Atmosphere

Question 1

What is the composition of atmospheric gases?

Answer 1

• 80% Nitrogen
• 20% oxygen
• small proportionso of other gases

Question 2

When did the Earth form?

Answer 2

4.6 billion years ago

Question 3

What planets did Earth have a similar atmosphere to 4.6 billion years ago?

what was there?

Answer 3

mars or venus

carbon dioxide, little or no oxygen gas

Question 4

Why is evidence for the early atmosphere limited?

Answer 4

• long time scale

Question 5

How did the early atmosphere form?

Answer 5

• volcanic activity released water vapour + CO2
• earth cools, condenses water vapour (fell as rain -> oceans)
• CO2 dissolved in oceans
• nitrogen released from volcanoes
• unreactive, builds up
• small proportions of methane and ammonia

Question 6

How was nitrogen produced in the early atmosphere?

Answer 6

• produced by volcanoes
• dentitrifying bacteria produced nitrogen
• ammonia reacted with oxygen

Question 7

How did carbon dioxide decrease?

Answer 7

• carbon dioxide dissolved in ocean
• sedimentary rocks made from carbonate ions released by CO2, react with metals to form insoluble carbonates
• coal formed from plant deposits, buried + compressed
• crude oil + natural gas = plankton deposited in mud on sea floor, covered, compressed
• algae and plants photosynthesised

Question 8

How did oxygen increase?

Answer 8

• algae first produced oxygen at 2.7 billion years ago
• next billion years plants evolved
• O2 percentage increased until animals can evolve

Question 9

What is the equation for photosynthesis?

Answer 9

6CO2+6H2O→C6H12O6+6O2

Question 10

What would happen if the greenhouse effect does not exist?

Answer 10

Earth would be too cold for life to exist

Question 11

What do greenhouse gases include?

Answer 11

• water vapour
• carbon dioxide
• methane

Question 12

Describe the greenhouse effect

Answer 12

1) energy transmitted from sun to earth by radiation
2) some radiation reradiated to space by earth’s atmosphere, clouds nad surface
3) remaining radiation absobed by earth’s surface, warming it up
4) warm surface emits radiation, warms atmosphere
5) greenhouse gases in atmosphere absorb radiation
6) absorbed radiation radiated in all directions, keeping atmosphere and surface warm

short wavelength radiation passes through atmosphere

long wavelength absobed

Question 13

What human activities contribute to the increase of CO2?

Answer 13

• burning fossil fuels
• deforestation

Question 14

What human activities contribute to the increase of methane?

Answer 14

• cattle farming
• rice fields
• decomposition of rubbish in landfill

Question 15

What are the impacts of climate change?

Answer 15

• more heat waves
• fewer cold periods
• more droughts/ rainfall in some places

Question 16

What is carbon footprint?

Answer 16

• total amount of greenhouse gases released over the lifetime of a event or product

Question 17

How can we reduce our carbon footprint?

Answer 17

• walk or cycle instead of driving
• eat less meat
• increase recycling
• alternative forms of energy

Question 18

What are the most common atmospheric pollutants?

Answer 18

• Carbon monoxide (CO)
• Sulfur dioxide (SO2)
• Nitrogen oxides (NOx)
• particulates (C)

Question 19

How is carbon monoxide produced?

Answer 19

• imcomplete combustion of a hydrocarbon fuel

Question 20

How is sulfur dioxide produced?

Answer 20

• burning coal or petrol
• contains sulfur, reacts with oxygen in air

Question 21

How are nitrogen oxides produced?

Answer 21

• in car engines
• N2 and O2 in air react in high temps

Question 22

How are particules produced?

Answer 22

• incomplete combustion of a hydrocarbon fuel

Question 23

What is the effect of carbon monoxide?

Answer 23

• toxic gas
• colourless and odourless, hard to detect

Question 24

What are the effects of sulfur dioxide and nitrogen oxides?

Answer 24

• causes respiratory problems
• combines with water vapour to cause acid rain

Question 25

What are the effects of particulates?

Answer 25

• global dimming
• can damage lung cells