C13: Earth's Atmosphere

Question 1

what is the atmosphere

Answer 1

layer of gas surrounding Earth

Question 2

what was early atmosphere composed of

Answer 2

mostly carbon dioxide

Question 3

how did oceans form

Answer 3

water vapour condensing as Earth cooled

Question 4

how did carbon dioxide levels decrease

Answer 4

• dissolved in oceans
• photosynthesis
• converted to fossil fuels
• precipitated as insoluble metal carbonates

Question 5

when did life start to appear and how did it affect the atmosphere

Answer 5

2.7 billion years ago - oxygen increased as it was released in photosynthesis

Question 6

how has amount of nitrogen in atmosphere changed

Answer 6

increased slowly as it is a very stable molecule

Question 7

why can scientists not be sure about the Earth’s atmosphere

Answer 7

it was billions of years ago and evidence is limited

Question 8

how much nitrogen in atmosphere today

Answer 8

about 80%

Question 9

how much oxygen in atmosphere today

Answer 9

about 20%ther

Question 10

than nitrogen and oxygen, what gases in atmosphere today

Answer 10

carbon dioxide
water vapour
noble gases

Question 11

what is a greenhouse gas

Answer 11

a gas that traps radiation from the sun

Question 12

what type of radiation do greenhouse gases absorb

Answer 12

longer wavelength infrared radiation

Question 13

three greenhouse gases

Answer 13

water vapour
carbon dioxide
methane

Question 14

two ways human activity has increased carbon dioxide

Answer 14

burning fossil fuels
deforestation

Question 15

two ways human activity has increased methane

Answer 15

rice farming
cattle farming

Question 16

what is global warming

Answer 16

increase in overall global temperature

Question 17

what is global climate change

Answer 17

change in long term weather patterns across the planet

Question 18

what are some effects of climate change

Answer 18

• rising sea levels
• extreme weather events
• changes in the amount and time of rainfall
• changes to ecosystems and habitats
• polar ice caps melting

Question 19

what is a carbon footprint

Answer 19

amount of carbon a product, process or person releases into the atmosphere over its lifetime

Question 20

how is carbon monoxide formed

Answer 20

incomplete combustion - colourless and odourless toxic gas

Question 21

how are particulates formed

Answer 21

incomplete combustion, leads to global dimming, respiratory problems and can casue cancer

Question 22

how is sulfur dioxide formed

Answer 22

sulfur impurities in fossil fuels react with oxygen in combustion and it is a gas which causes acid rain and respiratory problems

Question 23

how are oxides of nitrogen formed

Answer 23

atmospheric oxygen and nitrogen react in the heat of a combustion engine it causes acid rain and respiratory problems