C13 - The Earth’s Atmosphere

How did scientist know what gases were present in the Earths early atmosphere? [2 points]

• Gas bubbles trapped in rocks were placed in vacuum sealed containers.

• Light samples from planets and their moons.

How was oxygen introduced into the Earths atmosphere?

Plants such as algae carried out photosynthesis.

State how the Earths early atmosphere was formed. [4 points]

• The earth was a ball of molten rock.

• Volcanic activity caused the release of gasses.

• Earth cooled to 100° causing water vapour to fall as rain.

• Origin of Life removed CO₂ and added O₂.

What allowed animals to evolve? [ 2 points]

• Increase in oxygen levels due to photosynthesis.

• Plants provided food.

Suggest 2 possible sources of water in the Earths early atmosphere.

• Ice meteors warming upon entry and falling as rain.

• Water vapour condensing as the Earth cools down past 100°.

What layer in the atmosphere did oxygen form?

The o-zone layer.

Explain the term ‘Locked up carbon’.

Locked up carbon is carbon that is stored in long-term reservoirs such as fossil fuels, soil organic matter, and deep ocean sediments, preventing it from being released into the atmosphere as carbon dioxide.

What gases were present in the Earths early atmosphere?

• Carbon dioxide

• Methane

• Nitrogen

• Amonia

• Calcium Carbonate

• Water vapour

How was crude oil formed

Flashcard: Crude oil formed from dead plants and animals decaying at the bottom of the ocean under high pressure and heat over millions of years.

How did the concentration of CO₂ decrease in the Earths early atmosphere. [3 points]

• Dissolved into the oceans.

• Became locked up when it made carbonate rocks.

• Plants began to photosynthesise.

State the percentages of the gases in the Earths present atmosphere.

• Nitrogen (N₂) - 78%

• Oxygen (O₂) - 21%

• Argon (Ar) - 0.9%

• Carbon dioxide (CO₂) - 0.04%

Explain the greenhouse effect. [5 points]

1. Electromagnetic radiation from the sun passes through the Earth’s atmosphere.

2. The Earth absorbs most and heats up.

3. The Earth radiates energy as infrared.

4. Some infrared goes back into space.

5. Some is absorbed by the greenhouse gasses in the atmosphere and heats up the lower atmosphere.

How is coal formed?

Organic matter such as dead plants that have been compressed and heated over millions of years in the Earth's crust.

Name 3 greenhouse gases and give their state symbols.

• Carbon dioxide - CO₂

• Methane - CH₄

• Water vapour - H₂O

What is causing the increased greenhouse effect. [ 4 points]

• Increased combustion of fossil fuels.

• Increased cattle farming.

• Deforestation.

• Warmer Oceans ( Less CO₂ absorbed).

What is meant by carbon capture and storage?

• Pumping CO₂ deep underground to be absorbed into porous rocks.

Carbon footprint?

• The total amount of carbon dioxide emissions produced by an individual, group or location.

What are 4 consequences of rising levels of greenhouse gases?

• Rising sea levels.

• Extreme weather.

• Changes in temperature.

• Spreading of disease (mosquitos like warm climate).

Define Sustainability.

• Using the Earths resources to meet the needs of society and the future.

How is sulphur dioxide made and what is its effect?

• Fossil fuels cntain sulphur, when they are burnt they release it and it reacts with oxygen.

• S + O₂ → SO₂

• Causes acid rain.

• If taken deep into lungs may cause cancer.

How is carbon monoxide made and what is its effect?

• Made when a fossil fuel is burnt in a small supply of oxygen.

• CH₄ + O₂ → CO + C + H₂O

• Reduces your bodies ability to carry oxygen around the body.

Effects of global warming?

- rising sea level (thermal expansion)
- extreme weather
- drought
- famine
- reduced biodiversity & habitats: extinctions

Global Warming Mitigation

- the Paris agreement
- the London congestion charge
- carpool lanes
- less demand for meat
- taxing fossil fuels
- planting plants

Complete Combustion

- combustion that occurs when there is plenty of oxygen
- produces carbon dioxide and water vapour

Incomplete Combustion

- a fuel burns in insufficient oxygen
- producing carbon monoxide as a toxic product.

Pollutant Gases - Carbon Dioxide

- carbon in a hydrocarbon fuel reacts with plentiful oxygen
- causes global warming
- by trapping infrared radiation in our atmosphere that would usually be reflected into space

Pollutant Gases - Carbon Monoxide

- when hydrocarbons combust where there is a lack of oxygen
- binds to the hemoglobin in your red blood cells so they cannot carry oxygen around your body: oxygen starvation
- is toxic

Pollutant Gases - Sulphur Dioxide

- sulphur impurties in the fuel react with oxygen
- can damage the lungs and lead to asthma attacks
- dissolve in rain as it falls to make sulphuric acid (acid rain) which damages
buildings and plants

Pollutant Gases - Particulates

- when hydrocarbons combust where there is a lack of oxygen
- soot particules can cause lung damage
- can reflect light from the sun back into space leading to global dimming

Pollutant Gases - Nitrous Oxides

- nitrogen in the air reacts with oxygen in the high temperatures and pressures of an internal combustion engine
- can damage the lungs and lead to asthma attacks
- dissolve in rain as it falls to make nitric acid: acid rain which damages buildings and plants

Reducing Atmospheric Pollution

- filtering of waste gases to remove sulphur dioxides, oxides of nitrogen, soot etc
- keeping car engines maintained to prevent nitrogen reacting with oxygen to make oxides of nitrogen
- keeping boilers etc maintained to prevent incomplete combustion
- carbon capture
- using fuels with little or no sulphur in
- using less hydrocarbon fuels: renewable