Science f1 (Chapter 5)

8/4/2019 Science f1 (Chapter 5)

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Chapter 5

The air around us

Udara disekeliling kita


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Composition of air

Komposisi udara

The air that surrounds the earth is known as

the atmosphere.

Udara yang meliputi bumi dikenali sebagai

atmosfera.


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Composition

Komposisi

Percentage

Peratus

Nitrogen 78 %Oxygen 21 %

Carbon dioxide 0.03 %

Inert gas 0.97 %


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Nitrogen


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Nitrogen

Largest component of air

Komposisi udara yang terbesar

Inactive gas

Gas yang tidak aktif


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Oxygen


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Oxygen

Necessary for respiration, combustion, rusting

and decay

Diperlukan untukpernafasan, pembakaran,

pengaratan dan pereputan


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Released during photosynthesis

Dibebaskan semasafotosintesis


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Dissolved in water, is taken in by the aquatic

animal and plantsLarut di dalam air, digunakan oleh haiwan dan

tumbuhan akuatik.


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Carbon dioxide


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Carbon dioxide

Released during respiration, burning and decay

Dibebaskan semasapernafasan, pembakaran

dan pereputan

Absorbed by green plants during photosynthesis

Diserap oleh tumbuhan hijau semasafotosintesis


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Properties of oxygen and carbon

dioxide

Ciri-ciri oksigen dan karbon dioksida


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Solubility in water

Properties

Sifat

Oxygen

Oksigen

Carbon dioxide

Karbon dioksida

Solubility in water

Keterlarutan dalam air

Slightly soluble

Sedikit larut

Slightly soluble

Sedikit larut

Experiment:

Invert a test tube full with

oxygen/ carbon dioxide into abeaker of water

Observation:

Level of water rises a little in

the test tube


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Properties

Sifat

Oxygen

Oksigen

Carbon dioxide

Karbon dioksida

Solubility in sodiumhydroxide

Keterlarutan dalam

natrium hidroksida

Not solubleTidak larut

Very solubleSangat larut

Solubility in sodium hydroxide


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Experiment:


oxygen into a beaker of

sodium hydroxide

Observation:

Sodium hydroxide solution

does not rise in the test tube

Experiment:


carbon dioxide into a beakerof sodium hydroxide

Observation:

Sodium hydroxide solution

rises to fill up the test tube


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Properties Oxygen Carbon dioxide

Test with a glowing

wooden splinter

Ujian dengan kayu uji

berbara

Splinter ignites

Kayu uji menyala

Splinter goes out

Kayu uji terpadam

Test with a burning

wooden splinter

Ujian dengan kayu uji

menyala

Splinter ignites

Kayu uji menyala

Splinter goes out

Kayu uji terpadam

Test with wooden splinter


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Test with moist litmus paper

Properties Oxygen (neutral) Carbon dioxide

(acid)

Test with moist litmus

paper

Ujian dengan kertaslitmus

No effect

Tiada perubahan

Change moist blue

litmus paper to red

Menukarkan kertaslitmus biru kepada

merah


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Test with lime water


Test with lime water

Ujian dengan air kapur

No change

Tiada perubahan

Turns cloudy

Bertukar keruh


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Test with bicarbonate indicator


Test with bicarbonate

indicator

Ujian dengan penunjuk

bikarbonat

No change

Tiada perubahan

Change the colour from

red to yellow

Bertukar dari warna

merah kepada kuning


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Summary

Both oxygen and carbon dioxide are colorless (no color)and odorless (no smell)

Oksigen dan karbon dioksida tidak mempunyai warna dantidak berbau

Oxygen supports combustionOksigen membolehkan pembakaran

The presence of oxygen can be shown by using glowingwooden splinter

Kehadiran oksigen boleh dilihat dengan menggunakan

kayu uji berbara Ignites a glowing wooden splinter

Menyalakan kayu uji berbara


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Carbon dioxide is acidic

Karbon dioksida adalah bersifat asid The moist blue litmus paper turns red

Kertas litmus biru lembap bertukar kepada merah

The presence of carbon dioxide can be shown byusing lime water

Kehadiran karbon dioksida boleh dilihat dengan

menggunakan air kapur The lime water turns cloudy

Air kapur bertukar keruh


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Oxygen need for respiration

Respiration is a process which involves the

inhalation (breath in) and exhalation (breath

out) of air

Pernafasan ialah proses yang melibatkan

menarik nafas dan menghembus nafas.


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When a person breathes in air (inhale), oxygen is

taken in to oxidize (burn away) food In the form

of sugar (glucose) within the cells. This process

produces energy, carbon dioxide and waterApabila seseorang menarik nafas, oksigen masuk

untuk mengoksidakan (membakar) makanan

dalam bentukgula (glukosa) didalam sel. Prosesini menghasilkan tenaga, karbon dioksida dan

air.


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Respiration process

Glucose + oxygen water + carbon dioxide + energy


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Composition of inhaled and exhaled air

Composition

of air

Inhaled air Exhaled air

Nitrogen 78 % 78 %

Inert gases 0.9 0.9

Oxygen 21 % 16 %

Carbon dioxide 0.03 % 4 %Heat 25 oC 37 oC

Water vapors Less More


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Oxygen is needed for combustion

Combustion is a chemical reaction that occursbetween substance (fuel) and oxygen. Thisprocess gives out heat and light.

Pembakaran adalah tindakbalas kimia yangberlaku antara bahan bakar dan oksigen. Prosesini menghasilkan haba dan cahaya.

For combustion to take place, there must be

oxygen, fuel and heat.Untuk suatu pembakaran berlaku, mesti terdapatoksigen, bahan bakar dan haba.


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Common fuel

Carbon

Ex; coal and wood

Hydrocarbon

Ex; candle, petrol and diesel


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Carbon + oxygen heat + light + carbon dioxide

Hydrocarbon + oxygen heat + light + carbon dioxide + water vapour


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Effects of air pollution

Kesan pencemaran

Air pollution occurs when there aresubstances in the air that are harmful tohuman health and environment

Pencemaran udara berlaku apabila terdapatbahan di udara yang merbahaya terhadapkesihatan manusia dan persekitaran

These foreign substances are called pollutantsBahan asing ini dipanggil sebagaibahancemar


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Pollutant and their effects

PollutantBahan cemar

EffectsKesan

Carbon dioxide Increases temperature

Meningkatkan suhu

Greenhouse effect

Kesan rumah hijauSmoke Breathing difficulties

Masalah pernafasan

Low visibility

Jarak penglihatan rendah

HazeJerebu

Chlorofluorocarbon (CFC) Thins ozone layer

Menipiskan lapisan ozon

Nitrogen oxide and sulphur

dioxide

Acid rain


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Major effects of pollution

1. Health issues Pollutants are harmful to the lungs and respiratory

system (ex; lung cancer)

Bahan cemar berbahaya kepada paru-paru dan

sistem pernafasan (contoh; kanser peparu)2. Greenhouse effect

Carbon dioxide is trapped in the air, heat from theearth cannot escape into outer space. Temperature

on earth rise, resulting global warmingKarbon dioksida terperangkap didalam udara, habadari bumi tidak keluar ke angkasa lepas. Suhu dibumi meningkat, menyebabkan pemanasan global


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Science f1 (Chapter 5)