A-level Chemistry/OCR/Chains and Rings/Alkenes

Alkenes

The alkenes are unsaturated chains of carbon & hydrogen with one or more double or triple carbon carbon bonds. The simplest alkene is ethene $(C_2{H}_4)$ the general formula for simple alkenes is $C_n{H}_{2n}$. Notably, simple alkenes all end in the "ene" suffix, as opposed to the alkanes "ane" suffix. Another thing to note about alkenes is naming, the alkene functional group is the double bond, and thus when naming the compound the double bond defines if it's, for example, pent-1-ene or pent-2-ene.

$C{H}_2=CHC{H}_{2}C{H}_{2}C{H}_3$ is pent-1-ene.

$C{H}_{3}CH=CHC{H}_{2}C{H}_3$ is pent-2-ene.

Straight chain alkenes have marginally lower boiling points than their alkane counterparts & like the alkanes (and pretty much all homologous series), all simple alkenes have the same general formula, have similar chemical properties & show a trend in physical properties.

Bonding in Alkenes

The alkenes have a carbon double bond. The bonding in alkanes only consists of σ (sigma) bonds which means they're able to be twisted around...

Pictures coming soon!