Revision helper u7_bilingual_p16revised

Revision Helper 溫習錦囊 (Bilingual version) 雙語版本

Understanding Integrated Science for the 21st Century (3rd Edition) 最新綜合科學 — 邁進 21 世紀 (第三版)

© Aristo Educational Press Ltd 2012 © 雅集出版社有限公司 2012

1

20.1 Gases in the air 20.1 空氣中的氣體

What is air made of? 空氣中包含甚麼成分？

Q1

A1

Air is a mixture of gases. 空氣是由多種氣體混合而成。

nitrogen 氮

(78%)

oxygen 氧

(21%) carbon dioxide 二氧化碳 (0.03%)

noble gases貴氣體(~0.9%)

water vapour (variable) 水汽 (不定量)

other gases, e.g. exhaust (variable)

其他氣體，例如廢氣 (不定量)

1 Chapter

Revision notes Air and burning 20

Part

1 第部分 Revision notes 溫習筆記 Chapter

第章 20 Air and burning 空氣與燃燒




2

20.2 Testing for gases in the air 20.2 檢驗氣體

How do we test for gases in the air? 我們如何檢驗空氣中的氣體？

Q2

A2

Test for oxygen:

Oxygen can relight a glowing splint and cause

a burning splint to burn more brightly.

檢驗氧：

氧能使有餘燼的木條重燃，又能

使燃燒中的木條燒得更旺盛。

Test for carbon dioxide:

Carbon dioxide turns red hydrogencarbonate

indicator yellow and turns lime water from

colourless to milky.

檢驗二氧化碳：

二氧化碳能使碳酸氫鹽指示劑由

紅色轉為黃色，又能使石灰水由

透明變為乳濁。

Test for water:

Water turns dry cobalt chloride paper from blue

to pink.

檢驗水：

水能使乾燥的氯化鈷試紙由藍色

轉為粉紅色。

There is no simple test for nitrogen. 沒有簡單的方法來檢測氮。




3

What are the differences between

breathed air and unbreathed air?

呼出的空氣和未經呼吸的空氣有

甚麼差別？

Q3

A3

The following table shows the differences

between breathed air and unbreathed air.

下表顯示呼出的空氣和未經呼

吸的空氣之間的差別。

Breathed air

呼出的空氣

Unbreathed air

未經呼吸的空氣

Oxygen

氧

less

較少

more

較多

Carbon dioxide

二氧化碳

more

較多

less

較少

Nitrogen

氮

same

相同

same

相同

Water vapour

水汽

more

較多

less

較少

Temperature

溫度

higher

較高

lower

較低

20.3 Comparing breathed air and unbreathed air

20.3 比較呼出的空氣和

未經呼吸的空氣




4

20.4 Burning 20.4 燃燒

For a fire to occur, a fuel, oxygen and a high

temperature are needed.

燃料、氧和足夠高的溫度是燃燒

的必要條件。

These three conditions make up the fire triangle. 這三個條件稱為火三角。

What conditions are needed to start a fire? 生火需要哪些條件？

Q5

A5

oxygen 氧

high temperature 高溫

fuel

燃料

What happens when a fuel burns? 燃燒的過程中，會發生甚麼變化？

Q4

A4

When a fuel is burned, the chemical energy

stored in the fuel is changed to heat energy

and light energy. Water and carbon dioxide

are produced.

燃料燃燒時，當中儲藏的化學能會轉變成

熱能和光能。此外，燃燒的過程中還會產

生水和二氧化碳。

The process of burning can be summarised

by the following word equation:

燃燒的過程可總結為以下的文字方程式：

fuel + oxygen water + + +

high temperature carbon dioxide

heat energy

light energy

燃料 + 氧水 + + +

足夠高的溫度二氧化碳熱能光能




5

How can we put out a fire? 我們如何滅火？

Q6

A6

high

temperature 高溫

fuel 燃料

Since fuel, oxygen and high temperature are the

three conditions needed for burning, we can put

out a fire by removing any one of these

conditions.

由於燃料、氧和足夠高的溫度是燃

燒的必要條件，故此我們只要移除

任何一項條件，火就會熄滅。

The following table shows some methods of

putting out a fire.

下表顯示一些滅火的方法。

Method

方法

How it works

原理

Using water

使用水

Water can lower the temperature and the fire

triangle cannot be formed.

