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Biology (2nd Period) / Chemistry (4th Period) / Forensics (5th Period)

"Good morning. Today we will be doing an experiment with photosynthesis. As you may, or may not remember, photosynthesis is the process by which plants convert sunlight and carbon dioxide into sugar, thus feeding the plant and expelling oxygen. Also of note--oxygen is necessary for breathing. Interesting fact, wouldn't you think?"

The experiment is listed on a packet Ms. Sidle is passing around.

"Good morning. As I said on Monday, today we will learn how to balance chemical equations."

Balancing Chemical Equations
Sometimes, however, we have to do some work before using the coefficients of the terms to represent the relative number of molecules of each compound. This is the case when the equations are not properly balanced. We will consider the following equation:

Al + Fe3O4---> Al2O3

Since no coefficients are in front of any of the terms, it is easy to assume that one (1) mole of Al and one (1) mole of Fe304 react to form one (1) mole of Al203. If this were the case, the reaction would be quite spectacular: an aluminum atom would appear out of nowhere, and two (2) iron atoms and one (1) oxygen atom would magically disappear. We know from the Law of Conservation of Mass (which states that matter can neither be created nor destroyed) that this simply cannot occur. We have to make sure that the number of atoms of each particular element in the reactants equals the number of atoms of that same element in the products. To do this we have to figure out the relative number of molecules of each term expressed by the term's coefficient.

Balancing a chemical equation is essentially done by trial and error. There are many different ways and systems of doing this, but for all methods, it is important to know how to count the number of atoms in an equation. For example we will look at the following term.

2Fe3O4

This term expresses two (2) molecules of Fe3O4. In each molecule of this substance there are three (3) Fe atoms. Therefore in two (2) molecules of the substance there must be six (6) Fe atoms. Similarly there are four (4) oxygen a toms in one (1) molecule of the substance so there must be eight (8) oxygen atoms in two (2) molecules.

Now let's try balancing the equation mentioned earlier:

Al + Fe3O4---> Al2O3+ Fe

Developing a strategy can be difficult, but here is one way of approaching a problem like this.
1) Count the number of each atom on the reactant and on the product side.
2) Determine a term to balance first. When looking at this problem it appears that the oxygen will be the most difficult to balance so we'll try to balance the oxygen first. The simplist way to balance the oxygen terms is:

Al +3 Fe3O4---> 4Al2O3+Fe

Be sure to notice that the subscript times the coefficient will give the number of atoms of that element. On the reactant side, we have a coefficient of three (3) multiplied by a subscript of four (4), giving 12 oxygen atoms. On the product side, we ha ve a coefficient of four (4) multiplied by a subscript of three (3), giving 12 oxygen atoms. Now, the oxygens are balanced.
3) Choose another term to balance. We'll choose iron, Fe. Since there are nine (9) iron atoms in the term in which the oxygen is balanced we add a nine (9) coefficient in front of the Fe. We now have:

Al +3 Fe3O4---> 4Al2O3+9Fe

4) Balance the last term. In this case, since we had eight (8) aluminum atoms on the product side we need to have eight (8) on the reactant side so we add an eight (8) in front of the Al term on the reactant side.
Now, we're done, and the balanced equation is:

8Al + 3Fe3O4 ---> 4Al2O3 + 9 Fe

"Good afternoon. Today we will begin a study into the forensic science behind investigating arson."

Arson investigation involves the study of fire-damaged physical evidence and crime scenes to detect arson. The techniques involved in such investigations require a basic grounding in the chemistry of explosives, the materials used in the formation of explosives as well as the various ways in which explosives are interrelated and initiated.

She lectures extensively on what arson entails.

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Mac signs in and settles down to take notes. She's looking pretty cheerful, probably had a lot of coffee this morning.

Quinn's listening. Kinda. There are sciencey words and they're hard.

Edward signs in, and once again proceeds to doodle all over his notes.

Lilly sits next to Edward, participating in similar doodling behaviors.

Allie sits on the other side of Lilly and takes actual notes.

Izzie signs in.

Taking out her notebook, she carefully copies down the problems on the board.

