Modul A+ Kimia Tg 4_Pan Asia Publications

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K


andungan









Pengenalan kepada Kimia 5.3 Ikatan Kovalen
Bab 1 Introduction to Chemistry Covalent Bond ................................................................................92
5.4 Ikatan Hidrogen
1.1 Perkembangan Bidang Kimia dan Kepentingan dalam Hydrogen Bond ..............................................................................97
Kehidupan 5.5 Ikatan Datif
Development in Chemistry Field and Its Importance in Daily Dative Bond .................................................................................100
Life ...................................................................................................1 5.6 Ikatan Logam
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1.2 Penyiasatan Saintifik dalam Kimia Metallic Bond ...............................................................................102
Scientific Investigation in Chemistry ...............................................4 5.7 Sifat Sebatian Ion dan Sebatian Kovalen
1.3 Penggunaan, Pengurusan dan Pengendalian Radas serta Properties of Ionic Compounds and Covalent Compounds ..........103
Bahan Kimia
Usage, Management and Handling of Apparatus and Bab 6 Asid, Bes dan Garam
Chemical Materials ...........................................................................7 Acid, Base and Salt
Jirim dan Struktur Atom 6.1 Peranan Air dalam Menunjukkan Keasidan dan
Bab 2 Matter and the Atomic Structure Kealkalian
The Role of Water in Showing Acidic and Alkaline Properties ....109
2.1 Konsep Asas Jirim 6.2 Nilai pH
Basic Concepts of Matter ................................................................12 pH value .......................................................................................116
2.2 Perkembangan Model Atom 6.3 Kekuatan Asid dan Alkali
The Development of the Atomic Model .......................................... 18 Strength of Acids and Alkalis .......................................................120
2.3 Struktur Atom 6.4 Sifat-sifat Kimia Asid dan Alkali
Atomic Structure .............................................................................21 Chemical Properties of Acids and Alkalis ....................................123
2.4 Isotop dan Penggunaannya 6.5 Kepekatan Larutan Akueus
Isotopes and Its Uses ......................................................................27 Concentration of Aqueous Solution ..............................................125
Konsep Mol, Formula dan Persamaan Kimia
Bab 3 The Mole Concept, Chemical Formulae and 6.6 Larutan Piawai
Standard Solution ..........................................................................129
Equation 6.7 Peneutralan
Neutralisation ...............................................................................134
3.1 Jisim Atom Relatif dan Jisim Molekul Relatif 6.8 Garam, Hablur dan Kegunaan dalam Kehidupan Harian
Relative Atomic Mass and Relative Molecular Mass......................32 Salts, Crystals and Their Uses in Daily Life .................................141
3.2 Konsep Mol 6.9 Penyediaan Garam
Mole Concept ..................................................................................36 Preparation of Salts ......................................................................143
3.3 Formula Kimia 6.10 Tindakan Haba ke atas Garam
Chemical Formula .........................................................................43 Effect of Heat on Salts ...................................................................159
3.4 Persamaan Kimia 6.11 Analisis Kualitatif
Chemical Equation .........................................................................56 Qualitative Analysis ......................................................................163
Jadual Berkala Unsur Kadar Tindak Balas
Bab 4 Bab 7
The Periodic Table of Elements Rate of Reaction
4.1 Perkembangan Jadual Berkala Unsur 7.1 Penentuan Kadar Tindak Balas
The Development of The Periodic Table of Elements ....................61 Determining Rate of Reaction .......................................................177
4.2 Susunan Unsur dalam Jadual Berkala Unsur 7.2 Faktor yang Mempengaruhi Kadar Tindak Balas
The Arrangement of Elements in the Periodic Table of Elements ...63 Factors Affecting Rate of Reactions..............................................189
4.3 Unsur dalam Kumpulan 18 7.3 Aplikasi Faktor yang Mempengaruhi Kadar Tindak
Elements in Group 18 ....................................................................65 Balas dalam Kehidupan
4.4 Unsur dalam Kumpulan 1 Application of Factors that Affect the Rate of Reaction in Daily
Elements in Group 1 ......................................................................67 Life ................................................................................................202
4.5 Unsur dalam Kumpulan 17 7.4 Teori Perlanggaran
Elements in Group 17 ....................................................................75 Collision Theory............................................................................205
4.6 Unsur dalam Kala 3
Elements in Period 3 ......................................................................78 Bab 8 Bahan Buatan dalam Industri
4.7 Unsur Peralihan Manufactured Substances in Industry
Transition Elements .......................................................................84
8.1 Aloi dan Kepentingannya
Ikatan Kimia Alloy and Its Importance ...............................................................210
Bab 5 Chemical Bonds 8.2 Komposisi Kaca dan Kegunaannya
Composition of Glass and Its Uses ...............................................216
5.1 Asas Pembentukan Sebatian 8.3 Komposisi Seramik dan Kegunaannya
Basics of Compounds Formation ...................................................87 Composition of Ceramics and Its Uses .........................................217
5.2 Ikatan Ion 8.4 Bahan Komposit dan Kepentingannya
Ionic Bond ......................................................................................88 Composite Materials and Its Importance .....................................219