水能夠降低溫度，由於溫度不夠高，

火三角便不完整。

Using fire

extinguishers

(carbon

dioxide type)

使用滅火筒

(二氧化碳型)

Carbon dioxide type extinguishers release

carbon dioxide to displace the air (containing

oxygen) around the burning objects. This

cuts off the oxygen supply to the fire.

二氧化碳滅火筒釋出二氧化碳，能排除燃

燒中物體周圍含氧的空氣。這能切斷氧的

供應，使火三角不完整。

oxygen 氧

fuel 燃料

fuel 燃料

high

temperature 高溫




6

How can we prevent fire accidents at home? 我們能如何防止家居火警？

Q7

A7

The following are some guidelines to prevent fire

accidents at home.

以下是一些家居防火的安全守則。

Do not leave your cooking unattended.

煮食時，爐火必須有人看守。

Keep flammable materials away from stoves or heaters.

易燃物品必須置於遠離火爐

的地方。

Do not overload the sockets.

避免插座負荷過重。

Make sure all gas and electrical appliances are switched off before you leave the flat or go to bed.

外出或就寢前應檢查所有氣體爐具

和電器，確保已經關妥。

Keep matches and lighters out of reach of children. 應將火柴及打火機置於兒童

不能觸及的地方。

Never smoke in bed.

切勿在床上吸煙。




7

If a fire breaks out in your flat, you should 若居住的單位失火，你們應

keep calm. Tell anyone in your flat to leave.

close the door when you leave your flat.

do not try to take all valuables when you leave.

set off the fire alarm on your floor and shout

‘fire’.

leave the building using the nearest stairway.

Do not use the lift.

keep low to the floor where the air is fresher if

there is smoke.

call the Fire Services Department by dialing

‘999’ when you are safe.

保持鎮定，通知單位內所有人離開。

離開單位時把門關上。

切勿費時取回貴重物品。

啟動住所樓層的火警警報，並高呼「火

警」。

利用最接近的樓梯離開大廈，切勿使用

升降機。

假如遇到濃煙，便應盡量扒下，因為接

近地面的空氣較清新。

在安全情況下致電「999」通知消防處。

What should we do if a fire breaks

out in our flat?

若居住的單位失火，我們應採取

甚麼行動？

Q8

A8




8

We can obtain energy from the food we eat. 我們從每天進食的食物中獲取能量。

The chemical energy stored in food is changed

to useful forms of energy through a process

called respiration.

食物中儲存的化學能通過呼吸作用

的過程轉換成身體所需的能量形式。

The process of respiration can be summarised

by the word equation below:

呼吸作用的過程可以總結為以下文

字方程式：

food + oxygen water + carbon dioxide + energy

食物 + 氧水 + 二氧化碳 + 能量

Energy released from

respiration can be change to …

呼吸作用所釋出的能量可轉換成

How can we obtain energy? 我們如何獲取能量？

A9

kinetic energy when we walk or run

走路或跑步時所需的動能

sound energy when we talk or sing 說話或歌唱時的聲能

heat energy for keeping us warm 維持體溫的熱能

Q9

21.1 How do we obtain energy? 21.1 我們如何獲取能量？

21 How living things obtain energy 生物如何獲取能量

Chapter 第章




9

Why does breathed air contain less

oxygen but more carbon dioxide and

water vapour than unbreathed air?

為甚麼呼出的空氣比未經呼吸

的空氣含較少氧，而含較多二

氧化碳及水汽？

Q10

A10 This is because we use oxygen in the

air for respiration when we breathe in.

The carbon dioxide and water produced

in respiration is removed from the body

when we breathe out.

這是由於我們從吸入的空氣中

用去部分氧來進行呼吸作用，

而呼吸作用所產生的二氧化碳

和水又隨着呼氣排出體外。

Do different types of food contain the

same amount of energy?

不同食物所含的能量是否相同？

Q11

A11

No, different types of food contain different

amounts of energy.

不是，不同食物所含能量的多少會有所

不同。

The amount of energy provided by a certain

quantity of food is called its energy value.

食物的能量值是指某指定分量的該種

食物所能提供的能量。

Foods rich in fats or sugars have a high

energy value. They are called high-energy

foods.

