon.





I almost forgot, why this post is called "the moth". This country, being in large part a monstruous rainforest, has a lot of giant moth species. They're as big as birds. One of the math guys, the one next door to me, called me in to see if i could delicately deport a large dark moth from his room, without hurting it, kinda like what the US wants to do with the mexicans. Of course, while trying to grab it i snapped a bit of the wing off, thus hurting it. It's important to point out that adult moths (the ones that fly) don't bite as they don't have mouthparts that will allow them to do so. But anyway, i snapped a bit of the wing off and chased it around for a while. Eventually i got tired of chasing it to grab it with my hands and went and got one of the biology butterfly nets. And just like a cartoon character, chased the moth out of the room, into the hall, down the steps and caught it in front of the principal's office. Lots of people watched me do this. Ridiculous doesn't begin to describe it, but everyone myself included got a good laugh from it. The moth was safely released in the courtyard and flew away to become something else's foot. It sucks being at the bottom of the food chain.




Right now i'll go have lunch and later I'll sit around some more. Perhaps even write another piece. We'll see. Don't think so.

Every day is a free writing exercise.