Bab

3 Konsep Mol, Formula dan Persamaan Kimia

The Mole Concept, Chemical Formula and Equation





3.1 Jisim Atom Relatif dan Jisim Molekul Relatif
Relative Atomic Mass and Relative Molecular Mass


A Jisim Atom Relatif, JAR
Relative Atomic Mass, RAM
1. Atom adalah sangat kecil dan jisim satu atom tidak mungkin ditimbang dalam gram dengan menggunakan sebarang
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penimbang elektronik. Maka, ahli kimia membandingkan jisim sesuatu atom dengan atom piawai.
Atom is very small and it is impossible to weigh the mass of an atom in gram using any electronic balance. Thus, chemist compares
the mass of an atom with a standard atom.
2. Jisim sesuatu atom apabila dibandingkan dengan atom piawai dipanggil jisim atom relatif, JAR
The mass of an atom when compared to a standard atom is called relative atomic mass, RAM
3. Jisim atom relatif tidak mempunyai unit kerana jisim atom relatif bukannya jisim sebenar tetapi merupakan nilai
bandingan sahaja.
comparison
Relative atomic mass has no unit because it is not the actual mass but only a value.
4. Hidrogen/ Hydrogen
(a) Dipilih pada awalnya sebagai atom piawai.
Earlier chosen as the standard atom.
(b) Jisim satu atom hidrogen ditetapkan sebagai 1 unit.
The mass of one hydrogen atom was assigned 1 unit.
(c) Dipilih kerana merupakan atom yang paling ringan.
Chosen because its the lighest atom.
(d) Namun ditolak kerana/ However rejected because:
(i) Tidak semua unsur dapat bertindak balas dengan hidrogen.
Not many elements can react with hydrogen.
(ii) Wujud sebagai gas dan susah dikendalikan.
Exist as a gas and difficult to handle.
5. Oksigen/ Oxygen:
(a) Dipilih kerana/ Chosen because:
(i) Mudah dikendalikan berbanding dengan hidrogen.
Easier to handle than hydrogen.
(ii) Lebih mudah diperoleh.
More readily available.
(iii) Bertindak balas dengan hampir semua unsur.
React with almost all the elements.
(b) Namun ditolak kerana/ However rejected because:
(i) Kewujudan isotop O O O
18
16
17
8
8
8
Existence of isotopes O O O
16
18
17
8
8
8
(ii) Ahli fizik menggunakan jisim oksigen-16 sebagai piawai tetapi ahli kimia menggunakan nilai purata bagi
jisim 3 isotop sebagai piawai.
Physicists used the mass of oxygen-16 as the standard whereas chemists used the average value of the mass of 3 isotopes
as the standard.
6. Karbon-12/ Carbon-12:
(a) Jisim satu atom karbon-12 ditetapkan sebagai 12 unit.
The mass of one carbon-12 atom was assigned 12 units.
(b) Dipilih kerana/ Chosen because:
(i) Karbon-12 digunakan sebagai rujukan piawai dalam spektrometer jisim.
Carbon-12 was used as the reference standard in mass spectrometers.
(ii) Kebanyakan unsur berpadu dengan karbon-12.
Most elements combine with carbon-12.
(iii) Wujud dalam bentuk pepejal pada suhu bilik dan mudah dikendalikan.
Exist as a solid at room temperature and easy to handle.
(iv) Karbon-12 ialah isotop karbon dengan kelimpahan 98.89%, manakala isotop karbon-13 dan karbon-14
hanya 1.11%. Maka, jisim purata bagi tiga isotop adalah sama dengan 12.
Carbon-12 is the carbon isotope with 98.89%, abundant whereas carbon-13 and carbon-14 isotopes is only 1.11%.
Thus, the average mass of three isotopes is equal to 12.
32

7. Berdasarkan skala karbon-12, jisim atom relatif, JAR sesuatu unsur ialah jisim purata satu atom
1 karbon-12
unsur itu apabila dibandingkan dengan kali jisim satu atom .
12
Based on the carbon-12 scale, the relative atomic mass, RAM of an element is the average mass of one atom of
1 carbon-12
the element when compared with times the mass of one atom.
12

Jisim purata satu atom unsur/ Average mass of one atom of the element
Jisim atom relatif, JAR =
Relative atomic mass, RAM 1 × jisim satu atom karbon-12/ mass of one atom of carbon-12
12


Contoh/ Example:
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1 daripada satu atom karbon-12
12 C-12
1 of a carbon-12 atom
12
He
1 daripada satu atom karbon-12
12
1 of a carbon-12 atom
12

Rajah/Diagram 3.1

1
Berdasarkan Rajah 3.1, jisim 1 atom helium adalah 4 kali lebih besar daripada 12 kali jisim satu atom
karbon-12.
4 1
Based on Diagram 3.1, the mass of 1 helium atom is times greater than 12 times of the mass of one carbon-12
atom.
Maka, jisim atom relatif, JAR atom helium/ Therefore, the relative atomic mass, RAM of helium atom = 4

Contoh/ Example: 1
Diberi jisim 1 atom nitrogen ialah 14 kali lebih besar daripada kali jisim satu atom karbon-12. Tentukan jisim atom
12
relatif, JAR bagi satu atom nitrogen. 1
Given that the mass of 1 nitrogen atom is 14 times greater than 12 times the mass of 1 carbon-12 atom. Determine the relative
atomic mass, RAM of a nitrogen atom.
1
Jisim satu atom nitrogen = 14 kali lebih besar daripada kali jisim 1 atom karbon-12
12
1
Mass of one nitrogen atom = 14 times greater than times the mass of 1 carbon-12 atom
12
14 kali lebih besar Jisim karbon-12
14 times greater 1 Mass of carbon-12
= 14  [ 12  12 ]
= 14
∴ Jisim atom relatif, JAR atom nitrogen/ Relative atomic mass, RAM of nitrogen atom = 14

Contoh/ Example:
Tentukan berapa kali 2 atom argentum lebih besar daripada 4 atom aluminium.
Determine how many times greater are 2 silver atoms compared to 4 aluminium atoms.
[JAR/ RAM: Al = 27; Ag = 108]
Jisim 2 atom argentum = Q kali lebih besar daripada jisim 4 atom aluminium
Mass of 2 silver atoms = Q times greater than the mass of 4 aluminium atoms
Q kali lebih besar
Q times greater
2 atom Ag 4 atom Al
2 Ag atoms 4 Al atoms
2(108) = Q  4 (27)
JAR Ag 216 = Q  108 JAR Al
RAM of Ag RAM of Al
216 = Q
108
Q = 2
∴2 atom argentum ialah 2 kali lebih besar daripada 4 atom aluminium.
2 silver atoms are 2 times greater than 4 aluminium atoms.

