C13.1 - 13.5 - Earths Atmosphere✔️

Question 1

How much of the atmsophere is nitrogen?

Answer 1

78%

Question 2

How much of the atmsophere is oxygen?

Answer 2

20%

Question 3

What other proportions of various gases make up the atmosphere?

Answer 3

• Carbon dioxide
• water vapour
• noble gases

Question 4

Why is there not a definite answer to how the atmosphere formed?

Answer 4

Evidence is limited because of the time scale of 4.6 billion years

Question 5

Described the volcanic activity theory for the origin of the atmosphere?

Answer 5

During the first billions years of the earths existence there was intense volcanic activity that released gases that formed the early atmosphere and water vapour that condensed to form oceans

Question 6

Why may there been small proportions of methane and ammonie in the atmosphere?

Answer 6

Volcanoes produced nitrogen which gradually built up in the atmosphere

Question 7

What happend when the oceans formed (from the atmposphere and water vapour condensing)?what was produced?

Answer 7

Carbon dioxide dissolved in the water and carbonates were precipitaed producing sediments

Question 8

How did oxygen increase?

Answer 8

Algae and plants produced oxygen that is now in the atmosphere by photosynthesis - algae first produced about 2.7 billion years ago

Question 9

Symbol Equation for photosynthesis?

Answer 9

6Co₂ + 6H₂O - C₆H₁₂O₆ + 6O₂

Question 10

Word equation for photosynthesis?

Answer 10

Cabron dioxide + water - (light) - glucose + oxygen

Question 11

How did carbon dioxide levels decrease?

Answer 11

Alage and plants decreased the percentage of carbon dioxide in the atmosphere by photosynthesis - carbon dioxide was also decreased by the formation or sedimentary rock and fossil fuels that contain carbon

Question 12

How did levels of ammonia and methane decrease in the atmosphere?

Answer 12

Metane and ammonia reacted with oxygen produced from photosynthesis

Question 13

Importance of the greenhouse effect?

Answer 13

Natural greenhouse effect is important for maintaining temperatures high enough for use to survive

Question 14

Explain the greenhouse effect with refrence to waves?

Answer 14

• sun emits short-wave length radiation (eg ultraviolet light which warms the earth)
• earth looses heat by emitting long wavelength radiation (eg thermal infared)
• greenhouse gases absorb some of long wavelength radiation
• they re-radiate this thermal radiation in all directions including back to earth

Question 15

Two human activities which increase carbon dioxide?

Answer 15

• burning fossil fuels for electricity/running cars-
  Propane + oxygen - carbon dioxide + water

-deforestation - cutting down trees reduces the amount of co2 absorbed

Question 16

Two human activities which increase methane?

Answer 16

• cattle kept for meat and milk produce large amounts of methane

-landfill sites - decay of waste by microrganisms produces methane

Question 17

Issues of global climate change?

Answer 17

Rising sea levels,threats to ecosystems, and different patterns of food production around the world

Question 18

Define carbon footprint?

Answer 18

Is the total amount of carbon dioxide and other greenhouse gases emitted over the full cycle of a product,service or event

Question 19

How can carbon footprint be reduced? Give two exmaples for both carbon dioxide and methane?

Answer 19

Reducing emissions of carbon dioxide and methane - eg eating less meat reduces methane or charging more tax on polluting vehicles

Question 20

How can acid rain be formed? Enviromental issues?

Answer 20

Result of sulfur impurities in fuels being burnt which forms sufur dioxide which is an acidic gas which can kill animials and devestate aquatic life

Question 21

Issues with nitrogen from the air reacting with high temperatures in engines?

Answer 21

Forms oxides of nitrogen which can cause breathing problems and causes acid rain

Question 22

Issues with incomplete combustion?

Answer 22

Carbon monoxide gas is formed instead of all carbon in the fuel turning into carbon dioxide gas - can cause death because it takes the place of oxygen on red blood cells

Question 23

Issues with larger molecules reacting with oxygen in engines?

Answer 23

They do not always burn completley - tiny solid partilces containing carbon and unburnt hydrocarbons - which get carried in the air and reflect sunlight back to earth, causing global dimming

Question 24

How much of the atmospher is argon?

Answer 24

0.9%

Question 25

How much of the atmosphere is carbon dioxide?

Answer 25

0.04%

Question 26

Give two ways nitrogen is released into the atmosphere?

Answer 26

• combustion of fossil fuels
• use of nitrogen-containing fertilizers in agriculture