Booklet 9 - Evolution Of Earths Atmosphere

Question 1

what are the proportions of gases in the earth today?

Answer 1

80% nitrogen, 21% oxygen and small proportions of co2, h2o, and noble gases

Question 2

When do scientists believe the earth was formed, what was it like?

Answer 2

Formed 4.6 billion years ago, for the first billion years it was very hot and turbulent, covered in volcanoes belching fire and gases into the atmosphere

Question 3

What is it believed the volcanoes released?

Answer 3

Co2, h2o (g) and n2 which formed the early atmosphere similar to the atmosphere of mars and venus

Question 4

What would the water vapour from the volcanoes done?

Answer 4

Would’ve condensed to form the oceans,

- the atmospheres would be largely dominated by co2 with only a tiny amount of oxygen present

Question 5

What other gases are believed to have been present in trace amounts?

Answer 5

Methane and ammonia, which may have formed the first organic molecules containing C and N leading to the first living organisms

Question 6

How was oxygen produced?

Answer 6

When the first living organisms evolved to use sunlight to convert CO2, h2o to glucose by photosynthesis -> oxygen was produced

Question 7

What is the equation for the formation of oxygen?

Answer 7

6CO2 (g) + 6H2 (g) -> C6H12O6 (aq) + 6O2 (g)

Question 8

How did the percentage of oxygen increase?

Answer 8

Algae started the process 3.7 billion yrs ago, when plants evolved over the next billion years the % of oxygen increased to a level that enabled animals to evolve

Question 9

What did dissolved CO2 in the ocean form? How did this happen?

Answer 9

Insoluble carbon compounds (sediment)
- co2 was used by the ocean organisms to make CaCO3 shells, when these animals died they formed sedimentary rocks such as limestone

Question 10

What did crushed plankton form?

Answer 10

Crushed by rock over millions of years and formed fossil fuels eg crude oil

Question 11

What did plant and algae do in the decrease of levels in CO2?

Answer 11

They used co2 for photosynthesis & converting the glucose formed in thd process to starch, cellulose and wood

Question 12

What happended when plants eg ferns died?

Answer 12

They became compressed over millions of years, and in the absence of oxygen formed the fossil fuel coal containing mainly carbon

Question 13

What was happening to the carbon dioxide in the atmosphere?

Answer 13

It was gradually being removed from the atmosphere and locked up as sedimentary rock, fossil fuels and biomass

Question 14

What is a greenhouse used for? How does it work?

Answer 14

Used for maintaining a higher temperature inside than outside, heat energy from the sun is allowed inside but stops the same amount of energy from escaping

Question 15

How does plants grow in a greenhouse?

Answer 15

They grow faster as the heat energy builds up and temperature increases causing faster growth

Question 16

What are the three main greenhouse gases?

Answer 16

CO2, CH4 and H2O water vapour

Question 17

What form does the sun give out energy?

Answer 17

Electromagnetic radiation in the ultraviolet (shorter, higher energy), visible and infrared (lower, longer energy) wavelengths

Question 18

What does the electromagnetic radiation do?

Answer 18

Reaches the earth and heats up the surface providing warmth

Question 19

What energy does the earth give out?

Answer 19

Gives out radiation not as hot as the sun, in the form of longer, lower energy infrared radiation

Question 20

What do CH4, CO2 and H2O gases do to the radiation?

Answer 20

Absorb radiation of the infrared wavelength so this radiation doesnt fully escape and is retained and causes global warming

Question 21

Why is a certain amount of CO2 needed in the atmosphere?

Answer 21

The temperature of the earths atmosphere would be approx -19 degrees, all the water would be solid and life would not of yet had a chance to evolve

Question 22

Why are levels of CO2 increasing?

Answer 22

Burning fossil fuels - as population increases so does the demand for energy
Deforestation- fewer trees means less photosynthesis meaning less co2 removed from the atmosphere

Question 23

Why are levels of CH4 increasing?

Answer 23

Increased farming- farm animals produce methane and so does their manure when it decomposes
Landill sites - when waste is buried in landfill it decomposes and produces methane

Question 24

Why is it important for scientists to peer review their work?

Answer 24

Must be checked by scientists in the same area of research to ensure its scientifically valid and not fabrication

Question 25

Whats the difficulty with making predictions about matters concerning earth and what happens instead?

Answer 25

Its difficult to accurately model such a complex system so simplified models, speculation & opinion presented in the media are commonly accepted as fact

Question 26

What effect has climate change had on rising sea levels?

Answer 26

As the earth becomes warmer, the southern ice cap will melt, causing an increased volume if water in the oceans as well this as water warms it expands again increasing volume

Question 27

What effect has climate change had on storms?

Answer 27

Extreme weather events could become more frequent

Question 28

What effect has climate change had on changes in temperature & the amount, timing and distribution of rainfall?

Answer 28

Could affect food production by upsetting the growth of crops, many of which are dependent upon good levels of sunshine & reliable rainfall. There’s speculation dry lands eg Asia will become drier

Question 29

What effect has climate change had on wildlife?

Answer 29

Plants and animals whose cycles of hibernating/reproduction rely on seasonal factors eg temperature & moisture levels which may become disrupted along with their habitats. Eg animals may come out if hiberantion and find their normal prey haven’t appeared for spring

Question 30

What is carbon footprint?

