6.22 - Alkanes as fuels Flashcards
What is complete combustion?
When all of the atoms in the fuel are fully oxidised
What are the 2 products of complete combustion?
Water and carbon dioxide
Which product is bad? Why?
Carbon dioxide, because it is a greenhouse gas, and thus contributes to global warming
What is incomplete combustion?
When some of the atoms in the fuel are not fully oxidised
What products can form in incomplete combustion?
Solid carbon and carbon monoxide
What is bad about carbon monoxide?
It is a toxic, odourless, colourless gas that causes death by binding to haemoglobin in red blood cells (respiratory death)
What is the ultimate case of incomplete combustion?
When some of the hydrocarbon is just left unburnt
What do some molecules in crude oil contain?
Sulfur and sometimes nitrogen
What happens to the sulfur during combustion?
It forms sulfur dioxide, and then sulfur trioxide
What do these then form when dissolved in water in the atmosphere?
Sulfurous acid and sulfuric acid
What do these acids contribute to?
Acid rain, which damages the environment
What happens to the nitrogen during combustion?
It is oxidised, initially to nitrogen monoxide, but then to nitrogen dioxide
In the atmosphere, what happens to nitrogen dioxide?
It reacts with water to form both nitrous acid and nitric acid
What impact do these acids have?
Similar to the sulfurous acid and sulfuric acid
What is a catalytic converter?
A device that converts pollutants into safer compounds
