Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
34 Cards in this Set
- Front
- Back
what is the first problem with pilymers |
most aren't biodegradable. this means micro organisms can't break them down so they last for many years in landfill sites |
|
what's the second problem with polymers |
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 |
|
what's the third problem with polymers |
polymers can't be incinerated (burnt) because toxic gases are released like co2 (global warming) |
|
how can we control Co2 in the atmospher |
iron seeding of oceans converting co2 to hydro carbons |
|
how do we stop carbon monoxide releasing into our atmosphere |
make sure fuel burning appliances are serviced regularly |
|
why is carbon monoxide so bad |
it is odourless colourless and toxic so we cannot sense it until it harms us |
|
how does soot harm us |
small particles of soot collect in lungs when people breathe in sooty air causing lung diseases |
|
what else does soot do |
clogs up pipes that carry waste gases away and makes buildings dirty |
|
why is acid rain harmful environmentally |
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 |
|
how is sulfur dioxide formed |
most hydrocarbon fuels naturally contain some sulfur compounds. when the fuel burns the sulfur oxidises to sulfur dioxide |
|
explain the greenhouse effect |
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 |
|
why do we crack |
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 |
|
what is cracking used for |
some of the smaller molecules formed by cracking are used as fuels and some as polymers for plastic manufacture |
|
how does cracking work |
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 |
|
what's the polymer properties and use of ETHENE |
Poly(ethene) flexible, cheap, electrical insulator plastic bags and bottles or coating on electrical wires |
|
what's the polymer properties and uses of PROPENE |
Poly(PROPENe) flexible and strong buckets and crates |
|
what's the polymer properties and uses of chloroethene |
poly(chloroethene) or Pvc tough cheap and long lasting window frames and water pipes |
|
tetrafluoroethene |
poly(tetrafluoroethene) or PTFE tough and non stick non stick coating on pans |
|
word equation for complete combustion |
hydrocarbon + oxygen --> water + carbon dioxide |
|
word equation for incomplete combustion |
hydrocarbon + oxygen --> carbon + water + carbon monoxide |
|
how does fractional distillation work |
1) crude oil vaporised 2) vapour rises into column 3) at different stages fractions of oil condense according to their boiling point |
|
use of gases |
domestic heating cooking fuel for vehicles |
|
use of petrol |
fuel for cars |
|
use of keresene |
fuel for aircraft engines |
|
use of diesel oil |
fuel for diesel using cars and trains |
|
use of fuel oil |
fuel for large ships some power stations lubricating oil fuel for heating |
|
use of bitumen |
surface roads and roofs |
|
use of naptha |
making chemicals |
|
how do the trends differ further down the column |
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 |
|
advantages of Hydrogen |
only produces water when burnt not carbon dioxide and carbon monoxide releases nearly 3 times as much energy Per kg as petrol |
|
petrol advantages |
liquid - easy to store and transport releases more energy when it burns than fuels like coal or wood |
|
hydrogen disadvantages |
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 |
|
a good fuel.. |
1) should burn easily 2) shouldn't produce ash/smoke 3) easy to store and transport 4) should release bare heat energy |
|
what does a fuel cell do |
combines hydrogen and oxygen to form water which released energy |