Air Quality And Climate

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先生の方へ： Air Quality And Climate（Co-ordinated Sciences (Double Award) [CIE]、Chemistry）向けのすぐ使えるレッスンスライド, 復習ノート — レッスンで使うか、生徒がライブゲームとして遊ぶインタラクティブなクラス活動としてトピックを実施できます。

レッスンノート

Composition of Air

The composition of clean, dry air is approximately 78% nitrogen and 21% oxygen.
The remaining gases include carbon dioxide and trace quantities of noble gases (e.g., argon, neon).
This composition has remained relatively unchanged for about 200 million years.

Pie chart of the current atmosphere

Air Pollutants and Their Sources

Carbon dioxide (CO₂) is produced by complete combustion of carbon-containing fuels (e.g., CH₄ + 2O₂ → CO₂ + 2H₂O).
Carbon monoxide (CO) is produced by incomplete combustion (e.g., 2C₈H₁₈ + 10O₂ → 5CO + 3CO₂ + 9H₂O) and is toxic as it binds to haemoglobin, preventing oxygen transport.
Particulates (soot, C) are also from incomplete combustion (e.g., CH₄ + O₂ → C + 2H₂O) and cause respiratory problems and cancer.
Methane (CH₄) comes from digestive processes of animals, decomposition of vegetation, and bacterial action in swamps, rice paddies, and landfill sites.
Oxides of nitrogen (NOₓ) form when N₂ and O₂ react at high temperatures (e.g., in car engines, furnaces, lightning) and cause acid rain and photochemical smog.
Sulfur dioxide (SO₂) is produced by burning fossil fuels containing sulfur (e.g., S + O₂ → SO₂) and causes acid rain.

Effects of Air Pollutants

CO₂ and methane are greenhouse gases that contribute to global warming and climate change.
CO is poisonous – it combines with haemoglobin, reducing oxygen carriage in the blood.
Particulates cause respiratory problems and cancer.
NOₓ and SO₂ dissolve in rainwater to form acid rain, which corrodes metal structures, damages carbonate rocks/buildings, harms aquatic life, and pollutes crops/water.
NOₓ also irritates lungs, throats, and eyes, and contributes to photochemical smog.

How acid rain is produced

The Greenhouse Effect and Global Warming

The greenhouse effect is a natural process: the Sun's radiation warms Earth, and greenhouse gases (CO₂, CH₄) trap some infrared radiation emitted from the surface, keeping the planet warm.
Enhanced greenhouse effect occurs when increased concentrations of greenhouse gases trap more thermal energy, leading to global warming.
Consequences of global warming include rising sea levels (from melting glaciers), extreme weather, habitat loss, species extinction, migration of species, and spread of diseases.

Diagram showing how the greenhouse effect occurs

Reducing Climate Change

Reduce CO₂ emissions by using renewable energy (solar, wind, hydrogen), fuel-efficient vehicles (electric/hybrid), public transport, recycling, and reducing household energy use.
Planting trees (reforestation) removes CO₂ via photosynthesis.
Reduce methane emissions by decreasing livestock farming (methane from digestion).

Reducing Acid Rain

Use low-sulfur fuels to reduce SO₂ emissions.
Flue gas desulfurisation (FGD) in power stations: waste gases are sprayed with a lime slurry (calcium oxide/carbonate) which reacts with SO₂ to form calcium sulfate, removing 90–95% of SO₂.
Catalytic converters in vehicles remove oxides of nitrogen by redox reactions: 2NO + 2CO → N₂ + 2CO₂.

Sulfur dioxide scrubber

Catalytic Converters (Extended Tier Only)

Catalytic converters contain platinum and rhodium catalysts on a honeycomb structure to increase surface area.
They convert CO to CO₂ (2CO + O₂ → 2CO₂), NOₓ to N₂ (2NO → N₂ + O₂), and unburned hydrocarbons to CO₂ and H₂O (e.g., C₈H₁₈ + 12½O₂ → 8CO₂ + 9H₂O).