脂肪和糖含量高的食物的能量值都偏

高，我們稱這類食物為高能量食物。

The following are some examples of

high-energy foods:

以下是一些高能量食物的例子：

Instant noodles 即食麵

(1900 kJ per 100 g)

(每 100 g 1900 kJ )

French fries 炸薯條

(1300 kJ per 100 g)

(每 100 g 1300 kJ)

Chocolate 朱古力

(2460 kJ per 100 g)

(每 100 g 2460 kJ)




10

21.2 How do green plants obtain energy?

21.2 綠色植物如何獲取

能量？

How do green plants obtain energy? 綠色植物如何獲取能量？

Q12

A12

Green plants make their own food by a process

called photosynthesis.

綠色植物會進行光合作用自行製

造食物。

During this process, green plants change light

energy to chemical energy stored in the food

they produce.

過程中，光能會被轉換成化學能，

儲存在食物中。

The process of photosynthesis can be

summarised by the following word equation:

光合作用的過程可用以下的文字

方程式表示：

carbon dioxide + water food (starch) + oxygen

light energy

absorbed by chlorophyll

二氧化碳 + 水食物(澱粉) + 氧

葉綠素吸收

的光能

Sun 太陽

chlorophyll 葉綠素

light energy

光能

carbon dioxide from the air 空氣中的二氧化碳

starch 澱粉

oxygen released into the air

氧釋出空氣中

water from the soil 從泥土吸取的水分




11

What is the main product of photosynthesis?

How do you test the main product?

光合作用的主要生成物是

甚麼？我們如何檢測這主

要生成物？

Q13

A13

The main product of photosynthesis is starch. 光合作用的主要生成物是澱粉。

We can use iodine solution to test for starch.

It changes from brown to blue-black when

starch is present.

我們可用碘液檢測澱粉。如有澱粉，碘液

會由棕色變為藍黑色。

The presence of starch in green leaves shows

that the plant has carried out photosynthesis.

若葉片中含有澱粉，則表示該植物曾經進

行光合作用。

The following show the steps for testing starch

in green leaves:

以下顯示檢驗綠葉中的澱粉的實驗步驟：

Step

實驗步驟

Purpose of the step

目的

(1)

The leaf is boiled in water for

about two minutes.

把葉片放在沸水中加熱約兩分鐘。

To kill the leaf cells and destroy the cell membrane

so that iodine solution to be added later can enter

the cells.

殺死葉片細胞，並破壞其細胞，使稍後加入的碘

液可進入細胞內。

(2)

The leaf is put in hot alcohol.

把葉片浸於已加熱的酒精中。

To remove the chlorophyll of the leaf to make the

leaf lighter in colour so that the colour change of

the iodine test can be shown clearly.

去除葉片中的葉綠素，使綠葉褪色，以便碘液試

驗的顏色變化能清楚顯示出來。

(3)

The leaf is washed in hot water after soaking in hot alcohol.

把浸過酒精的葉片再浸入熱水中。

To remove the alcohol and to soften the leaf.

去除葉片上的酒精，並使葉片變軟。

(4)

A few drops of iodine solution is added to the leaf. 在葉片上加上數滴碘液。

To test for the presence of starch in the leaf.

檢驗葉片是否含有澱粉。




12

What are the necessary conditions for

photosynthesis?

植物要進行光合作用，需要具

備甚麼條件？

Q14

A14

chlorophyll in the green parts of the plant

植物綠色部分

所含有的葉綠素

Photosynthesis

光合作用

requires

需要

light from the Sun

源自太陽的光

carbon dioxide from the air

空氣中的

二氧化碳

water from the soil

泥土中的

水分




13

What are the roles of plants and

animals in a food chain?

動物和植物在食物鏈中擔任甚麼

角色？

Q15

A15

Green plants can produce their own food

and provide energy for animals. They are

called producers.

綠色植物能自行製造食物，並給動物提供

能量，因此綠色植物是大自然中的生產者。

Animals obtain their energy by feeding on

plants or other animals. They are called

consumers.

