C9 - Chemistry of the Atmosphere Flashcards
What is composition of the atmosphere?
Approximately 80% Nitrogen, 20% Oxygen and small amounts of CO2,water vapour and Nobel gases
What was the composition of the earth’s early atmosphere?
Lots of carbon dioxide and water vapour from volcanic eruptions and small amounts of methane and ammonia
How did the level of water vapour reduce?
The earth cooled so the water vapour condensed and formed oceans
Give 3 ways the level of CO2 decreased
The CO2 dissolved in oceans and formed sedimentary rocks such as limestone.
Plants evolved and photosynthesised which uses CO2 and produces O2.
CO2 taken in by animals and becomes part of their skeleton when they die, forming sedimentary rock
Why are greenhouse gases important for life on earth?
They maintain the earth’s temperature so it is high enough to support life
Name three greenhouse gases
Methane, water vapour and carbon dioxide
How do greenhouse gases maintain the earth’s temperature?
Short wavelength radiation from the sun is transmitted through the atmosphere and absorbed by the earth. It is re-emitted from the earth at a longer wavelength, which is absorbed by the greenhouse gases.
How have humans contributed to CO2 levels rising?
Deforestation of trees reducing photosynthesis, burning of fossil fuels.
How have humans contributed to methane levels rising?
Intensive cattle farming, rice paddy fields and decomposition in land fill sites.
What are 4 implications of global temperature increases from climate change?
Sea level rise - flooding and erosion
More frequent and severe storms.
Temperature and water stress for life on Earth.
Changes to distribution of wildlife.
What does the term carbon footprint mean?
The total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.
How can people reduce their carbon footprint?
Use less energy
Use renewable energy
Offset their emissions by planting trees
Carbon capture and storage.
Carbon taxes.
What elements do most fuels contain?
Carbon and or hydrogen and may contain sulphur impurities.
What are the products of complete combustion?
Carbon dioxide and water
What are the products of incomplete combustion?
Carbon monoxide, carbon particulates and water
When does incomplete combustion occur?
If there is a limited amount of oxygen
How does carbon dioxide form during combustion?
Carbon from the fuel reacts with oxygen from the air by complete combustion
How does carbon monoxide form during combustion?
Carbon from the fuel reacts with oxygen from the air by incomplete combustion
How does sulphur dioxide form during combustion?
Sulphur impurities in the fuel react with oxygen from the air
How do nitrogen oxides form during combustion of fuels?
Nitrogen from the air reacts with oxygen from the air inside a hot car engine
What problems are associated with carbon monoxide?
It is a toxic gas that can kill, it is hard to detect as it is colourless and odourless
What problems are associated with sulphur dioxide and nitrogen oxides?
They cause acid rain as well as respiratory problems.
What problems are associated with carbon particulates?
They cause global dimming and irritate the lungs.
What was the early climate of the earth?
Very hot.
What gases are released during a volcanic eruption?
Carbon dioxide, Nitrogen, Methane, Ammonia and water vapour.
How did the oxygen levels increase?
Algae and plants produced O2 through photosynthesis.
What does the CO2 in the oceans react with and forms what?
Reacts with metal ions and forms insoluble carbonates such as CaCO3.
Why is the greenhouse effect important?
To maintain temperatures high enough to support life on Earth.
What is carbon capture and storage?
CO2 is trapped in solvents and stored underground.
What are 5 problems with reducing carbon footprint?
Scientific disagreement over causes and consequences of climate change.
Lack of public information and education.
Lifestyle changes.
Expensive.
Needs international cooperation.
What are the advantages of complete combustion?
Less carbon particulates.
More energy is released.
Poisonous carbon monoxide not produced.
What gases are released when a fuel burns?
Sulfur dioxide, carbon dioxide, carbon monoxide, nitrous oxides.
Unburned hydrocarbons and solid particles are also released.
What does acid rain do?
Damages plants and buildings.
What problems do particulates cause?
Global dimming. Damage to lungs - health problems.
What is global dimming?
Reducing the amount of sunlight that reaches the Earth’s surface.
Why are scientists not certain about the early atmosphere?
4.6 billion years ago - not evidence.