33

Contoh/Example 1
Berapa kalikah 2 atom bromin lebih besar daripada 5 atom oksigen?
How many times greater are 2 bromine atoms compared to 5 oxygen atoms?
[JAR/ RAM: Br = 80; O = 16]

Penyelesaian/Solution :
Jisim 2 atom bromin = Q kali lebih besar daripada jisim 5 atom oksigen
Mass of 2 bromine atom Q times greater than the mass of 5 oxygen atoms
2 (80) = Q  5 (16)
160
80 = Q
Q = 2
∴ 2 atom bromin ialah 2 kali lebih besar daripada 5 atom oksigen.
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2 bromine atoms are 2 times greater than 5 oxygen atoms.


Contoh/Example 2 TP 3
Berapakah atom oksigen yang mempunyai jisim sama dengan satu atom sulfur?
How many oxygen atoms that have the same mass as one atom of sulphur?
[JAR/ RAM: S = 32; O = 16]

Penyelesaian/Solution :
Jisim Q atom oksigen = Jisim satu atom sulfur
Mass of Q atoms oxygen Mass of one atom sulphur
Q(16) = 1(32)
Q = 2
Bilangan atom oksigen/ Number of oxygen atoms = 2


Contoh/Example 3 TP 3

Jisim bagi 4 atom unsur X adalah sama dengan jisim bagi 5 atom oksigen. X bukan simbol sebenar bagi unsur itu. Berapakah
jisim atom relatif, JAR bagi unsur X?
The mass of 4 atoms of element X is equal to the mass of 5 oxygen atoms. X is not the actual symbol of the element. What is the relative
atomic mass, RAM of element X?
[JAR/ RAM: O = 16]

Penyelesaian/Solution :
Jisim 4 atom unsur X = Jisim 5 atom oksigen
Mass of 4 atoms element X Mass of 5 oxygen atoms
4(Q) = 5(16)
Q = 20
∴ Jisim atom relatif, JAR bagi unsur X/ Relative atomic mass, RAM of element X = 20
r



B Jisim molekul relatif, JMR dan jisim formula relatif, JFR
Relative molecular mass, RMM and relative formula mass, RFM
1. Jisim molekul relatif, JMR sesuatu molekul ditakrif sebagai jisim purata molekul itu apabila dibandingkan
1
dengan kali jisim satu atom karbon-12 .
12 1
Relative molecular mass, RMM of a molecule is defined as the average mass of the molecule when compared with 12
times the mass of one carbon-12 atom .

Jisim purata satu molekul
Jisim molekul relatif, JMR =
1 × jisim satu atom karbon-12
12
Average mass of one molecule
Relative molecular mass, RMM =
1
12 × mass of one atom of carbon-12



34

Contoh/ Example:
1 daripada satu atom karbon-12
12
O 1 of a carbon-12 atom
H H 12





Rajah/Diagram 3.2
1
Berdasarkan Rajah 3.2, jisim 1 molekul air ialah 18 kali besar daripada kali jisim satu atom karbon-12.
12

Based on Diagram 3.2, the mass of 1 water molecule is 18 times greater than 1 times of the mass of a carbon-12
atom. 12
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Maka, jisim molekul relatif bagi air/Therefore, the relative molecular mass of water = 18

2. Istilah jisim molekul relatif, JMR hanya boleh digunakan untuk bahan yang terdiri daripada molekul. Bagi sebatian
ion, istilah jisim formula relatif, JFR digunakan.
The term relative molecular mass, RMM can only be used for substances that are made up of molecules. For ionic compounds,
the term relative formula mass, RFM is used instead.


Contoh/Example 4 TP 3
Hitungkan jisim molekul relatif, JMR bagi setiap sebatian yang berikut.
Calculate the relative molecular mass, RMM for each of the following compounds.
[JAR/ RAM: C =12; Cl = 35.5; O = 16, H = 1, N = 14]
(a) Ammonia/ Ammonia, NH 3
(b) Asid etanoik/ Ethanoic acid, CH COOH
3
(c) Tetraklorometana/ Tetrachloromethane, CCl
4
Penyelesaian/Solution :
(a) Jisim molekul relatif ammonia, NH = 14 + 3 (1) = 14 + 3 (1) = 17
Relative molecular mass of ammonia 3
JAR N/ RAM of N JAR H/ RAM of H
2 C 4 H 2 O
(b) Jisim molekul relatif asid etanoik, CH COOH = 2 (12) + 4 (1) + 2 (16) = 24 + 4 + 32 = 60
3
Relative molecular mass of ethanoic acid
JAR C JAR H JAR O
RAM of C RAM of H RAM of O

(c) Jisim molekul relatif tetraklorometana, CCl = 12 + 4 (35.5) = 12 + 142 = 154
4
Relative molecular mass of tetrachloromethane
JAR C/ RAM of C JAR Cl/ RAM of Cl

Contoh/Example 5 TP 3
Hitungkan jisim formula relatif, JFR bagi setiap sebatian ion yang berikut.
Calculate the relative formula mass, RFM for each of the following ionic compounds.
[JAR/ RAM: O = 16; Mg = 24; N = 14; Cl = 35.5; S = 32; H = 1; Cu = 64]
(a) Magnesium oksida/ Magnesium oxide, MgO
(b) Kuprum(II) klorida/ Copper(II) chloride, CuCl 2
(c) Ammonium sulfat/ Ammonium sulphate, (NH ) SO
4 2 4
Penyelesaian/Solution :
(a) Jisim formula relatif magnesium oksida, MgO = 24 + 16 = 40
Relative formula mass of magnesium oxide
JAR Mg JAR O
RAM of Mg RAM of O
(b) Jisim formula relatif kuprum(II) klorida, CuCl = 64 + 2 (35.5)
2
Relative formula mass of copper(II) chloride = 135
(c) Jisim formula relatif ammonium sulfat, (NH ) SO = 2[14 + 4(1)] + 32 + 4(16)
4 2
4
Relative formula mass of ammonium sulphate = 132
35

Uji Kendiri 3.1


1. Tentukan jisim molekul relatif, JMR bagi bahan yang berikut. TP 3
Determine the relative molecular mass, RMM of the following substances.
[JAR/ RAM: H = 1; Cl = 35.5; O = 16; C = 12]

