GCSE AQA Chemistry- Chemistry of the atmosphere

What was the early chemistry of the atmosphere like?

Mainly carbon dioxide, some other gases

What factors and events caused the earth's early chemistry of the atmosphere?

High volcanic activity released carbon dioxide, water vapour which condensed to form the oceans, small proportions of methane and ammonia

What was the chemistry of the atmosphere like 2 billion years ago?

Still mainly carbon dioxide, but a higher proportion of nitrogen and oxygen, with a smaller amount being other gases.

What factors and events caused the chemistry of the atmosphere 2 billion years ago?

Green plants and algae evolve and carbon dioxide reduces and plants take it in and give out oxygen, microorganisms that can't tolerate oxygen die, carbon from carbon dioxide becomes locked in rocks formed from shells and skeletons of marine animals, other gases interact with oxygen to release nitrogen, nitrogen is produced by bacteria removing nitrates from decay plant material

What is the current chemistry of the atmosphere?

Mainly nitrogen (about 80%), with some oxygen (almost 20%) and very small amount of carbon dioxide which has decreased significantly and other gases, about 0-3% water vapour

Increase in oxygen

Algae first started producing oxygen about 2.7 billion years ago in photosynthesis, so levels of oxygen rose. This allowed plants to develop and even more oxygen to be produced over time

Decrease of carbon dioxide

Plants evolved so more was used in photosynthesis, carbon becomes locked in sedimentary rocks and fossil fuels, limestone contains calcium carbonate and is formed from shells and skeletons of sea creatures, sea water has absorbed some carbon, producing insoluble carbonates that are deposited as sediments, soluble hydrogen carbonates (this can cause the ocean to become acidic which harms marine life)

How does the greenhouse effect work?

High energy, short wavelength infrared radiation from the sun passes through the earth's atmosphere to the earth's surface. Some of this is absorbed by the earth. Lower energy, longer wavelength infrared radiation is reflected by the earth's surface. Greenhouse gases in the atmosphere absorb this outgoing radiation

Why we do we need greenhouse gases?

The earth would be too cold for water to be a liquid and it wouldn't be able to harbour life

Human activities that increase the amount of greenhouse gases

Carbon dioxide- Burning fossil fuels, deforestation

Methane- decomposition of rubbish in landfill sites, animal farming

Effects of climate change?

Rising sea levels, more frequent and severe storms, changes in amount and timing of rainfall, increased number of heatwaves, more drought, change in distribution of plants and animals, food shortage in some areas

What is a carbon footprint?

The full amount of greenhouse gases emitted by a product, service or event over its full life cycle

How can the carbon footprint be recycled?

Carbon capture and storage, carbon taxes and licenses, carbon off-setting, encouraging carbon neutral products

What are the problems with reducing the carbon footprint?

disagreement over the cause of climate change, lack of info in the public, reluctance to make lifestyle changes, economic considerations, disagreement between countries