Clean air Flashcards
what does the air contain?
oxygen, nitrogen, water vapour and carbon dioxide
what is carbon monoxide?
a poisonous gas formed by the incomplete combustion of petrol or diesel in car engines
what does oxides of nitrogen cause?
photochemical smog
and acid rain and are formed in the internal
combustion engine
what does sulfur dioxide cause?
acid rain that will kill
plants, kill aquatic life, erode stonework and
corrode metals and is formed when sulfur
impurities in fossil fuels burn.
purpose of a catalytic converter:
removes carbon monoxide from the exhaust gases of a car.
Recall the percentage composition by volume of
clean air:
- 21% oxygen
- 78% nitrogen
- 0.035% carbon dioxid
Describe how the present day atmosphere evolved:
• original atmosphere came from gases escaping
from the interior of the Earth
• photosynthesis by plants increased the
percentage of oxygen until it reached today’s
level.
Explain why it is important that atmospheric pollution
is controlled.
damages our surroundings and health
what does a catalytic converter change?
carbon monoxide into carbon dioxide
Describe one possible theory for how the present day
atmosphere evolved over millions of years (based
on the composition of gases vented by present day
volcanic activity):
• degassing of early volcanoes producing an
atmosphere rich in water and carbon dioxide
• condensing of water vapour to form oceans
• dissolving of carbon dioxide in ocean waters
• relative increase of nitrogen due to its lack of
reactivity
• development of photosynthetic organisms
• increase in oxygen levels due to photosynthesis
Evaluate the effects of human influences on the
composition of air
deforestation - less photosynthesis and wood burning increase carbon dioxide
increased human population - more pollutants and more carbon dioxide released
Explain how use of a catalytic converter removes
carbon monoxide from exhaust fumes using the
balanced symbol equation:
2CO + 2NO → N2 + 2CO2