Bahan Sebatian Jisim molekul relatif, JMR
Substance Compound Relative molecular mass, RMM
Gas hidrogen klorida
Hydrogen chloride gas HCl 1 + 35.5 = 36.5
Gas karbon dioksida
Carbon dioxide gas CO 2 12 + (2  16) = 44
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Air
Water H O (2  1) + 16 = 18
2
2. Tentukan jisim formula relatif, JFR bagi bahan yang berikut. TP 3
Determine the relative formula mass, RFM of the following substances.
[JAR/ RAM: Na = 23; Cl = 35.5; Cu = 64; N = 14; O = 16; C = 12; S = 32; Fe = 56]

Bahan Sebatian ion Jisim formula relatif, JFR
Substance Ionic compound Relative formula mass, RFM

Natrium klorida NaCl 23 + 35.5 = 58.5
Sodium chloride

Kuprum(II) nitrat Cu(NO ) 64 + 2[14 + (3 x 16)] = 188
Copper(II) nitrate 3 2

Natrium karbonat Na CO 2(23) + 12 + 3(16) = 106
Sodium carbonate 2 3

Kuprum(II) sulfat terhidrat CuSO .5H O 64 + 32 + 4(16) + 5(18) = 250
Hydrated copper(II) sulphate 4 2

Ferum(II) sulfat heptahidrat FeSO .7H O 56 + 32 + 4(16) + 7(18) = 278
Iron(II) sulphate heptahydrate 4 2






3.2 Konsep Mol
Mole Concept

1. Dalam kehidupan seharian, satu ‘dozen’ telur = 12 biji telur. Namun, dalam bidang kimia, satu ‘mol’ telur =
6.02  10 atau 602 000 000 000 000 000 000 000 biji telur.
23
In our daily life, a ‘dozen’ of eggs = 12 eggs. However, in chemistry field, one ‘mole’ of eggs = 6.02  10 or
23
602 000 000 000 000 000 000 000 eggs.
2. Unit mol digunakan dalam penyukatan kuantiti bahan. Satu mol bahan mengandungi 6.02214076  10 entiti
23
asas bahan tersebut.
The mole unit is used in measuring the quantity of substance. One mole of substance contains 6.02214076  10 elementary
23
entities of the substance.
3. Pemalar Avogadro, N ditakrif sebagai bilangan zarah yang terkandung di dalam satu mol bahan
A
itu, iaitu 6.02  10 mol . Sama ada bahan merupakan bahan atom, bahan molekul atau bahan ion.
–1
23
number of particles one mole
Avogadro constant, N is defined as the in of a substance, that is 6.02  10 mol .
23
–1
A
4. Sama ada bahan atom, bahan molekul atau bahan ion, bilangan zarah di dalam satu mol bahan adalah sama.
Whether it’s an atomic substance, a molecular substance or an ionic substance, the number of particles in one mole of substance
is the same.




36

(a) Bahan atom/ Atomic substance (b) Bahan molekul/ Molecular substance (c) Bahan ion/ Ionic substance







Kuprum/ Copper, Cu
Air/ Water, H O Kalium klorida/ Potassium chloride, KCl
2
1 mol bahan atom, Cu = 6.02  10
23
atom kuprum 1 mol bahan molekul, H O = 6.02  10 1 mol bahan ion, KCl = 6.02  10
23
23
2
1 mol of atomic substance, Cu molekul air unit formula KCl 23
atoms 1 mol of molecular substance, H O 1 mol of ionic substance, KCl = 6.02  10
= 6.02  10 copper 2 formula units of KCl
23
= 6.02  10 water molecules
23
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A Bilangan Mol dan Bilangan Zarah
Number of Moles and Number of Particles
1. Rajah 3.3 menunjukkan hubung kait antara bilangan mol dan bilangan zarah dengan menggunakan pemalar
Avogadro, N sebagai faktor penukaran.
A
Diagram 3.3 shows the relationship between the number of moles and the number of particles by using Avogadro constants, N
A
as the conversion factor.
 N
A
Bilangan mol/ Number of moles, n
Bilangan mol, n Bilangan zarah/ Number of particles: Bilangan zarah/ Number of particles
Number of moles, n Atom // Molekul/Molecule // Ion = N
A
 N
A
Rajah/Diagram 3.3


Contoh/Example 6 TP 3
Hitung bilangan atom bagi yang berikut/ Calculate the number of atoms of the following:
(a) 0.2 mol ferum/ iron, Fe
(b) 0.1 mol magnesium/ magnesium, Mg
[Pemalar Avogadro/ Avogadro constant, N = 6.02  10 mol ]
–1
23
A
Penyelesaian/Solution :
(a) Bilangan atom/ Number of atoms (b) Bilangan atom/ Number of atoms
= Bilangan mol  N / Number of moles  N A = Bilangan mol  N / Number of moles  N A
A
A
= 0.2  6.02  10 23 = 0.1  6.02  10 23
= 1.204  10 atom/ atoms = 6.02  10 atom/ atoms
23
22
Contoh/Example 7 TP 3
Hitung bilangan molekul bagi yang berikut/ Calculate the number of molecules of the following:
(a) 3 mol gas nitrogen/ nitrogen gas, N 2
(b) 0.25 mol molekul sulfur/ sulphur molecule, S 8
[Pemalar Avogadro/ Avogadro constant, N = 6.02  10 mol ]
–1
23
A
Penyelesaian/Solution :
(a) Bilangan molekul/ Number of molecules (b) Bilangan molekul/ Number of molecules
= Bilangan mol  N / Number of moles  N A = Bilangan mol  N / Number of moles  N A
A
A
= 3  6.02  10 23 = 0.25  6.02  10 23
= 1.806  10 molekul/ molecules = 1.505  10 molekul/ molecules
23
24







37

Bab
6 Asid, Bes dan Garam

Acids, Base and Salt





6.1 Peranan Air dalam Menunjukkan Keasidan dan Kealkalian
The Role of Water in Showing Acidic and Alkaline Properties


A Asid
Acids
1. Apabila asid dilarutkan dalam air, atom hidrogen di dalam molekul asid dibebaskan sebagai ion hidrogen, H .
+
When an acid is dissolved in water, hydrogen atom in the molecule of acid is released as a hydrogen ion, H .
+
2. Definisi Arrhenius bagi asid/ Arrhenius’s definition of an acid: TP 1
+
Bahan kimia yang mengion dalam air menghasilkan ion hidrogen, H .
A chemical substance which ionises in water to produce hydrogen ion, H .
+

Contoh/ Example:
(a) Gas hidrogen klorida ialah sebatian kovalen yang wujud dalam bentuk molekul.
Hydrogen chloride gas is a covalent compound exist in the form of molecule.
(b) Apabila hidrogen klorida melarut dalam air, molekul hidrogen klorida mengion kepada ion hidrogen, H +
dan ion klorida, Cl – dalam larutan akueus. Larutan akueus ini dinamakan asid hidroklorik, HCl.
When hydrogen chloride dissolves in water, hydrogen chloride molecule ionises to hydrogen ion, H + and
chloride ion, Cl . This aqueous solution is called hydrochloric acid, HCl.

