Topic 9- Chemistry of the atmosphere Flashcards
Describe the proportion of gases in the modern atmosphere:
- 78% Nitrogen
- 21% Oxygen
- Small quantities of carbon dioxide, water vapour and noble gases.
Describe the earths early atmosphere and how it was formed:
- The earth was hot when it was formed
- lots of volcanic activity, that gases were released from
- gases: co2, n2, h20
How did the amount of oxygen in the atmosphere increase?
Green algae and plants produced oxygen from photosynthesis which can be shown in the formula: 6co2 + 6h2o = c6h12o6 + 6o2.
As the amount of o2 gradually increased, so did the amount of plants.
How did the amount of carbon dioxide decrease?
a) Some co2 was used for photosynthesis
b) Some co2 was dissolved in the oceans, Where it reacted with metal ions to form insoluble carbonates, such as CaCo3.
Some co2 was used to form animal skeleton which is turned into sedimentary rock when they die.
What is the greenhouse effect?
Greenhouse gases maintain temperature in the atmosphere high enough to support life.
They allow short- wavelength radiation from the sun to pass through the earths atmosphere to the earths surface, but absorbs the outgoing long- wave length radiation from the earth causing an increase in temperature.
How have human activities led to an increase in greenhouse gases?
combustion, deforestation- carbon dioxide
agriculture, decomposition in land fills- methane
What are the potential effects of global climate change?
- Changes in rainfall patterns
- Changes in temperatures
- Polar ice caps melt, increased flooding, coastal erosion
- changes to the distribution of wildlife species
What is a carbon footprint?
The total amount of greenhouse gases emitted over the life cycle of a product, event, service.
How can you reduce carbon footprints?
- Renewable energy sources
- conserve energy
- tax companies
What are the advantages of complete combustion?
- less soot is made
- poisonous carbon monoxide isn’t produced
- more heat per gram of fuel is produced
How is pollution produced by combustion?
When a fuel burns, the gases released into the atmosphere are: (greenhouse gases)
solid particles and unburned hydrocarbons may also be released that form particulates (soot) in the atmosphere.
What are the issues involving sulfur dioxide and oxides of nitrogen?
Sulfur dioxide and oxides of nitrogen cause respiratory problems for humans and cause acid rain which damages buildings and plants.
What problems do particulates cause?
Particulates, such as carbon particles, cause global dimming by reducing the amount of sunlight that reaches the earths surface. Particulates cause lung problems for humans.
What causes global dimming?
Incomplete combustion causes particulates (soot) to be released. The clouds that they help to produce reflect the light from the sun back into space causing global dimming.
