I am suppose to name alkanes, but I don't know how to do it, if possible to give me an example on how to do it, but here is one of the questions I have to do.
CH3-CH-CH2-CH3
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CH3
You see the problem with trying to draw structures on this forum. It's almost impossible. Number the carbon chain so that the CH3 group is attached to the carbon with the smallest number; i.e., I assume it is attached to the C that is two from the left like this
CH3CH(CH3)CH2CH3 so you number from the left. The chain is 4 carbons long and it is saturated; therefore, it is an ane (because it is saturated--no double bonds), it is four C long so it is butane, and the methyl group is attached to C #2 so the full name is
2-methylbutane. Here is a site that shows a structure of what I think you are trying to draw.
The site didn't show up on this post is it possible for you to post it? Thanks.
Sorry about that. I didn't click the button at the right time.
http://chemistry.about.com/od/factsstructures/ig/Chemical-Structures---M/2-methylbutane.htm
To name alkanes, you need to follow a set of rules called the IUPAC (International Union of Pure and Applied Chemistry) rules for naming organic compounds. Here's an example of how to name the given structure:
1. Start by identifying the longest continuous chain of carbon atoms. In this case, the longest chain contains 4 carbon atoms, so it is a butane.
2. Number the carbon atoms in the chain from the end that gives the substituent (branch) the lowest possible number. In this case, numbering from the left gives the lowest number for the substituent.
CH3-CH-CH2-CH3
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CH3
3. Now, we have a methyl (CH3) substituent attached to the third carbon atom from the left. So, we write it as 3-methyl.
4. Combine the name of the substituent with the name of the parent chain separated by a hyphen. Thus, the complete name for this molecule is 3-methylbutane.
Remember, always count the longest continuous chain of carbon atoms to determine the parent chain, and locate and name any substituents based on their position in the chain.
I hope this example helps you with naming alkanes. Let me know if you have any further questions!