Chemistry of the Atmosphere Flashcards
For how many years has the proportion of atmospheric gases been much the same as today?
200 million
What proportion of the atmosphere is nitrogen
≈ 80%
What proportion of the atmosphere is oxygen?
≈ 20%
What proportion of the atmosphere is made from gases other than nitrogen and oxygen?
A small proportion
What gases make up the atmosphere other than nitrogen and oxygen?
Various others, including carbon dioxide, water vapour and noble gases.
Theories about what was in the Earth’s early atmosphere and how the atmosphere was formed have…
…changed and developed over time.
Why is evidence for the early atmosphere limited?
Because of the time scale of 4.6 billion years.
What is step one in the theory of the Earth’s Early atmosphere?
There was intense volcanic activity in the first billion years of the Earth’s existence.
Volcanoes released the gases which formed the early atmosphere, and water vapour.
What is the Earth’s atmosphere thought to have been like in the 1st billion years of its existence?
The atmospheres of Mars and Venus today.
What gases did intense volcanic activity release?
Carbon dioxide with little or no oxygen gas.
What is step two to the theory of Earth’s early atmosphere?
Earth cooled, so the water vapor condensed. This formed our oceans.
What is step three to the theory of Earth’s early atmosphere?
When the oceans formed, carbon dioxide dissolved in the water, forming carbon precipitates and sediments.
This reduced the amount of carbon dioxide in the atmosphere.
What produces the oxygen now in the atmosphere?
Green plants and algae.
How do green plants and algae produce oxygen?
Photosynthesis.
What is the photosynthesis word equation?
carbon dioxide + water to glucose + oxygen
When did algae first produce oxygen?
~ 2.7 billion yrs ago.
How did the percentage of oxygen in the atmosphere increase?
Oxygen appeared in the atmosphere soon after algae first produced it.
Over the next billion years, plants evolved and the percentage of oxygen gradually increased to a level that allowed animals to evolve.
How did levels of carbon dioxide decrease?
Algae and plants decreased the percentage of carbon dioxide in the atmosphere by photosynthesis.
Carbon dioxide was also decreased by the formation of sedimentary rock and fossil fuels that contain carbon.
Describe and explain the formation of deposits of limestone.
Limestone is a sedimentary rock made mostly of calcium carbonate deposits (from the shells and skeletons of marine organisms) that have been compressed over millions of years.
Describe and explain the formation of deposits of coal.
Coal is a sedimentary rock made from thick plant deposits that have been compressed over millions of years.
Describe and explain the formation of deposits of crude oil.
Reservoirs of crude oil are formed under the sea bed when deposits of plankton are trapped in rocks.
Describe and explain the formation of deposits of natural gas.
Reservoirs of natural gas are formed under the sea bed when deposits of plankton are trapped in rocks.
What is trapped working sedimentary rock?
Carbon, which helps to keep carbon dioxide levels in the atmosphere reduced.
What is sedimentary rock?
A type of rock formed from compressed layers of minerals and organic particles such as sand, mud, and shells.
What is the atmosphere?
A layer of gases surrounding the Earth that is held in place by gravity.
What is the difference between climate change and global warming?
Global warming refers to the overall increase in Earth’s temperature, whereas climate change is a consequence of global warming, and refers to the effects on the climate, like large-scale shifts in weather patterns.
What could an increase in the volume of ocean water lead to?
Seasonal flooding, or the submersion of low- lying areas.
Why are greenhouse gases in the atmosphere a good thing?
They maintain temperatures on Earth high enough to support life.
Name some greenhouse gases.
Carbon dioxide
Methane
Water vapour
Describe the greenhouse effect and how it effects global temperatures.
The sun gives out short wave radiation which is reflected back by the Earth as long wave/ thermal radiation.
The thermal radiation is absorbed by greenhouse gases in the atmosphere.
Greenhouse gases give out the thermal radiation in all directions including back towards the Earth, causing the temperature to rise.
(warmer and more stable).
Which greenhouse gases do human activities increase?
Carbon dioxide
Methane
Name two human activities that increase the amount of carbon dioxide in the atmosphere.
Deforestation, which reduces the amount of CO2 removed from the atmosphere by photosynthesis.
Burning fossil fuels, which releases the carbon ‘locked up’ in them.
Name two human activities that increase the amount of methane in the atmosphere
Agriculture: farm animals produce methane during digestion.
An increase in landfill sites and waste from agriculture means more methane (and CO2!) released by decomposition.
How do we know evidence for climate change is reliable?
It had been peer reviewed.
Why doesn’t everyone trust the evidence for climate change? .
The earth’s climate is too complex to fully understand and model.
The earth’s climate is too complex to fully understand and model.
What has this led to?
