C1 (2) Flashcards
What is fractional distillation?
Separation of a mixture by boiling, followed by condensation, which is successful because each component has a different boiling point
How is the fractional distillation of crude oil carried out?
Oil is heated to 450 degrees and pumped into bottom of column where it vaporises
Column is hot at bottom but cooler at top because as vaporised oil rises it cools and condenses
Where do longer hydrocarbons leave the fractioning column?
Near the bottom because they have high melting point
Where do shorter hydrocarbons leave the fractioning column?
Near the top because they have low melting points
What is the order for where different hydrocarbons leave the colum? Bottom to top
Bitumen Oil Diesel Kerotene Naptha Petrol LPG
As the size of a hydrocarbon increases what effects does it have on the properties?
Boiling point increases Less flammable More viscous (doesnt flow so easily) Less volatile (doesn't evaporate so easily)
What does cracking do?
Turns long alkane molecules into shorter, more useful alkene molecules to match supply and demand
(form of thermal decomposition)
What does cracking need in order to take place?
Lots of heat and a catalyst
What is an advantage and disadvantage of fossil fuels?
Conveinient source of energy
Very polluting and will run out
What are the advantages of disadvatages of biofuels?
Advantages:
Carbon neutral
Storage, transport and distribution costs are low
Disadvantages:
Production needs lots of energy
Few UK suppliers
What are two political problems associated with fossil fuels/oil?
Conflict in oil producing countries = prices increase
Oil producing countries think they have more power and influence
What are three environmental problems associated with fossil fuels/oil?
Oil leaks/spills
Oil damages bird feathers = making them not waterproof
Detergents break up oil but too many damage wild life
What seven things must be considered when choosing a fuel?
1) Availability
2) Pollution
3) Energy value
4) Cost
5) Storage
6) Ease of Use
7) Toxicity
When does complete combustion occur?
When there is plenty of oxygen
What is the equation for complete combustion of a hydrocarbon?
Hydrocarbon + oxygen = Carbon dioxide + water (+energy)
When does incomplete combustion occur?
When there is not enough oxygen
Very dangerous and poisonous
What is the equation for incomplete combustion of a hydrocarbon?
Hydrocarbon + oxygen = carbon dioxide + carbon monoxide + water (+energy)
What happened in phase 1 of the evolution of the atmosphere?
Volcanoes gave out steam and CO(2)
? Earth’s surface = originally molten and any atoms boiled away
? It cooled and a thin crust formed
? Volcanoes kept erupting and released gases from inside of earth
? Early atmosphere was mainly CO(2) and water vapour. WV later condensed = oceans
What happened in phase 2 of the evolution of the atmosphere?
Green plants evolved and oxygen produced
? Lots of CO2 dissolved in oceans
? New plants photosynthesis = remove CO2, gave O2
? O2 built up but CO2 locked in fossil fuels and sedimentary rocks
? Nitrogen gas put into atmos by ammonia and oxygen reacting and released by denitrifying bacteria
What happened in phase 3 of the evolution of the atmosphere?
Ozone layer allows evolution of complex animals
? O2 build up killed early organisms
? Evolution of complex organisms = made use of o2
? O2 created ozone layer to block harmful sun rays and more complex animals evolved
? Virtually no CO2 now
What produces carbon dioxide and what effect does it have?
Burning of fossil fuels
It is a greenhouse gas
What produces carbon monoxide and what effect does it have?
Incomplete combustion
Poisons red blood cells = fainting, coma or death
What produces sulfur dioxide and what effect does it have?
Power stations
Acid rain
? Lakes = acidic = plants and animals die
? Kills tress and damages limestone
What produces nitric oxides and what effect does it have?
Road traffic and power stations
Acid rain and smog