Air Quality, Climate and Water

Question 1

Which gas is most present in clean, dry air?

Answer 1

nitrogen

Question 2

What is the composition of clean, dry air?

Answer 2

78% nitrogen
20% oxygen
1% water vapour
0.97% argon (among other inert gases)
0.03% carbon dioxide and others

Question 3

How is carbon dioxide formed?

Answer 3

complete (and incomplete) combustion of carbon-containing fuels

Question 4

How is carbon monoxide formed?

Answer 4

incomplete combustion of carbon-containing fuels

Question 5

How are particulates (soot) formed?

Answer 5

incomplete combustion of carbon-containing fuels

Question 6

How is methane formed (2 ways) ?

Answer 6

decomposition of vegetation
waste gases from digestion in animals

Question 7

How are oxides of nitrogen formed?

Answer 7

nitrogen and oxygen in the air react in the heat of car engines

Question 8

How is sulfur dioxide formed?

Answer 8

combustion of fossil fuels that contain sulfur compounds

Question 9

What are common air pollutants?

Answer 9

carbon dioxide
carbon monoxide
soot/particulates
oxides of nitrogen
sulfur dioxide
methane

Question 10

What is the negative effect of carbon dioxide?

Answer 10

increases global warming, leads to climate change

Question 11

What is the negative effect of carbon monoxide?

Answer 11

toxic gas, binds to haemoglobin in your blood and reduces capacity to carry oxygen

Question 12

What is the negative effect of soot/particulates?

Answer 12

increases risk of cancer
increases risk of respiratory problems

Question 13

What are the negative effects of nitrogen oxides?

Answer 13

acid rain
photochemical smog
respiratory problems

Question 14

What is the negative effect of methane?

Answer 14

increases global warming, leads to climate change

Question 15

What is the negative effect of sulfur dioxide?

Answer 15

acid rain

Question 16

What are strategies to reduce the effects of climate change?

Answer 16

planting trees
reducing livestock farming
less use of fossil fuels
more use of hydrogen
renewable energy

Question 17

What are strategies to reduce the effects of acid rain?

Answer 17

catalytic converters in vehicles
using low-sulfur fuels
use of flue gas + calcium oxide for desulfurisation

Question 18

What is an obligatory product of incomplete combustion?

Answer 18

water

Question 19

What other products, besides water, can be formed from incomplete combustion?

Answer 19

soot, carbon monoxide, carbon dioxide

Question 20

What is the general word equation for complete combustion?

Answer 20

hydrocarbon + oxygen -> carbon dioxide + water

Question 21

Which two products are always formed from complete combustion?

Answer 21

carbon dioxide and water

Question 22

What two ways do greenhouse gases (CO2 and methane) cause global warming?

Answer 22

they absorb, reflect and emit thermal energy
reduce the loss of thermal energy to space

Question 23

How do oxides of nitrogen form in car engines?

Answer 23

nitrogen and oxygen in air react in the heat of a car engine

Question 24

What happens to nitrogen oxides in a catalytic converter?

Answer 24

they are reduced

Question 25

Define 'photosynthesis'.

Answer 25

the process which uses energy from light to convert water and carbon dioxide into oxygen and glucose in the presence of chlorophyll

Question 26

What is the word equation for photosynthesis?

Answer 26

carbon dioxide + water → glucose + oxygen

Question 27

What is the symbol equation for photosynthesis?

Answer 27

6CO2 + 6H2O → C6H12O6 + 6O2

Question 28

What are two tests to test the presence of water?

Answer 28

anhydrous cobalt (II) chloride anhydrous copper (II) sulfate

Question 29

What happens to anhydrous copper(II) sulfate when it is in contact with water?

Answer 29

it goes from white to blue

Question 30

What happens to anhydrous cobalt (II) chloride when it is in contact with water?

Answer 30

it goes from blue to pink

Question 31

How do you test for water purity?

Answer 31

boil water, if it boils at 100 degrees it is pure freeze water, if it freezes at 0 degrees it is pure

Question 32

Why is distilled water used in practical chemistry?

Answer 32

distilled water has less chemical impurities

Question 33

What potentially harmful substances can be found in water from natural sources?

Answer 33

some metal compounds some plastics sewage nitrates and phosphates

Question 34

Which beneficial substances can be found in water from natural sources?

Answer 34

dissolved oxygen some metal compounds

Question 35

Why are some plastics in water from natural sources harmful?

Answer 35

harm aquatic life

Question 36

Why is sewage in water from natural sources harmful?

Answer 36

has harmful microbes which can cause disease

Question 37

Why are nitrates and phosphates in water from natural sources harmful?

Answer 37

cause deoxygenation of water, damages aquatic life

Question 38

Why is dissolved oxygen in water from natural sources beneficial?

Answer 38

beneficial for aquatic life

Question 39

Why are some metal compounds in water from natural sources beneficial?

Answer 39

provide essential minerals for life

Question 40

What is the function of sedimentation and filtration in water treatment?

Answer 40

remove solids

Question 41

What is the use of carbon in water treatment?

Answer 41

removes smells and tastes

Question 42

What does chlorination do in water treatment?

Answer 42

kill microbes

Question 43

equation for what happens in the catalytic converter

Answer 43

2CO + 2NO -> 2CO2 + N2

Question 44

equation for formation of oxides of nitrogen

Answer 44

N2 + 2O2 -> 2NO2

Question 45

how catalytic converter reduces emissions of of pollutantants

Answer 45

- carbon monoxide converted to carbon dioxide (2CO + O2 -> 2CO2) - oxides of nitrogen are reduced to nitrogen - hydrocarbons are burned to make water - products: carbon dioxide, water, nitrogen

Question 46

what is the pH of rain

Answer 46

5.6 (naturally acidic) as it mixes with solutes in the air

Question 47

when CO2 and other solutes dissolve in rainwater, what is formed?

Answer 47

carbonic acid

Question 48

formation of acid rain

Answer 48

- some fossil fuels contain sulphuric impurities - when burnt sulfur react with oxygen, producing sulphuric dioxide - sulphuric dioxide dissolves in rainwater to make sulphuric acids which form acid rain

Question 49

problems with acid rain

Answer 49

- dissolve limestone (buildings) - destroy vegetation - kill water lief due to changing a lake, river, etc - damage human skin