environmental chemistry Flashcards
(25 cards)
what are the greenhouse gasses
carbon dioxide, methane, nitrous oxide, water vapour
what are carbon sinks
places that store carbon eg oceans, forests, limestone and soil
what are the main four gases in the average composition of the atmosphere up to an altitude of 25km in dry air
nitrogen 77%, oxygen21%, argon0.9%, carbon dioxide0.04%
why is earth the only planet in the solar system with oxygen
because earth is the only planet where photosynthesis takes place
describe an experiment which could determine how much of the air contains oxygen
put small fresh peices of copper in a silica tube
mix it with 100 cm of air
check how much air is in it after every few minutes
repeat untill the volume of air does not change
what is the cause of global warming
burning fossil fuels which is leading to rising co2 levels in the atmosphere
what is the reason for earths oceans losing thier capacity to absorb extra co2 from the atmosphere
solubility of gas decreases with increasing temperature
what is nirtogen
modt abundant gas in earths atmosphere, it is unreactive gas which has been building up gradually and it is mostly produced by denitrifying bacteria
what is oxygen
oxygen began building up rapidly when photosynthetic organisms came on the ecene eg cynobacteria and later plants
what is carbon dioxide
fourth most abundant gas, once it was the mıst dominant gas having leaked from volcanoes but today theres much less as it is dissolved in the oceans about 4.2 billion years ago and a lot was absorbed by plants and they were buried and becane compressed into coal deposits
what is methane
powerful greenhouse gas, only takes up 0.0002% of the atmosphere most comes from bacteria in swamps, rice paddy feilds. the guts from catle and landfill sites
what is ammonia
a colourless gas with a powerful and irritating smell, a tiny bit found in air and is the second most mass produced chemical (after sulfuric acid) over 100 million metric tons produced a year, most ammonia is turnes into fertiliser
what is global warming
the burning of fossil fuels leading to rising co2 levels in the atmosphere. greenhouse gases absorb heat so the atmosphere is warming up as the earths surface radiates heat. as the temperature rises more water evaporates from the oceans amplifying the effect of greenhouse gases
what is global dimming
a decrease in the amount of sunlight reaching the surface of the earth, believed to be caused by pollution in the atmosphere
what is thermal decomposition
a chemical reaction which uses heat to break down a compound into simpler substances
what is acid rain
rain naturally acidşc because co2 is a weakly acidic gas but when fossil fuels with high sulful content is burned sulfur dioxide is produced, it is more acidic than co2 and when it dissolves in water droplets it will make the rain more acidic another acidic gas is nitrous oxide
what is a carbon footprint
the amount of co2 released into the atmosphere as a result of a certain individual, organisation or community
what is sustainibility
using the earths natural resources which allows them to replenish and in a way that earths evo-systems can continue to flourish
what is a life cycle assessment
a technique to assess environmental impacts associated with all the stages of a products life form ‘cradle to grave’
What temperature is co2 less soluble at
Higher temperatures
Describe the link/relationship between the solubility of gas and the temperature
The higher the temperature, the less soluble the gas will be
Where in the worlds oceans does most of the co2 dissolve
Around the poles
Where lm the worlds oceans does absorption of co2 occur the least
The tropics
What will be the consequences of a warming ocean ? How will this affect the role of the oceans as a co2 sink
As the oceans warm, less co2 will be stored, this sink becomes less effective
