p5. chemistry in the atmosphere Flashcards
1
Q
name proportions of different gases in the atmosphere - earth
A
- 4/5 of nitrogen ( 80 % )
- 1/5 of oxygen ( 20 % )
- small proportions of other gases like :
~ carbon dioxide
~ water vapour
~ noble gases
2
Q
theory - where did the atmosphere come from
A
- intense volcanic activity
- released gas from early atmosphere = similar to mars and venus’ atmosphere
- they have :
~large amount of carbon dioxide
~ little or no oxygen
~ small amounts of other gases = ammonia, methane - also released water vapour = condensed as the earth cooled to form oceans
3
Q
describe the modern atmosphere
A
- approximately 200 million years - proportions of different gases have been relatively stable
- 80% nitrogen
- 20% oxygen
- other gases - carbon dioxide,water vapour and noble gases
4
Q
what produced oxygen for the atmosphere today and how
A
- algae and plants by photosynthesis
- carbon dioxide + water = glucose + oxygen
- algae produced around 2.7 billion years ago and then oxygen was produced
- plants then evolved and % of oxygen increased to the level where animals could evolve
5
Q
how did carbon dioxide decrease
A
- algae and plants due to photosynthesis
- carbon dioxide decreased formation of sedimentary rocks and fossils which contained carbon
6
Q
formation of :
limestone
coal
crude oil
natural gas
A
- limestone = layers of limey deposits build up on ocean floor and compacted over weight of water
- coal = from trees in dense forests in low-lying wetland areas
~ flooding caused wood from forests to be buried where oxidation couldn’t take place
~ compression and heating over years turns wood into coal - crude oil = ancient biomass ( plankton )
- natural gas = layers of decomposing plants and animals are subject to intense heat from earth and pressure of rocks
7
Q
purpose of greenhouse gases
- give examples
A
- maintain temperature on earth high enough to support life
- water vapour.carbon dioxide.methane
8
Q
how does the greenhouse effect work
A
- electromagnetic radiation at most wavelengths passes through the Earth’s atmosphere
- Earth absorbs most of the radiation and warms up
- Earth radiates energy as infrared radiation
- some of the infrared radiation goes into space
- some of the infrared radiation is absorbed by greenhouse gases in the atmosphere
- the lower atmosphere warms up
9
Q
human activities that increase greenhouse gases in atmosphere
A
- burning fossil fuels in vehicles and power stations releases carbon dioxide
- deforestation releases carbon dioxide and reduces absorption of carbon dioxide through photosynthesis
10
Q
four effects of global climate change
A
- glaciers and polar ice melting
- sea levels rising
- patterns of rainfall changing ,producing floods or droughts
- habitats changing
11
Q
what is carbon footprint
A
- total amount of carbon dioxide ( and other greenhouse gases ) which are emitted over the full cycle of a product,service or event
12
Q
how to reduce carbon footprint
A
- reducing emissions of carbon dioxide and methane
13
Q
give examples on reducing carbon footprint
A
- reduce,reuse,recycle
- reduce electricity usage
- reuse bottles and bags
- recycle plastic
14
Q
how is carbon monoxide produced
A
- incomplete combustion of any fuel containing carbon atoms
15
Q
how is soot ( carbon particles ) produced
A
- incomplete combustion of any fuel containing carbon atoms
