The Earth’s Atmosphere

Question 1

What is the purpose of the life cycle assessment?

Answer 1

To look at every stage of a product’s life to assess the impact it would have on the environment

Question 2

Treatment of fresh water:

Answer 2

> The water needs to be filtered (filter out the large solid bits)
Then the water is sterilised (harmful bacteria is killed using chlorine gas, ozone or UV light)

Question 3

Treatment of seawater:

Answer 3

• some countries are too dry to use surface or groundwater so use seawater
  > must be treated with desalination (takes away mineral components) can be done by desalination

Question 4

Distillation method:

Answer 4

Test the pH of the water using a pH meter (it should be neutral)
Heat the water up causing it to evaporate and will enter the condenser as steam
In the condenser it will cool into water
Test the pH again to check it’s neutral

Question 5

Test for hydrogen

Answer 5

Put a burning splint at end of test tube, if there’s hydrogen it will pop

Question 6

Test for oxygen

Answer 6

Put a glowing splint into a test tube of gas, the splint will relight if oxygen is present

Question 7

Test for carbon dioxide

Answer 7

Lime water - when carbon dioxide is shaken with limewater it turns cloudy

Question 8

Test for chlorine

Answer 8

Litmus paper - paper is bleached if chlorine is present

Question 9

Test for alkenes

Answer 9

Bromine water - bromine water turns colourless if alkene is present

Question 10

How was the atmosphere formed

Answer 10

Lots of volcanoes erupting and releasing lots of gases

Question 11

What was the atmosphere like at the beginning?

Answer 11

> mostly carbon dioxide
volcanoes released nitrogen + water vapour which built up in the atmosphere

Question 12

How were oceans formed?

Answer 12

Water vapour condensing

Question 13

How did carbon dioxide levels decrease?

Answer 13

> some dissolved into oceans
green plants and algae evolved and absorbed carbon dioxide during photosynthesis

Question 14

How did oxygen levels rise?

Answer 14

Green plants and algae produced it in photosynthesis
When oxygen levels were high enough, more complex life could evolve

Question 15

What is the composition of the atmosphere now?

Answer 15

80% nitrogen, 20% oxygen, small amounts of other gases

Question 16

What are carbon footprints?

Answer 16

A measure of the amount of carbon dioxide and other greenhouse gases released over the full life cycle of something

Question 17

Why is measuring carbon footprint really hard?

Answer 17

There are so many different factors to consider e.g. you have to consider sourcing the materials, making a product, using the product and the disposal of the product

Question 18

Consequences of global warming:

Answer 18

• ice caps melting -> rise in sea levels, increased flooding
• changes in rainfall patterns -> areas getting too much or too little water which can affect farming
• more intense and frequent storms
• affecting distribution of species in habitats due to changes in temperature and water availability

Question 19

What’s of reducing carbon footprints:

Answer 19

• renewable energy sources
• governments could tax companies or individuals based of the amount of carbon dioxide they emit
• governments can put a cap on emissions of all greenhouse gases that companies make
• capturing carbon dioxide before its released into the atmosphere and then storing it deep underground

Question 20

Why is making reductions of carbon emissions difficult?

Answer 20

• many governments are worried that it will impact the economic growth on communities and many countries don’t want to sacrifice their economic growth meaning it’s hard to make international agreements
• everyone needs to be on board (including all individuals in communities) and it’s hard to get people to make changes if they don’t want to

Question 21

What gases are released into the atmosphere during complete combustion of fossil fuels?

Answer 21

Carbon dioxide and water vapour

Question 22

What gases are released into the atmosphere in incomplete combustion?

Answer 22

Soot, carbon monoxide and carbon dioxide

Question 23

How is soulful dioxide released into the atmosphere?

Answer 23

During the combustion of fossil fuels that contain sulfur impurities - the sulfur in the fuel becomes oxidised

Question 24

How are nitrogen oxides created?

Answer 24

From a reaction between nitrogen and oxygen in the air, caused by the heat of burning

Question 25

How does nitrogen oxide form acid rain?

Answer 25

When the gases mix with clouds, they form dilute sulphuric acid or dilute nitric acid. This then falls as acid rain

Question 26

Why is carbon monoxide dangerous?

Answer 26

• it has no colour or smell making it hard to detect
• it binds to haemoglobin in your blood meaning less oxygen is able to travel around the body , this lack of oxygen can lead to fainting or even death

Question 27

What are particulates dangerous?

Answer 27

If inhaled they can get stuck in the lungs and cause damage.
- also bad for the environment as they can cause global dimming