Topic 9: Chemistry of the atmosphere – GCSE AQA Higher Chemistry revision notes

What this topic covers

Topic 9: Chemistry of the atmosphere has 3 subtopics:

• The composition and evolution of the Earth's atmosphere
• Carbon dioxide and methane as greenhouse gases
• Common atmospheric pollutants and their sources

Topic 9: Chemistry of the atmosphere lessons by subtopic

20 lessons, grouped by subtopic.

The composition and evolution of the Earth's atmosphere

• How Earth's Early Atmosphere Formed: Explore theories about how Earth's early atmosphere developed over 4.6 billion years, including the role of volcanic activity in releasing gases and forming the oceans.
• Changes in Early Atmospheric Composition: Investigate how the formation of oceans led to changes in atmospheric carbon dioxide levels and learn to evaluate evidence for different theories about Earth's early atmosphere.
• How Photosynthesis Increased Atmospheric Oxygen: Learn how algae and plants produced oxygen through photosynthesis, starting 2.7 billion years ago with algae and continuing as plants evolved, gradually increasing oxygen levels to enable animal evolution.
• How Earth's Atmosphere Changed Over Time: Explore the major changes in Earth's atmosphere throughout history and understand the key processes that caused these transformations, including the role of early life forms.
• How Photosynthesis Reduced Carbon Dioxide: Discover how algae and plants used photosynthesis to dramatically decrease atmospheric carbon dioxide levels and change Earth's atmospheric composition.
• Formation of Carbon-Rich Deposits: Learn how limestone, coal, crude oil and natural gas formed from ancient organisms, and understand how these sedimentary rocks and fossil fuels locked away atmospheric carbon dioxide.
• The composition of today's atmosphere: Learn about the main gases in Earth's atmosphere today, including the proportions of nitrogen, oxygen, and other trace gases
• The stability of atmospheric composition: Understand how the proportions of gases in Earth's atmosphere have remained stable for millions of years

Carbon dioxide and methane as greenhouse gases

• Human Activities That Increase Greenhouse Gases: Learn about the human activities that increase carbon dioxide and methane in the atmosphere, and understand the evidence linking these activities to global climate change.
• Evaluating Climate Change Evidence and Scientific Communication: Develop skills in evaluating the quality of climate change evidence, understand uncertainties in data, and learn about the importance of peer review and scientific communication.
• What are greenhouse gases and why are they important?: Learn about the key greenhouse gases in Earth's atmosphere (water vapour, carbon dioxide and methane) and understand how they maintain temperatures high enough to support life on our planet.
• How does the greenhouse effect work?: Explore the greenhouse effect by understanding how greenhouse gases interact with short wavelength radiation from the Sun and long wavelength radiation from Earth's surface.
• Understanding Carbon Footprints: Learn what carbon footprints are and how they measure the total greenhouse gas emissions from products, services and events throughout their entire life cycle.
• Reducing Carbon Footprints: Explore practical actions to reduce carbon dioxide and methane emissions, and understand the challenges and limitations that may prevent these actions from being implemented.
• Understanding Global Climate Change: Explore what global climate change is, how increased average global temperature drives climate change, and examine four key potential effects including rising sea levels, extreme weather, ecosystem disruption, and agricultural impacts.
• Scale and Implications of Climate Change: Analyze the global scale of climate change, assess the risks it poses to human society and natural systems, and evaluate the wide-ranging environmental implications for our planet's future.

Common atmospheric pollutants and their sources

• Fuel Composition and Combustion Products: Learn about the composition of common fuels and identify the products formed when they undergo complete and incomplete combustion, including carbon dioxide, water vapour, carbon monoxide, and particulates.
• Atmospheric Pollutants from Fuel Combustion: Explore how burning fuels produces atmospheric pollutants including carbon monoxide, soot, sulfur dioxide and nitrogen oxides, and learn to predict combustion products based on fuel composition and burning conditions.
• Toxic and Respiratory Pollutants: Explore the dangerous properties of carbon monoxide and how sulfur dioxide and nitrogen oxides affect human health and the environment through acid rain formation.
• Particulate Matter and Global Dimming: Investigate how particulates in the atmosphere cause global dimming effects and create serious health problems for humans.

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