unit 10.bilingual

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

28.1 Common acids 28.1 常見的酸

What substances commonly found in daily

life contain acids? Suggest some examples.

日常生活中有甚麼物品含

有酸？又有甚麼例子呢？

Q1

A1

Many drinks and foods that contain acids

taste sour.

日常生活中許多飲品和食品都含有

酸，它們都帶有酸味。

The figure below shows some examples of

drinks, foods and seasonings that contain

acids.

下圖展示一些含有酸的飲品、食品和調

味料的例子。

Besides, some personal care products,

household cleaners and some drugs also

contain acids.

另外，許多個人護理產品、家居清潔用

品和某些藥物也含有酸。

Soft drinks – contain carbonic acid

汽水含有碳酸

Vinegar – contains ethanoic acid

醋含有乙酸

Tea – contains tannic acid

茶含有單寧酸

Yoghurt – contains lactic acid

乳酪含有乳酸

Citrus fruits like grapefruit, lemon and orange – contain citric acid and ascorbic acid (vitamin C)

西柚、橙和檸檬等柑橘類水果含

有檸檬酸和抗壞血酸 (丙種維生素)

Grapes – contain tartaric acid

提子含有酒石酸

Apples – contain malic acid

蘋果含有蘋果酸

Spinach – contains oxalic acid

菠菜含有草酸

body shampoo 沐浴露

Aspirin

阿士匹靈

hair conditioner

護髮素

toilet cleaner

廁所清潔劑

1 Chapter

Revision notes Air and burning 20

Part

1 第部分 Revision notes 溫習筆記 Chapter

第章 28 Common acids and alkalis 常見的酸和鹼

body lotion 潤膚露




2

Q3

A3

Alkalis have a bitter taste and a slippery feel.

They are commonly found in household

cleaners such as glass cleaners, oven

cleaners and drain cleaners.

Many daily products such as soaps, alkaline

batteries, baking soda and toothpaste also

contain alkalis.

鹼帶有苦澀味，觸摸時會給人一種滑溜

的感覺。許多家居清潔用品，如玻璃清

潔劑、爐具清潔劑和通渠劑都含有鹼。

另外，一些日常用品如肥皂、鹼性電池、

梳打粉和牙膏等也含有鹼。

What substances commonly found in daily life

contain alkalis? Suggest some examples.

日常生活中有甚麼物品含

有鹼？又有甚麼例子呢？

Household cleaners and daily products that contain alkalis

一些含有鹼的家居清潔用品和日常用品

28.2 Common alkalis 28.2 常見的鹼

What acids are commonly found in the

laboratory? What should we pay attention to

when handling these acids?

實驗室中最常用的酸有哪

幾種？當我們使用這些酸

時，應採取甚麼安全措施？

Q2

A2

The most common acids used in the laboratory are

hydrochloric acid, sulphuric acid and nitric acid .

實驗室中最常用的酸包括氫氯酸、

硫酸和硝酸。

All these acids are corrosive. There are hazard

warning labels on the reagent bottles containing

them.

這些酸均具有腐蝕性，因此盛載這

些酸的試劑瓶都貼上危險警告標

籤。

When using acids for experiments, we should never

taste them. We must wear safety goggles and avoid

any direct contact with acids when we handle them.

我們不可以把做實驗時使用的酸放

進口中。在處理酸時，我們必須佩

戴安全眼鏡，並避免與酸直接接觸。

Acids commonly used in a school laboratory學校實驗室中常用的酸




3

What alkalis are commonly found in the

laboratory? What should we pay attention to

when handling these alkalis?

驗室中最常用的鹼有哪幾種？

當我們使用這些鹼時，應採取

甚麼安全措施？

Q4

A4

Alkalis commonly used in a school laboratory

學校實驗室中常用的鹼

The most common alkalis in the laboratory

include sodium hydroxide, calcium hydroxide

(lime water) and ammonia solution.

Sodium hydroxide and ammonia solution are

corrosive. We must wear safety goggles and

avoid any direct contact with these alkalis when

handling them.

The vapour from ammonia solution is irritating.

We should ensure good ventilation when

handling ammonia solution.

