Question

A straight-chain alkene with seven carbons has two double bonds and one bromine atom bonded to one of the carbons.
Which option correctly describes the general formula for this alkene? 
C7H9Br
C7H13Br
C7H7Br
C7H11Br

The answer I have is, C7H13Br. Is this correct?

Answer 1

I don't see how it can be C7H13Br, I think you put in your drawing only one double bond.

Answer 2

What could it be then?

Answer 3

C=C-C=C-C-C-C
2 H on C1
1 H on C2
1 H on C3
1 H on C4
2 H on C5
2 H on C6
3H on C7
So that straight chain diene is C7H12, Take one of the H atoms off any C and replace with a Br to make C7H11Br. OR this way.

Draw the straight chain C with C-C-C etc.
Put two double bonds in.
Add H atoms to each C to make 4 bonds on each.
Exchange a Br for one of the H atoms.
Count C
Count H
Count Br
It comes out C7H11Br.

Answer 4

Hey fun thing, a paper was literally just published that showed that a carbon with SEVEN bonds is possible. So it is theoretically possible