organic chemistry Flashcards
(41 cards)
what is crude oil?
a finite resource found in rocks made from a mixture of very large number of compounds- particulary hydrocarbon compounds (mostly alkanes)
how is crude oil formed?
over millions of years from effects of high pressure and temperature on remains of biomass - mainly plankton that was buried in mud
what are hydrocarbons?
compounds that contain hydrogen and carbon atoms ONLY
name first 4 alkanes
- methane
- ethane
- propane
- butane
monkey eat peanut butter
formula for alkanes
CnH2n+2
how can hydrocabons be separated in crude oil?
by fractional distillations into fractions that can be used to produce fuels and feedstosckl fro petrochemical industry
describe process of frational distiallation
- crude oil heated and vapourised
- vapours of hydrocarbons enter fractationing coloum that has temperature gradient
- vapours of hydrocarbons with high boiling points condense at bottom
- vapours of hydrocarbons with lower boiling points rise amd condense at top
temperature gradient- hot at bottom, cold at top
what is made from petrochemical industry
- polymers
- lubricants
- solvents
- detergents
what is made from crude oil- what are the fractions and their usages
order from top to bottom
- liquified petroleum gas- domestic heating and cooking
- petrol- fuel for cars
- kerosene- jet feul
- diesel- diesel engines
- heavy fuel oil- ships & power stations
what properties of hydrocarbons depend on molecule size and what are their trends
- viscosity- ^ hydrocarbons ^ viscosity
- due to increased intermolecular forces
- better lubricants, but not useful as fuel
- flammability- ^hydrocrabons , flammability
- useful as fuels
- boiling points- ^hydrocrabons ^boiling points
- increased intermolecular foces- ^energy
complete combustion of hydrocarbons:
- releases energy
- H & C oxidised to form water & carbon dioxide
what is cracking
hydrcarbons broken down to produce smaller, more useful molecules as demand for short chain hydrocarbons are more
2 types of cracking
and their conditions
Catalytic cracking
- high temperatures
- catalyst
Steam cracking
- high temperature
- steam
what does cracking produce
alkanes AND alkene
why are alkenes more useful?
- used to make polymers
- starting material for other chemicals
- more reactive than alkane
how to test for alkene
in bromine water
will turn colourless
formula for alkene
CnH2n
alkane vs alkene
- alkane
- alkene
- alkane- saturated
- alkene- unsaturated- fewer H atoms
- alkane- single carbon bonds
- alkene- carbon double bond
combustion of alkene
reaction w o2
can be compete or incomplete
incomplete more often’
^ smoky flame
hydrogenation of alkene
required conditions and outcome
- 150^C
- nickel catalyst
- alkene + hydrogen -> alkane (single bonds now)
hydration of alkene
required conditions and outcome
- 300^C
- 70atm- pressure
- water as steam
- phosporic acid as catcalyst
- alkene + steam (water) <> alcohol (reversible)
halogenation of alkene
- rapidly
di(halogen)(alkane) - dichloroethane
- double -> single
alcohol functional group
OH
alcohol condesed formulaes
CH3OH
CH3CH2OH
CH3CH2CH2OH
CH3CH2CH2CH2OH
