AQA GCSE Single Science Chemistry: Chemistry of the atmosphere

What is the proportion of gases in our atmosphere?

• 78% Nitrogen

• 21% Oxygen

• 1% Argon

• 0.03-0.04% Carbon dioxide

How did the proportion of oxygen in the atmosphere increase and carbon dioxide decrease?

• Photosynthesis of algae and plants reduced CO2 levels and increased O2 levels

• Formation of sedimentary rocks and fossil fuels reduced amount of carbon in atmosphere

Explain the greenhouse effect

• Solar radiation passes through atmosphere to be absorbed by the Earth, which reflects infrared radiation.

• Some of this radiation returns to space, but some is absorbed by greenhouse gases, which in trapping the heat, warm up the Earth

• The increase in greenhouse gases in our atmosphere increases this effect.

Which human activities increase the amount of greenhouse gases in the atmosphere?

• Deforestation- reduces intake of CO2 in photosynthesis and burning releases CO2

• Burning fossil fuels- combustion releases CO2 as product

• Farming cattle and rice releases methane

Name some effects of global warming

• Melting of icecaps and glaciers

• Sea level rise

• Habitat change

• Rainfall patterns changing

• Species distribution and migration patterns changing

Actions to take to reduce carbon footprint

• Individual: using public transport, boycotting unsustainable brands, recycling, install solar panels

• Local: petitioning and writing letters to council, car sharing, support local farmers by buying only locally-sourced produce

Why might actions to reduce your carbon footprint be difficult to take?

• Cost

• Convenience

• Accessibility

• Changes to lifestyle

What are the properties and effects of atmospheric pollutants?

• Carbon monoxide: toxic, colourless, odourless

• Sulfur dioxides and oxides of nitrogen: cause acid rain and respiratory problems in humans

• Particulates: cause global dimming and respiratory problems in humans