實驗室中最常用的鹼包括氫氧化鈉、

氫氧化鈣 (即石灰水) 和氨溶液。

氫氧化鈉和氨溶液都具有腐蝕性，我

們處理這些鹼時必須佩戴安全眼鏡，

並避免與它們直接接觸。

氨溶液會釋出具刺激性的氨蒸氣，使

用時應避免吸入，並保持空氣流通。




4

28.3 Indicators for testing acids and alkalis

28.3 測試酸和鹼的指示劑

Some plants contain pigments which change

colour when mixed with acids or alkalis. These

plant pigments can be used as natural

indicators to test for acids or alkalis.

In the 17th century, an Irish scientist, Robert Boyle

succeeded in preparing indicators from different

types of plants.

Red cabbage leaves, Hibiscus petals,

strawberries, blueberries and red roses can be

used as natural indicators. These plants contain

pigments which change colour when mixed with

acids or alkalis.

有些植物所含的色素，在酸性和鹼性

環境下會呈現不同的顏色，因此它們

可用作天然指示劑，以分辨酸和鹼。

在十七世紀，愛爾蘭科學家波義耳便

成功利用植物汁液製備天然指示劑。

紅色捲心菜、大紅花花瓣、草莓、藍

莓和紅玫瑰也可用作天然指示劑，這

些植物的汁液在酸性和鹼性環境下會

呈現不同的顏色。

What is natural indicator? Suggest some

examples of natural indicators.

甚麼是天然指示劑？又有甚

麼例子呢？

Q5

A5

Strawberry Blueberry Red rose 草莓藍莓紅玫瑰




5

What indicators are commonly used in the

laboratory to test for acids and alkalis?

實驗室中常用的指示劑有

哪些？

Q6

A6

Litmus and universal indicator are indicators

commonly used in the laboratory.

石蕊和通用指示劑是實驗室中常用

的指示劑。

1. Litmus 1. 石蕊

Litmus is a mixture of pigments extracted from

lichen.

Blue litmus is used to test for acidic solutions. It

changes to red in acidic solutions.

Red litmus is used to test for alkaline solutions.

It changes to blue in alkaline solutions.

Litmus is available in both solution form (litmus

solution) and paper form (litmus paper).

石蕊是從地衣中提取出來的色素混合

物。

藍色石蕊可用來測試酸性溶液。酸性

溶液可以使藍色石蕊變為紅色。

紅色石蕊可用來測試鹼性溶液。鹼性

溶液可以使紅色石蕊變為藍色。

石蕊可以製成溶液 (石蕊溶液)，亦可

以製成試紙 (石蕊試紙)。

red litmus paper

紅色石蕊試紙

blue litmus paper

藍色石蕊試紙




6

A6

2. Universal indicator 2. 通用指示劑

Universal indicator is a mixture of several

indicators.

It shows a wide range of colours depending on

the acidity or alkalinity of a solution.

It is used to indicate the degree of acidity and

alkalinity of a solution.

It is available in both solution form (universal

indicator solution) and paper form (pH paper)

通用指示劑是由多種指示劑混合而

成。

它會在不同酸度或鹼度 (即酸鹼

度) 的溶液中呈現不同的顏色。

它可用來測試物質的酸度和鹼度。

它可以製成溶液 (通用指示劑溶

液)，亦可以製成試紙 (pH 試紙)。

There is a pH colour chart on the bottle storing

universal indicator solution or the box storing pH

paper. It shows a series of colours. Each colour

on the chart corresponds to a pH value.

The pH value is a number showing how acidic or

alkaline a solution is. In general, the pH value

ranges from 0 to 14. This range of pH values is

known as the pH scale.

每一瓶通用指示劑溶液或每一盒

pH 試紙都附有 pH 顏色圖表，顯示

一系列的顏色，圖表的每一種顏色

對應於一個 pH 值。

pH 值是一個數字，用來顯示溶液的

酸鹼度，pH 值的範圍一般是由 0

至 14，這個範圍稱為 pH 標度。

pH paper

pH 試紙




7

What are the pH values of acidic, neutral

and alkaline solutions? Suggest some

examples for each kind of solutions.

酸性溶液、中性溶液和鹼性溶

液的pH值分別是多少？每種

溶液又有甚麼例子呢？

Q7

A7

An acidic solution has a pH value less than 7. The

lower the pH value, the more acidic the solution is.

An alkaline solution has a pH value greater than 7.

The higher the pH value, the more alkaline the

solution is.

