Cambridge IGCSE Chemistry
10.3Air quality and climate
Air quality and climate in Cambridge IGCSE Chemistry: what the syllabus expects you to know, the learning objectives and how to practise.
Subtopic42 practice questions2 lessons
Learning objectives
What the syllabus expects you to be able to do.
- 10.3.1State that clean, dry air is about 78% nitrogen and 21% oxygen, with the remainder a mixture of noble gases and carbon dioxide.
- 10.3.2State the sources of the air pollutants carbon dioxide (complete combustion of carbon-containing fuels), carbon monoxide and particulates (incomplete combustion of carbon-containing fuels), methane (decomposition of vegetation and waste gases from digestion in animals), oxides of nitrogen (car engines) and sulfur dioxide (burning fossil fuels that contain sulfur compounds).
- 10.3.3State the harmful effects of these pollutants: more carbon dioxide and methane increase global warming, leading to climate change; carbon monoxide is toxic; particulates increase the risk of respiratory problems and cancer; oxides of nitrogen cause acid rain, photochemical smog and respiratory problems; sulfur dioxide causes acid rain.
- 10.3.4State and explain ways of reducing climate change (planting trees, less livestock farming, less use of fossil fuels, more use of hydrogen and renewable energy such as wind and solar) and acid rain (catalytic converters in vehicles, low-sulfur fuels and flue-gas desulfurisation with calcium oxide).
- 10.3.5Describe photosynthesis as the reaction between carbon dioxide and water, using energy from light in the presence of chlorophyll, to produce glucose and oxygen.
- 10.3.6State the word equation for photosynthesis: carbon dioxide + water → glucose + oxygen.
- 10.3.7Supplement: describe how carbon dioxide and methane cause global warming through the absorption, reflection and emission of thermal energy, which reduces the loss of thermal energy to space.
- 10.3.8Supplement: explain how oxides of nitrogen form in car engines and describe their removal by catalytic converters, for example 2CO + 2NO → 2CO₂ + N₂.
- 10.3.9Supplement: state the symbol equation for photosynthesis, 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
Lessons
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Air pollution: sources, effects and control
40 min
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Greenhouse gases and climate change
35 min
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