organic chemistry

year 10

what is unsaturated

when there is a double bond ( alkene)

what homologues formula does an alkane have

CnH2n+2

what are the steps of fractional distillation for crude oil

• heat the crude oil at a high temperature 500-700 so that it vaporises

• the vapour travels up the fractional column

• as u go up the column , it gets cooler

• if the temperature is above a hydrocarbons boiling point, it condenses back into a liquid and falls to the bottom of the column

• the hydrocarbons at the bottom - have long chains of hydrocarbons and have high boiling points

• this works as every hydrocarbon in crude oil has a different melting point

• the further down the column, the thicker darker coloured oil + less flammable

• the liquid is then collected

what is the process of cracking?

catalyst cracking = includes zeolites and large hydrocarbon burned to form vapour - when the vapour comes into contact with the catalyst, the hydrocarbons break in half to form smaller chains

temperature - around 520-720

why is cracking useful?

so larger hydrocarbons like bitumen can be made smaller and put to use as fuel to become more flammable

what is the order of the hydrocarbons in the fractionating column from crude oil top to bottom

propane + butane (petroleum gasses) - petrol - kerosenem- diesel - heavy fuel oil - bitumen

why can combustion be risky?

as if there is insufficient oxygen , incomplete combustion will happen which produces carbon monoxide which is a toxic gas ( this cause respiratory issues but also binds to the red blood cell , taking oxygens place , so less oxygen carried around body)

• if there are impurities such as sulfur or nitrogen in the hydrocarbon , they can react with oxygen to form hydroxides which mix with clouds to form acid rain

conditions for cracking needed

high temp and need to come into contact with either a catalyst (zeolite) or steam

what is formed from incomplete combustion?

soot and carbon monoxide