chemistry of the atmosphere

Question 1

atmospheric gas proportions today

Answer 1

approximately 78% nitrogen approximately 21% oxygen small proportions of various other gases: - carbon dioxide - water vapour - noble gases.

Question 2

why is evidence of he early atmosphere limited?

Answer 2

because of the time scale of 4.6 billion years, therefore theories about what was in the Earth’s early atmosphere and how the atmosphere was formed have changed and developed over time

Question 3

gas proportions in early atmosphere

Answer 3

mostly carbon dioxide with little or no oxygen gas

Question 4

reasons for the early atmosphere

Answer 4

intenseVOLCANIC activity that released gases - volcanoes also produced NITROGEN (which gradually built up in the atmosphere), - small proportions of methane and ammonia - water vapour formed oceans

Question 5

how carbon dioxide decreased

Answer 5

• carbon dioxide dissolved in the ocean and
• carbonates were precipitated producing sediments
• photosynthesis (by algae and plants)
• formation of sedimentary rocks and fossil fuels that contain carbon
• marine aminals formed removing carbonates from the oceans to produce shells

Question 6

how oxygen increased

Answer 6

• photosynthesis (by algae and plants)

Question 7

word equation for photosynthesis

Answer 7

carbon dioxide + water –_{light energy}–> glucose + oxygen

Question 8

symbol equation for photosynthesis

Answer 8

6CO₂ + 6H₂O —> C₆H₁₂O₆ + 6O₂

Question 9

how many years ago did the earth form?

Answer 9

4.6 billion years ago

Question 10

when did the first photosynthetic organisms form?

Answer 10

2.7 billion years ago

Question 11

name greenhouse gases

Answer 11

Water vapour

carbon dioxide

methane

Question 12

explain the greenhouse effect

Answer 12

_sun emits SHORT wavelengt_h infrared radiation that enters the atmosphere and travels towards the Earth’s surface.

Earth ABSORBS some of this radiation

LONG wavelength radiation is REFLECTED back into the atmosphere.

Greenhouse gases can’t absorb the frequency of radiation emitted by the SUN (SHORT), but they can ABSORB the LONGER wavelength reflected radiation.

gases then RE-RADIATE this energy in all directions, including back towards Earth.

This increases the temperature at the Earth’s surface.

Question 13

good use of the greenhouse effect

Answer 13

maintains temperatures on Earth high enough to support life

Question 14

Human activities which contribute to an increase in greenhouse gases in the atmosphere

Answer 14

land fills (more decomposition which releases methane)

deforestation (less photosynthesis = less uptake of CO₂)

agriculture (animals release methane during digestion)

burining fossil fuels (releases carbon in the form of CO₂)

Question 15

scientific concensus on greenhouse effect

Answer 15

human activities will cause the temperature of the Earth’s atmosphere to increase at the surface

and that this will result in global climate change

(all based on PEER-REVIEWED evidence)

Question 16

models used for predictions of climate change

Answer 16

it is difficult to model such complex systems as global climate change

This leads to simplified models,

speculation and

opinions presented in the media (that may be based on only parts of the evidence and which may be biased)

Question 17

potential effects of global climate change

Answer 17

polar ice caps melting (rise in sea levels, thus flooding, and no habitat for polar bears, coastal erosion)

meteorological events increase (extreme floods/droughts, storms and natural disaster)

changes in water availability (changes in species distribution)

changes in precitipation

foos shortages/ famine

Question 18

define carbon footprint

Answer 18

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

Question 19

how to reduce carbon footprint for INDIVIDUALS

(release of methane/carbon dioxide)

Answer 19

reduce waste

use renewable resources

maximise energy efficiency

carbon off-setting

Question 20

how to reduce carbon footprint for GOVERNMENT

(release of methane/carbon dioxide)

Answer 20

emission caps

emission-based taxes

emission liscenes up to a certain cap (these must be bought)

carbon dioxide capture and storage technology

Question 21

Barriers to Reducing Carbon Footprints:

economic reasons

Answer 21

government worries making changes required may restrict economic growth, this is a major concerns for developing countries

Question 22

Barriers to Reducing Carbon Footprints:

social reasons

Answer 22

people in developed countries might not want to change lifestyle

there is a lack of education on the importance of changing lifestyle

Question 23

Barriers to Reducing Carbon Footprints:
political reasons

Answer 23

countires have different opinions on how to act

countires they don’t know what other countires would do when presented with potential international agreement

uncertainty

scientists also disagree (on causes and solutions)

Question 24

what is the major source of atmospheric pollutants

Answer 24

combustion of fuels

(most fuels, including coal, contain carbon and/or hydrogen and may also contain some sulfur)

Question 25

complete combustion

Answer 25

occurs with enough oxygen

produces: carbon dioxide, water

Question 26

incomplete combustion

Answer 26

occurs with not enough oxygen

produces: carbon dioxide, carbon monoxide, sut, particulates

(sulfur is produced if there are sulfur impurities in the fuel)

Question 27

problem with carbon monoxide

Answer 27

colourless

odourless

toxic (bonds to haemoglobin preventing uptake of oxygen)

Question 28

problem with particulates

Answer 28

increase global dimming (reflect light from space back out)

can cause pulmonary issues

Question 29

internal combustion engines in cars

Answer 29

when fossil fuels are burned in a confined space

at high temperatures

oxygen and nitrogen react to produce toxic nitrogen oxides

Question 30

problems with nitrogen oxides

Answer 30

can cause respiratory problems

Question 31

causes of acid rain

Answer 31

nitrogen oxides + water = nitric acid

sulfur dioxide + water = sulfuric acid

Question 32

effects of acid rain

Answer 32

steel corrosion

weathering of buildings/statues

insects, plants, aquatic organisms die