Air Quality Flashcards
How was the earth’s atmosphere formed?
Probably from gases given off during volcanic eruptions
Name 2 things that cause air pollution
Vehicles and power stations
What elements are found in hydrocarbons
Hydrogen and carbon
What is given off by incomplete combustion?
Carbon monoxide and carbon particulates
Name three gases that are pollutants
Carbon monoxide, sulfur dioxide and nitrogen oxide
How would you recognise an outlier
The result is different to all the others
How are the molecules in a gas arranged?
There is no structure, and lots of space between them
Has the earth’s atmosphere always been as it is today?
No
Can particulates be released by natural processes?
Yes
What 2 gases make acid rain?
Sulfur dioxide, and the nitrogen oxides
What do hydrocarbon fuels form when they burn in oxygen?
Water and carbon dioxide
Where are the nitrogen oxides form?
In hot car engines, from the nitrogen and oxygen in the air
What is the range of a set of results?
The difference between the highest and the lowest results
What is the mean?
The average
What is correlation?
A link between a factor and an outcome, but one does not need to cause the other.
What proves a causal link?
One factor always causes an outcome
What is the law of conservation of matter?
Matter cannot be created nor destroyed
The nitrogen oxides, as a group, are written how?
NOx, NO goes to NO2
An oxidation reaction does what?
Adds oxygen
A reduction reaction does what?
Removes oxygen
Name a disadvantage of biofuels?
They use land which could be used for growing food.
Name an advantage of biofuels?
They are carbon neutral in that the carbon that is released is being trapped again to produce more fuel.
Name a natural process that releases pollutants
Volcanoes
How is carbon dioxide removed from the atmosphere?
It dissolves in the sea and can be trapped in sedimentary rocks, and fossil fuels. It is removed by photosynthesis which can also be converted to fossil fuels.
What was the effect of plants on earth’s atmosphere?
They removed carbon dioxide, and released oxygen, so not the atmosphere is one fifth oxygen.
What happened to the water vapour in earth’s early atmosphere?
It condensed to form oceans.
Why is there sulfur dioxide in the atmosphere?
fossil fuels contain small amounts of sulfur, when they are burned the sulfur reacts with oxygen to form sulfur dioxide.
Why is sulfur dioxide in the atmosphere a problem?
It dissolves in water to form sulfurous acid, which forms acid rain which damages trees and buildings.
How can the amount of sulfur in the atmosphere be reduced?
Power stations can reduce it be desulfurisation of flue gases.
What is a catalytic converter?
A device in the exhaust of cars to remove nitrous oxides and carbon monoxide from the exhaust fumes.
What does the catalytic converter convert the carbon monoxide, and the nitrous oxides, to?
Carbon monoxide is oxidised to carbon dioxide. Nitrous oxides are reduced to nitrogen.
Write the word equation for the reaction that happens in a catalytic converter
Carbon monoxide + nitrogen monoxide => nitrogen and carbon dioxide
Why are modern fuels required to be “low sulfur”
Sulfur damages the catalyst in the catalytic converter
How are emissions of cars controlled in the UK?
The car emissions are tested as part of the annual MOT test, if the car fails the problem needs to be fixed.
Are electric cars “green”?
They do not give out pollutant gases when being used, so the atmosphere in our cities is much better. However, there are still pollutant gases given off at the power station when the electricity is generated.
How could you reduce electricity consumption in the home?
Switch appliance off, do not leave on standby. Turn off lights. Increase insulation.
How could you reduce pollution from power stations?
Reduce electricity use.
How can power stations remove particulates from their flue gases?
They can use electrostatic filters.
Which fossil fuels contain less sulfur?
Gas and oil.
Which fossil fuels can have sulfur removed?
Gas and oil. Coal it is much harder, it is in solid lumps.
What is the chemical process use to achieve flue gas desulfurisation?
Use calcium oxide and water to form calcium sulphate which can be sold as plaster. It is also possible to use sea water to absorb the sulfur oxide as sea water is naturally alkaline.
What are the disadvantages of electric cars?
Few charging points, limited range, long charging time.
