[Toyotataco4x4]

I have got to draw all the constitutional isomers for C4H8O. There are 31 and 13 of them are cyclic. I've got some but not all. So if anyone is up to answering my question I would appreciate it a lot!!!!!!!!!!!! Thank you

[macman104]

Well, you need to post what you have so far.  People may point out a few structures you have missed, but I doubt anyone is going to list all of them out for you.

[spirochete]

To get you started I'll suggest finding elements of unsaturation.  This tells you how many pi bonds and/or rings will be present in any isomer with a given molecular formula.  Each pi bond and ring connection removes 2 hydrogens from your molecular formula.

For saturated compounds containing only carbon, hydrogen and oxygen we expect 2N+2 hydrogens, where N equals the number of carbons.  Try drawing any compound with just those elements and you'll see this is true.

Now for calculating the # of elements of unsaturation there is a handy formula you can use: ((2N+2)-(# of hydrogens in actual compound))/2

I like to think of it as (expected number of hydrogens minus actual number of hydrogens)/2