Chemistry of the Atmosphere(9) Flashcards
Describe the proportions of gases in
the modern atmosphere
Describe the Earth’s early atmosphere and how it was formed (4 ways)
The Earth was hot when it was formed
There was significant volcanic activity
Gases have been released from these
volcanoes
These gases included CO2, N2, CH4, NH3, H2O
How did the amount of oxygen
in the atmosphere increase?
Algae and plants produced the atmospheric O2 by photosynthesis, which can be
represented by the equation: 6 CO2+ 6 H2O → C6H12O6+ 6 O2. As the amount of
gradually O2 increased, there were more plants that produced more oxygen.
How did the amount of carbon
dioxide in the atmosphere decrease?
Some CO2 was dissolved in the oceans, where it reacted with metal ions to form
insoluble carbonates, such as CaCO3, or was taken in by animals to become a part of
skeleton. When animal dies, this becomes a sedimentary rock.
Or
Some CO2 was used in photosynthesis to make oxygen.
What is the greenhouse effect?
Greenhouse gases in the atmosphere maintain temperatures on Earth high
enough to support life
What are greenhouse gases?
They allow short wavelength radiation from the sun to pass through the
atmosphere to the Earth’s surface, but absorb the outgoing long wavelength
radiation from the Earth causing an increase in temperature.
Example of greenhouse gases
Water vapour, carbon dioxide, and methane
Why is the greenhouse effect
necessary for life?
The greenhouse effect is a natural phenomenon. Without it, the Earth would be too cold for life to exist.
How have human activities led
to an increase in greenhouse gases?
Carbon dioxide – combustion and deforestation
Methane – increased farming and decomposition in landfills
What are the potential effects
of global climate change?
sea level rise, which may cause flooding and increased coastal erosion
more frequent and severe storms
changes in the amount, timing and distribution of rainfall
temperature and water stress for humans and wildlife
changes in the food-producing capacity of some regions
changes to the distribution of wildlife species
What is a carbon footprint?
A carbon footprint is the total amount of carbon dioxide and other greenhouse
gases emitted over the full life cycle of a product, service or event.
What actions can be taken to reduce a carbon footprint?
• increased use of alternative energy supplies
• energy conservation
• carbon capture and storage (where CO2 is trapped in solvents and stored
underground)
• carbon taxes and licences
• carbon off-setting including through tree planting
• carbon neutrality – zero net release.
What are the challenges faced with reducing a carbon footprint?
• scientific disagreement over causes and consequences of global climate change
• lack of public information and education
• lifestyle changes (people don’t want to give up their cars)
• economic considerations (it will cost money)
• incomplete international cooperation
What are the advantages of complete combustion?
• less soot (carbon particulates) is made with complete combustion
• more heat per gram of fuel is released with complete combustion
• poisonous carbon monoxide is not produced with complete combustion
How is pollution caused by combustion?
When a fuel burns, the gases released to the atmosphere include carbon dioxide,
water (vapour), carbon monoxide, sulphur dioxide and oxides of nitrogen.
Solid particles and unburned hydrocarbons may also be released that form
particulates in the atmosphere.
