What are non-metals ? Non-metals are those substances which are
not metals i.e. they do not ionize by electron loss and do not show
the characteristics of metals
Slide 3
Properties of Non-Metals Poor conductors of heat and
electricity Brittle, not malleable and ductile Dull in colour Low
in sonority
Slide 4
Chemical Properties React with air/oxygen to give covalent
acidic oxides ( although a few give neutral oxides e.g. CO ) React
with metals to form ionic compounds Do not react with dilute acids
Do not react with water except chlorine Tend to be oxidizing
agents
Slide 5
Common Non-metals We will be looking at : Hydrogen Chlorine
Oxygen Carbon Sulphur Nitrogen
Slide 6
Hydrogen It is a diatomic gas H 2 It is colourless and
odourless. It is almost insoluble in water and is the lightest
known substance.
Slide 7
Chemical Properties of Hydrogen It has a neutral pH It burns in
air/oxygen It combines with reactive metals to give hydrides : Mg +
H 2 MgH 2 It can act as a reducing agents e.g. in the extraction of
metals CuO + H 2 Cu + H 2 O
Slide 8
Uses of Hydrogen Manufacture of ammonia, nitric acid and nylon
Manufacture of margarine and other hydrogenated oils In welding As
fuel
Slide 9
Laboratory Preparation Hydrogen can be prepared by reacting an
acid with a metal Zn + 2HCl ZnCl 2 + H 2
Slide 10
Diagram of the Laboratory Preparation of Hydrogen
Slide 11
The Water Cycle
Slide 12
Slide 13
Water vapour in the atmosphere condenses and form water
droplets and precipitation occurs. If temperature is low we will
get snow or hail ( ice ). The water on the ground : percolates and
go underground runs off into rivers and the seas evaporates
Slide 14
Plants absorb water and loses it through a process called
transpiration Animals also intake water and lose through excretion
( sweat, urine or breathing )
Slide 15
Uses of water Domestic purposes e.g. drinking, washing,
cooking, cleaning Irrigation of crops Generation of electricity
Industrial processes Recreational activities
Slide 16
Slide 17
Chlorine
Slide 18
It is a diatomic gas Cl 2 It is a greenish-yellow gas with a
choking odour. It is more dense than air and is slightly soluble in
water.
Slide 19
Chemical Properties of Chlorine Readily combines with metals to
form chlorides : Mg + Cl 2 MgCl 2 It is a powerful oxidizing agent
It bleaches substances ( in the presence of moisture )
Slide 20
Uses of Chlorine Manufacture of plastics e.g. PVC Sterilize
water e.g. drinking supplies, swimming pools Preparation of
cleaning fluids and bleaching agents Manufacture of hydrochloric
acid
Slide 21
Laboratory Preparation Chlorine can be the oxidation of conc.
Hydrochloric acid by potassium manganate VII HCl (l) + KMnO 4 (s)
KCl (aq) + MnCl 2 (aq) + H 2 O (l) + Cl 2 (g)
Slide 22
Slide 23
Oxygen
Slide 24
Oxygen is the most abundant element on Earth. Approximately 50%
of the earths crust is composed of oxygen containing compounds,
while 20% of the atmosphere is free oxygen gas.
Slide 25
Oxygen is a diatomic gas O 2 although in the upper atmosphere
it exists in the allotrope form as ozone O 3. It is a colourless
odourless gas which is slightly soluble in water and has the same
density as air.
Slide 26
Chemical Properties It has a neutral pH of 7 Supports
combustion Combines with most elements to form oxides It is
involved in biological processes of respiration.
Slide 27
Uses of Oxygen In welding apparatus Rocket fuels Steel
manufacture Breathing equipment
Slide 28
Laboratory Preparation Oxygen is prepared by the catalytic
decomposition of hydrogen peroxide. 2H 2 O 2 (aq) 2H 2 O (l) + O 2
(g) MnO 2 is the catalyst used
Slide 29
Slide 30
Carbon
Slide 31
Carbon exists as many natural occurring allotropes ; diamond,
graphite, charcoal and coke.
Slide 32
Slide 33
Chemical Properties of Carbon Readily burns in oxygen to form
carbon dioxide. In limited supply of air carbon monoxide is formed.
It is a powerful reducing agent at high temperatures.
Slide 34
Carbon Dioxide Carbon dioxide is a colourless, odourless gas
which is slightly soluble in water. It is more dense than air and
is slightly acidic. The presence of carbon dioxide can be
determined by the formation of a precipitate with calcium
hydroxide.
Slide 35
Preparation Carbon dioxide is prepared by the reaction of a
carbonate and a dilute acid.
