Topic C7 - Organic Chemistry Flashcards
Crude Oil
- Finite Resource
- Mixture of many hyrdrocarbons
- Found in rocks and formed from dead plants
- fossils in mud
What are hydrocarbons?
Only contain hydrogen and carbon atoms
e. g
- methane
- ethane
- propane
- butane
What is crude oil used for?
- fuel stock chemicals for: - polymers - solvents - detergents - lubricants
Complete combustion
An oxidation reaction that occurs when a fuel reacts with plenty of oxygen
What does hydrocarbon + oxygen produce?
Carbon dioxide + water
Why are hydrocarbons used as fuels?
Because combustion releases a lot of energy
As the length of the hydrocarbon chain increases, the…?
1) Boiling point increases
2) Viscosity Increases
3) Flammability decreases
Fractional Distillation
A process used to seperate the hydrocarbons in crude oil into fractions according to their boiling points.
What happens to shorter hydrocarbons during FRACTIONAL DISTILLATION?
They have lower boiling point, so condense near the top of the column
E.g petrol
What happens to longer hydrocarbons during FRACTIONAL DISTILLATION?
Have higher boiling points so condense near the bottom of the column.
What are alkanes?
- Contain only single covalent bonds (they’re saturated).
- The simplest type of hydrocarbon
- Most hydrocarbons in crude oil are alkanes
What is the formula for the homologous series of alkanes?
CnH2n+2
How many carbon atoms in methane?
1
How many carbon atoms in ethane?
2
How many carbon atoms in propane?
3
How many carbon atoms in butane?
4
Methane Formula
CH₄
Ethane Formula
C₂H₆
Propane Formula
C₃H₈
Butane Formula
C₄H₁₀
What does CRACKING do?
Breaks down long-chain hydrocarbons into shorter, more useful ones.
What are alkenes useful for?
- Used to make polymers
- Starting material for making other chemicals
Cracking chemical equation
long chain alkane ->
shorter-chain alkane + alkene
How are long-chain hydrocarbons vaporised
Long-chain hydrocarbons vaporised by heating.
2 methods of CRACKING
1) Catalytic Cracking
2) Steam Cracking
How does CATALYTIC CRACKING work?
Hypercarbon vapour is passed over a hot powdered aluminium catalyst.
How does STEAM CRACKING work?
Hydrocarbon vapour is mixed with steam and heated to a very high temperature.
Alkenes are more reactive than alkanes, TRUE or FALSE?
TRUE
What does adding alkene to bromine water do?
Bromine + alkene water = colourless
Adding an alkene to bromine water causes it to change from orange to colourless.
