hydrocarbons Flashcards
what kind of resource is crude oil and where is it found
- finite resource
- rocks
how were crude oils formed
- remains of dead animals were buried in the mud
2. layers of rock formed on top of them creating a high pressure
what is a crude oil
crude oil is a mixture of different hydrocarbon compounds
what is the boiling point of crude oil
they are different as they contain a mixture of hydrocarbons with different boiling points
what is a fraction
a group of hydrocarbons with similar boiling points
how can crude oil be separated
with fractional distillation
what is an alkane
a saturated hydrocarbon with single C-C bonds with the formula of CnH2n+2
properties of shot chain hydrocarbons
- lower boiling point
- higher volatility (tendency to turn into gas)
- low viscosity (how easily it flows)
- higher flammability
properties of long chain hydrocarbons
- high boiling point
- lower volatility (tendency to turn into gas)
- high viscosity (how easily it flows)
- lower flammability
what is the purpose of fractional distillation
to separate crude oil into hydrocarbons with similar boiling points
what is the order of a fractionating column
- refinery/petroleum
- gasoline/petrol
- kerosine
- diesel
- residue
what is volatility
how easily a substance turns into a gas
what is viscosity
how easily a substance flows
what are the most useful hydrocarbons
short chain hydrocarbons
what are the products of the complete combustion of a hydrocarbon
carbon dioxide + water
what is incomplete combustion and what are the products formed
when there is not enough oxygen to oxidise the hydrocarbon, carbon monoxide and water are produced
where does cracking occur
in an oil refinery in stell vessels called crackers
what happens to a large fraction after it has been distilled from a crude oil
it is either
- passed over a hot catalyst
- mixed with steam and heated to a very high temperature
what kind of reactions take place as large hydrocarbons are cracked
thermal decomposition as larger hydrocarbons slip apart into smaller hydrocarbons which are more useful
what is an alkene
a hydrocarbon with at least one C=C double covalent bond
what kind of structure does an alkene have
it is unsaturated and has less hydrogen atoms in their molecules than alkanes.
which are more reactive, alkenes or alkanes
alkenes because they have the ability to create new bonds
how would you crack and alkene in a lab and test for the results
- heat a test tube with ceramic wool soaked in medicinal paraffin and a catalyst with a delivery tube into a water basin.
- the end of the delivery tube is underneath a boiling tube which contains water some way up
what is a positive test for an unsaturated hydrocarbon
it turns orange bromine water colourless
