Chemistry Of The Atmosphere Flashcards
What is the percentage of nitrogen in our atmosphere?
80%
What is the percentage of oxygen in our atmosphere?
20%
What other gases are in the atmosphere in small proportions?
Carbon dioxide, water vapour and noble gases
Why is the evidence for Earth’s early atmosphere limited?
Because it formed so long ago
How long ago did the early atmosphere form?
4.6 billion years
How do we think the Earth’s early atmosphere formed?
Volcanic activity that released gases
How do we think the oceans formed?
As the earth cooled, water vapour condensed
What other planets atmospheres may Earth’s have been like in the past?
Mars and Venus
How do we think nitrogen got into the atmosphere?
Volcanic activity
What other gases could have been in the early atmosphere in small proportions?
Methane and ammonia
Why did the formation of the oceans cause carbon dioxide levels to decrease?
Carbon dioxide dissolved in the water and carbonates precipitated producing sediments
How is oxygen released into the atmosphere?
Photosynthesis
What is the word equation for photosynthesis?
Carbon dioxide+Water-> Glucose+Oxygen
What is the formula equation for photosynthesis?
6CO2+6H2O-> C6H12O6+6O2
When did algae first appear on Earth?
2.7 billion years
How long did it take for oxygen levels to build up so that animals could evolve?
A billion years
Why did the percentage of carbon dioxide decrease further when plants evolved?
Photosynthesis removed it from the atmosphere. It became locked in sedimentary rocks and in fossil fuels
Why are some greenhouse gases in the atmosphere important?
They maintain temperatures on Earth high enough to support life
What are examples of greenhouse gases?
Water vapour, carbon dioxide and methane
What human activities increase the amount of carbon dioxide in the atmosphere?
Burning fossil fuels and deforestation
What human activities increase the amount of methane in the atmosphere?
Farming cattle, agriculture and dumping waste in landfills
What are the potential effects of global climate change?
Ice caps melting, sea levels rising, patterns of rainfall changing and habitats changing
What is the carbon footprint?
The total amount of carbon dioxide and other greenhouse gases emitted over the full cycle of a product, service or event
What is a major source of atmospheric pollutants?
Burning fossil fuels
