Chemistry Of The Atmosphere Flashcards
How long have the proportions of the gases in the atmosphere been like today
200 million years
What are the gases found in today’s atmosphere (5)
Nitrogen,oxygen,carbon dioxide,water vapour,noble gases
What are the percentages of the gases in today’s atmosphere
Nitrogen = 80% Oxygen = 20% Other gases = <1%
What timescale is evidence for the early atmosphere limited too
4.6 billion years ago
What theory is given for the earth’s early atmosphere
- First billion years intense volcanic activity released lots of CO2 and water vapour 2. When the earth cooled the water vapour condensed to form oceans 3. Over time carbon dioxide levels started to decrease 4. Algae and plants evolved 5. Oxygen levels started to increase and animals were able to evolve
What planet is the earths early atmosphere suggested to be like
Mars and Venus, consisting mainly of carbon dioxide and little to no oxygen
What other gas was released by volcanoes
Nitrogen N2,methane CH4,ammonia NH3
What are the four ways carbon dioxide levels were reduced
- Dissolved into oceans 2. Plants took it in for photosynthesis 3. Carbonates precipitated producing sediments 4. Locked in fossil fuels
How did the percentage of oxygen increase in the early atmosphere
Algae and plants released it during photosynthesis
What is the word equation for photosynthesis
Carbon dioxide + water —> glucose + oxygen
What is the balanced symbol equation for photosynthesis
6CO2 + 6H2O —> C6H12O6 + 6O2
When did algae first appear?
2.7 billion years ago
What did the increase in oxygen from algae and plants lead to
Enabled animals to evolve
What useful substances have been formed as carbon dioxide decreased
Limestone,coal,crude oil, natural gas
What type of gas maintains the temperature on earth to be high enough to support life
Greenhouse gases
Examples of greenhouse gases
Water vapour,carbon dioxide,methane
Describe the greenhouse effect
The sun emits short wavelength radiation which passes through the earth’s atmosphere and is absorbed by the earth’s surface ,the earth emits long wavelength radiation back towards space,some gets trapped by greenhouse gases causing earth to heat up more
What green house gases are increased due to human activity
Carbon dioxide and methane
What human activities are increasing the level of carbon dioxide and methane
CO2 increases: burning fossil fuels,deforestation
Methane increases: farming cattle,rice paddy fields,landfill sites
What do scientists believe human activity will do to the Earths’s temperature
Increase it leading to climate change
What is the temperature of the earth increasing normally referred to as
Global warming
Why is it difficult to predict global warming
Based on simply models,speculation and opinion presented in the media
What is the issue with climate change presented in the media
Based on opinion,speculation only parts of evidence reported can be biased
What are the main four potential effects of global climate change?
Glaciers/ice caps melting,sea levels rising,rainfall patterns changing - causing droughts and floods,habitats changing
What is causing climate change?
Increase in average global temperature
What is carbon footprint?
Total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product,service or event
How can carbon footprint be reduced
By reducing emissions of carbon dioxide and methane
How can we reduce emissions of carbon dioxide and methane
Reduce use of cars (cycle/walk), eat less meat,recycle,solar panels
What is the major source of atmospheric pollutants
Combustion of fuels
What do most fuels contain
Carbon,hydrogen sometimes sulphur
What gases can be released into the atmosphere when a fuel is burnt
Carbon dioxide,water vapour,carbon monoxide,sulphur dioxide,nitrogen,particulates
What do particulates contribute to?
Global dimming (smog)
How are oxides of nitrogen produced when burning a fuel?
High temperature in car engines causes oxygen and nitrogen in the air to react
How is sulphur dioxide produced when burning a fuel?
Fuels contain sulphur as an impurity, when the fuel is burnt the sulphur reacts with oxygen to form sulphur dioxide
What do oxides of nitrogen and sulphur dioxide lead to?
Acid rain,respiratory problems
What does carbon dioxide contribute to and why?
Global warming as its a greenhouse gas
What are the issues with the production of carbon monoxide?
It’s a toxic gas, it prevents blood from carrying oxygen to your cells for respiration
Why is it hard to detect if carbon monoxide is formed?
Its odourless and colourless so it can’t be seen
