Chemistry of the atmosphere

• What is one theory which suggests where the early atmosphere came from?

  Suggests that the early atmosphere came from intense volcanic activity which released gases that made the early atmosphere very similar to the atmospheres of Mars and Venus today
• What does the atmosphere of the Earth's early atmosphere and today's atmosphere of Venus and Mars include?

  • Little amount of carbon dioxide
  • Little or no oxygen
  • Small amounts of other gases, e.g ammonia and methane
• What did Volcanic activity also release, and what did it do?

  • Released water vapour, which cooled and condensed as the Earth cooled to form oceans
  • Nitrogen, which gradually built up in the atmosphere because it is unreactive
• What percentage of gases make up the Earth's atmosphere today?

  • Nitrogen - Approximately 80%
  • Oxygen- Approximately 20%
  • Other gases - Approximately 1%?
• When do scientists believe that algae first evolved?

  Approximately 2.7 billion years ago
• How did oxygen increase in the atmosphere?

  • Photosynthesis by primitive plants and algae released oxygen, which gradually built up in the atmosphere.
  • Eventually, the amount of oxygen present in the atmosphere enabled animals to evolve
• How did carbon dioxide decrease in the atmosphere?

  • As the oceans formed, carbon dioxide dissolved to form soluble carbonate compounds, decreasing it's amount in the atmosphere
  • Carbon compounds were then precipitated as sedimentary rocks, e.g limestone
• State another reason why carbon dioxide levels decreased in the atmosphere

  Carbon dioxide was absorbed from the oceans into photosynthetic plants to use for photosynthesis
• How was the fossil fuel coal formed?

  • Formed from trees which were dense in forests in low-lying wetland areas
  • Flooding caused the wood to be buried in a way that prevented oxidation taking place
  • Compression and heating took place over millions of years, turning the wood into coal
• How was crude oil and natural gas formed?

  • Formed from simple plants and tiny animals living in oceans and lakes
  • These small organisms died and their remains sank to the bottom where they were buried under sediments
  • The lack of oxygen prevented oxidation from occurring
  • Over millions of years, heat and pressure turned the remains of the organisms into crude oil and natural gas
• State the 3 greenhouse gases:

  • Water vapour
  • Methane
  • Carbon dioxide
• What do these greenhouse gases do? (Methane, water vapour, CO2)

  • Absorb heat radiated from the earth
  • Release energy in all directions, which keeps the earth warm
• State how the greenhouse effect works:

  1. Electromagnetic radiation at most wavelengths passes through the Earth's atmosphere
  2. The Earth absorbs most of the radiation and warms up
  3. The Earth radiates energy as infrared radiation
  4. Some of the infrared radiation goes into space
  5. Some of the infrared radiation is absorbed by greenhouse gases in the atmosphere
  6. The lower atmosphere warms up
• What human activities are increasing the amount of greenhouse gases?

  • Farming cattle (Releases Methane)
  • Farming rice in patty fields (Releases Methane)
  • Burning fossil fuels in vehicles and power stations (Releases Carbon Dioxide)
  • Deforestation (Releases Carbon Dioxide) and reduces the absorption of Carbon Dioxide through photosynthesis
• What piece of evidence supports that human activities are causing an increase in greenhouse gases, causing global warming?

  Evidence in peer-reviewed journals
• What is the difference between Climate and Weather?

  Climate refers to the average weather conditions over longer periods and over large areas

  Weather refers to the day-to-day condition of the atmosphere
• What was climate changed caused by in the Earth's early atmosphere?

  Natural changes, such as volcanic eruptions and changes in the energy that reaches the Earth from the sun
• What is the difference between global warming and climate change?

  Global warming refers to the warming of the climate, whereas climate change refers to the long-term alteration of weather patterns
• State the effects of global warming:

  • Glaciers and polar ice melting
  • Sea levels rising
  • Patterns of rainfall changing, producing floods or droughts
  • Habitats changing
• Suggest two reasons why climate change leads to rising sea levels.

  • Water from melting glaciers and polar ice enters the oceans
  • As the Earth’s temperature increases, seawater warms up and expands
• What is meant by a 'Carbon footprint'?

  The total amount of carbon dioxide (+ other greenhouse gases) which are emitted over the full life cycle of a product, service or event
• What would the carbon footprint of a car include the carbon dioxide emitted by?

  • Machinery whilst the metal is extracted from the Earth's crust and processed
  • Power stations which generate the electricity used to manufacture a car
  • The machinery which is used to dispose of/recycle the car
• How might somebody increase their carbon footprint?

  • Use electricity at home generated from fossil fuels
  • Use a gas-powered boiler at home, which produces carbon dioxide for heating and water
  • Travel to school by bus and car
  • Eat beef or rice that has been farmed using methods which release methane
  • Travel abroad on an aeroplane
• State 3 ways somebody could reduce their carbon footprint

  • Fit solar panels onto the roof of their house, reducing the amount of electricity they use which has been generated from fossil fuels
  • Using a bike to travel instead of driving
  • Improve their home insulation, e.g loft insulation which will reduce the amount of gas burned in the boiler
• What is a problem with incomplete combustion?

  • Carbon monoxide is produced which is a poisonous gas
  • Carbon monoxide can bind to the haemoglobin in your red blood cells, preventing them from carrying oxygen to the cells in your body
• What problems can particulate carbon cause (From incomplete combustion)

  • Irritates the lining of the lungs, making asthma worse
  • May cause cancer
  • Can cause global dimming, reducing rainfall
• How is sulfur dioxide caused?

  • When sulfur atoms are present in some fossil fuels are oxidised
• When sulfur dioxide is further oxidised, what can it be oxidised to?

  Sulfur trioxide (gas) , which can dissolve in rainwater to make acid rain, a dilute solution of sulfuric acid.
• What negative effects does acid rain have on the environment?

  • Harms and kills animals and plants, especially those that live in aquatic environments
  • Can damage man-made objects e.g statues and buildings
• What inside a car engine can make oxides of nitrogen?

  • High temperatures and pressures inside a car engine can cause nitrogen and oxygen in the air to react together to make oxides of nitrogen
• What two compounds made inside engines are formed when nitrogen reacts with oxygen?

  NO and NO2
• What can NOx gases cause?

  • Acid rain
  • React in the atmosphere with other pollutants to make photochemical smog, having major health effects e.g causing death or asthma attacks
• List the pollutants which could be produced when Diesel is burned incompletely inside a car engine.

  Carbon monoxide, particulate carbon, sulfur dioxide and nitrogen oxides.