A neutral solution has a pH value of exactly 7.

The figure below shows the pH scale and the pH

values of some common substances.

酸性溶液的 pH 值低於 7，pH 值

愈低表示酸度愈高。

鹼性溶液的 pH 值高於 7，pH 值

愈高表示鹼度愈高。

既不屬酸性又不屬鹼性的溶液屬

中性，它們的 pH 值是 7。

下圖展示 pH 標度及一些常見物

質的 pH 值。

pH value

pH 值

hydrochloric acid 氫氯酸

orange juice 橙汁

distilled water glass cleaner drain cleaner 蒸餾水玻璃清潔劑通渠劑

Cola black coffee detergent lime water 可樂黑咖啡洗潔精石灰水

high acidity low acidity low alkalinity high alkalinity 酸度高酸度低鹼度低鹼度高

neutral

中性




8

Universal indicator can only give a rough

measurement of the pH value of a solution.

What can we use to obtain a more accurate

pH value of a solution?

通用指示劑只能粗略測試出

溶液的 pH 值，我們可利用甚

麼儀器來更準確地量度溶液

的 pH 值？

Q8

A8

We can use a pH meter to measure the pH

value of a solution more accurately.

The reading measured by the pH meter can be

accurate to two decimal places.

我們可利用pH計來更準確地量度溶液

的 pH 值。

pH 計所量度的讀數可準確至小數點後

兩個位。

probe 探測器

pH value displayed pH 值

pH meter

pH 計




9

Yes, acids react with some metals such as

magnesium, aluminium, iron and zinc. These

metals are corroded by acids.

酸會與某些金屬 (例如鎂、鋁、鐵和

鋅) 產生反應，它們均會被酸腐蝕。

During the reactions, hydrogen is produced.

Heat is also given out.

金屬與酸所產生的反應會釋出氫，還

會放出熱能。

We can test for hydrogen using the burning

splint test. When a burning splint is put near the

mouth of the test tube containing hydrogen, a

‘pop’ sound is heard.

我們可利用燃燒中的木條來測試

氫。當我們把燃燒中的木條放在盛有

氫的試管管口時，會聽到「卜」一聲。

Do acids react with metals? 酸能否與金屬產生反應？

A13

Q13

burning splint 燃燒中的木條

hydrogen 氫

Yes, acids react with calcium carbonate in some

building materials such as marble and limestone.

These building materials are corroded by acids.

During the reaction, carbon dioxide is formed.

酸會與建築材料 (例如大理石和

石灰石) 中的碳酸鈣產生反應。這

些建築材料會受到酸腐蝕。

酸與碳酸鈣所產生的反應會釋出

二氧化碳。

Do acids react with building materials? 酸能否與建築材料產生反應？

Q10

A10

29.1 Corrosive nature of acids 29.1 酸的腐蝕性質

29 Acids and corrosion 酸和腐蝕

Chapter 第章




10

29.2 Acid rain 29.2 酸雨

What are the causes and effects of

acid rain?

酸雨是怎樣形成的？酸雨對環境

造成甚麼影響？

Q11

A11

Burning fossils fuels produces sulphur dioxide and

nitrogen oxides.

Sulphur dioxide and nitrogen oxides react with water

and oxygen in the atmosphere to form sulphuric acid

and nitric acid respectively.

These acids dissolve in rainwater to form acid rain.

The effects of acid rain on the environment include

corroding metal products and building materials,

killing organisms living in water and damaging plants.

The diagram below summarises the formation of acid

rain and its effects on the environment.

燃燒化石燃料會釋出大量的二氧

化硫和氮氧化物。

二氧化硫和氮氧化物會與大氣中

的水和氧產生反應，分別形成硫

酸和硝酸。

硫酸和硝酸溶解在雨水中，並形

成酸雨。

酸雨對環境的影響包括腐蝕金屬

製品和建築材料、毒害水生生物

及破壞林木。

下圖概括了酸雨的形成過程及酸

雨對環境所造成的影響。

acidic gases (e.g. sulphur dioxide and nitrogen oxides) released into the atmosphere

酸性氣體 (如二氧化硫和氮氧

化物) 釋放到大氣中

acidic gases carried by the wind

酸性氣體隨風飄送

acidic gases dissolve in rainwater to form acid rain

酸性氣體溶解在雨水中，形

成酸雨

acid rain corrodes metal products and building materials, kills organisms living in water and damages plants

酸雨腐蝕金屬製品和建築材料、毒害水

生生物及破壞林木

1

2

3

4




11

What preventive measures can be

done to help control acid rain?