–
HCl (ak/aq) → H (ak/aq) + Cl (ak/aq)
+
(c) Ion hidrogen akueus, H akan bergabung dengan molekul air, H O untuk membentuk
+
2
ion hidroksonium, H O . +
+
3 . Ion ini lazimnya ditulis sebagai H .
hydroxonium ions, H O
+
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An aqueous hydrogen ion, H will combine with the water molecules, H O to form
+
3
2
in aqueous solution. This ion commonly written as H .
+
H H H H
H Cl O O + Cl –
H
Rajah/Diagram 6.1 Pembentukan ion hidroksonium, H O
+
3
Formation of hydroxonium ions, H O +
3
Ekstra Tip
Ekstra
+
Untuk memberikan sifat asid, ion sebenar yang wujud di dalam larutan akueus ialah ion hidroksonium, H O .
3
Namun untuk memudahkan penerangan, ion hidrogen, H sering digunakan untuk mewakili ion hidroksonium,
+
H O .
+
3
To give the acidic properties, the real ions present in the aqueous solution are the hydroxonium ion, H O . However, to make the
+
3
+
description easier, the hydrogen ion, H is often used to represent the hydroxonium ion, H O .
+
3
B Kebesan Asid
Basicity of Acids
1. Kebesan asid ialah bilangan ion hidrogen, H yang boleh dihasilkan bagi satu molekul asid yang mengion dalam
+
air.
Basicity of an acid refers to the number of hydrogen ions, H that can be produced by one molecule of acid ionises in water.
+


109

TP 1
Asid/Acid




Asid monoprotik Asid diprotik Asid tripotik
Monoprotic acid Diprotic acid Tripotic acid


Asid yang menghasilkan hanya satu Asid yang menghasilkan dua ion Asid yang menghasilkan tiga ion
ion hidrogen per molekul dalam air. hidrogen hidrogen per molekul
Acid that produces only one hydrogen ion per molekul dalam air. dalam air.
per molecule in water. Acid that produces two hydrogen ions Acid that produces three hydrogen ions
per molecule in water. per molecule in water.
3.©PAN ASIA PUBLICATIONS
Contoh/ Example:
Asid hidroklorik/ Hydrochloric acid Contoh/ Example:
HCl → H + Cl – Asid sulfurik/ Sulphuric acid Contoh/ Example:
+
Asid nitrik/ Nitric acid H SO → 2H + SO 2– Asid fosforik/ Phosphoric acid acid
+
2
4
4
+
HNO → H + NO 3 – Asid etanadioik/ Ethanedioic acid H PO ⇌ 3H + PO 4 3–
+
3
4
3
Asid etanoik/ Ethanoic acid H C O ⇌ 2H + C O 2–
+
CH COOH ⇌ CH COO + H + 2 2 4 2 4
–
3
3
Rajah/Diagram 6.2 Pengelasan asid berdasarkan kebesan asid
The classification of acids based on the basicity of the acids
Tip SPM
Asid formik, HCOOH digunakan dalam penggumpalan lateks. Walaupun molekul asid formik mempunyai 2 atom
hidrogen, asid formik masih asid monoprotik kerana hanya satu ion hidrogen, H yang boleh dihasilkan oleh satu
+
Tip
molekul asid yang mengion dalam air.
SPM
Formic acid, HCOOH is used in latex coagulation. Although a molecule of formic acid has 2 hydrogen atoms, the formic acid is still a
+
monoprotic acid because only one hydrogen ion, H can be produced by one acid molecule when ionised in water.
C Alkali
Alkalis
1. Bes ialah bahan kimia yang bertindak balas dengan asid menghasilkan garam dan air sahaja.
salt water
Base is a chemical substance that reacts with acid to produce and only.
2. Oksida logam dan hidroksida logam merupakan bes.
Metal oxides and metal hydroxides are base.
Contoh/ Example:
MgO (p/s) + H SO (ak/aq) → MgSO (ak/aq) + H O (ce/l)
4
2 4 Garam/ Salt 2
Ca(OH) (ak/aq) + 2HNO (ak/aq) → Ca(NO ) (ak/aq) + H O (ce/l)
2 3 3 2 2
Garam/ Salt
TP 2 Magnesium oksida, MgO dan kalsium hidroksida, Ca(OH) ialah bes kerana kedua-dua bahan ini bertindak balas
2
dengan asid untuk menghasilkan garam dan air sahaja.

