How many isomers have hydrocarbons must we know?

[Nomvalt]

Is it true that we need to know all the structural isomers for butane? How many isomers of hydrocarbons do we need to know?

[m@tty]

I just looked at the study design and there is nothing said about isomers in unit 3, but in unit 1 they said:

structural isomers of C4H10

Which seems to indicate what you are saying, but they may well extend on this. My teacher said something about a question in a previous exam like this, I don't know..

[Martoman]

Butane only has two? What is so hard about remembering them??? If you forget it you can generate it logically??? 

[kazoospasm]

One of the exams from the previous study design asked for the isomers of C4H9Cl, and I doubt this part of the course has changed much .