Chemistry of the Atmosphere

• What was the early atmosphere made mostly of?

  Carbon dioxide.
• How did the oceans form?

  Water vapour condensed.
• How did the amount of carbon dioxide in the atmosphere decrease to today's levels?

  It dissolved into oceans, photosynthesis, formed fossil fuels and sedimentary rock
• How did the amount of oxygen in the atmosphere increase to today's levels?

  Photosynthesis of algae and plants.
• How has the amount of nitrogen in the atmosphere changed over time?

  Increased because it is unreactive.
• Why can't scientists be sure about the composition of the early atmosphere?

  It was billions of years ago and so evidence is limited.
• What is the current composition of the atmosphere?

  80% nitrogen, 20% oxygen, less than 1% carbon dioxide, water vapour and noble gases.
• Name three greenhouse gases.

  Carbon dioxide, methane and water vapour.
• What type of radiation is emitted by the sun and absorbed y the Earth?

  Short wavelength radiation
• What type of radiation is emitted by the Earth?

  Long wavelength infrared radiation.
• What type of radiation do greenhouse gases absorb?

  Long wavelength infrared radiation.
• Give two ways that recent human activities have increased carbon dioxide levels.

  Burning fossil fuels, deforestation
• Give two ways that recent human activities have increased methane levels.

  Cattle farming, rice farming, (increased waste production).
• What is global warming?

  An increase in the overall global average temperatures.
• What is climate change?

  The change in long term weather patterns across the planet.
• Name some consequences of climate change.

  Ice caps melting, sea levels rising, floods, changes in the rainfall, extreme weather e.g. storms, changes to habitats.
• What is a carbon footprint?

  The amount of CO2 or other greenhouse gases that a product, service or event release into the atmosphere over their lifetime.
• Name some ways we can reduce carbon footprints.

  Renewable or nuclear energy, more efficient technology, less waste, taxes, carbon capture and storage.
• Why isn't it easy to reduce carbon footprint?

  Costly, reduce economic growth, lack of commitment from other countries.
• What are the products of complete combustion?

  Carbon dioxide and water.
• Name two possible products of incomplete combustion and issues associated with them.

  Carbon monoxide - toxic gas (reduces oxygen in blood).

  Carbon particulates (soot) - respiratory problems and glabal dimming.
• What are the issues associated with sulfur dioxide and nitrogen oxides released during combustion?

  Respiratory problems and acid rain.