Fractional Distilation: Flashcards
What is the first purpose of alkanes?
= fuels
What is the second purpose of alkanes?
= starting material for the production of organic molecules
= [
Where do we find alkanes?
= crude oil
= mixture of straight chain + branched chain alkanes + other chemicals
- formed from remains of plants and animals
= heat and pressure causes the chemicals to form crude oil
Is crude oil renewable or non-renewable?
= non-renewable
How do we seperate these alkanes?
= fractional distillation
How are alkanes molecules attracted to eachother?
= intermolecular forces
= vanderwall forces
What are the boiling points of alkanes?
= longer carbon chain- higher boiling point- greater surface area for the formation of vanderwall forces
= shorter carbon chain- lower boiling point
What is the first stage?
= crude oil is heated in a furnace- coverts to gas
= crude oil vapours + liquids pass into fractionating collumn
= hotter at the BOTTOM
= cooler at the TOP
What is the second stage?
= crude oil vapours makes its way up the fractionating collumn
= different levels have collecting trays
= at some point the alkane would reach a temperature cooler than the boiling point- condeneses back into a liquid and passes out of the collum
Where are alkanes with collected?
=shorter chains- at the top of the collumn
= longer chains- at the bottom
Where are alkanes with very long chains collected?
= form a thick liquid- bitumem collected fro,m the bottom
Where are alkanes with very short chains collected?
= do not condense
= top of the collum as a gas
=
What does the fraction contains?
= number of alkanes with similar boiling points
What do we need these alkanes for top to bottom?
= petrol
= kerosene
= diesel
= lubricating oil
= fuel oil
