HELP!!! naming structures!!! so confused!?

Question

k so I drew them in paint. THANK YOU!!

http://img166.imageshack.us/my.php?image=structuresci2.jpg

Answer 1

1 = 2,4-dimethylpentane

2 = 3-methylpent-2-ene or 3-methyl-2-pentene

3 = 1-bromo-3-methylbenzene

4 = 1,2-dimethylpropanethiol

The best advice I can give you is to follow these rules. First, for acyclic compounds, find the longest cabon chain and that is the parent compound. In your case, 5 carbon atoms make the longest chain. One you know what the parent compound is, you just have to add in the substituents in priority order. And for aromatic and cyclic compounds, follow the priority rules for naming the substitution around the largest ring system and you home free! I know, its not that simple but if you practice, you will get the hang of it!!!

Answer 2

1= 2,4-dimethylpentane

    The longest chain that you can find is 5 carbons therefore its pent.......and there are no double/triple bonds so its an alkane. The structure has two methyl (CH4) groups giving dimethy and these are located at carbons 2 and 4.

2= 3-methylpent-2-ene

    Similar to 1 but this is an alkene as it has a double bond. This changes the end to ene, and we must specify where the double bond is, in this case its at carbon 2 giving pent-2-ene.

3= 1-bromo-5-methylbenzene

     This is a ring structure with a delocalised pi system of the name benzene. It has one bromide atom bonded at carbon one and one methyl group at carbon 5. (We say 1-bromo-5-methyl rather than 1-methyl-5-bromo as it goes in alphabeticle order in cases like this)

4= 1-?-2,3-dimethylbutane

    I am unsure what is attached to carbon one. It is hydrogen and sulphur, but am unsure of the molecule name. Perhaps hydrogen sulphide if you put one hydrogen rather than 2.

Answer 3

1----2,4 DIMETHYLPENTANE

2----3 METHYLPENT-2-ENE

3----2 BROMOBENZENE

4.....???

Answer 4

1. 2,4-dimethylpentane

The longest chain is 5 carbons long, and the side-chains are at positions 2 and 4.

2. 3-methyl-2-pentene

3. 3-bromotoluene

4. 1,2-dimethyl-1-propanethiol