甚麼措施可減少酸雨的形成？

Q12

A12

The most effective way to control acid rain is to

reduce the emission of air pollutants such as

sulphur dioxide and nitrogen oxides.

The government has taken a wide range of

measures to reduce the emission of these air

pollutants from vehicles and power stations.

To be responsible citizens, we should use

public transport and save electricity in order to

help reduce the emission of air pollutants.

要有效減少酸雨的形成，我們必須先

減少空氣污染物 (如二氧化硫和氮

氧化物) 的排放量。

香港特區政府近年已採取了多項措

施，以減少來自汽車和發電廠的空氣

污染物排放量。

我們作為社會的一份子，也應使用公

共交通工具和節約能源，以協助減少

空氣污染物排放量。




12

30.1 Uses of acids and alkalis 30.1 酸和鹼的應用

A13

Fresh food may spoil due to the action of

micro-organisms.

Most micro-organisms cannot grow and reproduce in

an acidic medium.

Foods can be preserved by soaking them in acids.

Therefore, acids can be used as food preservatives.

For example, vinegar (contains ethanoic acid) can be

used to preserve cucumbers and scallions. We say

that these foods are pickled with vinegar.

新鮮食物變壞主要是由微生物

引起的。

酸性介質可以減慢微生物的生

長和繁殖。

我們可以把食物浸在酸中來保

存，故此酸可作為食品防腐劑。

例如，白醋含有乙酸，可用來保

存青瓜和蕎頭。

Q13 Why can acids be used as food

preservatives?

為甚麼酸可作為食品防腐劑？

Foods preserved in vinegar 保存在白醋中的食物

cucumber 青瓜

scallion 蕎頭

30 Uses of acids, alkalis and neutralisation 酸、鹼及中和作用的應用

Chapter 第章




13

What is browning? Why can acids

be used to prevent browning?

水果出現變褐的現象是甚麼意思？

為甚麼可用酸來防止水果變褐？

Q14

A14

Browning occurs in many fruits such as apples,

bananas and pears. When these fruits are cut

open and exposed to air, they turn brown.

Enzymes inside the fruits can speed up the

browning process. However, they can only

function properly within a certain range of pH

value.

Therefore, the browning of fruits can be slowed

down by putting them in environments with pH

that the enzymes cannot function properly.

許多水果，例如蘋果、香蕉和梨都會

出現變褐的現象。這些水果切開並暴

露於空氣中後會變褐。

水果內的酶會加速變褐的過程。然

而，酶只有在特定的 pH 值範圍內才

能發揮它的功能。

因此，我們把水果置於酶不能正常發

揮功能的 pH 環境中，便可減慢水果

變褐的過程。

A15

Q15 Why can both acids and alkalis be used as household cleansing agents? Suggest some examples of acidic and alkaline household cleansing agents.

為甚麼酸和鹼可用作家居清

潔劑？有甚麼家居清潔劑含

有酸或鹼？

Household cleansing agents contain acids

which can react with stains to form substances

that are soluble in water

The following are two household cleansing

agents containing acids.

含有酸的家居清潔劑可跟頑固的污漬

反應，並產生可溶於水的物質。

下圖展示兩種含有酸的家居清潔劑。

Toilet cleaner 廁所清潔劑 Rust remover 除銹劑

Toilet cleaner can be used to remove limescale (contains mainly calcium carbonate) in a toilet bowl. 廁所清潔劑可清除廁盆上的污垢 (主要含

有碳酸鈣)。

A rust remover can be used to remove rust (oxides of iron) on an iron object.

除銹劑可清除鐵製品上的鐵銹 (鐵的氧化物)。




14

A15

On the other hand, household cleansing

agents contain alkalis which can react with

greases to form substances that can be easily

washed away by water.

The following are three household cleansing

agents containing alkalis.

另一方面，含有鹼的家居清潔劑可與

油脂反應，所產生的物質可輕易用水

沖走。

下圖展示三種含有鹼的家居清潔劑。

Drain cleaner 通渠劑 Oven cleaner 爐具清潔劑

Drains cleaners that contain sodium hydroxide are commonly used to clear the grease from a drain.