動物靠攝食植物或其他動物獲取能量，故

稱為消費者。

The following are some examples of food

chains:

以下是一些食物鏈的例子：

grass (producer) rabbit (consumer) tiger (consumer)

草 (生產者) 兔 (消費者) 老虎 (消費者)

water plant (producer) fish (consumer) shark (consumer)

水草 (生產者) 魚 (消費者) 鯊魚 (消費者)

eaten by eaten by

被兔吃掉被老虎吃掉

eaten by eaten by

被魚吃掉被鯊魚吃掉




14

22.1 Gaseous exchange in animals

22.1 動物的氣體交換

22 Gaseous exchange between living things and the environment 生物與環境之間的氣體交換

Q16

6

A16

What is gaseous exchange in animals? 甚麼是動物的氣體交換？

Chapter 第章

Gaseous exchange refers to the transfer of

oxygen and carbon dioxide between our body

and the environment during breathing.

在我們的身體與環境之間，氧和二

氧化碳不斷轉移，這個轉移過程稱

為氣體交換。

When we breathe in, we take in oxygen from

the air for respiration.

當我們吸氣時，我們會從空氣中取

得氧來進行呼吸作用。

When we breathe out, we give out carbon

dioxide produced to the air.

當我們呼氣時，我們會把呼吸作用

所產生的二氧化碳釋出到環境中。




15

22.2 Gaseous exchange in humans

22.2 人類的氣體交換

Q17

A17

Which parts of our body are responsible

for gaseous exchange?

我們身體的哪些部分負責進

行氣體交換？

We have a respiratory system for gaseous

exchange.

我們的身體內有呼吸系統，以進行氣體

交換。

The following diagram shows the different

parts of our respiratory system.

下圖顯示人類呼吸系統的各主要部分：

nasal cavity 鼻腔

trachea 氣管

bronchus 支氣管

bronchiole 小支氣管

air sac 氣囊

intercostal muscle

肋間肌

rib

肋骨

lung

肺

diaphragm

橫膈膜




16

Q18

8

A18

7

The exchange of oxygen and carbon dioxide

takes place in the air sacs in the lungs.

人類的氣體交換是在肺內的氣囊中

進行的。

The following diagram shows gaseous

exchange in an air sac.

下圖顯示氣囊內的氣體交換：

In which part of respiratory system does

gaseous exchange take place?

人類的氣體交換是在呼吸

系統的哪部分進行的？

Oxygen in the air passes through the thin walls of the air sac into the blood in the blood capillaries.

空氣中的氧穿過氣囊和微血管

的薄壁，進入血液。

Carbon dioxide passes through the walls of the blood capillaries and the air sacs, and goes into the air sacs.

血液中的二氧化碳穿過微血管和

氣囊的薄壁，繼而進入氣囊。

blood with less oxygen

氧含量較

少的血液

capillary 微血管

blood rich in oxygen

氧含量較多的血液

air sac

氣囊

oxygen氧

carbon dioxide 二氧化碳




17

A19

7

How does our respiratory system draw air

into and out of our lungs repeatedly for

gaseous exchange?

我們是如何不斷地吸入和呼出

空氣，以進行氣體交換？

There is a breathing mechanism in our respiratory

system.

呼吸系統的呼吸機制使空氣進出身

體，讓氣體交換得以進行。

Breathing is the physical process controlled by the

action of the intercostals muscles and the

diaphragm.

呼吸是把空氣吸入和呼出肺部的動

作，這是由肋間肌和橫膈膜控制的。

The breathing mechanism is summarised below: 下圖總結了人類的呼吸機制：

Breathing in 吸氣 Breathing out 呼氣

intercostal muscles contract

肋間肌收縮

daphragm contracts

橫膈膜收縮

ribs move upwards and outwards

肋骨向上和向外移動

diaphragm becomes flattened

橫膈膜呈扁平狀

volume of chest cavity increases

胸腔的體積增加

gas pressure inside the chest cavity decreases (lower than the atmospheric pressure)

胸腔內的氣壓下降 (低於大氣壓強)

air is drawn into the lungs

空氣被吸進肺內

intercostal muscles relax

肋間肌鬆弛

diaphragm relaxes

橫膈膜鬆弛

ribs move downwards and inwards

肋骨向下和向內移動

diaphragm becomes dome-shaped

橫膈膜呈拱形

volume of chest cavity decreases

胸腔的體積減少

gas pressure inside the chest cavity increases (higher than the atmospheric pressure)

胸腔內的氣壓上升 (高於大氣壓強)

air is forced out of the lungs

空氣被擠出肺外

rib

肋骨

Intercostal muscle

肋間肌

diaphragm 橫膈膜

back bone 脊柱

lung

肺

air 空氣

rib

肋骨

Intercostal muscle

肋間肌

diaphragm 橫膈膜

back bone 脊柱

lung

肺

air 空氣

Q19

8




18

In the daytime在日間

Green plants carry out both respiration and

photosynthesis.

