Air and Water

Question 1

Testing for water (2)

Answer 1

anhydrous copper (II) sulfate + water –> hydrous copper (II) sulfate

anhydrous cobalt (II) chloride + water –> hydrous cobalt (II) chloride

Question 2

Treating water (5)

Answer 2

water goes to water treatment plant

water filtered through coarse gravel to remove dirt

water filtered through fine gravel + sand to remove small particles

chlorine passed through to kill bacteria

water supplied to homes + industry

Question 3

Composition of air (3)

Answer 3

78% Nitrogen

21% Oxygen

Other gases 1%

Question 4

Source of carbon monoxide

Answer 4

incomplete combustion of fossil fuels + other carbon sources

Question 5

Effects of carbon monoxide

Answer 5

poisonous gas that combines with hemoglobin in red blood cells –> stops them from carrying oxygen

Question 6

Source of Nitrogen oxides

Answer 6

car engines

Question 7

Effect of Nitrogen oxides (2)

Answer 7

acid rain - combines with water in air

Nitrogen dioxide - can cause respiratory diseases (bronchitis)

Question 8

Source of Sulfur Dioxide

Answer 8

combustion of fossil fuels which contain sulfur compounds

Question 9

Effect of Sulfur Dioxide

Answer 9

causes acid rain - damages buildings + living organisms

Question 10

Uses of catalytic convertors

Answer 10

fitted in cars - converting harmful gases into less harmful ones

Question 11

Reactions in a catalytic convertors (3)

Answer 11

2NO –> N2 + O2

2CO + O2 –> 2CO2

2NO + 2CO –> N2 + 2CO2

Question 12

Define corrosion (2)

Answer 12

when metals react with oxygen in air

layer of metal oxide form on surface of metal

Question 13

Examples of barriers to stop metals coming into contact with oxygen and air (2)

Answer 13

Plastic

Grease

Question 14

Define Galvanisation (2)

Answer 14

coating a metal in a layer of zinc

zinc will act as a barrier against air + water

Question 15

Define sacrificial protection (2)

Answer 15

more reactive metal will corrode instead of protected metal

will give electrons to protected metal to stop it reacting with air + water

Question 16

Natural Sources of carbon dioxide (3)

Answer 16

volcanic eruptions

respiration

naturally ocurring fires

Question 17

Artificial sources of carbon dioxide (3)

Answer 17

burning fossil fuels

deliberate forest fires

production of cement

Question 18

Sources of methane in atmosphere (3)

Answer 18

paddy fields

anaerobic decomposition of waste

digestive processes of farm animals

Question 19

Essential elements for plants (3)

Answer 19

Nitrogen

Phosphorous

Potassium

Question 20

Purpose of Haber process

Answer 20

ammonia for fertilisers

Question 21

Haber process chemical equation

Answer 21

N2 (g) + 3H2 (g) ⇌ 2NH3

Question 22

How is nitrogen acquired through the Haber process

Answer 22

from air through fractional distillation

Question 23

How is hydrogen produced for the Haber process

Answer 23

reacting methane/natural gas with steam

Question 24

Requirements for the Haber Process (2)

Answer 24

High pressure (200 atm) = ensure high yield of ammonia

moderately high temperature (450 degrees) = reaction does not reverse into reactants

Question 25

How can carbon dioxide be artificially produced (in a lab) (2)

Answer 25

calcium carbonate + hydrochloric acid –> carbon dioxide + water + calcium chloride

copper (II) carbonate / zin carbonate –> copper/zinc oxide + carbon dioxide