含有氫氧化鈉的通渠劑常用來清理堵塞的

渠道。

Grease left on the oven surface can be removed by using an oven cleaner. 殘留在爐具上的油脂可使用爐具清潔劑來

消除。

Glass cleaner 玻璃清潔劑

Greasy films on the windows can be removed by using a glass cleaner. 玻璃窗上的油脂可使用玻璃清潔劑來清除。




15

30.2 Uses of neutralisation 30.2 中和作用的應用

What is neutralisation? 甚麼是中和作用？

Q16

A16

Acids and alkalis react with each other when

they are mixed together. This reaction is called

neutralisation.

During neutralisation, the pH value of the

solution changes.

The point where the acid completely

neutralises the alkali as shown by the colour

change of the indicator can be regarded as the

end-point.

當酸和鹼混合時，它們會產生反應。這種

酸和鹼之間的化學反應稱為中和作用。

當酸和鹼混合時，溶液的 pH 值會出現變

化。

利用指示劑的顏色變化可測定酸和鹼剛好

完全中和時的狀態，此狀態可稱為終點。




16

What products are formed in neutralisation

reaction?

中和作用會產生甚麼物質？

Q17

A17

When an acid neutralises an alkali (or vice

versa), salt and water are formed, and heat is

given out.

Neutralisation can be represented by the

following word equation.

acid + alkali salt + water

For example, hydrochloric acid reacts with

sodium hydroxide to produce sodium chloride

and water. The word equation of this reaction

can be written as:

hydrochloric acid + sodium hydroxide

sodium chloride + water

We can also use chemical symbols to

represent the above substances. The chemical

symbols for hydrochloric acid, sodium

hydroxide, sodium chloride and water are HCl,

NaOH, NaCl and H2O respectively. Therefore,

the reaction can be represented by the

following equation:

HCl + NaOH NaCl + H2O

酸和鹼發生中和作用時，會生成鹽和水，

並釋出熱能。

中和作用可用以下文字方程式表示：

酸 + 鹼鹽 + 水

例如，氫氯酸與氫氧化鈉發生反應，產生

氯化鈉和水，該反應的文字方程式可以寫

成：

氫氯酸 + 氫氧化鈉氯化鈉 + 水

以上的化學物質可以用化學符號來表

示。氫氯酸、氫氧化鈉、氯化鈉和水的化

學符號分別是 HCl、NaOH、NaCl 和

H2O。因此，這反應也可用以下方程式表

示：

HCl + NaOH NaCl + H2O

Sodium chloride is the table salt we add to our food for taste. 氯化鈉是我們日常食用的餐桌鹽。




17

What are the uses of neutralisation in daily life?

中和作用在日常生活中有

甚麼應用？

Q18

A18

The following are some examples of common applications

of neutralisation.

以下是中和作用常見的應用。

1. Neutralisation of stomach acid 1. 中和胃酸

Antacids can be used to relieve stomach upset. Many

antacids contain an alkali which can neutralise excess acid

in our stomach.

制酸劑可舒緩胃部不適。許多制

酸劑都含有鹼，可以用來中和過

多胃酸。

2. Treatment of industrial waste containing acids and alkalis 2. 處理酸性和鹼性工業廢料

To reduce pollution, industrial waste should be treated

before it is discharged. Alkalis (e.g. calcium hydroxide) can

be used to neutralise acidic waste while acids (e.g.

sulphuric acid) can be used to neutralise alkaline waste.

工業廢料在排放之前必須經過

處理，以減少造成污染。廢料

中的酸可用適量的鹼 (例如氫

氧化鈣) 來中和；而廢料中的

鹼則可用適量的酸 (例如硫

酸) 來中和。

The Chemical Waste Treatment Centre at Tsing Yi is responsible for the collection, processing and final treatment of the chemical waste.

位於青衣的化學廢物處理中心專門負責收集和處理

化學廢料。

Antacid tablets of different brands 從藥房購買的不同制酸劑。




18

A18

3. Treatment of wasp, bee, mosquito and ant stings 3. 治療蟲螫

The stings of bees, ants and mosquitoes contain an

acid. We can wash the affected area with an alkaline

substance, such as soap to neutralise the acid.

