Organic Chemistry

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Discus: SAT/ACT Tests and Test Preparation: October 2003 Archive: Organic Chemistry
By Scion (Scion) on Thursday, October 23, 2003 - 11:53 pm: Edit

hey all u AP Chem ppl, does anyone know a good website for alkane/alkene/alkyne nomenclature? thanks. or what also would be good is if any of u can explain it well to me. thanks

By Encomium (Encomium) on Friday, October 24, 2003 - 01:31 am: Edit

I can explain it!

It's quite easy.

There are prefixes for the number of carbons in a carbon chain:
meth = 1 C
eth = 2C
prop = 3C
but = 4C
pent = 5, hex = 6, hept = 7,...etc.

Alkanes have the general formula CnH2n+2

So methane is
C (1) H (2x1 + 2) = CH4
ethane = C2H6
propane C3H8


Alkenes have adouble bond between two of the Carbons in the chain. That takes away 2 hydrogens.

Alkenes have a general formula:

methene is CH2
ethene is C2H4
propene is C3H6

Alkynes have the general formula CnH2n-2 because there is a triple bond in there, taking away 4 hydrogens from the all single bonded alkanes.

butyne is C4H6
hexyne is C6H10

Now, if you want to get into some functional groups lets do this:

alcohols: Basically you take off an H at the end, and add an OH. the name ends in -ol

methanol CH3OH (or CH4O)
ethanol C2H5OH (or C2H6O)
propanol C3H7OH (or C3H8O)
Basically you take the alkane and add an O, or you take the alkyl group (CnH2n+1) and add the functional group OH

amines: take the alkyl group (CnH2n+1) and add NH2...these are weak bases.

methanamine (or methyl amine) is CH3NH2 (CH5N)
ethanamine (ethyl amine) C2H5NH2 (C2H7N) basically you're adding NH to the formula because you're taking off the end H of the chain and adding the functional group -NH2

carboxilyc ? acids. The forumlas for these are trickier, but still doable. The carboxyl group is COOH, and acts as a weak acid. Basically what I do (and this isn't always the smartest way but it works) is say a net ionic equation asks for butanoic acid:

1) First I take the alkyl group of propane (C3H7)
2) Then i add the COOH at the end:
C3H7COOH or C4H8O2....

It's quick.

here I hope that made sense

By Scion (Scion) on Friday, October 24, 2003 - 01:41 am: Edit

hey thanks a lot. by the way, what is ur ap chem class learning right now? my class is so behind-we've only done 2 chapters! (gases & thermodynamics)

By Longhorn (Longhorn) on Friday, October 24, 2003 - 02:03 am: Edit

you might want to use Organic Chemistry by Morrison and Boyd - an excellent book for understanding organic chem (its probably AP level or higher - indians use it for IIT preps). there's no site better than Google for chem, I almost always found everything I wanted to on it. often you can find 3d models (pdb files) and 2d diagrams of whatever you want

By Hikarikun (Hikarikun) on Friday, October 24, 2003 - 03:06 am: Edit

are u guys taking AP Chem right now?

I took AP chem last 5 on it...

Organic Chemistry part is the one that least appears on the exam.

So teachers don't take that chapter seriously...

my teacher didn't teach it...she just gave out WS from honors chem...

Probably organic chem and nuclear stuffs are the least important...I think

Equilibrium chapter is the most important...because #3(required calculation problem) is always about equilibrium =)

By Encomium (Encomium) on Friday, October 24, 2003 - 12:34 pm: Edit

My AP chem class is currently on gases, but we mixed in a lot of stuff we've done
basic chem, atoms, molecules, ions, stoichiometry, descriptive chemistry (net ionics), redox, redox titrations, precipitation titrations, 1,000,000,000 labs, standardization, all that stuff....

we have a 100% pass rate on the AP chem exam also
we did orgo b/c it's on the net ionic section and in my school like everyone gets a 100% on that section since he drills everything into us

By Scion (Scion) on Friday, October 24, 2003 - 04:07 pm: Edit

hey encomium, since ur school's good at descriptive chem, do u have any websites that might be helpful for that? cuz my teacher is just hopeless. wow, 100% pass rate? thats awesome

By Dkm (Dkm) on Wednesday, October 29, 2003 - 05:56 pm: Edit

man u ppl have it easy in AP chem..i did these things in 10th grade..i am doing IB chem HL....its HELL!

By Hikarikun (Hikarikun) on Wednesday, October 29, 2003 - 08:57 pm: Edit

I did it in 10th grade and AP chem teacher just assumed that we know those things...

By Scion (Scion) on Wednesday, October 29, 2003 - 09:28 pm: Edit

whats the difference btwn ap and ib?

By Dkm (Dkm) on Thursday, October 30, 2003 - 06:52 am: Edit

a lot...if u do higher level...IB goes into more depth..SL is pretty much the same

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