11 Air and Water

Question 1

what colour is Hydrated Copper(II) sulfate crystals

Answer 1

Blue

Question 2

What colour is anhydrous copper (II) sulfate crystals

Answer 2

white

Question 3

What colour is hydrated cobalt(II) chloride

Answer 3

pink

Question 4

What colour is anhydrous cobalt(II) chloride

Answer 4

blue

Question 5

What are the two tests for water

Answer 5

Hydrated Copper(II) sulfate ⇌ anhydrous copper(II) sulfate + water

Hydrated cobalt(II) chloride ⇌ Anhydrous cobalt(II) chloride + water

Question 6

Why is water treated

Answer 6

To make it potable (safe to drink)

Question 7

Explain the stages of water treatment (2)

Answer 7

Filtration - used to filter out large floating materials (microorganisms remain)

Chlorination - Chlorine gas bubbled through water to kill microorganisms. (May make water acidic but it is further treated with alkali to make it neutural)

Question 8

Composition of air (3)

Answer 8

78% nitrogen
21% oxygen
1% noble gases, water vapour,
carbon dioxide

Question 9

Common pollutants in the air (3)

Answer 9

Carbon monoxide

Nitrogen oxides

Sulfur dioxide

Question 10

Sources of the common pollutants (3)

Answer 10

Carbon monoxide - produced during the incomplete combustion of fossil fuels or other carbon sources

Nitrogen oxide - Car engine

Sulfur dioxide - combustion of fossil fuels with sulfur compounds inside

Question 11

Adverse effects of consuming common pollutants (3)

Answer 11

Carbon monoxide - poisonous gas that combines with hemoglobin preventing them from carrying oxygen

Nitrogen oxides - Combines with water in the air to form acid rain

Sulfur dioxide - causes acid rain, which can damage building and living organisms

Question 12

How can sulfur pollutants be reduced? (2)

Answer 12

Using low sulfur fuels (which had a lot of sulfur removed at oil refineries)

Using flue gas desulfurisation

Question 13

What are catalytic converters and what do they do (2)

Answer 13

fitted in cars to ensure toxic nitrogen and carbon monoxides are not emitted

Harmful gases passed over a hot catalyst converting them into less harmful gases

Question 14

How do catalytic converters look

Answer 14

honeycomb shape

Question 15

What reactions occur in catalytic converters (3)

Answer 15

2CO + O2 → 2CO2

2NO + 2CO → N2 + 2CO2

2NO → N2 + O2

Question 16

Define corrosion

Answer 16

when a reaction between a metal and oxygen leads to a layer of metal oxide being formed on the surface of the metal

Question 17

What happens when iron corrodes (2)

Answer 17

very brittle coating known as rust forms

eventually the iron will weaken and fall apart

Question 18

What are the conditions required for iron to corrode (2)

Answer 18

water

oxygen

Question 19

Equation for iron corrosion

Answer 19

iron + water + oxygen —> hydrated iron(III) oxide

2Fe + 2H2O + O2 —> Fe2O3.H2O2

Question 20

How to prevent rusting

Answer 20

Using barrier that stops water and oxygen from coming into with the iron

Question 21

What is galvanisation

Answer 21

coating iron in a layer of zinc

Question 22

Role of zinc in galvanisation (2)

Answer 22

acts as a barrier against air and water

if zinc is damaged, it will offer SACRIFICIAL PROTECTION

Question 23

How does sacrificial protection work? (2)

Answer 23

more reactive metals corrode in preference to less reactive metals (above reactivity series), metal can be protected from corroding.

The more reactive metals give away electron to less reactive metal, turning the less reactive metal into an ion

Question 24

Natural sources of CO2 (3)

Answer 24

volcanic eruptions

respiration by living organisms

naturally occuring fires

Question 25

Artificial sources of CO2 (3)

Answer 25

Burning fossil fuels

Deliberate forest fires

Production of cement

Question 26

Main sources of methane (3)

Answer 26

paddy fields, where rice is grown

digestive processes in farm animals

anaerobic decomposition of waste in landfills

Question 27

What are greenhouse gases

Answer 27

gases in the earth’s atmosphere that trap heat

Question 28

does CO2 and methane contribute to greenhouse gases?

Answer 28

yeah

Question 29

What are the essential elements needed for healthy plant growth (3)

Answer 29

nitrogen

phosphorus

potassium

Question 30

Define fertilisers

Answer 30

compounds that can be added to a plant to help them grow

Question 31

What are NPK fertilisers

Answer 31

fertilisers that contain nitrogen, phosphorus and potassium

Question 32

What is the haber process used to create

Answer 32

Ammonia (NH3)

Question 33

Eqt for haber process

Answer 33

N2 + 3H2 ⇌ 2NH3

Question 34

How are the raw resources needed for the haber process collected? (2)

Answer 34

Nitrogen is extracted from the air through fractional distillation

Hydrogen is produced by reacting methane/natural gas with steam

Question 35

What are the raw resources needed for haber process (2)

Answer 35

nitrogen

hydrogen

Question 36

What catalyst does the haber process use?

Answer 36

Iron (III) oxide catalyst to lower temperature

Question 37

What is the pressure used in the haber process

Answer 37

200 atm, to achieve a high yield of ammonia

Question 38

Why is the temperature used in haber process 450 degrees?

Answer 38

To make process more economical

Question 39

What is the displacement reaction that produces ammonia?

Answer 39

ammonium salt + strong base → ammonia + salt + water