[hockey101]

Ok, I'm having trouble on some questions that keep asking me what do the numbers in the names tell you and why do some names have no numbers.   

I have managed to do alkane, alkene, and alkyne on my own but am having a hard time figuring out alcohol and ketone. 

I believe the characteristic part of Alcohol is C-O, and for Ketone
C-C and C=C (single and double bonds). 

So my question is if the position of the numbers for alcohol has to deal with C-O (which I believe is Carbon to Oxygen bond?) and for Ketone is it where the single bond C-C and the double bond C-O are together? 

If that's right, why do some of them not have numbers?

[Borek]

Give examples of names that you don't understand.

[hockey101]

I did Alcohol and Ketone

[Borek]

These are not examples of names, these are classes of compounds.

[hockey101]

Well my worksheet asks what the names tell you in Ketone and Alcohol and why some of them don't. 

She did give us an entire sheet with examples of each compound.

An example for Alcohol with a number would be 1-hexanol and without ethanol

For Ketone:  With number- 2-pentanone; without numbers:  butanone 

[AWK]

There is only one butanone, and there is only one ethanol - hence numbers may be omitted.

[Mr. Inquisitive]

The number indicates the position of the double bond and the substituent (if there's any).