Chemistry of the environment

Question 1

Define anhydrous

Answer 1

Substance contains no water

Question 2

Cobalt(II) chloride colour when anhydrous

Answer 2

blue

Question 3

Cobalt(II) chloride colour when hydrated

Answer 3

pink

Question 4

Copper (II) sulfate colour when anhydrous

Answer 4

white

Question 5

Copper (II) sulfate colour when hydrated

Answer 5

blue

Question 6

Describe how using these melting and boiling points can determine whether water is pure [2]

Answer 6

1) impurities increase the boiling points of water (Boil above 100)
2) impurities decrease the melting point of water (Melt below 0) 

Question 7

List the process of water treatment [3]

Answer 7

1) Sedimentation/filtration
2) Filtration/Carbon treatment
3) Chlorination

Question 8

Explain sedimentation and filtration [3]

Answer 8

1)Water in the tank stays for hours
2) Particles sinks to the bottom of the tank
3) Water is then filtered

Question 9

Explain carbon treatment

Answer 9

Carbon removes taste and odour

Question 10

Explain chlorination [2]

Answer 10

1) chlorine is used to kill bacteria
2) Only an appropriate amount is used to ensure it isn’t dangerous to consume

Question 11

State the three elements found in NPK fertilisers.

Answer 11

Nitrogen, potassium, phosphorus

Question 12

What does Nitrogen do in NPK fertilisers

Answer 12

Makes chlorophyll and protein and promotes healthy leaves

Question 13

What does Potassium do in NPK fertilisers

Answer 13

Potassium promotes growth and healthy fruit and flowers

Question 14

What does Phosphorus do in NPK fertilisers

Answer 14

Phosphorus promotes healthy roots

Question 15

What are the sources of these elements in NPK fertilisers?

Answer 15

1) Ammonium ions and nitrate ions are sources of soluble nitrogen.
2) Phosphate ions are a source of soluble phosphorus.
3) Potassium compounds dissolve in water to produce potassium ions

Question 16

What is the 4 components of air

Answer 16

nitrogen,
oxygen
argon and other noble gases
carbon dioxide

Question 17

% of nitrogen in air

Answer 17

78

Question 18

% of oxygen in air

Answer 18

21

Question 19

% of argon and other noble gases in air

Answer 19

0.9

Question 20

% of carbon dioxide in air

Answer 20

0.04

Question 21

State how carbon dioxide, CO2 are released into the atmosphere and their adverse effects [2]

Answer 21

1) From combustion of carbon-containing fuels
2) Leads to global warming

Question 22

State how carbon monoxide, CO are released into the atmosphere and their adverse effects [2]

Answer 22

1) From incomplete combustion of carbon-containing fossil fuels
2) Toxic and combines with haemoglobin which prevents it from carrying oxygen

Question 23

State how particulates are released into the atmosphere and their adverse effects [2]

Answer 23

1) From incomplete combustion of carbon-containing fossil fuels
2) causes cancer and respiratory issues

Question 24

state how methane, CH4 and waste gases are released into the atmosphere and their adverse effects [2]

Answer 24

1) From waste gases of agriculture
2) Causes global warming

Question 25

State how nitrogen oxides, NOx are released into the atmosphere and their adverse effects. [2]

Answer 25

1) Reaction of nitrogen with oxygen in high temperatures and bacterial action in soil.
2) Causes photochemical smog, Acid rain, pollutes crops, and irritate lungs, throat, and eye which leads to respiratory problems.

Question 26

State how sulfur dioxide, SO2 is released into the atmosphere and its adverse effect. [2]

Answer 26

1) Combustion of sulfur-containing fossil fuel and
2) causes acid rain

Question 27

Most cars have a catalytic converter. Describe what it does. [3]

Answer 27

1) Series of transition metal catalysts
2) Honeycomb structure within converter to maximise surface area for reaction
3) Series of Redox reaction occurs which neutralises pollutant gas

Question 28

Write the word and balanced SYMBOL equation for the catalytic conversion of nitrogen dioxide

Answer 28

2NO → N2 + O2
Nitric dioxide -> Nitrogen + oxygen

Question 29

Write the word and balanced SYMBOL equation for the catalytic conversion of carbon monoxide

Answer 29

2CO + O2 → 2CO2
Carbon monoxide + oxygen -> Carbon dioxide

Question 30

State the word and symbol equations for photosynthesis

Answer 30

 carbon dioxide + water —Light—> Oxygen + Glucose

6CO2 + 6H2O -> 6O2 + C6H12O6

Question 31

How are the oxides of nitrogen formed in car exhausts? [2]

Answer 31

1) Car engine causes combustion by heating up quickly
2) Acts as catalyst that binds nitrogen and oxygen together

Question 32

Explain the strategies used to reduce the effects of acid rain

Answer 32

Reduce sulphur dioxide emissions by using fuels that contain low levels of sulphur, and flue gas desulfurization. 

Question 33

Explain the strategies used to reduce the effects of climate change. [2]

Answer 33

  1) Reducing carbon dioxide emissions by using renewable energy, recycling and reforestation
2) Reduce livestock farming reduces methane emission

Question 34

Describe how these greenhouse gases cause global warming [3]

Answer 34

1) Light is emitted from the sun.
2) Sunlight is absorbed and some reflected by the surface. 
3) sunlight passes through atmosphere but greenhouse gases trap the sunlight, causing global warming

Question 35

What would be the most effective as a fertiliser

Answer 35

contain the most elements from nitrogen, phosphorous and potassium.

Question 36

Ammonium salts and nitrate salts are commonly used as fertilisers [3]

Answer 36

Ammonium nitrate, NH4NO3
Ammonium phosphate, (NH4)3PO4
Potassium nitrate, KNO3

Question 37

Write the balanced symbol and word equation for respiration

Answer 37

C6H12O6 + 6O2 => 6CO2 + 6H2O
Glucose + oxygen -> carbon dioxide + water

Question 38

What air pollutant is made when coal is burnt in power station [5]

Answer 38

1) carbon dioxide
2) methane
3) Sulphur dioxide
4) carbon monoxide
5) Nitrogen oxides

Question 39

Name of water that is safe to drink

Answer 39

Potable water

Question 40

4 steps of making potable water from freshwater

Answer 40

1) Screening
2) Sedimentation
3) FIltration
4) Sterilisation

Question 41

Desalination

Answer 41

1) If freshwater supplies are limited, desalination of seawater is used
2) Desalination can be done by distillation or by reverse osmosis