Check out the molecular formula of hydrocarbon.Proceeding from it, it makes a formula first unbranched carbon skeleton (carbon chain).
Above each carbon atom, mark its serial number.
Then arrange the hydrogen atoms in the chain.Do not forget: the carbon is tetravalent.
Reduce the carbon chain by one atom.Position it as a side branch of the carbon chain.Do not forget that the atoms, which are located at the outer atoms in the chain may not be the lateral branches.
determine which edge closer lateral branch.Number the carbon chain again, since this region.Arrange the hydrogen atoms in accordance with the valence of carbon.
Determine whether you can have a side branch at the other carbon atoms in the chain
.In the case of positive findings, make a formula isomers.If this is not possible, reduce the carbon chain has an atom and position it as another lateral branch.Note: near one carbon atom can have no more than 2 side branches.
Arrange the serial numbers of carbon atoms from the edge, which is located closest to the lateral branch.Of each atom located by hydrogen atoms given carbon valency.
Again, check whether there is an opportunity to arrange side branches at other carbon atoms in the main chain.If such a possibility exists, then make a possible isomers of formula - if not even reduce carbon atom chain and position it as a lateral branch.Now number the entire chain of atoms, and try again to make formula isomers.In the event that has two lateral branches are at the same distance from the edges of the circuit, start numbering from the edge, whose side branches more.
Continue these steps until until exhausted all possibilities for the location of the lateral branches.