Science- Chemistry 1b

Oils, Earth and Atmosphere.

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Cracking and Fractional Distallation

Cracking- turning long chained molecules into shorter one's- makes Alkanes and Alkenes.

Smaller molecules more useful, e.g. Petrol.

To do this you must vapourise it and pass it over a catalyst.


Crude oil is separated by Fractional distillation, in a column. 

Bottom of column is hottest and thickest- longer molecules.

Top of column is gases.





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Alkanes and Alkenes

Alkane molecules have a single bond- saturated. Formular- Cn2n+2

Alkene molecules have a double bond- unsaturated because they can make more links. formular- CnC2n  Double the amount of hydrogen molecules.

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Plant oils and emulsions

Plant oils are extracted form food by squeezing and crushing them, they contain essential fatty acids.

Oils dont dissolve in water, mixing oil and water makes a emulsion- this is when droplets of one liquid are suspended in another liquid. e.g. mayonnaise is an emulsion of olive oil and vinegar.  


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Extracting and using plant oils

Vegetable oils can be turned into fuels.

Biodiesel is made form begetable oils and is a renewable source- good for the environment.

vegetable oils are unsaturated (good) and animal fats are saturated (bad)- saturated increase the cholesterol on the blood.

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