alkanes Flashcards
general formula
CnH2n+ 2
type of bonding present in alkanes
single covalent bonds (sigma bonds)
what is the shape and bond angle aroudn each carbon atom in alkanes
- tetrahedral
- 109.5 degrees
what are 3 steps in free radical substituition
initiation
propogation
termination
initiation
UV light breaks the halogen bond
propogation
radical react with alkanes to form new radicals
termination
radicals combine to form stable molecules
what is a free radical
a species with an unpaired electron
- highly reactive
why does free radical substituition require UV light
UV light provides energy for homolytic fission
what is the main type of reaction alkanes undergo with halogens
free radical substituition
what is cracking
Breaking long-chain alkanes into smaller alkanes and alkenes
why is cracking useful
it produces shorter hydrocarbons like gasoline
what are the 2 types of cracking
thermal cracking
catalytic cracking
what are the conditions for thermal cracking
temp: 700-1200
high pressure: 7000kPA
what does thermal cracking produce
alkenes
what products does catalytic craking produce
branched hydrocarbons
what is reforming in hydrocarbons
converting straight chained alkanes into branched or cyclic hydrocarbons
what catalyst is used for reforming
silica or alumina