綠色植物同時進行呼吸作用和光合作用。

Under bright light, the rate of photosynthesis is

higher than that of respiration. The amount of

carbon dioxide absorbed for photosynthesis is

greater than that produced in respiration. As a

result, there is a net uptake of carbon dioxide

from the air by green plants.

在強光下光合作用的速率高於呼吸作用的速

率，因此光合作用所吸入的二氧化碳，較呼

吸作用所釋出的二氧化碳為多，結果綠色植

物在日間從空氣中淨吸入二氧化碳。

The amount of oxygen produced in

photosynthesis is greater than that absorbed

for respiration. As a result, there is a net

release of oxygen from green plants.

光合作用所釋出的氧，較呼吸作用所吸入的

氧為多，結果綠色植物在日間淨釋出氧到空

氣中。

At night 在夜間

Photosynthesis stops and only respiration

occurs. Therefore, green plants take in oxygen

and release carbon dioxide.

光合作用完全停止，只有呼吸作用繼續進

行，於是綠色植物在夜間只吸入氧而釋出二

氧化碳。

Q20

A20

7

How is the gaseous exchange in green

plants in daytime and at night respectively?

綠色植物在日間和夜間進行氣體

交換的情況是怎樣的?

Net exchange of gases

淨氣體交換

Respiration

呼吸作用

Photosynthesis

光合作用

carbon dioxide

二氧化碳

oxygen

氧

oxygen

氧

carbon dioxide

二氧化碳

oxygen

氧

Net exchange of gases

淨氣體交換

Respiration

呼吸作用

carbon dioxide

二氧化碳

oxygen

氧

oxygen

氧

carbon dioxide

二氧化碳

carbon dioxide

二氧化碳

22.3 Gaseous exchange in plants

22.3 植物的氣體交換




19

22.4 Balance of carbon dioxide and oxygen in nature

22.4 自然界中二氧化碳

和氧的平衡

The balance of carbon dioxide and oxygen in

nature is maintained by photosynthesis of

green plants and respiration of living things.

綠色植物進行光合作用，而生物進行呼吸作

用，這樣有助自然界中的二氧化碳和氧含量

保持平衡。

Q21

8

A21

releases

釋出 taken up by

被吸入為

oxygen

氧

carbon dioxide

二氧化碳

photosynthesis of green plants

綠色植物進行

光合作用

releases

釋出 taken up by

被吸入為

respiration of animals and plants

動物和植物

進行呼吸作用

How is the balance of carbon dioxide

and oxygen maintained in nature?

二氧化碳和氧如何在自然界中

保持平衝？




20

Q22

8

A22

The following human activities increase the

amount of carbon dioxide in the atmosphere.

以下人類活動會增加大氣中的二氧化碳含量：

Generating electricity

燃燒化石燃料來產生電力

Transport

駕駛汽車

Industrial activities

工業活動

Cutting down trees

砍伐樹木

What are human activities that cause

increasing amount of carbon dioxide

in the atmosphere?

哪些人類活動會導致大氣中的

二氧化碳含量增加？




21

Carbon dioxide is one of the greenhouse gases. 二氧化碳是一種溫室氣體。

The increasing amount of carbon dioxide in the

atmosphere enhances the greenhouse effect.

大氣中的二氧化碳含量增加會

加劇溫室效應。

Since more heat from the Sun is trapped by the

greenhouse gases, the average temperature of

the Earth gradually increases. This is known as

global warming.

由於被大氣中的溫室氣體所困

住的熱能愈來愈多，故此地球的

平均溫度逐漸上升，這現象稱為

全球增溫。

The following are some possible harmful effects

of global warming:

以下是全球增溫的負面影響：

Rising temperatures increase melting of ice. Organisms in the polar regions will lose their habitats and suffer from shortages of food. 溫度上升令冰層加速化，生

活在極地的生物會因此喪

失生境或面臨食物短缺的

危機。

Increased melting of ice may also lead to rise in sea levels. Costal areas and low-lying islands (e.g. Maldives) will face a higher risk of flooding. 冰層加速熔化導致海平

面上升，沿岸低窪地區可

能會被淹沒。

Climate changes may result. Extreme weather conditions such as droughts will become more frequent.