Simplified models, speculation and opinions presented in the media that may be based on only parts of the evidence or biased.
What is the scientific consensus about climate change?
-Hunan activities will cause the temperature if the Earth’s atmosphere to increase at the surface
-This will result in global climate change
Describe uncertainties in the scientific evidence base.
Reports in the media are NOT peer reviewed. So, data may be presented in a way that is oversimplified/inaccurate. This can leave it open to misinterpretation.
Bias e.g giving data that supports an idea but none against it.
What is a major cause of climate change?
An increase in average global temperature.
Briefly describe four potential effects of global climate change.
1) Polar ice caps melting = rise in sl = increased flooding and coastal erosion
2) Changes in rainfall patterns = drought or flooding = impacts food security
3) Frequency and severity of storms might increase
3) Changes in temperature affects migration patterns and hence the distribution of species.
You need to…
…discuss the scale, risk, and environmental implications of global climate change. x
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.
How can the carbon footprint be reduced?
By reducing emissions of carbon dioxide and methane.
Describe actions to reduce emissions of carbon dioxide and methane.
-Using renewable energy sources
-Governments can put a cap on the amount of greenhouse gases that a business can emit and issue licenses for set amounts of emissions up to this point
-Governments can impose taxes in companies according to the amount of gasses they emit to encourage them to cut down on emissions.
-Carbon Capture and Storage
-Recycling rather than disposal in landfill
-Creation siring fewer/more sustainable raw materials
Give reasons why it’s difficult to measure the carbon footprint.
There arre many factors to consider i.e the carbon emitted at each stage of an object lifetime including sourcing all the parts.
However rough calculations do help to see what the worst emitters are to avoid them in the future.
Why is making reductions in the emissions of carbon dioxide and methane difficult?
-Alternative technologies not fully developed
-Governments worry about the impact in the economy, particularly for developing countries
-It’s hard to make international agreements bc countries don’t want to sacrifice their economic development if others won’t do the same
-Individuals must be willing and educated enough to change their lifestyles
Give 4 factors you’d need to consider when calculating the carbon footprint of a car
-How all the raw materials were sourced
-The manufacturing process
-The total amount of fuel it used over its lifetime
- How it’s disposed of
CCS
A technology that allows us to trap carbon and store it deep underground.
What is a major source of atmospheric pollutants.
The combustion of fuels/hydrocarbons.
What gases might be released into the atmosphere when a fuel is burned?
Carbon dioxide, water vapor (complete combustion)
Carbon monoxide, particulates (incomplete combustion)
Sulfur dioxide, Oxides of nitrogen.
What are particulates?
Solid particles of carbon/ ‘soot’.
What is the problem with carbon particulates?
-Respiratory problems if particulates get stuck in our lungs and cause damage.
-Global dimming
What is global dimming?
Where smog reflects sunlight into space so less reaches the Earth.
What do most fuels contain?
-Carbon and/or hydrogen
-They may also contain some sulfur
What forms particulates?
Solid particles and unburned hydrocarbons released when fuels are burned.
Describe how sulfur dioxide is produced through the burning of fuels.
Impurities (e.g. sulfur) are oxidised to form e.g. sulfur dioxide.
Describe how oxides of nitrogen are produced by burning fuels.
Nitrogen reacts with oxygen to form nitrous oxides at really high temperatures.(e.g in the combustion chamber of a car)
Why is it important to communicate the results of scientific research to a wide range of audiences?
-Results might show the public should change their habits
-Results might provide ideas that can be developed into new technology
-E.g. info on fullerenes needs to be relayed to doctors so they can make informed decisions about using fullerene drug delivery systems in treatment
What is the problem with sulfur monoxide?
-If breathed in, it diffuses into our bloodstream and binds to haemoglobin
-This reduces the amount of oxygen that haemoglobin can carry
-So, less oxygen is transported to the tissues, which can cause symptoms such as fainting, coma and death
What is the problem with sulfur dioxide AND oxides of nitrogen?
-Respiratory problems if the gases gets into our lungs and cause damage
-Acid rain
How is acid rain formed?
Sulfur dioxide OR oxides of nitrogen mix with clouds
The gases dissolve to form dilute sulfuric or dilute nitric acid
This falls as acid rain
What are the adverse effects of acid rain?
-It damages certain buildings and statues
-It corrodes metals
-It damages plants directly by falling on leaves
-It makes the soil more acidic, which harms plants indirectly
How can we test for sulfur impurities in fuel?
Bubble the gases from combustion through a solution containing universal indicator.
If the solution turns red, this indicates the presence of sulfuric acid (formed from SO₂ which would have dissolved).
What makes carbon monoxide hard to detect?
It’s both colourless and odourless.
