3.2.2 Alkanes As Fuels Flashcards
Test card
Test card
Complete combustion reaction
Burn alkanes with plenty of oxygen the products are water and carbon dioxide
Burning alkanes
(as fuels)
releases LOTS of energy
examples of where alkanes are burnt/used
3
power stations
central heating systems
car engines
etc
Disadvantage of burning alkanes
produces lots of pollutants
Incomplete combustion
When an alkane burns in the presence of insufficient oxygen
Carbon monoxide
can be a product of incomplete combustion
poisonous
binds to haemoglobin in red blood cells instead of oxygen
less oxygen can be carried around the body
Carbon monoxide removed
removed from exhaust gases by CATALYTIC CONVERTERS on cars
Carbon
aka soot
formed by incomplete combustion
Soot causes
breathing problems
build up in engines which means they don’t work properly
Burning fossil fuels
produces co2 which is a greenhouse gas
can contribute to climate change
greenhouse effect
Unburnt hydrocarbons
not all the fuel molecules are burnt in engines
NOx
oxides of nitrogen
How are NOx formed
high pressure and temperature in a car engine caused nitrogen and oxygen from the air to react together
ground-level ozone
hydrocarbons and oxides of nitrogen react in the sunlight form ground-level ozone which is a major component of smog
ground-level ozone
causes
irritation of eyes
lung damage
aggravates respiratory problems
oxides of nitrogen and unburnt hydrocarbons removed bu
catalytic converters on cars remove from exhaust
Sulphur
fossil fuels burnt = sulphur
sulphur dioxide SO2 formed in air
dissolved with moisture in the atmosphere = sulphuric acid = acid rain
Acid rain
causes
destroys vegetation and trees
corrodes buildings and statues
kills fish in lakes
SO2 removed
Calcium carbonate or calcium oxide mixed with water in power station = alkaline slurry
reacts with SO2 = forms calcium sulphate (harmless salk)
