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A little Chemistry Help... please?


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Alright, I'm taking AP Chemistry next school year, and we got summer homework for the class. (That's just unfair!)

 

I've been reading through the chapter for the past hour without understanding a word of it. I'm doing some work with Formation of Ionic Compounds.

 

I have no idea what to do with it after figuring out what Valence Electrons each element has. (E.G. Sodium has 1, Nitrogen 5) Somehow, with that information, we're supposed to figure out how many atoms of Sodium is needed as well as how many atoms of Nitrogen, then how many electrons have to be taken away and added in order to make the total charge 0.

 

How this is done... I have no idea whatsoever.:confused:

 

If anybody could help me with this, I would be very grateful.

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First thing's first: why are you trying to make a compound of nitrogen and sodium? :p

 

IIRC it's the atom's charge in conjunction with the valence electrons that will help you figure out how many atoms. For instance if you want to combine sodium (Na) and chlorine (Cl) to make table salt, you need to know the following:

 

Each atom wants to have a full shell of 8 electrons, and a molecule is most stable with a neutral charge.

 

Sodium has 1 valence electron. To make it happy it must give up one electron (giving it a +1 charge). Chlorine has 7 valence electrons. To make it happy it must steal one electron (giving it a -1 charge). Therefor if you've got a sodium with a +1 charge and a chlorine with a -1 charge, you need one of each atom of each element to neutralize the charge.

 

Basically what would happen is your chlorine would happen upon your sodium and go "hey, you've got an extra electron -- GIMME!" and the chlorine would steal the sodium's 1 valence electron, making both atoms happy. So they'd, uh... kinda be a couple? :p

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Oookkkaaayyy then..............

 

Actually, that made a lot more sense than the book.

 

Yeah, I don't know why I want Sodium Nitrate either, but I figure the book's author(s) knew what they were doing.

 

Thanks a lot, I might actually be able to finish this stupid homework! (Then start some English HW!)

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Well nitrate is actually a compound itself -- NO3. Tossing that at you right off the bat is cruel, because to do it you'd need to know that nitrate has a -1 charge.

 

I did just teach you the 'cheat' way to do it, though. Basically if you have two elements you're trying to combine, just figure out what their charges would be and whatever the charge of Element A is will be the number of atoms for Element B and vice versa.

 

Here's a little explanation of ionic compounds and bonding. If you can figure out the basis of the bond, figuring out the rest comes much easier. :)

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Oookkkaaayyy then..............

 

Actually, that made a lot more sense than the book.

 

Yeah, I don't know why I want Sodium Nitrate either, but I figure the book's author(s) knew what they were doing.

 

Thanks a lot, I might actually be able to finish this stupid homework! (Then start some English HW!)

 

EDIT:: Inyri beat me.

 

_EW_

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The advantage of chemistry is that while it is much work involved' date=' you are not at the mercy of the teachers oppion about you. It's nice with subjects that dosen't punish you if you happen to be hated by the teachers.[/quote']Hehe, try taking physics with a teacher that used to work for NASA :crybaby:

 

Thank goodness for grading on a curve.

 

EDIT: Whoops, you said "advantage". Apologies.

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Inyri: Inorganic chemistry can be good fun, our textbook provided (if you had half a brain) the instructions needed to make terrorist style fertilizer bombs.

 

Achilles: Eish, never did much physics, too much mathematics involved (got 4 in maths, 6 in chemistry, go figure). Anyway I think having "genius" teachers are a good thing, they can usually explain why you're wrong when you argue with them, instead of just saying "the teacher is always right, even when proven wrong".

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Of course' date=' 'cause it lack booms!!![/quote']

o_0

 

I really recommend that you don't turn your back on an organic experiment. Seriously.

 

Edit: A-Level Chemistry hurt my back...

bookshs0.jpg

 

The 900 page tome at the bottom was my bible...

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The advantage of chemistry is that while it is much work involved' date=' you are not at the mercy of the teachers oppion about you. It's nice with subjects that dosen't punish you if you happen to be hated by the teachers.[/quote']

 

*Muhahahah* See I used to do really well in Chemistry; only because I played football (soccer) with my Chemistry teacher, and generally he would be, shall we say still be intoxicated from last night's illegal activities; as such, I always looked forward to Chemistry - being good at sport does have it's perks :xp:

 

Hehe, try taking physics with a teacher that used to work for NASA

 

Was he interesting or boring? I never minded hard, demanding teachers as long as they were interesting. I only ever gave the boring ones a hard time.

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*Muhahahah* See I used to do really well in Chemistry; only because I played football (soccer) with my Chemistry teacher, and generally he would be, shall we say still be intoxicated from last night's illegal activities; as such, I always looked forward to Chemistry - being good at sport does have it's perks :xp:

Plus, there are essay questions on the A2 papers of the A-Level (the AS portion of the A-Level uses a different format of exam). "Explain, with reference to molecular interactions, why X is more red than Y when cinnamon is added" and so on. So you'd be at the mercy of the examiner to decide if you were using precise enough language and so forth.

 

Chemistry isn't all maths...

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Ungh...AP chem...you have my sypathy. :p I chose AP Environmental Science instead, no math involved. :D Same here, the interesting teachers made life better. Class is so much easier when you actually stay awake and don't zone out. And, your right, summer projects suck! I have 5 of them. :headbump

 

As Palvos said, its not all math. I saw a released AP Chemistry exam and about 1/4- 1/3 of it was theory.

 

Edit: I reccomend the Princeton Review's Cracking the AP Chemistry Exam. I've never seen it myself but I got their cracking the AP U.S. History one and it saved my life. ;)

 

~HOP

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Pavlos: I only took chemistry this year, and that was all boring (but easy) theory, the explosions I made myself at home (not counting the experiment I, err, spiced up).

 

J7: If I still had chemistry this year, I'd hate you, and if I didn't get top grades when I had it, I'd send something from Russia with "love":D

 

Summer struglers: Look on the bright side, I need to learn Russian as a summer project:(

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Was he interesting or boring? I never minded hard, demanding teachers as long as they were interesting. I only ever gave the boring ones a hard time.
He was fascinating. Any teacher that starts stories with, "When we were designing the shuttle..." is automatic win.

 

Big surprise that he was also all kinds of geeky so the tests were fun. Stuff like, "Explain why the newest mountain dew commercial violates the laws of physics" and stuff like that. I never confirmed it, but I think he awarded geek points if you could massage star trek trivia into your answers. :)

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My chemistry teacher didn't like to teach so for the most part she just gave us assignments and told us to come in if we needed help, and then when we did come in, she would (not) answer our question by asking the question we had just asked only with a different wording. The only reason I passed was because my friend and I made calculator programs that did a lot of the stuff we "Learned", and then gave them to the other people in the class so if they had an answer we couldn't get with our programs they would just give it to us. It was beautiful when the teacher left for 2 weeks, we had a guy who had helped design missiles for the air force who actually taught us, I think I learned more from him in those 2 weeks than I did from my normal teacher the rest of the year.

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