Alkanes

what are single C-C and C-H bonds made of ?

sigma bonds allowing free rotation

general formula for alkanes

CnH2n+2

what is the trend in boiling points of alkanes ?

bp of straight-chain alkanes incs with chain length due to incd sa and so incd ldn forces between molecules.

why are alkanes non polar ?

bcs of their CH bonds also making them immiscible in water

why are alkanes so unreactive ?

they require a rlly high activation energy so are generally unreactive

what are the general products of complete combustion

water and CO2

products of incomplete combustion ?

CO and water - maybe soot

what is the first step in free radical substitution (using Cl2 as an example)

initiation: the weakest bond is broken

in this case the Cl-Cl bond is broken using UV light

what is the second stage of free radical substitution? (reaction between Cl2 and CH4 as an example)

propagation :

the free radicals are vv reactive so the Cl free radical abstracts a hydrogen atom from methane forming a methyl radical

this methyl radical is also vv reactive so reacts w/ a chlorine molecule producing a chlorine radical and the whole process starts over again

what is the third stage of free radical substitution? (reaction between Cl2 and CH4 as an example)

termination : the radicals are removed bringing an end to the reaction

limitations of free radical substitution?

a mixture of products bcs of the many possible reactions

substitutions at many diff positions along the chain