cracking hyrdocarbons and plastics Flashcards Preview

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Flashcards in cracking hyrdocarbons and plastics Deck (17):
1

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

2

does cracking produce alkenes or alkanes

both

alkenes= unsaturated

alkanes - saturated

3

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

4

what are plastics made from

made of polymers

5

what are polymers made from

lots of small molecules called monomers

6

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

7

what is a designer polymer

a polymer that has special properties to do a particular job

eg packaging material, softer linings for dentures

8

what is a smart polymer

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

eg light sensitive plasters

9

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

10

what's bad about non biodegradable plastics

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

11

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

12

what are the advantages of biodegradable plastics

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

13

what are the disadvantages of biodegradable plastics

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

14

why do people crack hydrocarbons

to make them more useful, to make more fuels

15

what does = represent

double carbon bond (unsaturated )

16

what is the fortunes got alkene's

CnH2n

17

name the polymers for ethene and propene

polyethene

polypropene