C9 Chemistry of the Atmosphere

Has the atmosphere changed a lot since the formation of the Earth 4.6 billion years ago?

Yes.

What was the condition of the atmopshere like during the formation of the Earth?

It consisted a lot of CO2, as well as comprising some other gases

What was a key factor that shaped the atmosphere 4 billion years ago? [4]

Intense volanic activity that releases: - Mainly Carbon Dioixde - Water vapour - Small proportions of methane and ammonia

What occured between 3-4 billions years ago? [2]

- Decrease in CO2 and other gases - Increase in Oxygen and Nitrogen

What was the condition of the amosphere 2 billion years ago?

The amount of CO2 decreased, with nitrogen and oxygen increasing.

What were some key factors that shaped the atmosphere 2 billion years ago? [6]

Green plants and algae evolve and: - Carbon dioxide is reduced as the plants take it in and give out oxygen - Microorganisms that can't tolerate oxygen are killed off - Carbon from CO2 becomes locked up in sedimentary rocks formed from the shells and skeletons of marine organisms - Other gases react with oxygen to release nitrogen - Nitrogen is also produced by bacteria removing nitrates from decaying plant material

What occured between 1 billions years ago? [2]

- Decrease in carbon dioxide - Increase in nitrogen and oxygen

What is the condition of the amosphere now? [3]

- Comprises of about 80% nitrogen - 20% oxygen - Small proportions of other gases such as water vapour, CO2

How long has the proportions of gases in the atmosphere been more or less the same for?

200 million years

What is the quantity of water vapour present in our atmosphere?

0-3%

Do algae and plants photosynthesise?

Yes

What happens during photosynthesis?

Carbon Dioxide and water react to produce glucose and oxygen

When did algae first started producing oxygen?

2.7 billion years ago

What happened over the next billion years? [Plants]

Plants evolved and the amount of oxygen in the atmosphere increased

What happened as the level of oxygen in the atmosphere increased?

There was enough to allow animals to evolve

What has happened to the level of carbon dioxide as plants and algae have evolved?

It has decreased

Why has the level of carbon dioxide decrease as plants and algae evolve?

Because plants use carbon dioxide during photosynthesis

Why else has carbon dioxide decreased? [Rocks]

As carbon becomes locked up in sedimentary rocks and fossil fuels

What does limestone contain?

Calcium Carbonate

What can calcium carbonate (limestone) be formed from?

Shells and skeletons of sea creatures

What is coal?

A sedimentary rock formed from plants deposits that were buried and compressed over millions of years

True or false: The level of carbon dioxide in the atmosphere has also reduced by the reaction between CO2 and sea water?

True

What does the reaction between carbon dioxide and sea water produce? [2]

- Insoluble carbonates that are deposited as sediment - Soluble hydrogen carbonates

Why is carbon dioxide dissolving in the oceans dangerous?

As it can harm marine life such as coral reefs

What is emitted from the sun that passes through the atmosphere and reaches the Earth's surface?

High energy, short wavelength infrared radiation

What happens to the infrared radiation from the Sun that passes through our atmosphere and reaches the surface?

It is absorbed by the Earth

What happens to lower energy, longer wavelength infrared radiation? [R]

It is reflected by the Earth's surface

What do greenhouse gases in the Earth's atmosphere absorb?

The outgoing infrared radiation, which increases the Earth's temperature

What would happen to the Earth if there was no greenhouse gases?

Earth would be too cold for water to be a liquid and would not be able to support life

What do greenhouse gases include? [3]

- Carbon Dioxide - Water Vapour - Methane

What can human activites increase?

Levels of greenhouse gases in the atmosphere

Has the amount of carbon dioxide in the atmosphere increased over the last 100 years?

Yes.

What does the increase in CO2 in our atmosphere correlate to?

To the increase in the amount of fossil fuels being burnt

What do fossil fuels contain?

Carbon that has been locked up for millions of years

What is released when you burn fossil fuels?

Carbon Dioxide

What can deforestation lead to?

An increase in carbon dioxide into the atmosphere as there are fewer trees to taking up the gas for photosynthesis

What activities that increase the levels of methane in the atmosphere? [2]

- Decomposition of rubbish in landfill sites - Increase in animal farming

What do many scientists believe that the increase in levels of greenhouse gases will cause?

That the temperature of the Earth's surface will increase and result in global climate change

Why is it difficult to produce and accurate model for such a complicated system?

Because many factors are involved

Why may some people views be biased when speaking about climate change?

As they may be paid by companies that produce greenhouse gases

What can be caused if the global temperature increases?

Can cause global climate change

What would the impact of global climate change be? [7]

- Rise in sea levels - Frequent and severe weather - Changes in the amount/timing of rainfall - Increase in heatwave events - Droughts - Changes to distribution of plants and animals - Food shortages

Why may a rise in sea levels be dangerous?

Can cause devastating floods and more coastal erosion

Why may changes in the amount and timing of rainfall be a impact?

Some areas may receive more rain with other areas receiving less

Why may a increase in heatwave events be dangerous?

Harmful to people and the wildlife

Why are changes to the distribution of plants and animals concerning?

Some areas may have become too hot for species to survive and other areas are warm enough to become habitable

Why will food shortages in some areas occur?

Due to changes in the amount of food a country can produce

What is the carbon footprint of a product, service or event the total of?

Total amount of carbon dioxide and other greenhouse gases that are emitted over its full life cycle

For a product, is the production, use and disposal of the time included in the carbon footprint?

Yes

How can the carbon footprint be reduced? [6]

- Using alternative energy supplies - Wasting less energy - Carbon capture and storage (CSS) - Carbon taxes and licences - Carbon off-setting - Encouraging people to choose carbon-neutral products

Why can carbon capture and storage (CSS) be used to reduce carbon footprint?

Prevents carbon dioxide from being released into the atmosphere

Why does carbon taxes and licences reduce the carbon footprint?

Deters companies and individuals from choosing options that release lots of greenhouse gases

What is an example of carbon off-setting?

Tree planting

What are some problems that occur over reducing carbon footprint? [5]

- Disagreement between scientists over the causes and consequences of climate change - Lack of information and knowledge in the general population - Reluctance of people to make lifestyle changes - Economic considerations - Disagreement between countries as to what should be done

What are the economic considerations that are taken into account when reducing carbon footprint?

The high cost of producing electricity from alternative energy resources rather than using cheaper fossil fuels