-
Be aware that the increase in respiratory
illnesses such as asthma in young people may be caused by an increase in air
pollution.
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You should have developed ideas about air pollution and how it can be
prevented eg the use of catalytic converters to reduce atmospheric pollution.
-
You should appreciate the
timescales of the evolution of the Earth's atmosphere and the ethical issues around human influences on the atmosphere,
which until recently has been relatively unchanged for millions of years.
-
Know about an experiment to determination of the composition
of clean air i.e. the % oxygen in it.
-
Know that air contains oxygen, nitrogen, water vapour and carbon
dioxide.
-
You should understand how
photosynthesis, respiration and combustion affect the level of carbon dioxide
and the level of oxygen in the air.
-
You should appreciate the time line showing the sequence of
events in the evolution of the atmosphere.
-
Know that oxygen, nitrogen and carbon dioxide levels in the present day
atmosphere are approximately constant.
-
Be able to relate the common pollutants found in air to the environmental
problem the pollutant causes and/or to the source of the pollutant:
-
carbon
monoxide – a poisonous gas formed by the incomplete combustion of petrol or
diesel in car engines
-
oxides of nitrogen – causes photochemical smog and acid
rain and are formed in the internal combustion engine
-
sulfur dioxide – causes
acid rain that will kill plants, kill aquatic life, erode stonework and corrode
metals and is formed when sulfur impurities in fossil fuels burn.
-
Know that a catalytic converter
removes carbon monoxide from the exhaust gases of a car.
-
Know that the percentage composition by
volume of clean air: is 21% oxygen, 78% nitrogen and 0.035% carbon dioxide.
-
Be able to describe the main
processes in a simple carbon cycle involving:
-
photosynthesis
-
respiration
-
combustion.
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Be able to describe how the present day atmosphere evolved:
-
HT only: Be able to evaluate the effects of human influences on the composition of
air, for example:
-
deforestation
-
population.
-
HT only: Be able to 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.
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Be able to interpret data about the effects of atmospheric pollutants.
-
HT only: Be able to explain why the high temperature inside an internal combustion engine allows
nitrogen from the air to react with oxygen to make oxides of nitrogen.
-
Be able to explain
why it is important that atmospheric pollution is controlled.
-
You should understand that a
catalytic converter changes carbon monoxide into carbon dioxide.
-
HT only: Be able to explain how use
of a catalytic converter removes carbon monoxide from exhaust fumes using the
balanced symbol equation:
-
Notes
