C9- Crude oil and fuels
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Crude oil def? How is it extracted? Made of what? Is eventually used for?
A mixture made from remains of biomass from microscopic organisms (algae and plankton) Drilling Different hydrocarbons Petrol and diesel fuel
2 living organisms that made up crude oil
Algae and plankton
How was crude oil made?
Remains from algae and plankton buried under layers of rock, creating high pressure and temperature, lack of oxygen
Hydrocarbon
A compound that contains only hydrogen and carbon atoms
How to make crude oil useful?
Fractional distillation to separate the substances
What are alkanes? What mainly consists of alkanes?
Saturated hydrocarbons, contain maximum number of hydrogen atoms Crude oil
What do straight lines in alkanes represent? General formula for alkane molecules?
Single covalent bonds CnH 2n+2
First 6 alkanes?
Methane Ethane Propane Butane Pentane Hexane
Alkane state at room temp depends on..? Why?
Depends on intermolecular forces Bigger forces, higher boiling point
Smaller chains of hydrocarbons Boiling point? Volatility? Viscosity? Flammability?
Lower, weak intermolecular forces, need less energy to overcome High volatility- turns into gas easily Low viscosity, very runny Highly flammable
Larger chains of hydrocarbons? Boiling point? Volatility? Viscosity? Flammability?
Higher, stronger intermolecular forces, more energy to overcome Low volatility High viscosity Lower flammability
How is crude oil separated? Into what and its def?
Fractional distillation Fractions- groups which have similar boiling points
Describe the process of fractional distillation of crude oil
Crude oil heated at around 400 oc, fed into fractionating column as vapour, some is drawn off as a liquid at bottom Temperature gradient in the column, coolest at top. Vapours rise until they reach their boiling point, then cool and condense These fractions collected as a liquid Hydrocarbons with lowest boiling points move to top of column where coolest
What are the products of complete combustion of a hydrocarbon? What does incomplete combustion of a hydrocarbon produce?
Carbon dioxide and water Carbon monoxide
How to test the products of complete combustion of a hydrocarbon?
Gas produced from flame, travels through ice bath where it condenses due to ice and the water turns blue cobalt chloride paper pink. Gas then bubbled through limewater, where carbon dioxide turns it cloudy
Complete combustion… Oxygen? More likely in? H atoms become? C atoms become? Products cause?
Enough oxygen Small alkanes and blue bunsen flame Water Carbon dioxide Contributes to climate change
Incomplete combustion Oxygen? More likely in? H atoms become? C atoms become? Products cause?
Not enough oxygen Large alkanes and yellow bunsen flame Water Carbon monoxide or carbon (soot) Carbon monoxide is toxic, carbon causes lung disease
How to work out… in combustion of hydrocarbon equation? CO2 atoms? H2O atoms? O2 atoms?
CO2= number of C atoms in hydrocarbon H2O= CO2 +1 O2= CO2 + (1/2 x H2O)
What is cracking? What type of reaction is it?
Process of breaking down long hydrocarbons into shorter more useful ones like, alkanes and alkenes Thermal decomposition
General formula for alkenes? How to tell alkenes?
CnH2n Unsaturated, contains double bond between C atoms
How to test for an unsaturated hydrocarbon?
Bromine solution will turn from orange to colourless
Difference between thermal and catalytic cracking
Thermal- high temp and pressure Catalytic- low temp and pressure
Thermal cracking Takes place in? Temp? Pressure? Catalyst?
Industry 450-750oc 70 atm None
Catalytic cracking industry? Temp? Pressure? Catalyst?
500oc 1atm Zeolites