Chemistry - Chemistry of the atmostphere Flashcards
How long have the proportions of the gasses in the atmosphere been like today
200 million years
What are the gases and percentages found in today’s atmosphere
Nitrogen = 80%
Oxygen = 20%
Other gasses (including carbon dioxide, water vapour and Nobel gases( = <1%
What timescale is evidence for the early atmosphere limited to
4.6 billion years
What planets is the earth’s early atmosphere suggested to be like
Mars and Venus, consisted mainly of carbon dioxide and little or no oxygen
What other gas were released by volcanoes
nitrogen methane and ammonia
What are the four ways carbon dioxide is reduced
- dissolved into the oceans
- Plants took it in for photosynthesis
- Carbonates precipitated producing sediments
- locked in fossil fuels
How did the percentage of oxygen increase in the early atmosphere
Algae and plants released it during photosynthesis
Word equation for photosynthesis
Carbon dioxide + water -> glucose + oxygen
Describe the greenhouse effect
- first the sun emits short wavelength radiation which passes through the earths atmosphere and is absorbed by the earths surface
- The earths surface emits any excess radiation as long wavelength radiation towards space.
- some of the long wavelength radiation makes its way through the earths atmosphere however some do not as greenhouse gasses traps them.
- this is then emitted to the earths surface causing it to heat up more resulting in the earths average temperature to increase.
When did algae first appear
2.7 billion years ago
What did the increase in oxygen from algae and plants lead to
Enables animals to evolve
What useful substances have been formed as carbon dioxide increased
Limestone, coal, crude oil and natural gas
What type of gas maintains the temperature on earth to be high enough to support life
Greenhouse gasses
Examples of greenhouse gasses
Carbon dioxide
water vapour
methane
What greenhouse gases are increased due to human activity
carbon dioxide increasing due to
-burning fossil fuels
-deforestation reducing carbon being taken In for photosynthesis
methane increasing due to
-farming cattle
-farming rice paddy fields
-landfill sites (rubbish decomposes and releases methane)
-\swamps
What do scientists believe humans activity will do the temperature of the earth
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 media
What is the issue with climate change presented in the media
Based on opinion, speculation, only parts of evidence and can be biased
What is causing climate change
increase in average global temperature
What are the main four potential effects of global change
glacier and polar ice caps melting
sea levels rising
patterns in rainfall changing
habitats changing
What is the carbon footprint
the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event
Major source of atmosphere pollutants
combustion of fuels
what do most fuels contain
Carbon, hydrogen and some contain sulfur
How can a carbon footprint be reduced
By reducing emissions of carbon dioxide and methane
what do particulates contribute to
global dimming
How are oxides of nitrogen produced when burning a full?
High temperature in car engines cause oxygen and nitrogen in the air to react
How is sulfur dioxide produced when burning a fuel
Fuels contain sulfure as an impurity when the fuel is burnt the sulfur reacts with oxygen to form sulphur
What do oxides of nitrogen and sulfur lead to
Acid rain respiratory problems
What does carbon dioxide contribute to and why
global warming as it is a greenhouse gas
What are the issues with the production of carbon monoxide
it is a toxic gas, prevents blood from carrying oxygen to your cells for respiration
Why is it hard to detect if carbon monoxide is formed
it Is odourless and colourless so can’t be seen
What theory is given for the earth’s early atmosphere?
1.First billion years intense volcanic activity released lots of carbon dioxide and water vapour (alongside other gases such as methane, nitrogen and ammonia)
- When the Earth cooled the water vapour was able to cool and condensed to form oceans the oceans.
- Overtime carbon dioxide levels started to decrease.
- Algae and plants evolved
- Oxygen levels started to increase and animals were
then able to evolve
Balanced symbol equation for photosynthesis
6CO2 + 6H2O -> C6 H12 O6 + 6O2
How can we reduce carbon emissions?
reduce use of cars (cycle/walk instead)
eat less meat
ensure any trees cut down are replanted
recycle and reuse materials
install solar panels in your home
What gases can be released into the atmosphere when fuel is burnt?
Carbon dioxide
Water vapour
Sulphur dioxide
Oxides of nitrogen
Others - Particulate (microscopic particles)
Describe how natural deposits formed
Plankton
Mud
High temp and pressure
Describe how natural deposits formed
Plankton
Mud
High temp and pressure
