Alkanes Flashcards
what are alkanes
they are a homologous series of saturated hydrocarbons
what’s alkanes general formula
CnH2n+2
are alkanes reactive and why
no due to strong covalent bonds between atoms
although alkanes are unreactive what can they do
alkanes can burn in oxygen (combustion)
and they can react with halogens to form halogenoalkanes
explain the trend in BP of straight chain alkanes
as chain length increases/mr surface area contact increases, more van der waals forces can form between molecules which takes more energy to break
what happens to BP with branched isomers of alkanes
BP decreases as the more branched a molecule is, less van der waal forces can form between molecules
are alkanes polar or non polar
why
non polar
C-H do not have a large difference in electronegativity
are alkanes soluble in water
no
what are alkanes used for
fuels and as starting materials (pharmaceuticals)
how is crude oil made
it is a fossil fuel and is formed from the remains of plants and animals and over millions of years heat and pressure convert these chemicals into crude oil
it is non renewable
what is in crude oil
a complex mixture of mainly alkanes (straight,branched and cycloalkanes),
some aromatic compounds (contains benzene)
and other compounds containing S,O,N
what is most of the crude oil mixture
what is in most demand
longer chain alkanes
shorter chain ones like naptha
what is cracking
cracking is the breaking of longer chain alkanes into smaller ones
cracking includes breaking the strong C-C covalent bonds
why do we carry out cracking (2(
1) shorter chains are higher in demand
2) alkenes are used to make plastic and polymers
are alkenes highly reactive
yea
