What does CH2 stand for in chemistry.?

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[QUESTION]:
the question i'm being asked is what is the name of the aromatic compound C6H5CH2CH2CH2Cl.
I know that the C6H5 is a benzene ring but i'm trying to figure out how to name the rest of it.
any help would be greatly appreciated.
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[RESPONSE]:
Hey! I'm going to give you a quick lesson so you'd never have to ask again (hopefully).

C6H6 is Benzene
C6H5 is a Phenyl group

CH2 - Methylene
CH3 - Methyl
CH4 - Methane

Here's how I think of it.
You need to count all the Carbons first, that are not grouped up (a chain).
C6H5 is a functional group, so don't necessary count the Carbons there.
In the case of (Cl)-CH2-CH2-CH2-(C6H5) , there are 3.
3 - Propane
4 - Butane
5 - Pentane
6 - Hexane
7 - Heptane
8 - Octane... etc.

Then you have to position it, like Carbon #1, Carbon #2..
We say that the Cl is on Carbon #1 of the three.
So we say 1-chloro....
And where is the phenyl? It's on Carbon #3!
So now we say 1-chloro-3-phenyl...
Now, there are three single-bonded carbons total, that makes it a propane.
So it's called 1-chloro-3-phenylpropane.

Note: If there are double bonds, then replace -ane with -ene.
If there are triple bonds, then replace -ane with -yne.

That should probably get you started...
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SRC: https://answers.yahoo.com/question/index?qid=20080220200902AAGuTep
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