Combustion of alkanes 3 Flashcards
What device is fitted into all new petrol cars to reduce emissions?
Catalytic converters are installed in exhaust systems
What pollutants do catalytic converters reduce?
They reduce carbon monoxide (CO), nitrogen oxides (NOx) and unburnt hydrocarbons
Why is sulfur dioxide less of a problem in modern petrol engines?
SUlfur is now removed from petrol, reducing sulfur dioxide emissions
What is the structure of a catalytic converter?
A honeycomb made of ceramic material coated with platinum and rhodium metals
What are the catalysts in a catalytic converter?
Platinum and rhodium metals
Why is the honeycomb shape used in catalytic converter?
It provides a large surface area, allowing a small amount of expensive metals to be effective
Where do the reactions take place in a catalytic converter?
On the surface of the catalyst, on the layer of platinum and rhodium metals
How do catalytic converters reduce pollutants?
Polluting gases pass over the catalyst and react to form less harmful products
How does carbon dioxide behave like glass in the atmosphere?
It traps infrared radiation, preventing heat from escaping and warming the Earth’s atmosphere
Why do greenhouse gases become warm inside?
Visible rays from the sun pass through the glass, are absorbed by objects inside, and re radiated as infrared energy, which cannot escape
What are the main greenhouse gases?
Carbon dioxide, water vapour and methane
How could rising temperatures affect water vapour levels?
Higher temperatures lead to more water vapour, enhancing greenhouse warming, though increased cloud formation may offset this by reflecting solar radiation
What does “carbon neutral” mean?
An activity that produces no net carbon dioxide emissions overall