Catalytic converter

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練習問題

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1.What is the approximate percentage of nitrogen in clean, dry air?
Easy
- A21%
- B78%
- C1%
- D0.04%
2.Which gas is produced by the complete combustion of carbon-containing fuels?
Easy
- Acarbon monoxide
- Bcarbon dioxide
- Cmethane
- Dsulfur dioxide
3.Carbon monoxide is toxic because it combines with haemoglobin in the blood and prevents it from carrying oxygen.
Easy
True or false?
4.State one adverse effect of particulates (soot) on human health.
Easy
5.Complete the sentence about the greenhouse effect.
Easy
Greenhouse gases such as ____ and ____ absorb thermal energy and re-emit it, trapping heat in the atmosphere.
6.Match each pollutant to its primary source.
Medium
- Sulfur dioxide
- Oxides of nitrogen
- Methane
- Combustion of fossil fuels containing sulfur
- High temperature reactions in car engines
- Digestive processes of animals
7.The complete combustion of methane produces carbon dioxide and water. How many moles of oxygen are required to completely combust 2 moles of methane? (Equation: CH4 + 2O2 → CO2 + 2H2O)
Medium
- A4
- B3
- C6
- D5
8.Name one strategy to reduce carbon dioxide emissions from vehicles.
Easy

もっと問題

9.Arrange the following steps in the formation of acid rain from sulfur dioxide in order.
Medium
- Sulfur dioxide dissolves in rainwater
- Sulfur dioxide is released from power stations
- Acid rain falls to the ground
10.In a catalytic converter, which reaction helps to reduce nitrogen monoxide emissions?
Medium
- A2NO → N2 + O2
- B2CO + O2 → 2CO2
- CCH4 + 2O2 → CO2 + 2H2O
- DC + O2 → CO2
11.State one consequence of global warming on sea levels.
Easy
12.Flue gas desulfurisation uses a slurry of calcium oxide and calcium carbonate to remove sulfur dioxide from waste gases.
Medium
True or false?
13.Which two gases are the main components of clean, dry air?
Easy
- Anitrogen and oxygen
- Boxygen and carbon dioxide
- Cnitrogen and argon
- Doxygen and water vapour
14.Carbon monoxide is produced by the complete combustion of carbon-containing fuels.
Easy
True or false?
15.Which of the following is a source of methane?
Easy
- Acomplete combustion of fossil fuels
- Bincomplete combustion of petrol
- Cdigestive processes of animals
- Dreaction of nitrogen with oxygen in car engines
16.What is the main adverse effect of sulfur dioxide on the environment?
Easy
- Ait contributes to the greenhouse effect
- Bit causes acid rain
- Cit is toxic to humans
- Dit produces photochemical smog
17.In a catalytic converter, which reaction reduces nitrogen monoxide?
Hard
- A2NO → N₂ + O₂
- B2NO + 2CO → N₂ + 2CO₂
- C2CO + O₂ → 2CO₂
- DC₈H₁₈ + 12½O₂ → 8CO₂ + 9H₂O
18.The enhanced greenhouse effect is caused by an increase in the concentration of greenhouse gases due to human activities.
Easy
True or false?
19.Select all the gases that are considered greenhouse gases. (Select all that apply)
Medium
- Acarbon dioxide
- Boxygen
- Cmethane
- Dnitrogen
- Ewater vapour
20.Arrange the following steps in the formation of acid rain from sulfur dioxide in the correct order.
Medium
- sulfur dioxide dissolves in rainwater
- sulfur dioxide is released from power stations
- acid rain falls to the ground
- sulfur dioxide reacts with oxygen and water to form sulfuric acid
21.Match each air pollutant to its primary source.
Medium
- Carbon monoxide
- Oxides of nitrogen
- Sulfur dioxide
- Methane
- Incomplete combustion of fossil fuels
- High-temperature reactions in car engines
- Combustion of fossil fuels containing sulfur compounds
- Digestive processes of animals
22.Arrange the following steps in the greenhouse effect in the correct order starting from the Sun's radiation.
Medium
- Earth's surface absorbs energy and re-emits it as infrared radiation
- Greenhouse gases absorb some infrared radiation and re-emit it in all directions