肥皂可中和蜜蜂、螞蟻及蚊子螫過

的傷口上的酸性物質。

The sting of a wasp is alkaline. We can apply an acidic

substance, such as vinegar, on the affected area to

neutralise the alkali.

醋可中和黃蜂螫過的傷口上的鹼性

物質。

4. Regulation of pH values of soil 4. 調節土壤的 pH 值

Many plants do not grow well in soil which is too

acidic or too alkaline. If the soil is too acidic, farmers

will add slaked lime (calcium hydroxide) to the soil

before growing crops. On the other hand, if the soil is

too alkaline, farmers may add sulphur to the soil.

大多數植物都不適宜於過酸或過鹼

的土壤中生長。假如土壤的酸性過

高，農夫需要定期加入帶有鹼性的

熟石灰 (氫氧化鈣) 以中和土壤中

的酸。另一方面，假如土壤的鹼性

過高，農夫會在土壤中加入硫。

mosquito 蚊子

wasp 黃蜂

The farmer is adding slaked lime to neutralise acidic soil.

農夫在土壤加入熟石灰以中和土壤中的酸。




19

30.3 Handling acids and alkalis 30.3 處理酸和鹼的方法

What are the potential hazards of acids and

alkalis? What safety precautions should we

take when handling them?

Wash the affected area with slow running

water for at least 10 minutes to avoid further

damage to it.

使用酸和鹼時有甚麼潛在

危險？當我們使用這些溶

液時應採取甚麼安全措？

A19

The following shows some potential hazards of acids

and alkalis, and the corresponding safety precautions

we should take when handling them.

下圖顯示使用酸和鹼時的潛在危險，及我

們使用這些溶液時應採取的安全措施。

Potential hazard 1: Concentrated acids or concentrated alkalis can cause blindness if they get into the eyes.

潛在危險 1：

如果濃酸或濃鹼濺進眼睛，可能會引致失明。

Safety precaution 1: Wear safety goggles.

安全措施 1：

佩戴安全眼鏡。

Potential hazard 2: The vapour of concentrated acids or concentrated alkalis is corrosive.

潛在危險 2：

濃酸或濃鹼的蒸氣具腐蝕性。

Safety precaution 2: Carry out the experiment in a fume cupboard.

安全措施 2：

在煙櫥內進行實驗

PPotential hazard 3: Concentrated acids or concentrated alkalis can burn skin and flesh.

潛在危險 3：

濃酸或濃鹼會腐蝕皮膚和肌肉。

Safety precaution 3: Wear protective gloves.

安全措施 3：

戴上保護性膠手套。

Q19




20

How should we treat accidents and

emergencies involving acids and alkalis?

一旦在實驗室使用酸或鹼時發

生意外，我們應如何處理？

Q20

A20

When an accident involving acids or alkalis occurs,

we must keep calm. We should report it to our

teacher and take the following measures.

一旦在實驗室使用酸或鹼時發生意外，必須

保持冷靜，立即向老師報告，並依照下列的

方法處理：

1. Wash the affected area with slow running water

for at least 10 minutes to avoid further damage

to it.

1. 用清水慢慢沖洗沾有化學品的部位最少 10

分鐘，以防止受傷組織遭到進一步破壞。

2. If the eye is hurt, keep the affected eye

open with one hand and rinse it with the

eyewash bottle.

2. 若眼睛受傷，應用手把受傷的眼睛撐

開，用洗眼瓶徹底沖洗。

3. Gently remove any contaminated clothing.

Care must be taken to avoid further contact

with the acids or alkalis.

3. 小心地把沾有酸或鹼的衣物除下，並應避免

再次與酸或鹼接觸。

4. If the accident is serious, keep washing

the affected area until the ambulance

crew arrives. A sample of the acids or

alkalis should be taken to the hospital for

reference.

4. 若傷勢嚴重，則應不停沖洗受傷部位，

直至救護車到達。應把傷者連同引致灼

傷的酸或鹼樣本一併送往醫院。




21

What are the proper procedures in diluting

concentrated acids and alkalis?

稀釋濃酸和濃鹼的正確步驟

是怎樣的？

Q21

A21

The following shows the proper procedures in

diluting concentrated acids and alkalis.

下圖顯示稀釋濃酸和濃鹼的正確步驟。

CORRECT正確

INCORRECT不正確

Carry out the process inside a fume cupboard.

