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chemistry
chemistry paper 2
organic chemistry
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Cards (18)
what is cracking?
a
thermal decomposition
reaction
what are the 2 types of cracking called?
1
catalytic
cracking
2
steam
cracking
what is the formula for alkanes?
CnH2n+2
what is the formula for alkenes?
CnH2n
how does catalytic cracking work?
heat
the
hydrocarbons- vaporise
pass
vapour
over
hot powdered
aluminium
oxide
(
catalyst
)
as they come into contact with the catalyst the
long
hydrocarbons split into
2
smaller hydrocarbons
how does steam cracking work?
heat
the
hydrocarbons- vaporise
mix vapour
with
steam
heat the
mixture
up to very
high temperatures
causes
long chains
to
split
into
smaller
ones
what is the cracking equation?
long
chain
alkane --> shorter
alkane
+
alkene
what is the test for alkenes?
Bromine
water test, goes
orange
to
colourless
if present
what are alkenes added together to make?
Polymers
(
plastics
)
what is crude oil made from?
plankton
how is crude oil separated?
Fractional distillation
what do crude oil contain a mixture of?
Hydrocarbons
what are hydrocarbons?
a compound of
hydrogen
and
carbon
ONLY
what are alkanes?
Hydrocarbons with
single
bonds. they are a
saturated
substance which means they can't form new
bonds
with other substances
what are the first 4 alkanes?
methane
ethane
propane
butane
what is the 1st stage in fractional distillation?
heating
the
crude
oil
why do longer chains have higher boiling points?
they have more
weak
intermolecular
forces so they require more
energy
to
overcome
the forces
what are alkenes?
Hydrocarbons with at least 1
carbon
double
bond, they are
unsaturated
which means they can form new bonds to other substances