Zusammenfassung der Ressource
OCR 21st century C1
- Atmosphere and AIr
- The 15km thick atmosphere that
surrounds the Earth is made up
of 78% nitrogen, 21% oxygen
and 1% argon
- Air is made up of small
molecules with large
spaces inbetween them.
Molecules are groups of
atoms joined together
- Other gases such as sulfur
dioxide, carbon
monoxide/dioxide, nitrogen
dioxide, water vapour or
particulates may be released
into the atmosphere by human
activity such as burninf fossil
fuels in power stations and for
transport or by natural
processes (e.g. volcanoes).
- Sulfur dioxide is formed when fuels
containing sulfur compounds are burned.
Sulfur dioxide reacts with water and oxygen
in the air to produce acid rain. This removes
sulfur dioxide from the air, but the acid rain
corrodes buildings and kills plants.
- Nitrogen monoxide
reacts in the atmosphere
to form nitrogen dioxide.
- NO is formed during the combustion of
fuels in air, and is subsequently
oxidised to nitrogen dioxide NO2 (NO
and NO2 are jointly referred to as ‘NOx’)
- Nitrogen dioxide also reacts
with water and oxygen in the
air to produce acid rain. Can
cause breathing problems
- (from the reaction between atmospheric nitrogen
and oxygen at the high temperatures inside engines)
- Carbon monoxide is
produced when fuel is
burned in an insufficient
supply of oxygen. It is a
poisonous gas that reduces
the amount of oxygen the
blood can carry
- Incomplete
combustion
- Carbon dioxide
dissolves in rain
water and sea water.
It is used by plants in
photosynthesis.
Excess levels of CO2
can give rise to
global warming
- Deposited on
surfaces,
making them
dirty. Can be
breathed into
the lungsand
can worsen
asthma and
lung infections
- Early Atmosphere
- Earth’s early atmosphere was probably
formed by volcanic activity and consisted
mainly of carbon dioxide and water vapour
- Water vapour condensed to form
the oceans when the Earth cooled
- The evolution of
photosynthesising organisms
added oxygen to, and removed
carbon dioxide from, the
atmosphere
- carbon dioxide was
removed from the
atmosphere by
dissolving in the oceans
and then forming
sedimentary rocks, and
by the formation of
fossil fuels
- human activity has
small amounts of
carbon monoxide,
nitrogen oxides and
sulfur dioxide to the
atmosphere
- human activity has
added extra carbon
dioxide and small
particles of solids
(e.g. carbon) to the
atmosphere
- Production of Pollutants
- Coal is mostly
carbon and
impurities
- combines with
oxygen from the
air to produce
carbon dioxide
- These combustion reactions involve oxidation
- petrol, diesel fuel and
fuel oil are mainly
compounds of
hydrogen and carbon
- Hydrogen from the fuel
combines with atoms
of oxygen from the air
to produce hydrogen
oxide (water).
- Fuels burn more
rapidly in pure
oxygen which can
be obtained from
the atmosphere
- can be used to support
combustion (e.g. in
oxy-fuel welding torches)
- Reactions
- during the course of a
chemical reaction the
numbers of atoms of
each element must be
the same in the products
as in the reactants, thus
conserving mass
- understand
that in a
chemical
reaction the
properties
of the
reactants
and
products are
different.
- understand that atoms are
rearranged during a
chemical reaction interpret
representations of the
rearrangement of atoms
during a chemical reaction
- Reducing Pollution
- pollution caused by
power stations that
burn fossil fuels
- removing sulfur dioxide
and particulates from
the flue gases emitted
by coal-burning power
stations
- using sea
water
- naturally
alkaline
- Using an
alkaline
slurry e.g. a
spray of
calcium oxide
and water
- When mixed with air and sprayed with the
lurry, the sulfur dioxide in flue gases reacts
and forms solid calcium sulphate. this solid
is removed allowing clean gas to escape
- Waste gases from the
furnace, containing
particulates are
passed into the
electrostatic
precipitator
- The particulates
pass though a
negatively cahrged
metal grid and lose
electrons picking up
a negative charge
- They
attract to
the positive
plate
- The particulates are removed
and waste gases pass through
- removing sulfur
from natural gas
and fuel oil
- using less
electricity
- to produce less carbon
dioxide, less fossil
fuels need to be burnt
- Vehicular
pollution
- burning less fuel, for example by
having more efficient engines
- using low
sulfur fuels
- using catalytic converters (in which
nitrogen monoxide is reduced to
nitrogen by loss of oxygen, and
carbon monoxide is oxidised to
carbon dioxide by gain of oxygen)
- adjusting the
balance between
public and
private transport
- having legal limits
to exhaust
emissions (which
are enforced by
the use of MOT
tests)
- Alternatives
- Biofuels
- Renewable source
made from plant
matter
- The growing of these
crops requires CO2
which is released
back into the
atmosphere when the
fuels burn.
- Crops are
grown for fuel
instead of food
- 2-3% of fuel can
be mixed into
fuel without
changing engines
- Electric
vehicles
- Don't produce
waste gases
- Electricity comes
from fossil fuel
burning power
stations
- Need regular and
long recharging
- Air Quality