Topic 8- Fuels Flashcards
What is a hydrocarbon
A compound of only hydrogen and carbon
What is an alkane?
Saturated hydrocarbon
no double bonds
What is an alkene?
Unsaturated hydrocarbon
could have more hydrogen
What is complete combustion?
Fuel burns with enough O2 to make water and carbon dioxide
rather than water and carbon monoxide
CO vs CO2
What is crude oil?
-A mixture hydrocarbons arranged in chains or rings
-a finite resource
-Used in industry (fuels)
What is cracking?
Breaking long chain hydrocarbons into shorter chaines (higher demnd/more useful)
-Produces an alkane
-Produces an alkene
What are the first 4 Alkanes?
C2H2n+2
Methane
Ethane
Propane
Butane
then in greek numbers
pentane, hexane, heptane, octane…
How is crude oil seperated
Industrial fractional distillation (column)
-Heated and vaporised
-Each column has a lower temperature
-The hydrocarbons will condense at different columns (differentt boiling points)
-And are collected as liquids
What are produced as crude oil is fractionally distilated?
-Gas
-Petrol
-Kerosene
-Diesal oil
-Fuel oil
-Bitumen
What are gases used for?
-Domestic cooking
-Domestic heating
What is petrol used for used for?
-Cars
What is kerosene used for?
-Aircrafts
What is diesal oil used for?
-Cars and trains
What is fuel oil used for?
-Large ships
-Power stations
What is bitumen used for?
-Surface roads and roofs
Pattern of viscosity?
-Les viscous (shorter chain)
-More viscous (longer chaine
Pattern of flammability?
-More flammable (shorter chain)
-Less flammable (longer chain)
What is a homologeous series?
-Series have same formula (differ by number of CH2 units)
-Have similar but gradual variation in chemical properties
What is formed when hydrocarbons are cobusted?
-Water + CO2
-Realeases energy (exothermic)
Why does incomplete combustion produce carbon monoxide?
-Not enough oxygen
-Makes CO bonds rather than CO2
How does carbon monoxide behave as a toxic gas
-Binds to heameglobin more easily than oxygen
-Starves body of oxygen
What are the problems caused by incomplete combustion of hydrocarbons?
soot and CO
Soot:
-Air pollution
-Breathing problems
Carbon monoxide:
-Greenhouse gas
-Toxic
soot is pure CARBON
What do hydrocarbon/ fossil fuel impurities cuase?
acid rain
SULFUR IMPURITIES
How do sulfur impurities cuase acid rain?
-Combustion into SO2
-Reacts in clouds (water) into H2SO4
-Which is acid rain
What affects does acid rain have?
-Kill animals
-Contaminate water sources
-Erode/corrode buildings
What pollution do car fumes form?
-NO and NO2
-Produces activation energy allowing Nitrogen and Oxygen to react
What are the effects of NO and NO2?
-Greenhouse gas
Advantages of using hydrogen as fuel?
-Renewable
-Does not create polllutants
-Releases more energy (than petrol)
Disadvantages of using hydrogen as fuel?
-Needs electrolysis to break from water (expensive + time consuming)
-Needs storing in special engine (highly flammable)
What is cracking of hydrocarbons?
-Breaking larger saturated alkanes into
-Smaller unsaturated Alkanes
-And alkene
Why is cracking necessary?
-Production of more useful shorter hydrocarbon molecules§
