t9-chemistry of the atmosphere

Question 1

describe the earth’s early atmosphere

Answer 1

intense volcanic activity which released gases to make up the atmosphere
lots of CO2
little 02
small amounts of other gases
water vapour condensed as earth cooled to form oceans

Question 2

how did oxygen amount increase

Answer 2

plants made food through photosynthesis, producing O2
photosynthesis producing 02 gradually built up the atmosphere

Question 3

how did formation of sedimentary rocks decrease CO2 concentration

Answer 3

co2 dissolved in oceans to form soluble carbonate compounds
compounds precipitated as sedimentary rocks

Question 4

how did uptake of co2 by organisms decrease co2 concentration

Answer 4

-it was absorbed from oceans for photosynthesis
-most photosynthetic organisms turned into fossil fuels, which contain carbon
-the organisms died, turning into sedimentary rocks

Question 5

how was coal formed

Answer 5

trees in dense forests were flooded which caused wood to be buried in a way that prevented oxidation
compression and heating for millions of years turned wood into coal

Question 6

how was crude oil formed

Answer 6

plants and animal which lived in the ocean died and their remains sank to the bottom which were buried under sediments
lack of O2 prevented oxidation

Question 7

what are greenhouse gases

Answer 7

co2
water vapour
methane

Question 8

what is the greenhouse effect

Answer 8

gases allow short wavelength radiation to pass through the atmosphere to the earth’s surface
gases absorb outgoing wavelength radiation from earth causing temperature to increase

Question 9

why is the greenhouse effect important for life

Answer 9

earth would be much colder so life can’t exist

Question 10

how have human activities lead to an increase in greenhouse gases

Answer 10

combustion and deforestation produce CO2
increased farming produces methane

Question 11

potential effects of climate change

Answer 11

sea level rise
more frequent and severe storms
changes in rainfall