Slide 36
Slide 37
Uses of Carbon dioxide As a refrigerant As a fire suppressant
In sodas
Slide 38
Carbon cycle
Slide 39
Sulphur
Slide 40
Sulphur is found in the earths crust as a free element and as
sulphides and sulphates. The free sulphur occurs as two allotropes,
monoclinic and rhombic.
Slide 41
Chemical Properties Burns in air to form sulphur dioxide
Combines with most metals to form sulphides.
Slide 42
Uses Manufacture of sulphuric acid Manufacture of gunpowder and
matches Manufacture of fungicides and pesticides Vulcanization of
rubber
Slide 43
Sulphur is obtained by the Frasch process where the sulphur is
mined directly from the earth in its elemental form.
Slide 44
Sulphuric acid
Slide 45
Concentrated sulphuric acid is a colourless, odourless, oily
liquid. It is a powerful dehydrating liquid. Diluting conc.
sulphuric acid is a very exothermic reaction and must be done
cautiously.
Slide 46
Uses Manufacture of fertilizers Manufacture of white paint
Manufacture of soaps and detergents Refining of petroleum
Vulcanization
Slide 47
Manufacture Sulphuric acid is manufactured by the Contact
process which has three stages. 1.Sulphur is burned in air to form
sulphur dioxide S (s) + O 2 (g) SO 2 (g) 2.The sulphur dioxide is
oxidized to sulphur trioxide 2SO 2 (g) + O 2 (g) 2SO 3 (g)
Slide 48
3.The sulphur trioxide is dissolved in concentrated sulphuric
acid to form oleum which is diluted to form sulphuric acid. H 2 SO
4 (aq) + SO 3 (g) H 2 S 2 O 7 (l) H 2 S 2 O 7 (l) + H 2 O (l) 2H 2
SO 4 (aq)
Slide 49
Slide 50
Nitrogen
Slide 51
Nitrogen forms 78% of the air by volume. It is a colourless,
odourless gas which is insoluble in water and has the same density
as air.
Slide 52
Nitrogen is notoriously inert. However it will combine with
oxygen at high temperatures to form nitrous oxides. This occurs
during lightning discharges and in the engines of vehicles. It will
also combine with hydrogen under certain conditions of temperature
and pressure to form ammonia.
Slide 53
Uses & Manufacture As a refrigerant As an inert atmosphere
in packaging Manufacture of ammonia Nitrogen is obtained by
fractional distillation of air.
Slide 54
Slide 55
Slide 56
Ammonia Ammonia is a colourless gas with a pungent, choking
smell. It is less dense than air and is very soluble in water.
Chemical formula NH 3 Dissolved ammonia is called aqueous ammonia
NH 3 (aq) or ammonium hydroxide NH 4 OH
Slide 57
Chemical properties Dissolves in water to give a weakly alkali
solution. It is the only common alkali gas. Combines directly with
acids to form ammonium salts Acts as a reducing agent
Slide 58
Laboratory Preparation Ammonia can be prepared by heating an
ammonium salt with an alkali. 2NH 4 Cl (s) + Ca(OH) 2 (s) 2NH 3 (g)
+ CaCl 2 (aq) + 2H 2 O (l)
Slide 59
Slide 60
Industrial Preparation Ammonia is prepared by the Haber
Process. Purified Nitrogen and Hydrogen gases are passed over a
finely divided iron catalyst at 350 400 o C and a pressure of 250
to 300 atmospheres. N 2 (g) + 3H 2 (g) 2NH 3 (g)
Slide 61
Slide 62
Slide 63
Uses of Ammonia Water purification Cleaning agent Refrigerant
Manufacture of fertilizers Manufacture of nitric acid Manufacture
of nylon
Slide 64
GasColourOdourTest HydrogenNone Gives a pop with a lighted
splint. No effect on litmus OxygenNone Relights a glowing splint.
No effect on litmus Carbon dioxideNone Turns lime water cloudy then
colourless AmmoniaNonePungentDense white fumes formed when in
contact with hydrogen chloride. Turns moist red litmus blue.
Sulphur dioxideNoneChokingReduces potassium dichromate and
manganate VII Turns moist blue litmus red. Hydrogen chloride
NoneIrritatingDense white fumes formed when in contact with
ammonia. Turns moist blue litmus red.
ChlorineYellow-greenIrritatingMoist blue litmus turns red and then
bleached. Nitrogen dioxide BrownIrritatingMoist blue litmus turns
red. Water vapourNone Cobalt chloride paper turns from blue to
pink.