Science Edexcel: C1 Topic 5

Front 1

what is the first problem with pilymers

Back 1

most aren't biodegradable. this means micro organisms can't break them down so they last for many years in landfill sites

Front 2

what's the second problem with polymers

Back 2

many can be recycled. this reduces the disposal problems and amount of crude oil used but different polymers must be separated which is difficult and expensive

Front 3

what's the third problem with polymers

Back 3

polymers can't be incinerated (burnt) because toxic gases are released like co2 (global warming)

Front 4

how can we control Co2 in the atmospher

Back 4

iron seeding of oceans

converting co2 to hydro carbons

Front 5

how do we stop carbon monoxide releasing into our atmosphere

Back 5

make sure fuel burning appliances are serviced regularly

Front 6

why is carbon monoxide so bad

Back 6

it is odourless colourless and toxic so we cannot sense it until it harms us

Front 7

how does soot harm us

Back 7

small particles of soot collect in lungs when people breathe in sooty air causing lung diseases

Front 8

what else does soot do

Back 8

clogs up pipes that carry waste gases away and makes buildings dirty

Front 9

why is acid rain harmful environmentally

Back 9

it reacts with limestone and metals so damages buildings and statues, affects the waxy layer on leaves of trees and makes it difficult for them to absorb the minerals they need for growth, makes rivers too acidic for aquatic life to survive

Front 10

how is sulfur dioxide formed

Back 10

most hydrocarbon fuels naturally contain some sulfur compounds. when the fuel burns the sulfur oxidises to sulfur dioxide

Front 11

explain the greenhouse effect

Back 11

1) Suns rays enter earths atmosphere

2) heat reflected back from earths surface

3) heat absorbed by green house gases and gets trapped in earths atmosphere

4) earth becomes hotter

Front 12

why do we crack

Back 12

large hydrocarbon molecules aren't efficient. they don't flow easily and are hard to ignite. crude oil often contains many large and not enough small to meet demand

Front 13

what is cracking used for

Back 13

some of the smaller molecules formed by cracking are used as fuels and some as polymers for plastic manufacture

Front 14

how does cracking work

Back 14

fractions containing large hydrocarbon molecules are vaporised and passed over a hot catalyst this breaks down chemical bands in the molecules and forms smaller ones

Front 15

what's the polymer properties and use of ETHENE

Back 15

Poly(ethene)

flexible, cheap, electrical insulator

plastic bags and bottles or coating on electrical wires

Front 16

what's the polymer properties and uses of PROPENE

Back 16

Poly(PROPENe)

flexible and strong

buckets and crates

Front 17

what's the polymer properties and uses of chloroethene

Back 17

poly(chloroethene) or Pvc

tough cheap and long lasting

window frames and water pipes

Front 18

tetrafluoroethene

Back 18

poly(tetrafluoroethene) or PTFE

tough and non stick

non stick coating on pans

Front 19

word equation for complete combustion

Back 19

hydrocarbon + oxygen --> water + carbon dioxide

Front 20

word equation for incomplete combustion

Back 20

hydrocarbon + oxygen --> carbon + water + carbon monoxide

Front 21

how does fractional distillation work

Back 21

1) crude oil vaporised

2) vapour rises into column

3) at different stages fractions of oil condense according to their boiling point

Front 22

use of gases

Back 22

domestic heating

cooking

fuel for vehicles

Front 23

use of petrol

Back 23

fuel for cars

Front 24

use of keresene

Back 24

fuel for aircraft engines

Front 25

use of diesel oil

Back 25

fuel for diesel using cars and trains

Front 26

use of fuel oil

Back 26

fuel for large ships

some power stations

lubricating oil

fuel for heating

Front 27

use of bitumen

Back 27

surface roads and roofs

Front 28

use of naptha

Back 28

making chemicals

Front 29

how do the trends differ further down the column

Back 29

bitumen have large molecules, a high boiling point, doesn't ignite easily, a lot of smoke, high viscosity (very thick and doesn't flow)

this all changes further up the column

Front 30

advantages of Hydrogen

Back 30

only produces water when burnt not carbon dioxide and carbon monoxide

releases nearly 3 times as much energy Per kg as petrol

Front 31

petrol advantages

Back 31

liquid - easy to store and transport

releases more energy when it burns than fuels like coal or wood

Front 32

hydrogen disadvantages

Back 32

is a gas and has to be stored at high pressures

filling stations would need to be adapted for hydrogen to be used in cars

Front 33

a good fuel..

Back 33

1) should burn easily

2) shouldn't produce ash/smoke

3) easy to store and transport

4) should release bare heat energy

Front 34

what does a fuel cell do

Back 34

combines hydrogen and oxygen to form water which released energy