chemistry of the atmosphere

Question 1

proportions of gases in atmosphere for last 200 million years till now

Answer 1

• 4/5 nitrogen- 80%
• 1/5 oxygen- 20%
• small proportions of various other gases, i.e. CO2, H2O(g) and noble gases

Question 2

why was evidence for Earth’s early atmosphere limited?

Answer 2

because of the time scale of 4.6 billion years

Question 3

what does one theory of beginning of Earth suggest?

Answer 3

• intense volcanic activity that released gases that formed the early atmosphere
• water vapour condensed to form oceans

Question 4

early Earth’s atmosphere

Answer 4

• mainly CO2
• little to no O2
• N2 released by volcanoes building up
• CH4, NH3- small proportions

Question 5

what reduced CO2 in early atmosphere?

Answer 5

• CO2 dissoved in the water of the formed oceans
• carbonates precipitated producing sediments

Question 6

how did O2 increase?

Answer 6

• algae and plants produced O2 by photosynthesis
• algae first produced it 2.7 bilion years ago- soon after O2 appeared in atmosphere
• plants evolved and O2 gradually incrareess to a level that enabled plants to evolve

Question 7

how did CO2 decrease?

5

Answer 7

• algae and plants decreased % CO2 by photosynthesis
• carbonates precipitated- forming sediments in seabed
• dissolved in oceans
• animals that fed on plants trasnfered carbon into them and remains turned into sedimentary rocks
• dead organims turn into fossil fuels

Question 8

3 greenhouse gases

Answer 8

• carbon dioxide
• methane
• water vapour

Question 9

what is the greenhouse effect?

Answer 9

• short wavelength radiation- UV- emitted from sun
• some absorbed by Earth’s surface- others re- emitted as long wavelength radiation- infrared out
• however radiation gets trapped inside atmosphere due to greenhouse gases- trapping extra heat energy- becomes hotter

Question 10

human activites that increase CH4

Answer 10

• more waste sent to landfils due to increase in human population- decay of organic waste
• increased levels of farming- raising livestock

Question 11

human activities that increase CO2

Answer 11

• driving
• consuming electricity- energy
• deforestation

Question 12

effects of climate change?

4

Answer 12

• rising sea levels- melting of ice, flooding, habitat destruction, erosion to coastal regions
• droughts- crop failure, collapse of argicultural production, food production comprised
• extreme weather- loss of life, destruction of infrastructure and ecosystems
• storms- intensity increasing, more destructive

Question 13

what is the carbon footprint

Answer 13

the total amount of CO2 and other greenhosue gases emitted over full life cycle of product, service or event

Question 14

how to reduce the carbon footprint

6

Answer 14

hi

• reducing emissions of carbon dioxide and methane
• using renewable energy supplies instead of fossil fuels
• public transport > private cars
• electric vehicles
• buying locally sourced food to reduce food miles
• carbon capture scheme

Question 15

what is carbon capture

Answer 15

-range of technologies used to trap atmospheric CO2 from power generations and otehr industies
- carbon is then stored deep undergound in porous rocks
- to restore balance in carbon cycle

Question 16

difficulties to overcome to reduce levels of greenhouse gases

Answer 16

• government slow to act
• resistance to change ways
• alternate technologies still new
• too expensive

Question 17

what is a major source of atmospheric pollutants?
and what do they contain

Answer 17

combustion of fuels
carbon, and/or hydrogen and sometimes sulfur

Question 18

products of burning fuels

Answer 18

• carbon dioxide
• water vapour
• sulfur dioxide
• carbon monoxide
• oxides of nitrogen (high temperatures)
  .
• carbon particulates- soot

Question 19

inomplete combustion

Answer 19

• insufficent oxygen to burn
• relases soot and carbon monoxide

Question 20

effects of carbon monoxide

Answer 20

toxic gas- colourless and odourless

Question 21

effects of sulfur dioxide and oxides of nitrogen

Answer 21

• acid rain- corrosion of those made from carbonate rocks, damage to aquatic organisms
• respiratory problems- smog

Question 22

effets of particulates- soot

Answer 22

• global dimming
• human health problems

Question 23

how are… prodcued?
- oxides of nitrogen
- carbon monoxide
- soot
- sulfur dioxide

Answer 23

• oxides of nitrogen- combustion of fuels in car engines- high temperatures in engine causes nitrogen in air to react with oxygen
• carbon moxide- incomplete combustion
• soot- incomplete combsution
• sulfur dioxide- fossile fuels contain abit- combustion- sulfur oxidised