chem p2

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734H

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What’s crude oil?
its a mixture of a very large number of compounds
How was crude oil formed ?
It’s formed over millions of yrs ago . It’s found in rocks and formed from remains of plankton buried in mud.
What’s hydrocarbons ?
compounds that contain hydrogen and carbon atoms only which are found in crude oils called alkanes .
what’s alkanes ?
They are saturated and contain single bonds only
What’s a molecular formula?
its a simple count of the no. Of each sort of atom present in the molecules .
What’s the molecular formula for methane?
C1H4
What’s the molecular formula for Ethane?
C2H6
What’s the molecular formula for Propane?
C3H8
What’s the molecular formula for Butane ?
C4H10
What’s the molecular formula for Pentane?
C5H12
What’s the formula for molecular
Cn H2n+2
How's fractional distillation work?
Crude oils heated
Most of the compounds in crude oil evaporate and turns into a gas
gases enter the column and rise
as they rise they also cool because there’s a temp gradient inside the column. It’s hot at the bottom and cooler near the top
when a substance reaches a height in the column where the temps equal its boiling point it condenses to from a liquid
the condensed fraction is separated and flows out through a pipe
Each fraction contains hydrocarbons with similar boiling points
Properties of hydrocarbons - viscosity
How easily it burns
Properties of hydrocarbons - b.p
how thick a liquid is
Properties of hydrocarbons - flammability
the temp at which the liquid boils or gas condenses
What’s complete combustion?
It’s when fumes burn in plenty of O to produce CO2 and water vapour
What’s incomplete combustion?
It’s when fuels r burnt w out a sufficient supply of O
What’s cracking of hydrocarbons ?
it’s when larger less useful molecules are broken down into smaller more useful molecules that can be used
2 methods for cracking
THERMAL which is heated at a high temp
CATALYTIC which passes over a zeolite catalyst