Magnesium oxide, MgO and calcium hydroxide, Ca(OH) are bases because both substances react with acids to produce
2
salt and water only.
Alkali ialah bes yang boleh melarut dalam air dan mengion kepada ion hidroksida, OH .
–
Alkali is a base that is soluble in water and ionises to hydroxide ion, OH .
–
Contoh/ Example:
Natrium hidroksida, NaOH ialah alkali kerana boleh melarut dalam air dan mengion kepada ion natrium, Na dan
+
ion hidroksida, OH . .
–
Sodium hydroxide, NaOH is an alkali because it can dissolve in water and ionises to sodium ions, Na and
+
hydroxide ions, OH . .
–

110

Air + – Na +
Water Na OH OH –
Na + OH – OH –
Na +


Rajah/Diagram 6.3 Ion hidroksida, OH terhasil apabila NaOH melarut dalam air
–
Hydroxide ions, OH formed when NaOH dissolve in water
–
4. Definisi Arrhenius bagi alkali/Arrhenius’s definition of an alkali: TP 1
–
Bahan kimia yang mengion dalam air untuk menghasilkan ion hidroksida, OH ./ A chemical substance which ionises
in water to produce hydroxide ions, OH –
Asid nitrik©PAN ASIA PUBLICATIONS
Contoh/ Example:
Rajah 6.4 menunjukkan tindak balas antara gas ammonia, NH dan air, H O.
3
2
Diagram 6.4 shows the reaction between ammonia gas, NH and water, H O.
3 2

N H H H H
H H + N + + O –
O H H
H
H
Air, H 2 O + Ion hidroksida, OH –
Gas ammonia, NH 3 Ion ammonium, NH 4
Water, H 2 O + Hydroxide ion, OH –
Ammonia gas, NH 3 Ammonium ion, NH 4
Rajah/Diagram 6.4
(a) Mengapakah ammonia akueus yang terhasil ialah alkali? TP 2
Why aqueous ammonia formed is an alkali?
Ammonia akueus ialah alkali kerana molekul ammonia yang mengalami pengionan dapat menghasilkan
ion hidroksida, OH./ Aqueous ammonia is an alkali because the molecules of ammonia that undergo ionisation can
–
produce hydroxide ions, OH .
(b) Lengkapkan persamaan kimia yang berikut.
Complete the following chemical equation.
NH (g/g) + H O (cec/l) ⇌ NH (ak/aq) + OH (ak/aq)
–
+
3 2 4
D Kegunaan Asid, Bes dan Alkali
Uses of Acids, Bases and Alkalis
Jadual/Table 6.1 TP 2

Asid Kegunaan Bes atau alkali Kegunaan
Acid Uses Base or alkali Uses
Asid metanoik Untuk menggumpalkan lateks Magnesium hidroksida Untuk membuat antasid
Methanoic acid To coagulate latex Magnesium hydroxide To make antacid




Asid karbonik Untuk membuat minuman bergas Kalsium oksida/ kalsium Untuk meneutralkan
Carbonic acid To manufacture fizzy drinks hidroksida tanah berasid
Calcium oxide / calcium hydroxide To neutralise acidic soil

Untuk membuat baja dan bahan letupan Natrium hidroksida Untuk membuat sabun
Nitric acid To manufacture fertiliser and explosive Sodium hydroxide To manufacture soap



Asid sulfurik Untuk membuat detergen, cat dan Ammonia akueus Untuk membuat agen
Sulphuric acid sebagai elektrolit dalam akumulator Aqueous ammonia pencuci
asid plumbum. To manufacture washing
To manufacture detergent, paint and as agent
electrolyte in the lead-acid accumulator.

111

E Peranan Air dalam Menunjukkan Keasidan dan Kealkalian
The Role of Water to Show Acidity and Alkalinity
1. Asid menunjukkan sifat keasidannya apabila terlarut dalam air.
An acid shows its acidic properties when it is dissolved in water.
2. Molekul asid mengion dalam larutan akueus membentuk ion hidrogen, H . Kehadiran ion hidrogen, H menyebabkan
+
+
asid dapat menunjukkan sifat keasidannya.
Acid molecules ionise in aqueous solution to form hydrogen ions, H . The presence of hydrogen ion, H is responsible for the
+
+
acidic properties.
Contoh/ Example: H O
HCl (ak/aq) 2 H (ak/aq) + Cl (ak/aq)
–
+
Eksperimen 6.1
©PAN ASIA PUBLICATIONS
Tujuan/Aim:
Eksperimen
Mengkaji peranan air dalam menunjukkan sifat keasidan.
To study the role of water in showing acidic properties.

Pernyataan masalah/Problem statement:
Adakah air diperlukan untuk membolehkan asid menunjukkan sifat keasidan?

Is water needed to allow an acid to show its acidic properties?
Hipotesis/Hypothesis:
Air diperlukan oleh asid untuk menunjukkan sifat keasidan.
Water is needed for an acid to show its acidic properties.

Pemboleh ubah/Variables:
(a) dimanipulasikan/manipulated: Kehadiran air/ Presence of water

(b) bergerak balas/responding: Perubahan warna pada kertas litmus biru/ Colour change on blue litmus paper
(c) dimalarkan/fixed: Jenis asid/ Type of acid
Bahan/Materials:
Pepejal asid oksalik, C H O , air suling, kertas litmus biru
2
4
2
Solid oxalic acid, C H O , distilled water, blue litmus paper
2 2 4
Radas/Apparatus:
Tabung uji, rak tabung uji
Test tubes, test tube rack
Prosedur/Procedure:
1. Satu spatula pepejal asid oksalik, C H O dimasukkan ke dalam sebuah tabung uji.
2
2
4
A spatula of solid oxalic acid, C H O is added in a test tube.
4
2
2
2. Sehelai kertas litmus biru yang kering dimasukkan ke dalam tabung uji.
A piece of dry blue litmus paper is inserted into the test tube.
3. Perubahan warna pada kertas litmus biru diperhatikan dan direkodkan.
Changes to the colour of the blue litmus paper is observed and recorded.
3
4. 2.0 cm air suling ditambahkan ke dalam tabung uji dan digoncang.
2.0 cm distilled water is added to the test tube and shaken well.
3
5. Perubahan warna pada kertas litmus biru diperhatikan dan direkodkan.
Change to the colour of the blue litmus paper is observed and recorded.
Keputusan/Results:
Jadual/Table 6.2
Kandungan Pemerhatian
Content Observation
Pepejal asid oksalik, C H O 4 Warna kertas litmus biru kekal tidak berubah.
2
2
Solid oxalic acid, C H O The colour of the blue litmus paper remains unchanged.
2 2 4
Pepejal asid oksalik, C H O + air suling Warna biru kertas litmus berubah menjadi merah.
4
2
2
Solid oxalic acid, C H O + distilled water The colour of the blue litmus paper turns red.
2 2 4
112

Perbincangan/Discussion:

1. Ion hidrogen bertanggungjawab untuk menunjukkan sifat keasidan.
Hydrogen ions are responsible to show the acidic properties.