Answer 30

The amount of carbon dioxide and other greenhouse gases given out over the full cycle of a product, a service or an event

Question 31

Describe the carbon footprint of a plastic bag?

Answer 31

• drill for crude oil
• heat & vapourise crude oil in fractional distillation
• heat alkanes to crack them to make ethene
• provide heat & pressure to polymerise ethene to make polyethene
• transport plastic bags to shop
• transport used plastic bags to waste disposal sites
• if the bag is incinerated then more co2 is generated

Question 32

What are the first two ways of reducing carbon footprint?

Answer 32

• increase the use of alternative energy sources eg wind turbines
• increase the efficiency of out use of energy by using more efficent engines in cars, increasing insulation in homes, use of low energy lightbulbs

Question 33

What does developing more carbon capture storage units do in reducing carbon footprint?

Answer 33

As most electricity is from burning fossil fuels, CCS plants are built into the power station, co2 can be stored deep into the ground. Upto 90% of co2 emissions from a power plant can be removed this way

Question 34

What is carbon off setting?

Answer 34

Actions that are put into place to reduce the emission of greenhouse gases to compensate for the release of greenhouse gas elsewhere eg planting more trees

Question 35

What are carbon neutral fuels? How does it work?

Answer 35

Trees are grown, cut down and used as fuel. This a carbon neutral method as when trees grow they absorb co2 from the atmosphere, & when they’re burned, no new co2 is produced.
- The trees can be replaced making the process renewable & forms part of the carbon cycle

Question 36

How does the fermentation of crops work?

Answer 36

Ethanol is made from the fermentation of crops, whilst growing, will have absorbed co2. When ethanol is combusted in a car engine, the co2 produced is the same as originally absorbed

Question 37

How do scientists not agreeing affect the chance of reducing carbon footprint?

Answer 37

Scientists that dont often agree on the causes and consequences of climate change makes the effort to reduce the problem more difficult

Question 38

What is the problem with the methods of reducing co2 emissions?

Answer 38

they are expensive eg implementing CCS plants are costly to build and run, which could mean the costs are passed onto the general public via electricity bills which may not be too welcome. -> reduces the chance of reducing carbon footprint

Question 39

What has the increased usage of tablets and mobile phones done?

Answer 39

Increased the demand for electricity, but many people’s lifestyle both at home and work heavily rely on electricity and those gadgets -> which becomes an obstacle for reducing carbon footprint

Question 40

Whats the Kyoto protocol or newly updated to the Paris agreement about?

Answer 40

Many counties are apart of it and are making successful efforts to reduce their emissions, china and india are exempt and places like USA dont agree with the agreement

Question 41

What substances are produced from burning hyrdrocarbons?

Answer 41

Carbon dioxide, water vapour, carbon monoxide, soot particulate, unburnt hydrocarbons, sulphur dioxide & gas oxides of nitrogen

Question 42

How is CO2 made? Whats the equation?

Answer 42

Large amounts of this gas are made when any alkane is completely combusted ie theres lots of oxygen to convert all of the H to H2O and all of the C to CO2.

• C8H18 (l) + 12.5 O2 (g) -> 8CO2 (g) + 9O2 (g)

Question 43

How are CO and C made? What are the equations?

Answer 43

If an engine is old or poorly maintained, oxygen is less able to reacg alkane molecules in time to convert all of the C to co2. Instead CO and C are made in incomplete combustion

• CO = - C8H18 (l) + 8.5 O2 (g) -> 8CO2 (g) + 9O2 (g)
• C = - C8H18 (l) + 4.5 O2 (s) -> 8CO2 (g) + 9O2 (g)

Question 44

What are problems with carbon monoxide and carbon particles?

Answer 44

Carbon monoxide is toxic (odourless& colourless to detect)
Carbon particles ie soot are harmful by inhalation and may be carcinogenic, also may cause global warming as it reflects sunlight back into space

Question 45

How are unburnt hyrdrocarbons made? Whats wrong them?

Answer 45

They escape from the car engine before combustion and are left as a rainbow residue on the road. And can vapourise to cause photochemical smog -> harmful to health.

Question 46

How and what are NOx and HNO3 made?

Answer 46

NOx is the general name given to oxides of nitrogen eg NO, NO2. They’re made when N2 and O2 combine at high temperatures in the presence of a spark in a combustion engine

Question 47

How are NOx ans HNO3 harmful? Whats the equation?

Answer 47

NOx is harmful the respiratory system which can react futher with h2o and o2 in the atmosphere to make acid rain -> nitric acid, HNO3 its very strong
- N2 (g) + O2 (g) -> 2 NO(g)

Question 48

How is SO2 made?

Answer 48

SO2 is released during the combustion of fossil fuels, eg coal that contain sulfur impurities, the sulfer then becomes oxidised. When sulphur is mixed with clouds dilute sulphur dioxide gas is made: S(s) + O2 (g) -> SO2 (g)

Question 49

What’s harmful about SO2?

Answer 49

SO2 is an harmful gas which is harmful to the respiratory system, it’s soluble in water and will combine with rain and oxygen to produce another type of acid rain -> sulfuric acid HsSO4

Question 50

how was carbon removed from the atmosphere as it dissolved in oceans?

Answer 50

the dissolved CO2 went through a series of reactions to form carbonate precipitates that formed sediments on the seabed