5. atmosphere
• Layer of air = atmosphere
• Consist of many gases (eg:
nitrogen, oxygen, carbon
dioxide, inert gas)
• Also contain dust,
water vapour, microorganism
AIR
6. atmosphere
• Layer of air = atmosphere
• Consist of many gases (eg:
nitrogen, oxygen, carbon
dioxide, inert gas)
• Also contain dust,
water vapour, microorganism
AIR
• Helium
• Argon
• Neon
• Xenon
• krypton
7. 7.1 COMPOSITION OF AIR
Air is a mixture of nitrogen, oxygen, carbon dioxide and inert gas
THE COMPOSITION OF
AIR
AVERAGE PERCENTAGE
OF ITS COMPONENTS BY
VOLUME
Nitrogen 78 %
Oxygen 21 %
Carbon Dioxide 0.03 %
Inert gases and others 0.97 %
8. Nitrogen is
an inactive
gas
Oxygen makes up
1
5
(one-fifth) of the air.
Very important for
respiration
Carbon dioxide
important for
photosynthesis
Air also contains
water vapour,
microorganism
and dust
9. Nitrogen is
an inactive
gas
Oxygen makes up
1
5
(one-fifth) of the air.
Very important for
respiration
Carbon dioxide
important for
photosynthesis
Air also contains
water vapour,
microorganism
and dust
10. EXPERIMENT: TO DETERMINE THE PERCENTAGE OF OXYGEN IN THE AIR
5
4
3
2
1
Water level increase to the level marked 1.
It shows that composition of oxygen is 1/5 or 21% of the
air.
11. Nitrogen is
an inactive
gas
Oxygen makes up
1
5
(one-fifth) of the air.
Very important for
respiration
Carbon dioxide
important for
photosynthesis
Air also contains
water vapour,
microorganism
and dust
41. conditions needed for combustion
by removing one of the
conditions needed, we can
prevent
combustion
42. Prove that fuel is needed for
combustion
Glass rod and
stone will not
burn while
wood and
candle will
burn
+
43. Prove that air (oxygen) is needed
for combustion
If we put a glass
plate over the
chimney, the
flame finally goes
off because the air
is not available.
44. Prove that heat is needed for
combustion
in the presence
of water, the
ignition
temperature of
paper is not
reached
57. 7.3 AIR POLLUTION
Unwanted substances in the air that
are harmful to living things and
environment
Common air pollutants are dust,
carbon monoxide, lead,
chlorofluorocarbon (CFC), pesticides
58.
59. CAUSES AND EFFECTS OF AIR POLLUTION
1. Health problem –asthma, lung cancer, headache, death
60. 2. Building and infrastructures – Acid rain corrodes
concrete/limestone buildings, speeds up iron rusting
CAUSES AND EFFECTS OF AIR POLLUTION
61. CAUSES AND EFFECTS OF AIR POLLUTION
3. Plants and animals –Depletion/damage of food resources (water acid
smoke decrease sunlight reaching to earth)
62. CAUSES AND EFFECTS OF AIR POLLUTION
4. Climate–haze, greenhouse effect, thinning of ozone layer and acid rain
63. WAYS TO PREVENT AND CONTROL AIR POLLUTION
1. Law enforcement–fine smokers, fine person who conduct open
burning, prohibit factories (away from housing area)
64. WAYS TO PREVENT AND CONTROL AIR POLLUTION
2. Education – educate effect/way to prevent air pollution, organize
campaign, encourage usage of public transport
65. WAYS TO PREVENT AND CONTROL AIR POLLUTION
3. Sciece and technology – implement hybrid technology, choose
HCFC refrigerator, install filter in smoke chimneys
67. Nitrogen is
an inactive
gas
Oxygen makes up
1
5
(one-fifth) of the air.
Very important for
respiration
Carbon dioxide
important for
photosynthesis
Air also contains
water vapour,
microorganism
and dust
72. Inert gas
Helium in hot air
balloon
Argon gas in
light bulb
Neon gas in advertising
light
73. atmosphere
• Layer of air = atmosphere
• Consist of many gases (eg:
nitrogen, oxygen, carbon
dioxide, inert gas)
• Also contain dust,
water vapour, microorganism
AIR
74. oxygen
• Combustion of rocket engine
• Welding and steel cutting • Preparation
of various
compound
75. - green plants are the only living things that can be absorb
and reduce carbon dioxide
- When a lot of trees are cut down, carbon dioxide which
is released through respiration, combustion and
decomposition will increase the percentage of carbon
dioxide in the atmosphere
82. CAUSES AND EFFECTS OF AIR POLLUTION
4. Climate–haze, greenhouse effect, thinning of ozone layer and acid rain
83. CAUSES AND EFFECTS OF AIR POLLUTION
1. Health problem –breathing difficulties and cough
84. 5. (c) the visiability distance is limited / shorter
85. 6 (a) Caused by natural processes such as
• The decay of organisms (dead bats)
• Respiration of bats/other animals
86. 6 (a) Caused by natural processes such as
• The decay of organisms (dead bats)
• Respiration of bats/other animals
6 (b) • Flame of the torch will extinguish when the
oxygen level is too low
• The use of the torch can warn us not to
continue the exploration
87. 6 (c) No
• Because we don’t know the exact amount of
oxygen in the cave
• The torch will increase the level of carbon
dioxide in the cave
88. 6 (c) No
• Because we don’t know the exact amount of
oxygen in the cave
• The torch will increase the level of carbon
dioxide in the cave
6 (d) • use the oxygen sensor
• We can know the exact level of oxygen and
take precautions
89. 7 (a) • Villagers are concerned about their health
• Quarry project will cause air pollution
90. 7 (a) • Villagers are concerned about their health
• Quarry project will cause air pollution
7 (b) • Job opportunities
• Can earn money
91. 7 (a) • Villagers are concerned about their health
• Quarry project will cause air pollution
7 (b) • Job opportunities
• Can earn money
7 (c) • Yes
• The project can cause health problems to the
villagers
92. 8 (a) • Green plants need light energy for
photosynthesis
• If lack of light, photosynthesis will decrease
• Plants that do not get enough sunlight will die
• Thus, farmers should replace sunlight with
light energy from lamps (suitable intensity)
