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    Hello all

    Basically i'm stuck on a very small part of Organic Chemistry, but it's driving me mad lol. When presented with a name 3-ethyl-2-methylhexane for example, I know how to draw it out pretty well and the side chains - but how do you know the amount of atoms for every CH?

    The images for chemguide will help me explain:

    This is the original:
    http://www.chemguide.co.uk/basicorg/...s/alkane4b.GIF

    Then after they fill the hydrogen atoms:
    http://www.chemguide.co.uk/basicorg/...s/alkane4c.GIF

    I know it's probably very obvious, but how do they fill in all the CH's in the whole organic compound?
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    You can fit four bonds onto each of those carbons so around each C, the number of Hs you'll have is 3, 1, 1, 2, 2, 3; though the second image shows that. Is that what you wanted to know?
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    Every carbon atom can bond to 4 different atoms. Hydrogens will fill up the empty bonds that haven't been used.
    CH2 shows that the carbon is already attached to two other groups allowing two hydrogens to be bonded, while CH3 is only bonded to one other group leaving space for 3 hydrogen bonds.
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    (Original post by HSethi)
    Hello all

    Basically i'm stuck on a very small part of Organic Chemistry, but it's driving me mad lol. When presented with a name 3-ethyl-2-methylhexane for example, I know how to draw it out pretty well and the side chains - but how do you know the amount of atoms for every CH?

    The images for chemguide will help me explain:

    This is the original:
    http://www.chemguide.co.uk/basicorg/...s/alkane4b.GIF

    Then after they fill the hydrogen atoms:
    http://www.chemguide.co.uk/basicorg/...s/alkane4c.GIF

    I know it's probably very obvious, but how do they fill in all the CH's in the whole organic compound?
    Every carbon has 4 bond

    so if you can draw it out just count the number of bonds remaining and place a hydrogen there
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    Ok, I understand that C has to bond with H four times, but why are the CHs which are bonded with the side chain, only CH? And how do you work out the side chains as well? Sorry about this, but for some reason it's not sticking.
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    (Original post by HSethi)
    Ok, I understand that C has to bond with H four times, but why are the CHs which are bonded with the side chain, only CH? And how do you work out the side chains as well? Sorry about this, but for some reason it's not sticking.
    As everyone has said already, every carbon must have 4 bonds. Just count the number of C-C bonds there already and add the appropriate number of C-H bonds to make the total number of bonds for each carbon 4. When a carbon has a side chain coming off from it, it has 3 C-C bonds already so to make it 4, you place one hydrogen there, giving you CH. The hydrogens are placed on the side-chains in exactly the same way as the backbone.
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    Ahhh, right. Thanks alot Kyri - I understand it now. Cheers.
 
 
 
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