cracking hyrdocarbons and plastics

Question 1

how do you crack a hydrocarbon

Answer 1

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

Question 2

does cracking produce alkenes or alkanes

Answer 2

both

alkenes= unsaturated

alkanes - saturated

Question 3

what is the test to see if a hydrocarbon is an Alkene or an alkane

Answer 3

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

Question 4

what are plastics made from

Answer 4

made of polymers

Question 5

what are polymers made from

Answer 5

lots of small molecules called monomers

Question 6

how do monomers join together to form polymers ( POLYMERISATION)

Answer 6

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

Question 7

what is a designer polymer

Answer 7

a polymer that has special properties to do a particular job

eg packaging material, softer linings for dentures

Question 8

what is a smart polymer

Answer 8

a polymer that may have their property changed by light, tempreture and other things

eg light sensitive plasters

Question 9

what do we do with old plastics

Answer 9

recycle them and finding new uses

eg, bottles into clothing

or ends up as rubbish in landfill tips

Question 10

what’s bad about non biodegradable plastics

Answer 10

it is an eyesore, it harms wildlife and takes up valuable space in landfill sites

Question 11

what’s a biodegradable plastic

Answer 11

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

Question 12

what are the advantages of biodegradable plastics

Answer 12

1. preserves crude oil
2. doesn’t take up land
3. no problems with waste disposal

Question 13

what are the disadvantages of biodegradable plastics

Answer 13

1. could cause higher food prices because farmers sell their corn for plastic
2. destory habitats and affect global warming- cutting down trees to make room for farmland
3. some products break down in light but not when they are buried in a landfill site

Question 14

why do people crack hydrocarbons

Answer 14

to make them more useful, to make more fuels

Question 15

what does = represent

Answer 15

double carbon bond (unsaturated )

Question 16

what is the fortunes got alkene’s

Answer 16

CnH2n

Question 17

name the polymers for ethene and propene

Answer 17

polyethene

polypropene