~*~

Phoebe signs in and takes good notes while also looking around for Lana and Maia

Maia was again sitting in the very back of the class. She gave Phoebe a smile though.

Lana signs in and comes ot sit next to Phoebe. "Hey, how's it going?"

"Cole... sang to me last night."

Lana smiles. "Really? That's so nice. He and I talked some the other night. And... I know he's done some stuff, but he really does love you, Phoebe, and I don't believe he would ever hurt you - despite the song the other day."

"I don't know what's going to happen with us... but I know he didn't mean to scare me or hurt me." She shakes her head. "Lana? He sang Cher!"

Lana smiles again. "He *really* loves you if he did that. Are you guys going to talk? try to work things out? I'd be glad to be there as kind of a buffer if you want."

"We talked some last night. I love him and he loves me, but if we can't get past some things... I don't know."

"Phoebe..." Lana takes a deep breath. "I... I just feel really strongly that you guys are supposed to be together. And I think he'd do *anything* to make that happen. And I really think that in your heart you want to be with him. So... I'm willing to do anything I can to help you guys work this out."

She hesitates, "Plus... Crowley? Really scares me. And I don't know why and that scares me even more."

"I love him, too, I just... the things that he wants to do... it's hard to deal with. He's my soulmate Lana, but he may be the one that causes my death."

She sighs. "Why is everyone so afraid of him? He doesn't scare Kiki or I... then again... he does go out of his way to scare others. I am so confused."

"Soulmates don't come along every day, Phoebe. You shouldn't throw love away when it comes calling your name. Some things are worth the risk."

She makes a little face, "Crowley... He just... I only ever saw him Saturday, but he just... terrified me. Bel, made me angry when he was singing, but he didn't scare me. Crowley..." she shuddered.

"Can you keep a secret, I mean even from Shep, Lana."

Lana hesitates. "I can keep a secret - and yes, even from Shep, but if it's something I think could hurt you or someone else, I couldn't promise."

"Crowley can't hurt me. Both he and Aziraphale made sure of it."

Lana feels a wave of relief sweep over her. "You have no idea how relieved that makes me feel. Thank God."

Then a thought occurs to her. "Phoebe... would he try to do something to your friends to keep you? I'm not so worried for me, I'm not going anywhere near him, but Kiki... she... something bad happened to her last week and she's not quite herself yet. And she trusts him..."

Phoebe shakes her head. "No, he won't. Kiki and I have both been attacked, and both times he's stepped in. In fact... well, Kiki and I are going to do some investigating."

"Investigating?" Lana looks a little nervous. "Investigating what?"

Phoebe looks down. "uhmm... we want to know why we were attacked."

"I'm probably going to regret this, but if you need some help..." Lana takes a deep breath. "I'd be glad to do what I can. I'm not a witch or anything, but I can do research or stuff like that."

"Thank you."

Lana shakes her head, "Now I know I must be crazy."

"But I love you." She smiles.

Lana laughs. "I love you too. Which reminds me... I ended up telling Shep about the, um... singing we did Saturday morning..."

Phoebe blushes a bright red. "And he said?"

Lana looks down and blushes a little more. He kissed me and did that cheeky Shep grin and said he never would have guessed."

"Lana, that's great!"

"Yeah..." Lana has a sort of dreamy look on her face. "It is. And I finally told him that I just didn't know what to say to people when they asked if we're dating and he said as long as I wasn't looking to get married at the monet, he was pretty much content with anything."

Phoebe grins wickedly. "So... karoake to celebrate?"

"Karaoke? You didn't get enough singing over the weekend?"

Maia signed in and took notes

Lana smiled at Maia.

Kilt-Dude signs in and pays close attention. He hadn't personally used arson himself, but it seemed to be an interesting enough topic to hold his attention.

(Who cannot spell "Thespian," for that matter.)

She's behind her desk, ~~surfing LiveJournal~~ grading papers.

~~OMG don't find bugporn until I can make emo posts about youuuuuuuuuu. Heh.~~

~~:O!!!~~

~~lolz~~

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