2. Warna kertas litmus biru tidak berubah dalam tabung uji yang berisi pepejal asid oksalik, C H O tetapi berubah
2
4
2
menjadi merah apabila pepejal asid oksalik, C H O dilarutkan di dalam air. Terangkan mengapa.
4
2
2
The colour of blue litmus paper remain unchanged in the test tube containing the solid oxalic acid, C H O but turns red when solid
4
2
2
oxalic acid, C H O is dissolved in water. Explain why.
2 2 4
Asid oksalik, C H O hanya menunjukkan sifat keasidannya dengan kehadiran air. Tanpa air, pepejal asid oksalik,
2
2
4
+
C H O hanya wujud sebagai molekul dan ion hidrogen, H tidak hadir. Maka, kertas litmus biru tidak berubah
2
4
2
©PAN ASIA PUBLICATIONS
warna. Apabila dilarutkan di dalam air, molekul asid oksalik, C H O mengion untuk menghasilkan ion hidrogen,
4
2
2
+
+
H . Kehadiran ion hidrogen, H membolehkan asid menunjukkan sifat keasidannya. Maka, warna kertas litmus biru
berubah kepada merah./ Oxalic acid, C H O only shows its acidic properties in the presence of water. Without water, solid
2
2
4
+
oxalic acid, C H O only exists as molecules and hydrogen ions, H do not present. So, blue litmus paper does not change its colour.
2 2 4
+
+
When it is dissolved in water, acid molecules ionise to produce hydrogen ions, H . The presence of hydrogen ions, H causes the
acid to show its acidic properties. Therefore, the colour of blue litmus paper changes to red.
3. Apakah definisi secara operasi bagi asid dalam eksperimen ini?
What is the operational definition of acid in this experiment?
Asid ialah bahan kimia yang menukarkan kertas litmus biru kepada merah apabila kertas litmus biru dicelupkan
ke dalam asid yang telah dilarutkan di dalam air./ Acid is a substance that changes the blue litmus paper to red when blue
litmus paper is dipped in an acid that is dissolved in water.
Kesimpulan/Conclusion:
Hipotesis diterima. Air diperlukan untuk membolehkan asid menunjukkan sifat keasidan.
Hypothesis is accepted. Water is needed for an acid to show its acidic properties.
3. Tanpa air, asid kering wujud dalam molekul kovalen. . Ion-ion hidrogen, H + tidak wujud. Maka,
asid kering tidak menunjukkan sifat keasidannya.
covalent molecules. Hydrogen ions, H +
Without water, dry acid exists as . do not exist. So, dry acid does
not show its acidic properties.
(a) Apabila gas hidrogen klorida dilarutkan ke dalam air, asid hidroklorik dihasilkan. Asid hidroklorik
mengion dalam air untuk membentuk ion-ion hidrogen, H + . Maka, asid hidroklorik
boleh menunjukkan sifat keasidan. .
hydrochloric acid
When hydrogen chloride gas is dissolved in water, is produced. Hydrochloric acid
ionises hydrogen ions, H .
+
in water to form . Therefore, hydrochloric acid can show
acidic properties.
.
(b) Apabila gas hidrogen klorida dilarutkan ke dalam metilbenzena, gas hidrogen klorida wujud dalam
molekul kovalen. . Ion-ion hidrogen, H + tidak wujud. Maka, gas hidrogen klorida tidak

menunjukkan sifat keasidan.
covalent molecules.
When hydrogen chloride gas is dissolved in methylbenzene, hydrogen chloride gas exists as .
Hydrogen ions, H +
do not exist. So, hydrogen chloride gas does not show acidic properties.









113

Gas hidrogen klorida Gas hidrogen klorida
Hydrogen chloride gas Hydrogen chloride gas


Cl –
H + H Cl
–
Cl – –
Ion hidrogen H + Molekul neutral H Cl
Hydrogen ions Neutral molecules
–
H + Cl – H Cl
Air Metilbenzena
Water Methylbenzene
Rajah/Diagram 6.5
4. Alkali hanya menunjukkan sifat kealkalian dengan kehadiran air. TP 2
©PAN ASIA PUBLICATIONS
Alkali only shows its alkaline properties in the presence of water.
5. Alkali melarut dalam air untuk menghasilkan ion hidroksida, OH – . Kehadiran ion hidroksida, OH
–
menyebabkan alkali menunjukkan sifat kealkalian.
hydroxide ions, OH –
Alkali dissolves in water to produce . The presence of hydroxide ions, OH is responsible for the
–
alkaline properties.
Pautan Interaktif

Mengkaji peranan air dalam menunjukkan sifat kealkalian.
To study the role of water in showing alkaline properties.


Contoh/ Example:
1. Ion Ba dan ion OH dalam pepejal barium hidroksida tertarik antara satu sama lain oleh
–
2+
daya elektrostatik yang kuat . Ion-ion ini tidak boleh bergerak bebas . Maka, pepejal
barium hidroksida tidak menunjukkan sifat kealkaliannya.
strong electrostatic forces.
Ba ions and OH ions in solid barium hydroxide are attracted to each other by .
–
2+
more freely.
These ions are not able to . Therefore, solid barium hydroxide does not show its alkaline
properties.
2. Apabila dilarutkan ke dalam air, pepejal barium hidroksida mengion membentuk ion Ba dan ion OH yang
–
2+
boleh bergerak bebas. . Maka, larutan barium hidroksida menunjukkan sifat kealkaliannya
kerana kehadiran ion OH .
–
When dissolved in water, the solid barium hydroxide ionises to form Ba ions and OH ions that are able to
–
2+
move freely.
. Therefore, barium hydroxide solution show alkaline properties due to the presence of
OH ions.
–
Tambah air –
Add water OH – Ba 2+ Ion barium dan ion hidroksida
Dalam keadaan pepejal, 2+ OH bergerak bebas dalam air.
ion barium dan ion hidroksida OH – Ba 2+ OH – Ba 2+ Ba OH – Barium ions and hydroxide ions
tidak bergerak bebas. Ba 2+ can move freely in water.
In solid state, barium ions Ba 2+ OH – Ba 2+ OH – OH – Ba 2+
and hydroxide ions are
not free to move.
Rajah/Diagram 6.6
Contoh/ Example:
1. Apabila dilarutkan ke dalam air, gas ammonia mengion untuk membentuk ion NH dan ion OH yang boleh
+
–
4
bergerak bebas. . Maka, larutan akueus ammonia menunjukkan sifat kealkaliannya kerana
kehadiran ion OH .
–
When dissolved in water, the ammonia gas ionises to form NH ions and OH ions that able to
–
+
4
move freely.
. Therefore, aqueous ammonia solution shows alkaline properties due to the presence of
OH ions.
–
114