- Sun emits radiation that enters Earth's atmosphere
- Some energy is reflected from Earth's surface
23.Which of the following are consequences of global warming? (Select all that apply)
Medium
- ARising sea levels
- BIncreased frequency of earthquakes
- CExtinction of species
- DMigration of species to cooler areas
- EDecrease in atmospheric carbon dioxide
24.Catalytic converters reduce nitrogen monoxide emissions by oxidising it to nitrogen dioxide.
Medium
True or false?
25.In a catalytic converter, which reaction reduces nitrogen monoxide (NO) to nitrogen gas?
Hard
- A2NO → N2 + O2
- B2NO + 2CO → N2 + 2CO2
- C2NO + O2 → 2NO2
- DNO + CO → N2 + CO2
26.Arrange the following steps in the process of flue gas desulfurisation in the correct order.
Medium
- Waste gases pass into a scrubbing chamber
- Calcium compounds react with sulfur dioxide to produce calcium sulfate
- Spray a wet slurry of calcium oxide and calcium carbonate
- Sulfur dioxide is removed from the waste gases
27.Which of the following are products of the incomplete combustion of a hydrocarbon? (Select all that apply)
Medium
- ACarbon dioxide
- BCarbon monoxide
- CWater
- DSoot (carbon)
- ESulfur dioxide
28.A student investigates the effect of a catalyst on the decomposition of hydrogen peroxide. Which statement about catalysts is correct?
Easy
- AA catalyst increases the activation energy of a reaction.
- BA catalyst is used up during the reaction.
- CA catalyst provides an alternative reaction pathway with a lower activation energy.
- DA catalyst changes the products of a reaction.
29.In a laboratory experiment to measure the percentage of oxygen in air, a student uses a gas syringe to collect 100 cm³ of air and passes it over hot copper powder. The volume of gas remaining after the reaction is 79 cm³. What is the percentage of oxygen in the air sample?
Medium
- A21%
- B79%
- C29%
- D100%
30.A student investigates the effect of a catalyst on the decomposition of hydrogen peroxide. Which of the following are correct statements about catalysts? (Select all that apply)
Medium
- ACatalysts increase the rate of a reaction.
- BCatalysts are used up during the reaction.
- CCatalysts provide an alternative reaction pathway with lower activation energy.
- DCatalysts change the position of equilibrium.
- ECatalysts are specific to certain reactions.
31.In a catalytic converter, the reaction 2NO → N₂ + O₂ reduces nitrogen monoxide to nitrogen gas.
Medium
True or false?
32.Which of the following pollutants is produced by the reaction of nitrogen with oxygen in the high temperatures of car engines?
Easy
- ACarbon monoxide
- BSulfur dioxide
- COxides of nitrogen
- DParticulates
33.A student measures the mass of a sample of air before and after passing it over hot copper. The mass increases. Which gas in the air has been removed by the copper?
Easy
- Anitrogen
- Boxygen
- Ccarbon dioxide
- Dargon
34.Which of the following are products of the reaction between nitrogen monoxide and carbon monoxide in a catalytic converter? (Select all that apply)
Medium
- Anitrogen
- Boxygen
- Ccarbon dioxide
- Dcarbon monoxide
- Enitrogen dioxide
35.Place the following steps in the correct order to describe how acid rain forms from sulfur dioxide.
Medium
- Sulfur dioxide dissolves in rainwater
- Sulfur dioxide is released from power stations
- Sulfurous acid or sulfuric acid forms
- Fossil fuels containing sulfur are burned
36.A sample of polluted air contains 0.01% sulfur dioxide by volume. If the total volume of air is 1000 m³, what volume of sulfur dioxide is present?
Medium
- A0.1 m³
- B1 m³
- C10 m³
- D100 m³
37.Which of the following is a consequence of global warming?
Easy
- AIncreased rate of photosynthesis
- BRising sea levels
- CDecreased atmospheric carbon dioxide
- DMore oxygen in the air
38.In a catalytic converter, a honeycomb structure is used to support the catalyst. What is the main reason for using a honeycomb structure?
Medium
