cracking hyrdocarbons and plastics Flashcards
how do you crack a hydrocarbon
soack up the hydrocarbon with some wool, then heat a catalyst
thermal decomposition takes place and the large molecules are split to form smaller ones
does cracking produce alkenes or alkanes
both
alkenes= unsaturated
alkanes - saturated
what is the test to see if a hydrocarbon is an Alkene or an alkane
add bromine water to it
if it’s a alkene it will go colourless. it is unsaturated and therefore the carbon can bind onto the bromine
if it’s a alkane it won’t react and the bromine water will stay orange because the bonds are saturated so can’t bind onto it
what are plastics made from
made of polymers
what are polymers made from
lots of small molecules called monomers
how do monomers join together to form polymers ( POLYMERISATION)
the alkene’s double Bond between the carbon atoms break and it opens up
the double bond is replaced by a single bond
then the monomers can join together to make a polymer
what is a designer polymer
a polymer that has special properties to do a particular job
eg packaging material, softer linings for dentures
what is a smart polymer
a polymer that may have their property changed by light, tempreture and other things
eg light sensitive plasters
what do we do with old plastics
recycle them and finding new uses
eg, bottles into clothing
or ends up as rubbish in landfill tips
what’s bad about non biodegradable plastics
it is an eyesore, it harms wildlife and takes up valuable space in landfill sites
what’s a biodegradable plastic
they rot away in the soil when we we we dump them and can be broken down my micro-organisms
adding cornstarch (PLA) speeds up decomposition
what are the advantages of biodegradable plastics
- preserves crude oil
- doesn’t take up land
- no problems with waste disposal
what are the disadvantages of biodegradable plastics
- could cause higher food prices because farmers sell their corn for plastic
- destory habitats and affect global warming- cutting down trees to make room for farmland
- some products break down in light but not when they are buried in a landfill site
why do people crack hydrocarbons
to make them more useful, to make more fuels
what does = represent
double carbon bond (unsaturated )
