Paper 2- Unit 7 Organic chemistry Flashcards
Crude oil is…
a mixture of hydrocarbons
An alkane is…
a saturated
hydrocarbon1
a hydrocarbon is,,,
a compound made of hydrogen and carbon only
first 5 alkanes
Methane Ethane Propane Butane Pentane
General formula for an alkane
C n H 2n+2
Fractional distillation in 4 steps
Evaporation- of the difference length hydrocarbons
Separation- long chains at the bottom, short chains at the top
Condensation- longer chains condense at higher temperatures, shorter chains condense at lower temperatures
Collection- each fractions (with similar BP) are collected
What is cracking?
When a long chained alkane
is split up into
smaller chained alkane and an alkene
What is an alkene?
An unsaturated hydrocarbon
contains a c=c (double) bond
Conditions for cracking
Heat hydrocarbon
over a catalyst
Name the first 3 alkenes
ethene
propene
butene
The test for an alkene is…
bromine water
turns orange to colourless
Problem with particulate
global dimming
problem with carbon monoxide
toxic gas
which is a silent killer
Problem with carbon dioxide
green house gas
causes global warmin
Problem with sulphur dioxide
dissolves in the clouds
forming acid rain
What is a finite resource?
one that will run out
Long hydrocarbons have higher melting points than smaller chains because..
the inter molecular forces
are stronger
as they have more atoms/higher Mr
Longer chains are more viscous (sticky) than shorter chains as..
intermolecular forces
are stronger
as they have more atoms/higher Mr
harder to separate
Complete combustion
hydrocarbon + oxygen –>
Complete combustion
hydrocarbon + oxygen –> carbon dioxide + water
Test for water
anhydrous copper sulphate
turns white
to blue
Test for carbon dioxide
Limewater
goes clear to cloudy
due to white ppt formed