- ATo increase the surface area available for reaction
- BTo reduce the mass of the catalytic converter
- CTo allow exhaust gases to flow more slowly
- DTo absorb heat and prevent the converter from overheating
39.Particulates (soot) are produced by the complete combustion of carbon-containing fuels.
Easy
True or false?
40.Arrange the following steps in the correct order to show how a catalytic converter reduces nitrogen monoxide and carbon monoxide emissions.
Medium
- Nitrogen monoxide and carbon monoxide diffuse into the honeycomb.
- The catalyst provides a surface for the reaction.
- Nitrogen monoxide is reduced to nitrogen gas.
- Carbon monoxide is oxidised to carbon dioxide.
- The products, N₂ and CO₂, leave the converter.
41.A student investigates the effect of a catalyst on the decomposition of hydrogen peroxide. Which of the following statements about catalysts is correct?
Easy
- AA catalyst increases the rate of reaction by providing an alternative pathway with lower activation energy.
- BA catalyst is used up during the reaction.
- CA catalyst changes the products of the reaction.
- DA catalyst increases the yield of the reaction.
42.Which gas is the most abundant in clean, dry air?
Easy
- ANitrogen
- BOxygen
- CCarbon dioxide
- DArgon
43.Which of the following gases are greenhouse gases? (Select all that apply)
Medium
- ACarbon dioxide
- BOxygen
- CMethane
- DNitrogen
- ESulfur dioxide
44.Arrange the following steps in the correct order to describe how the enhanced greenhouse effect leads to global warming.
Medium
- Greenhouse gases absorb thermal energy radiated from Earth
- Earth's surface absorbs solar radiation and re-emits it as thermal energy
- Increased concentration of greenhouse gases traps more thermal energy
- Average global temperature rises
45.Complete the sentence: The greenhouse gas that is produced during the complete combustion of fossil fuels is ___.
Easy
The greenhouse gas that is produced during the complete combustion of fossil fuels is ____.
46.State one effect of particulates (soot) on human health.
Easy
47.What is the percentage of oxygen in clean, dry air?
Easy
48.Complete the sentence about acid rain formation.
Easy
Sulfur dioxide dissolves in rain to form ____ ____.
49.Calculate the percentage of nitrogen in clean, dry air if the percentages of the other main components are: oxygen 21%, argon 0.9%, carbon dioxide 0.04%, and the rest is nitrogen.
Medium
50.State one strategy to reduce methane emissions from agriculture.
Easy
51.Complete the sentence about the composition of air.
Easy
The two main gases in clean, dry air are ____ and ____.
52.A power station burns coal containing 2.5% sulfur by mass. If the station uses 1000 tonnes of coal per day, calculate the mass of sulfur dioxide (SO2) produced per day assuming all sulfur is converted to SO2. (Relative atomic masses: S = 32, O = 16)
Medium
53.Explain how flue gas desulfurisation reduces sulfur dioxide emissions from power stations.
Medium
54.Explain how catalytic converters reduce the emission of nitrogen monoxide and carbon monoxide from car exhausts. Include the chemical equation in your answer.
Hard
55.Explain how flue gas desulfurisation reduces sulfur dioxide emissions from power stations. Include the chemicals used and the product formed.
Medium
56.What is the percentage of oxygen in clean, dry air?
Easy
- A25 %
- B23 %
- C19 %
- D21 %
57.Calculate the percentage of nitrogen in clean, dry air if the percentages of the other main components are: oxygen 21%, argon 0.9%, carbon dioxide 0.04%, and the rest is nitrogen.
Easy
- A78.06 %
- B70.25 %
- C85.87 %
- D93.68 %
58.A power station burns coal containing 2.5% sulfur by mass. If the station uses 1000 tonnes of coal per day, calculate the mass of sulfur dioxide (SO2) produced per day assuming all sulfur is converted to SO2. (Relative atomic masses: S = 32, O = 16)
Medium
- A55 tonnes
- B60 tonnes
- C45 tonnes
- D50 tonnes

