If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:2:56

Correction - 2-propylheptane should never be the name!

Video transcript

in the last video we tried to draw a two propyl propyl heptane and we did our best attempt at drawing it but it was pointed out that this wouldn't even be called two propyl heptane to begin with so you actually should never see something called two propyl heptane and let me show you what I'm talking about so when you see something like this you might immediately say and well the way we drew it was actually correct it just wouldn't be called two propyl heptane so you say heptane so that is a seven carbon alkane no double bond so 1 2 3 4 5 6 7 and then on the second carbon so you have 1 2 3 4 5 6 7 we have a propyl group propyl that is 3 carbons so on the second carbon we have a propyl group that's 3 carbons so that is 1 2 3 and so the way we drew it was just like this and so someone gave you two propyl heptane this would be what you would draw but you wouldn't call this two propyl heptane because remember if you're given the molecule you look for the longest chain and the longest chain here is not the heptane chain it is not one two three it is not this thing in magenta and in this kind of move color it's this chain where you start over here if you start over here 1 2 3 4 5 6 7 8 9 you actually get a longer chain so this would actually be the backbone of this molecule right over there that right over there would be the backbone and so you would number it and you start numbering closest to the group that's attached to 1 2 3 4 5 6 7 8 9 so you have nine carbons in your backbone so we're dealing with nonane we're dealing with nonane and you have a methyl group one carbon attached to the fourth carbon of our main backbone so this is going to be four four methyl four methyl this is our methyl group right here for methyl for methyl nonny so it was brought up I think the the username is my Knock - and they correctly corrected me that there would never be such a thing as - propyl heptane i just made that up if someone were to word a kind of labeled this molecule they would call it for methyl non aid and asked you to draw it but either way both of these would point you to the right direction this would just be the incorrect name for it because you'd be looking at if someone gave you this molecule you named it this way that would be incorrect so I apologize for this this is for methyl nonane if you do heptane you're not finding the longest chain