Organic chemistry

Give a structural formula of 3,4-dimethylhex-2-ene

Give a structural formula of 3,4-dimethylhex-2-ene

Hi there! (:
just thought i'd answser this since probably need to start thinking of chemistry soon again when I go back to uni lol 😊
I would start by splitting it into parts:
3,4-dimethylhex-2-ene - its a 6 carbon chain (hex = 6)
3,4-dimethylhex-2-ene - the 2 here is the carbon which the double bond from the alkene will be! (its an alkene because ends in "ene")
3,4-dimethylhex-2-ene - di-methyl means that its 2 methyl branches (CH3) one on the 3rd and the other on the 4th carbon
then each carbon should have 4 bonds attached so make sure you include all your hydrogens! - ive attached an image of the answer so you can see it if you haven't already got it by now (im a little late to the post!),
in this answer ive drew both the skeletal and the structual formulae since its a bit clearer on the skeletal to see the bonds/branches - these both mean the same thing (aka im just lazy with drawing hydrogens when im scribbling stuff😅), i have also labelled each carbon in the longest chain so you can see it clearly - but if its asking for strucutral your looking to include them all! (the right hand side of image) hope this helps🤗
Emily
Year 3, Chemistry
Official University Of Strathclyde Rep

Whilst the above post is almost correct (you are missing a hydrogen on the displayed formula - don’t forget your own advice regarding the valence state of carbon!), it’s worth being aware that the intepretation of the term “structural formula” will depend on exam board and qualification level. Edexcel A level, for example, would typically expect the so called condensed formula, e.g. CH3CH=C(CH3)CH(CH3)CH2CH3.
Not that it’s hugely relevant, but your given answers aren’t the only correct responses - what do you notice about the groups around the alkene functional group and why might this suggest another response is equally acceptable?
And also given you want to start thinking about chemistry again, you might also spot that if you were to draw a 3D representation of the molecule, there are more possible responses yet - why is this the case and in all, how many acceptable structures would you be able to draw if you drew a 3D structural formula?

thanks for spotting my hydrogen lol - clearly been a wee while since I drew out the full structures of anything instead of the skeletal oops!😅
yep multiple ways to draw, you've got your different configurations with the E/Z alkene geometry and also with the 4th carbon of the chain you've got a tetrahedral sp3 stereocentre where u can think about its chrirality with R/S (: - so you've got 4 sterochemical isomers of one another & 3D wise you've got a bunch of single bond rotations you can play about with that will change the apperance but not the chemical strucutre
also to the person originally making this post - dont stress about all this stuff if you havent covered it already just having a yap lolol!! (:
Emily
Year 3, Chemistry
Offiicial University Of Strathclyde Rep