フラッシュカード

What is the approximate composition of clean, dry air?

78% nitrogen, 21% oxygen, and the remaining gases include carbon dioxide and trace quantities of noble gases.

What are the main sources of carbon dioxide in the atmosphere?

Complete combustion of carbon-containing fuels such as fossil fuels (e.g., methane: CH4 + 2O2 → CO2 + 2H2O).

What adverse effect does carbon dioxide have on the environment?

It increases global warming, which leads to climate change.

How is carbon monoxide produced and what is its adverse effect?

It is produced by incomplete combustion of carbon-containing fuels. It is toxic, as it combines with haemoglobin in the blood and prevents it from carrying oxygen.

What are particulates and what are their adverse effects?

Particulates are particles of carbon (soot) produced by incomplete combustion. They cause respiratory problems and cancer.

What are the sources of methane?

Waste gases from digestive processes of animals, decomposition of vegetation, and bacterial action in swamps, rice paddy fields, and landfill sites.

How are oxides of nitrogen formed and what are their adverse effects?

They are formed when nitrogen and oxygen react at high temperatures (e.g., in car engines). They produce photochemical smog, acid rain, and cause respiratory problems.

What is the main source of sulfur dioxide and its adverse effect?

Combustion of fossil fuels containing sulfur compounds (e.g., S + O2 → SO2). It dissolves in rain to form acid rain, which corrodes structures and damages aquatic life.

What is the difference between complete and incomplete combustion of hydrocarbons?

Complete combustion in excess oxygen produces CO2 and H2O. Incomplete combustion in oxygen-deficient conditions produces CO, H2O, and sometimes carbon particulates.

Explain the greenhouse effect.

The Sun's energy enters the atmosphere; some is reflected, some is absorbed by Earth and re-emitted as infrared radiation. Greenhouse gases (e.g., CO2, methane) absorb some of this thermal energy and re-emit it, trapping heat and keeping Earth warm.

What is the enhanced greenhouse effect?

The increase in concentration of greenhouse gases due to human activity, which traps more thermal energy and causes global warming.

List three consequences of global warming.

Rising sea levels due to melting glaciers, extinction of species due to habitat destruction, and migration of species to more habitable areas.

How can carbon dioxide emissions be reduced?

By using renewable energy (solar, wind), fuel-efficient vehicles, reducing vehicle use, recycling, reducing energy consumption, and planting trees (reforestation).

How can methane emissions be reduced?

By reducing the amount of livestock farming, as methane is produced during digestion in animals.

What are two strategies to reduce acid rain?

Using catalytic converters in vehicles to remove oxides of nitrogen, and flue gas desulfurisation to remove sulfur dioxide from power station emissions.

Describe flue gas desulfurisation.

Waste gases from coal-fired power stations are sprayed with a wet slurry of calcium oxide and calcium carbonate, which react with sulfur dioxide to produce calcium sulfate, removing 90-95% of SO2.

What is the function of a catalytic converter?

It converts harmful exhaust gases (oxides of nitrogen, carbon monoxide, unburned hydrocarbons) into less harmful substances (N2, CO2, H2O) using redox reactions on transition metal catalysts.

Write the equation for the reaction of nitrogen monoxide with carbon monoxide in a catalytic converter.

2NO + 2CO → N2 + 2CO2

What are the products of complete combustion of a hydrocarbon?

Carbon dioxide and water.

What are the products of incomplete combustion of methane?

Carbon monoxide and water, or carbon (soot) and water, depending on oxygen availability.

Why is carbon monoxide dangerous to humans?

It combines with haemoglobin in the blood, preventing oxygen transport.

What is the source of particulates?

Incomplete combustion of carbon-containing fuels, such as fossil fuels.

Name two greenhouse gases.

Carbon dioxide and methane.

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