應在煙櫥內進行。

Wear protective gloves and safety goggles.

應戴上保護性膠手套及安全眼鏡。

Add concentrated acid or alkali slowly to a

large amount of water.

把濃酸或濃鹼慢慢加入大量水中。

Stir the solution continuously and slowly when

you are adding concentrated acid or alkali.

把濃酸或濃鹼加入水時，要小心地不斷攪拌

溶液。

Do not breathe in fumes from the cupboard.

避免吸入煙櫥內的煙霧。

Add water to concentrated acid or alkali.

把水加入濃酸或濃鹼中。

Carry out the procedures with bare hands.

沒有戴上保護性膠手套。

protective gloves

保護性膠手套

concentrated acid/alkali

濃酸或濃鹼

water

水

no protective gloves 沒有戴上保護性膠手套

water

水

concentrated acid/alkali

濃酸或濃鹼




22

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. Lemons contain citric acid. □

2. Alkalis have a slippery feel. □

3. Alkaline solutions turn blue litmus paper red. □

4. Litmus can be used to indicate the degree of acidity or alkalinity of a substance. □

5. The pH value of glass cleaner is less than 7. □

6. Some metals react with acids to produce hydrogen. □

7. The pH value of acid rain is lower than 5.6. □

8. When an acid is added to an alkali, the pH value of the resulting solution increases. □

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 statements about acids are correct?

(I) All acids are not safe to consume.

(II) Some drugs contain acid.

(III) Vinegar contains ethanoic acid.

A. (I) and (II) only

B. (I) and (III) only

C. (II) and (III) only

D. (I), (II) and (III) □

2. Which of the following substances are corrosive?

(I) Nitric acid

(II) Calcium hydroxide

(III) Ammonia solution





3. Which of the following substances has a pH value greater than 7?

A. Tap water

B. Apple juice

C. Drain cleaner

D. Hair conditioner □

Part

2 第部分 Revision exercise 單元練習




23

4. Which of the following substances does not react with an acid?

A. Limestone

B. Copper

C. Eggshell

D. Zinc □

5. Which of the following gases will be given out when an acid reacts with magnesium?

A. Oxygen

B. Nitrogen

C. Hydrogen

D. Carbon dioxide □

6. Which of the following are the effects of acid rain on the environment?

(I) It damages statues made of marble.

(II) It kills organisms living in water.

(III) It damages plants.





7. Which of the following gases may cause acid rain?

(I) Nitrogen oxides

(II) Nitrogen

(III) Sulphur dioxide





8. Which of the following substances will be formed when an acid neutralises an alkali?

(I) Water

(II) Salt

(III) Carbon dioxide








24

C. Short questions 短問題

1. The following table shows the pH values of five substances.

Substance A B C D E

pH value ~ 9 ~ 5 ~12 ~ 2 ~ 7

(a) Which substance(s) is/are acidic, neutral and alkaline?

_____________________________________________________________________

(b) Which substance is the most acidic?

_____________________________________________________________________

(c) Which substance is the most alkaline?

_____________________________________________________________________

(d) How does the pH value of the mixed solution change when substance A is added to

substance D?

_____________________________________________________________________

2. Alice carries out an experiment to study the reaction between dilute hydrochloric acid and

aluminium. The following diagrams show the steps.

(a) What do you observe after aluminium is added to the test tube?

_____________________________________________________________________ (b) She then puts a burning splint near the mouth of the test tube to test for the gas.

What do you hear?

_____________________________________________________________________

(c) What gas is formed when aluminium reacts with dilute hydrochloric acid?

_____________________________________________________________________

aluminium

dilute hydrochloric acid

aluminium

inverted rubber stopper

burning splint




25

Answers 答案

A. True or false questions 是非題

1. T

2. T

3. F

4. F

5. F

6. T

7. T

8. F

B. Multiple-choice questions 多項選擇題

1. C

2. B

3. C

4. B

5. C

6. D

7. B

8. A

C. Short questions 短問題

1. (a) Substances B and D are acidic. Substance E is neutral. Substances A and C are

alkaline.

(b) Substance D is the most acidic.

(c) Substance C is the most alkaline.

(d) The pH value of the solution increases.

2. (a) Some colourless gas bubbles are given out.

(b) A ‘pop’ sound

(c) Hydrogen

Part