C9 - chemistry of the atmosphere

what is combustion

an exothermic reaction between a fuel and oxygen

what happens at incomplete combustion

as well as carbon dioxide, solid particles of soot and unburnt fuel are released into the atmosphere and carbon monoxide can be produced

what damage can particulates in the air cause

• if inhaled, they can get stuck in the lungs and cause damage.

• they themselves, or the clouds they help to produce, reflect sunlight back into space. this means less light reaches the earth - causing global dimming

what problems does carbon monoxide cause

• stops the blood from carrying oxygen around the body by binding to the haemoglobin in your body. a lack of O₂ can lead to fainting, coma or death.

• carbon monoxide has no colour or scent so it is very hard to detect

what happens when sulfur dioxide and nitrogen oxides are produced during combustion

when these gasses mix with clouds they form dilute sulfuric / nitric acid. this then falls as acid rain.

acid rain kills plants and damages buildings and statues. it makes metals corrode.

phase 1 of evolution of the atmosphere

the earths surface was covered in volcanoes billions of years ago.

the early atmosphere was mainly CO₂ with virtually no oxygen.

volcanic activity also released nitrogen which build up over time as well as water vapour.

phase 2 of the evolution of the atmosphere

when the water vapour in the atmosphere condensed it formed the oceans.

lots of carbon dioxide disolved in the oceans.

green plants and alge evolved and absorbed some of the arbon dioxide for photosynthesis

phase 3 of the evolution of the atmosphere

green plants and alge produced oxygen by photosynthesis.

as oxygen built up in the atmosphere, more complex life could evolve

about 200 million years ago the atmosphere reached a composition similar to todays

how do greenhouse gasses contribute to global warming

greenhouse gasses don’t absorb the incoming short wavelength radiation from the sun but they do absorb the long wavelength radiation that gets reflected back off the earth. they then re-radiate it in all directions including back to earth. the long wavelength radiation is thermal radiation so it results in warming the surface of the earth

consequences of climate change

1. polar ice caps melting - rise in sea levels - increased flooding

2. changes in rainfall patterns - too much or little in certain areas may affect food production

3. frequency and severity of storms increase

4. affect wild species - leading to differences in their distrubution

what is a carbon footprint

a measure of the amount of carbon dioxide and other greenhouse gasses released over the full life cycle of something

ways to reduce carbon footprint

• use renewable energy sources

• more efficient processes to cut down waste

• governments could tax people based on the amount of greenhouse gasses they emmit

• technology that captures the CO₂ before it is released into the atmosphere and stores it deep underground