C11 Flashcards
Composition of the atmosphere?
78%nitrogen 21% oxygen 0.04% carbon dioxide 0.9% argon Rest is various other gases , water vapour and noble gases
How long has the proportions of gases been the same as today?
For about 200 million years
How old is the earth?
4.6 billion years old
What has happened to theories of the earth during the first billions of years?
Ideas have changed over time as it is difficult to measure over such a vast amount of time
How did the earth look for the first billion years?
Surface was covered in volcanoes that erupted and released lots of gases. This was how the early atmosphere was formed. Intense volcanic activity, extremely explosive.
What was the early atmosphere like?
Probably mostly carbon dioxide with very little to no oxygen. Quite like the atmosphere of mars and venus today.
What lead to the build up of nitrogen in the atmosphere over the first billion of years?
Volcanoes released nitrogen , which built up in the atmosphere over time , as well as water vapour and small amounts of methane and ammonia
How were oceans formed ?
When the water vapour released by volcanoes condensed
Why did carbon dioxide begin to be removed from the early atmosphere?
Dissolved in the oceans. This dissolved carbon dioxide, then went through a series of reactions to form carbonate precipitates that forms sediments on the seabed reducing the carbon dioxide in the atmosphere.
How did plants remove carbon dioxide from the atmosphere?
Green plants and algae evolved and absorbed some of the carbon dioxide so they could carry out photosynthesis.
What happened as marine animals evolved?
Shells and skeletons contained carbonates from the ocean. Some carbon from the ocean and atmosphere got locked up in rocks and fossil fuels after the organisms died.
What happens when marine animals and plankton died?
Fall to the sea bed and get buried by layers of sediment . Over millions of years , they become compressed and form sedimentary rock , oil and gas- trapping carbon within them and helping to keep carbon dioxide levels in the atmosphere reduced.
What is produced when plankton and marine animals fell to the bottom of the ocean ?
Fossil fuels were formed after immense compression
What is formed from plankton deposits?
Crude oil and natrual gas. Fossil fuels formed reservoirs under seabed when they get trapped in rocks
What forms coal?
Sedimentary rock formed by thick plants deposits
How did oxygen come into the atmosphere?
As well as plants absorbing carbon dioxide , they also produced oxygen by photosynthesis
What is photosynthesis?
When plants use light to convert carbon dioxide and water into glucose
When did algae and green plants evolve?
Algae evolved about 2.7 billion years ago . Then over the next billion years green plants began to evolve
Equation (word and symbol) for photosynthesis?
Carbon dioxide + water —> glucose + oxygen
6CO2 + 6H20 —-> C6H12O6 + 6O2
What happened as oxygen levels built up in the atmosphere?
More complex eukaryotic life forms could evolve(animal)
Examples of greenhouse gases?
Carbon dioxide, methane and water
What do greenhouse gases do?
Act as an inuslating layer in the earths atmosphere , allows the earth to be warm enough to support life
How do greenhouse gas particles interact with radiation and how does it lead to the greenhouse effect
Dont absorb incoming short wavelength radiation from the sun , but they do absorb long wavelength radiation that gets reflected back of the earth. This is thermal radiation so it results in warming of the earths surface. This is the greenhouse effect
What human activity increases the amount of green house gases in the atmosphere?
- deforestation: fewer tress means less co2 is removed from the atmosphere via photosynthesis
- burning fossil fuels: carbon that was locked up in these fuels is released as co2
- agriculture: more farm animals produce more methane through digestive processes
- creating waste: more landfill sites and more waste from agriculture means more co2 and methane released by co2 and methane released by decomposition pf waste
What does the greenhouse effect lead too?
Climate change , temperature of the earths surface has been increasing, most scientists believe it to be from carbon dioxide in the atmosphere. Unfortunately it is difficult to understand as there are a lot of variables that could add to the change in climate.
Why climate change research is difficult to model?
Climate change is such a complex system. This elads to simplified models, speculation and opinions presented by the media that may ne based on evidence or a bias
What are the consequences of climate change?
- could lead to polar ice caps meltiny. Causing a rise in sea levels , increasing floods and coastal erosion.
- change in rainfall patterns may cause some regions to get too little or too much water, this may effect ability to produce food.
- frequency and severity of storms may increase
- may effect wild species leading to differences in distribution
What is the carbon footprint?
A measure of the amount of carbon dioxide and other greenhouse gases released over the full life cycle of a product , service or event
How to reduce the carbon footprint?
- renewable energu sources of nuclear energy used instead fossils
- more efficient processes could conserve energy and cut waste . Lots of waste decomposes to release methane
- government could tax based on amount of greenhouse gases they emit
- government could put a cap on emissions of all greenhouse gases companies can make
- technology cam be used to capture co2 before its released into atmosphere, can be stored underground in rocks and oil wells
Why reduction in carbon footprint is still difficult ?
- lots of work to be done of carbon reducing technology
- governments worried intervention would effect economic growth
- hard to make international agreements as not everyone is on board
- difficult to change lifestyle
What make up fossil fuels such as oil and coal?
Hydrocarbons
What happens to compounds in oil and coal when combusted.
Carbon and hydrogen are oxidised so that carbon dioxide and water vapour are released into the atmosphere.
What is complete combustion?
When there is lots of oxygen , all the fuels burn
What is incomplete combustion?
When there is not enough oxygen , some of the fuel does not burn . Under these conditions solid particles (particulates)of soot (carbon) and unburnt fuels are released and carbon monoxide can be produced as well as carbon dioxide.
How particulates in the air can cause problems?
- if inhaled they can get stuck in the lungs and can cause damage
- also bad for environment , clouds they produce reflect sunlight back into space os less light reaches the earth causing global dimming.
What problems does carbon monoxide from incomplete combustion cause?
- stops blood from doing proper job of carrying oxygen around the body
- binds to haemoglobin instead of oxygen
- lack of oxygen can lead fainting , a coma or even death
- hard to detect as does not have a colour or smell
What gas is released from complete combustion that is oxidised?
Sulfur dioxide
How is nitrogen oxide created.
Rreaction between nitrogen and oxydgn in the air , caused by heat of the burning
What happens when nitrogen oxide and suflur dioxide mix ?
Form dilue sufluric acid or dilute nitric acid , whcih falls as acid rain.
What does acid rain do?
Kills plants and. Damages buildings and statues. Aso makes metal corrode
