Air Quality & Climate (Cambridge (CIE) IGCSE Combined Science: Chemistry): Flashcards
Exam code: 0653
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Define air pollutant.
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Cards in this collection (28)
Define air pollutant.
An air pollutant is a gas or particle present in the atmosphere due to human activities that has harmful effects on living organisms or the environment.
What is the approximate percentage composition of nitrogen and oxygen in clean, dry air?
Clean, dry air contains approximately 78% nitrogen and 21% oxygen. The remaining 1% is a mixture of noble gases and carbon dioxide.
Sulfur dioxide is produced by the combustion of fossil fuels that contain .......... compounds, and its main adverse effect is causing ...........
Sulfur dioxide is produced by the combustion of fossil fuels that contain sulfur compounds, and its main adverse effect is causing acid rain.
True or False?
Carbon monoxide is produced by the complete combustion of carbon-containing fuels.
False.
Carbon monoxide is produced by the incomplete combustion of carbon-containing fuels when there is insufficient oxygen. Complete combustion produces carbon dioxide.
Why is carbon monoxide dangerous to humans?
Carbon monoxide is a toxic gas that combines with haemoglobin in the blood. This prevents haemoglobin from carrying oxygen around the body, which can be fatal.
What are two sources of methane as an air pollutant?
Methane is produced from:
Waste gases from digestion in animals (e.g. livestock)
Decomposition of vegetation in swamps, rice paddy fields, and landfill sites
Oxides of nitrogen are produced in car engines when nitrogen reacts with oxygen at .......... temperatures.
Oxides of nitrogen are produced in car engines when nitrogen reacts with oxygen at high temperatures.
True or False?
Particulates produced from incomplete combustion can cause respiratory problems and cancer.
True.
Particulates (soot) are produced from the incomplete combustion of carbon-containing fuels. They increase the risk of respiratory problems and cancer when inhaled.
What is the difference between complete and incomplete combustion of a hydrocarbon fuel?
Complete combustion occurs in excess oxygen and produces carbon dioxide and water only. Incomplete combustion occurs in oxygen-deficient conditions and produces carbon monoxide, water, and sometimes carbon particulates (soot).
Define acid rain.
Acid rain is rainfall made acidic by the dissolution of pollutant gases such as sulfur dioxide and oxides of nitrogen. It causes corrosion to metals, buildings, and damage to aquatic ecosystems.
Define the greenhouse effect. (Extended Tier Only)
The greenhouse effect is the process by which greenhouse gases such as carbon dioxide and methane absorb thermal energy re-emitted from the Earth's surface and re-emit it in all directions, reducing the energy lost to space and keeping the Earth warm.
How do greenhouse gases reduce the loss of thermal energy to space? (Extended Tier Only)
Greenhouse gases such as carbon dioxide and methane absorb thermal energy re-emitted from the Earth's surface. They then re-emit this energy in all directions, including back towards Earth, so less energy escapes into space.
True or False?
All of the Sun's energy that reaches Earth is absorbed by the Earth's surface. (Extended Tier Only)
False.
Some of the Sun's energy is reflected from the Earth's surface back into space. Only some is absorbed, re-emitted as thermal energy, and then partially trapped by greenhouse gases.
As the concentration of greenhouse gases increases, more thermal energy is .........., causing the Earth's average temperature to rise in a process called ........... (Extended Tier Only)
As the concentration of greenhouse gases increases, more thermal energy is trapped, causing the Earth's average temperature to rise in a process called global warming.
What is the enhanced greenhouse effect? (Extended Tier Only)
The enhanced greenhouse effect is when increasing concentrations of greenhouse gases — due to human activity — trap more thermal energy than normal. This causes the Earth's average temperature to rise above natural levels, leading to global warming.
State three consequences of global warming. (Extended Tier Only)
Climate change due to rising average temperatures
Rising sea levels as glaciers melt, causing flooding in low-lying areas
Loss of habitat and extinction of species due to changing conditions
True or False?
The two main greenhouse gases are carbon dioxide and methane. (Extended Tier Only)
True.
Carbon dioxide and methane are the two main greenhouse gases responsible for the greenhouse effect and global warming.
Greenhouse gases absorb thermal energy from Earth's surface and re-emit it in .......... directions, which .......... the amount of thermal energy lost to space. (Extended Tier Only)
Greenhouse gases absorb thermal energy from Earth's surface and re-emit it in all directions, which reduces the amount of thermal energy lost to space.
Why might rising global temperatures cause the spread of disease? (Extended Tier Only)
A warmer climate allows disease-carrying organisms (such as mosquitoes) to survive and spread into regions that were previously too cold for them. This increases the geographic range of diseases they carry.
Define acid rain.
Acid rain is rainfall made acidic by the dissolution of sulfur dioxide (and oxides of nitrogen) in rainwater. It causes damage to metal structures, carbonate rock buildings, and aquatic ecosystems.
How does planting trees help to reduce climate change?
Trees absorb carbon dioxide during photosynthesis. This reduces the amount of carbon dioxide in the atmosphere, lowering the greenhouse effect and slowing global warming.
Using .......... fuels reduces the amount of sulfur dioxide produced when fuels are burned, which reduces the formation of acid rain.
Using low-sulfur fuels reduces the amount of sulfur dioxide produced when fuels are burned, which reduces the formation of acid rain.
True or False?
Reducing livestock farming helps to lower methane emissions.
True.
Animals produce methane during digestion. Reducing the number of livestock means less methane is released into the atmosphere, which lowers the greenhouse effect.
Why do renewable energy sources help reduce global warming?
Renewable energy sources such as wind and solar do not release carbon dioxide during electricity generation. Replacing fossil fuels with renewables reduces carbon dioxide emissions and slows global warming.
Give two ways in which the number of vehicles on the road can be reduced to lower carbon dioxide emissions.
Using public transport instead of individual cars
Car-sharing between people travelling to the same destination
True or False?
Acid rain is caused solely by sulfur dioxide.
False.
Acid rain is caused by sulfur dioxide and oxides of nitrogen. However, the CIE syllabus focuses specifically on sulfur dioxide as the main cause.
Burning fossil fuels releases .........., so decreasing their use by using more .......... energy reduces global warming.
Burning fossil fuels releases carbon dioxide, so decreasing their use by using more renewable energy reduces global warming.
Why does reducing household energy consumption help to slow climate change?
Most household energy comes from burning fossil fuels, which releases carbon dioxide. Using less energy means less fuel is burned, so fewer carbon dioxide emissions are released into the atmosphere.
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