1. Observe prefixes. Hept is the prefix for the number 7, and I thus postulate that Heptene is associated with C7H14 as this is the only molecule with 7 C's or H's.

There are two molecules starting with Prop. (Propyne, Propane)There are two molecules starting with But. (Butyne, Butene)There are 2 molecules with 3 C's, and 2 molecules with 4 C's.There is only 1 molecule with 2 C's. Therefore Ethyne matches with C2H2.

Next observe there are three suffixes: -ene, -yne and -ane.

I postulated that Heptene is associated with C7H14. Here 14 is twice 7, so I assume this is the rule for the suffix -ene.

There is one other molecule with suffix -ene. This is Butene. Also C4H8 is the only structure where H's are twice C's. Therefore Butene = C4H8, and the prefix But- refers to the 4 C's. There is only one other molecule with 4 C's, which is C4H6. Therefore C4H6 = Butyne.

Therefore -yne refers to the combination where H = 2C - 2.

Finally Prop- must correspond to 3 C's. Propyne must be C3H4. Leaving Propane = C3H8.

*Edited on ***August 16, 2012, 10:11 pm**