2. Apabila dilarutkan ke dalam propanon, gas ammonia wujud sebagai molekul kovalen. .
Ion OH – tidak wujud. Maka, gas ammonia tidak menunjukkan sifat kealkaliannya.
covalent molecules. OH ions
–
When dissolved in propanone, ammonia gas exists as . .
do not exist. So, ammonia gas does not show its alkaline properties.


Gas ammonia Gas ammonia
Ammonia gas Ammonia gas
Ion ammonium
Ammonium ions
OH – NH 4 + NH 3
NH 4 + Molekul NH
Ion hidroksida OH – neutral 3
Hydroxide ions – +
©PAN ASIA PUBLICATIONS
OH NH 4 Neutral NH 3
molecules
Air Propanon
Water Propanone
Rajah/Diagram 6.7




Uji Kendiri 6.1

1. Berdasarkan definisi Arrhenius, takrifkan yang berikut.
Based on Arrhenius’s definition, define the following.
(a) Asid/ Acid
+
Bahan kimia yang mengion dalam air untuk menghasilkan ion hidrogen, H ./ A chemical substance that ionises in
water to produce hydrogen ions, H .
+

(b) Alkali/ Alkali
–
Bahan kimia yang mengion dalam air untuk menghasilkan ion hidroksida, OH ./ A chemical substance that ionises in
water to produce hydroxide ion, OH .
–

2. Terangkan kebesan asid sulfurik, H SO .
2
4
Explain the basicity of sulphuric acid, H SO .
2
4
Asid sulfurik, H SO ialah asid diprotik kerana boleh mengion di dalam air untuk menghasilkan dua ion hidrogen, H +
2 4
per molekul asid./ Sulphuric acid, H SO is a diprotic acid because it can ionise in water to produce two hydrogen ions, H per
+
2 4
molecule of acid.
3. Rajah di bawah menunjukkan perbualan antara Siti dengan emaknya. KBAT Mengaplikasi
Diagram below shows a conversation between Siti and her mother.
Mak, mengapakah sabun yang
baru dikeluarkan daripada
kotak tidak berasa licin?
Mum, why the soap taken out
from its box don't feels slipery?





Berdasarkan pengetahuan anda, cadangkan penjelasan yang emak Siti patut berikan.
Based on your knowledge, suggest an explanation that Siti's mother should give.
Tanpa air, ion hidroksida, OH di dalam sabun tidak dapat bergerak bebas tetapi masih terikat dalam struktur
–
kekisinya. Maka, sabun tidak dapat menunjukkan sifat kealkaliannya./ Without water, hydroxide ions, OH in soap cannot
–
move freely but still are bonded in the lattice structure. Therefore, soap cannot show its alkaline properties.











115

6.2 Nilai pH
pH Value

A Nilai pH Asid dan Alkali
The pH Values of Acids and Alkalis
1. Skala pH dengan julat pH daripada 0 hingga 14 digunakan untuk menunjukkan keasidan dan kealkalian sesuatu
larutan akueus.
pH scale with the pH range of 0 to 14 is used to indicate the acidity and the alkalinity of an aqueous solution.

Semakin berasid Semakin beralkali
More acidic More alkaline
Neutral


0 1 2 3 4 5 6 7 8 9 10 11 12 13 14


Rajah/Diagram 6.8 Skala pH/ pH scale
2. pH merupakan suatu pengukuran logaritma ke atas kepekatan ion hidrogen, H + yang terkandung di dalam
suatu larutan akueus. +
pH is a logarithmic measurement towards the concentration of hydrogen ions, H in an aqueous solution.

pH = –log [H ]
+
• log = logaritma asas 10/ logarithm to the base 10
• [H ] = kepekatan ion hidrogen, H (mol dm ) di dalam larutan akueus/
+
–3
+
concentration of hydrogen ions, H (mol dm ) in the aqueous solution
–3
+
3. Larutan dengan nilai pH kurang daripada 7 adalah berasid manakala larutan dengan nilai pH lebih daripada 7
adalah beralkali.
A solution with a pH value less than 7 is acidic whereas the solution with a pH value greater than 7 is alkaline.
Contoh/ Example:
• pH 1 - 2: asid kuat/ strong acid
• pH 3 - 6: asid lemah/ weak acid
= – (–0.7) ©PAN ASIA PUBLICATIONS
• pH 7: neutral/ neutral
• pH 8 - 11: alkali lemah/ weak alkali
• pH 12 - 14: alkali kuat/ strong alkali
4. Nilai pH bagi sesuatu larutan akueus boleh diukur dengan menggunakan: TP 1
The pH values of an aqueous solution can be measured by using:
(a) Penunjuk universal / Universal indicator
(b) Meter pH / pH meter
(c) Kertas pH / pH paper



Contoh/Example 1 TP 3

Hitung nilai pH bagi asid nitrik, HNO yang mempunyai kepekatan ion hidrogen 0.2 mol dm .
–3
3
Calculate the pH value of nitric acid, HNO with a concentration of 0.2 mol dm hydrogen ions.
–3
3

Penyelesaian/Solution :
Diberi bahawa kepekatan ion hidrogen = 0.2 mol dm –3
Given that the concentration of hydrogen ions
pH = –log[0.2]
= 0.7
∴Nilai pH asid nitrik/ pH value of nitric acid, HNO = 0.7
3









116

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