Chemistry topic 9 Flashcards
(18 cards)
What was phase 1 of the evolution of the atmosphere?
Billion years ago, the surface was covered in volcanoes that erupted and released lots of gases, scientists believe this is how the early atmosphere was formed.
The atmosphere was mostly carbon dioxide with virtually no oxygen, quite like Mars and Venus.
Volcanic activity also release nitrogen which builds up in the atmosphere overtime, as well as water vapour and methane and ammonia.
What was phase 2 of the evolution of the atmosphere?
Water vapour in the atmosphere condensed forming oceans. Carbon dioxide was removed as it dissolved in the oceans, then reacted to form carbonate precipitates that formed sediment on the seabed.
Green plants and algae evolved to absorb some of the CO2 so they could carry out photosynthesis. Later on marine animals, evolved their shells and skeletons containing carbonates from the oceans. Some of the carbon these organisms took in from oceans and the atmosphere became locked up in rocks and fossil fuels after they died.
What is crude oil?
Natural gas formed from the deposits of plankton, phone reservoirs under the sea bed when they get trapped in the rocks.
What is coal?
A sedimentary rock made from thick plant deposits
What is limestone?
Sedimentary rock made from calcium carbonate deposits from the shells and skeletons of marine organisms.
What was phase 3 of the evolution of the atmosphere?
As well as absorbing carbon dioxide from the atmosphere, green plants and algae produced oxygen by photosynthesis.
Algae evolved first about 2. 7 billion years ago, then over the next billion years green plants also evolved.
As oxygen levels built-up animals began to evolve. 200 million years ago the atmosphere reached a composition similar to today ; 80% nitrogen, 20% oxygen, then small amounts of other gases, such as CO2 and water vapour.
What is the equation for photosynthesis?
Carbon dioxide + water - glucose + oxygen
What is the negative effects of greenhouse gases?
Carbon dioxide, methane and water vapour act like an insulating layer in the earths atmosphere, allowing the Earth to be warm to support life.
All particles absorb radiation, greenhouse gases don’t, but they do absorb the long wavelength radiation that gets reflected back of the Earth. They then re-radiate it in all directions, this long wave radiation is thermal so results in warming the surface of the Earth (greenhouse effect).
Which forms of human activity affect the amount of greenhouse gases in the atmosphere?
Deforestation (removes CO2, photosynthesis).
Fossil fuels (releases carbon)
Agriculture (produces methane)
Creating waste (CO2 and methane released by decomposition)
What are the dangerous consequences of climate change?
An increase in global temperatures could lead to ice caps melting, rising sea temperatures, increased flooding, coastal erosion.
Changes in rainfall patterns leads to flooding.
Severity of storms increase.
Changes in severe temperatures.
How do we measure carbon footprints?
It’s difficult to do because there are so many factors to consider such as counting the emissions released (e.g. having to count the parts of a toaster and a mission is released when making it and using it).
What is carbon footprint?
A measure of the amount of carbon dioxide and other greenhouse gases released over the full cycle of something such as transport.
What are the different ways of reducing carbon footprints?
Renewable energy sources.
Using more efficient processes, to conserve energy and cut waste.
Governments do tax companies based on the amount of greenhouse gases they emit.
Governments can put a cap on emissions of greenhouse gases that companies make.
There’s also technology which can capture CO2, and store it deep underground.
Why is reducing our carbon footprint so hard?
Governments are worried about impacts on the economic growth of communities, could be bad for peoples well-being and worse for developing countries.
International agreements with other countries.
Some individuals don’t want to change.
What problems can imcomplete combustion cause? (Solid particles of carbon and unburnt fuel)
If inhaled can get stuck in lungs and lead to respiratory problems.
Bad for the environment, reflect sunlight, back to space, causing global warming.
What are the negative effects of carbon monoxide from combustion of fossil fuels?
Can stop your blood from carrying oxygen around the body.
Find the haemoglobin in your blood that normally carries oxygen so less oxygen can be transported.
Lack of oxygen can lead to fainting or even death.
Doesn’t have any colour or smell, so it’s hard to detect.
What is released in the combustion of fossil fuels?
Fossil fuels, such as crude oil contain hydrocarbons. The carbon and hydrogen a oxidised, so CO2 and water vapour are released into the atmosphere. Complete combustion only happens when there’s plenty of oxygen.
If there’s not enough, some of the fuel doesn’t burn, this is called incomplete combustion when solid particles of carbon and unburnt fuel a released and carbon monoxide can be produced as well as carbon dioxide.
What are the negatives of sulphur dioxide and oxides of nitrogen being released in combustion?
Sulphur dioxide is released during combustion of fossil fuels that contain sulphur impurities, the sofa in the fuel becomes oxidised.
Nitrogen oxides are created from a reaction between nitrogen and oxygen in air caused by heat of burning.
When these gases mix with clouds, they form dilute, sulphuric, acid or dilute nitric acid, which then falls as acid rain.
Acid rain kills plants, damages buildings, makes metal corrode. It’s bad for human health and causes respiratory problems if breathed in.