氣候轉變導致旱災等天災

頻仍。

Q23

8

A23

What are the effects of increasing amount

of carbon dioxide in the atmosphere on us?

大氧中的二氧化碳含量

增加會帶來甚麼影響？

Sun

太陽

Some heat energy is reflected into space.

部分熱能被反射回太空

Some heat energy is trapped by greenhouse

gases in the atmosphere. 部分熱能被溫室氣體吸收

Most heat energy from the Sun is absorbed by the Earth’s surface.

大部分來自太陽的熱能由地面吸收

Earth 地球

atmosphere 大氣層




22

22.5 Effects of air pollution and smoking on our health

22.5 空氣污染和吸煙

對健康的影響

Q24

8

A24

Sulphur dioxide, nitrogen oxides, carbon

monoxide and suspended particulates are

common air pollutants in Hong Kong.

二氧化硫、氮氧化物、一氧化碳

及懸浮粒子是本港常見的空氣污

染物。

The following table shows the main sources of

some common air pollutants and their effects

on our health:

下表列出一些常見空氣污染物的

主要來源及其對健康的影響：

Air pollutant

空氣污染物

Main sources

主要來源

Effects on our health

對健康的影響

sulphur dioxide

二氧化硫

power stations

發電廠

causes irritation to the respiratory

system and the eyes

刺激呼吸系統和眼睛

nitrogen oxides

氮氧化物

vehicles

汽車

cause irritation to the respiratory

system and the eyes

刺激呼吸系統和眼睛

carbon monoxide

一氧化碳

vehicles

汽車

reduces the amount of oxygen in

blood

減少血液中的氧含量

cause dizziness, headaches, fainting

or even death

引致暈眩、頭痛、昏厥或甚至死亡

suspended particulates

懸浮粒子

vehicles and

factories

汽車和工廠

cause respiratory problems

(e.g. coughing and wheezing)

引致呼吸系統不適

(例如：咳嗽和氣喘)

cause respiratory diseases

(e.g. bronchitis and asthma)

引致呼吸系統疾病

(例如：支氣管炎和哮喘)

damage lung tissues

破壞肺組織

What are the common air pollutants in

Hong Kong? Where do they mainly come

from? How do they affect our health?

哪些是本港常見的空氣污染

物？它們主要來自哪裏？它

們如何影響我們的健康？




23

Q25

8

A25

The following shows what we can do to reduce

air pollution:

以下列出我們能如何減少空氣污染：

On the road在路上 At home 在家中

Use mass public transport.

Use energy-saving appliances.

使用公共交通工具

使用節能電器

Maintain car engines properly.

注意汽車的保養維修

Turn off appliances when they are not in use.

關掉沒有人使用的電器

Turn off car engines while waiting.

停車等候時應關掉引擎

When using air conditioners, do not set the temperature too low.

把冷氣調校到合適的溫度，以免因溫度

過低而浪費電力

What can we do to reduce air pollution? 我們可以如何減少空氣污染？




24

Q26

8

A26

Some harmful substances in cigarette smoke

are tar, nicotine and carbon monoxide.

香煙煙霧中含有焦油、尼古丁和

一氧化碳。

The effects of these harmful substances in

cigarette smoke are shown below:

以下顯示香煙煙霧中一些有害物

質對健康的影響。

What are the harmful substances in cigarette

smoke? What are the effects of these harmful

substances on our health?

香煙煙霧中含有哪些有害

物質？這些有害物質對我

們的健康有甚麼影響？

Nicotine 尼古丁

Causes addiction

引致上癮

Increases heartbeat rate and blood pressure

令心跳加速和血壓上升

Causes heart diseases in the long term

長遠會引致心臟病

Carbon monoxide一氧化碳

Reduce the oxygen content in blood

減少血液中的氧含量

Causes heart diseases in the long term

長遠會引致心臟病

Tar 焦油

Causes lung cancer

引致肺癌

Causes coughs and other respiratory diseases, e.g. bronchitis

引致咳嗽和呼吸系統疾病，

例如支氣管炎




25

A. True or false questions 是非題

Write ‘T’ for a true statement or ‘F’ for a false statement in each box provided.

