science (chemistry)


making crude oil useful

crude oil,coal and natural gases are fossil fuels

fossil fuels are:

formed over millions of years, they cant be reused because they are used up fast.

crude oil

its found in the earths crust. its transported using piplines or trucks, oil can cause oil spills which goes into the sea and this is called slick. its harms animals and beaches 

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Fractional distillation

crude oil is made up of hydrocarbons. A hydro carbon is made up of hydrogen atoms and carbon atoms. 

diiferent hydrocarbons have different boiling points. this means it can be seperated using fractions.

the column has a temperature gradient, which makes it hotter at the bottom. 

fractions with low boiling points (gas) leaves at the top. 

fractions with high boiling points stay at the bottom ( bitumen)

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Hydrocarbons can be described aalkanes or alkenes.

Alkane molecules get broken down into smaller, more useful, molecules.

cracking needs a catalyst, high temp, high pressure.

its used to make more petrol from naptha. its also used to make alkene molecules to make polymers.

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forces between molecules

there is strong covalent bonds between the atoms. 

weak intermolecular forces.

the longer the molecule the stronger the force is.

heating allows the molecules to sperate mixtures of hydrocarbons.

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Complete combustion 

Blue Flame!! 

CH4+ 202--- CO2 +2H20

methane + oxygen---- Carbon dioxide +water 

wheb fuels react with oxygen they burn and release useful heat energy. 

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Combustion 2

imcomplete combustion 

Yellow flame!!  

methane+oxygen---- carbon monoxide +water 

when it burns without enough oxygen thats when it creates imcomplete conbustion.

its creates a poisonous gas and leads to soot. 

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