Organic Chemistry (C7 Topic) Flashcards
What is crude oil?
A mixture of many hydrocarbons
What are hydrocarbons?
Only containing hydrogen and carbon atoms
How is crude oil found and formed?
Found in rocks and formed from dead plants and animals (which spent millions of years buried in mud)
What is crude oil processed to produce?
Fuels, solvents, detergents, lubricants
What is complete combustion?
An oxidation reaction that occurs when a fuel reacts with plenty of oxygen
Word equation for combustion?
Hydrocarbon + oxygen
➡️ Carbon dioxide + water
Why are hydrocarbons used as fuels?
Combustion releases a lot of energy
As the length of hydrocarbon chains increase, the boiling point…?
Increases
As the length of hydrocarbon chains increase, the viscosity…?
Increases
As the length of hydrocarbon chains increase, the flammability…?
Decreases
What is fractional distillation?
A process used to separate hydrocarbons in crude oil into fractions according to boiling point
Is the fractional distillation column hotter at the top or bottom?
Bottom
What happens to crude oil at the start of the fractional distillation process?
Crude oil (before entering the column) is heated until most has evaporated
Why do longer hydrogen carbons condense near the bottom of the column?
They have higher boiling points
Why do shorter hydrocarbons condense near the top of the column?
They have Lower boiling points
In order of Top (coolest) to bottom (hottest) what is fractions off first to last?
(At the top)
•LPG: Liquified petroleum gas
•Petrol
•Kerosene
•diesel oil
•heavy fuel oil
What are Alkanes?
The simplest type of hydrocarbons, containing only single covenant bonds (saturated)
What is the general formula for Alkanes?
Cn H2n+2
Order of the first 5 Alkanes:
Methane, Ethane, Propane, Butane, Pentane
What is the formula of Methane?
CH4
What is the Formula of Ethane?
C2H4
What is Cracking?
Breaking down long-chain hydrocarbons into shorter more useful ones.
Word equation for cracking?
Long-chain alkane ➡️ Shorter chain alkane + Alkene
What is Alkenes use?
Used to make polymers and are a staring material for making other chemicals
What are the 2 Methods of Cracking?
Catalytic and Steam
Once long chain hydrocarbons are vaporised by heating, then what happens in Catalytic cracking?
Hydrocarbon vapour is passed over a hot powered aluminium catalyst..
Once long chain hydrocarbons are vaporised by heating, then what happens in Steam cracking?
Hydrocarbon vapour is mixed with steam and heat to a very high temperature
What can be done to determine an Alkane from Alkene?
Add an Alkene to bromine water
If an Alkene is present, what will happen to the bromine water?
Change from orange to colourless