細閱以下句子，正確的在方格內填上「T」，不正確的則填上「F」。

1. Carbon dioxide turns hydrogencarbonate indicator from yellow to red. □

2. Breathed air contains more water vapour than unbreathed air. □

3. Water is produced when a fuel is burned. □

4. Foods rich in fat or sugar have a high energy value. □

5. Iodine solution can be used to test for the presence of starch. □

6. At night, green plants carry out both respiration and photosynthesis. □

7. Breathing is controlled by the action of the intercostal muscles only. □

8. Carbon monoxide is one of the harmful substances in cigarette smoke. □

B. Multiple-choice questions 多項選擇題

Choose the correct answer for each of the following questions.

選出正確的答案，然後在空格內填上代表該答案的英文字母。

1. Which of the following gases is the major component of air?

A. Oxygen

B. Nitrogen

C. Carbon dioxide

D. Noble gases □

2. Which of the following gases can turn limewater from colourless to milky?

A. Oxygen

B. Nitrogen

C. Carbon dioxide

D. Water vapour □

3. Fire blanket is one of fire safety equipment in the school laboratory. Which of the following

about fire blanket are correct?

(I) It is put over the fire.

(II) It puts out a fire by cutting off the supply of oxygen.

(III) It helps cool down the fuel.

A. (I) and (II) only

B. (I) and (III) only

C. (II) and (III) only

D. (I), (II) and (III) □

Part

2 第部分 Revision exercise 單元練習




26

4. Which of the following is/are produced during respiration of living things?

(I) Water

(II) Oxygen

(III) Carbon dioxide

A. (I) only

B. (II) only

C. (I) and (III) only

D. (II) and (III) only □

5. Which of the following is NOT necessary for photosynthesis to take place?

A. Light

B. Carbon dioxide

C. Water

D. Oxygen □

6. When carrying out an iodine test, the leaf is first boiled in water for about two minutes. What

is/are the purposes of this step?

(I) It can kill the leaf cells.

(II) It can soften the leaf.

(III) It can remove the chlorophyll of the leaf.

A. (I) only

B. (III) only

C. (I) and (II) only


7. Which of the following is NOT a consumer?

A. Grass

B. Rabbit

C. Fox

D. Lion □

8. Which of the following is NOT a part of the human respiratory system?

A. Nasal cavity

B. Rib

C. Bronchus

D. Liver □

9. Which of the following will NOT occur when you are breathing out?

A. The intercostal muscles relax.

B. The diaphragm becomes dome-shaped.




27

C. The ribs move downwards and inwards.

D. The chest increases in size. □

10. Which of the following air pollutants mainly come(s) from power stations?

(I) Sulphur dioxide

(II) Nitrogen oxides

(III) Suspended particulates

A. (I) only

B. (II) only

C. (I) and (III) only


C. Short questions 短問題

1. The photos below show some living things.

hawk snail bird water plant

(a) Construct a food chain with the above living things.

____________________________________________________________________.

(b) Which of the above living things is/are producer(s)?

____________________________________________________________________.

(c) Which of the above living things is/are consumer(s)?

____________________________________________________________________.

2. The following diagrams show the steps of an experiment to test for the presence of starch in

a leaf.

Step (a) Step (b) Step (c) Step (d)

hot water

iodine solution alcohol

water




28

(a) Arrange the steps in the correct order.

____________________________________________________________________.

(b) What is the purpose of step (d)?

____________________________________________________________________.

(c) What is the colour change of the iodine solution if starch is present in the leaf?

____________________________________________________________________.

Answers 答案

A. True or false questions 是非題

1. F

2. T

3. T

4. T

5. T

6. F

7. F

8. T

B. Multiple-choice questions 多項選擇題

1. B

2. C

3. A

4. C

5. D

6. C

7. A

8. D

9. D

10. A

C. Short questions 短問題

1. (a) water plant snail bird hawk

(b) water plant

(c) snail, bird and hawk

2. (a) b, d, a, c

(b) Its purpose is to remove chlorophyll in the leaf.

(c) Iodine solution changes from brown to blue-black.

Part