6$03/(Doret Spykerman • Clarisa · PDF fileAll matter is made up of small particles of...

Physical SciencesChemistry Grade 10

Textbook and Workbook

Santie du Plessis • Carlien Fanoy Marga Koelman • Patricia Lees-Rolfe

Judy McDougall • Hela RouxDoret Spykerman • Clarisa SteynSAMPLE

Doc ScientiaPosbus 7011

Ansfrere 1711

www.docscientia.co.za

For any queries and feedback: [email protected]

Jacques Fanoy or Stephan FanoyOffice: 011 472 8728

Fax: 086 546 1423

ISBN: 978-1-920537-13-5

First edition December 2009Second edition December 2010

Third edition December 2011Revised edition December 2012; 2013; 2014; 2015

Graphic design: Helene Jonck

All rights reserved. No part of this publication may be reproduced in any form or by any means –

mechanical or electronic, including recordings or tape recordings and photocopying – without the prior permission of the publisher.SAMPLE

Unit Page

KNOWLEDGE AREA MATTER AND MATERIALS 13

Unit 1 MACROSCOPIC PROPERTIES OF MATTER 13

Activity 1 15

Case study: Mopani worms 16

1.1 Mixtures 17

Practical activity 1 19

1.2 Pure substances 20

Activity 2 21


1.3 Names and formulae of substances 23

Activity 3 28

Exercise 1 29

1.4 Properties of materials 31


Activity 4 34

1.4.1 Electrical conductors and insulators 35

Experiment 1 35

1.4.2 Thermal conductors and insulators 37

Experiment 2 37

1.4.3 Magnetic and non-magnetic materials 39

Experiment 3 39

Exercise 2 41

Summary of Unit1 43

Mind maps of Unit 1 44

Unit 2 STATES OF MATTER AND THE KINETICMOLECULAR THEORY 45

2.1 States of matter 45


2.1.1 Different states 46


2.1.2 Determining the state of a substance by looking at melting and boiling points 51

Exercise 3 52

Experiment 4 53

2.2 The kinetic molecular theory 56

Exercise 4 57

Summary of Unit 2 60


Unit 3 THE ATOM: THE BASIC BUILDING BLOCK OF ALL MATTER 63

3.1 Atomic models 63

Activity 5 65

3.2 Atomic structure 66

Activity 6 68

3.3 Isotopes 69

Exercise 5 70

3.4 Electron configuration 73

Exercise 6 75

INDEX

SAMPLE



Unit 4 THE PERIODIC TABLE 83

4.1 Composition 83

4.2 Information 84

4.2.1 General information 84

4.2.2 Zigzag line 85

4.2.3 Valence electrons 85

4.2.4 Reactivity 86

4.2.5 Atomic mass and atomic number 86

4.2.6 Trends in the Periodic Table (periodicity) 87

Activity 7 89

4.2.7 Atomic radius 90

4.2.8 Ionisation energy 90

4.2.9 Electron affinity 92

4.2.10 Electronegativity 91

Activity 8 93

Exercise 7 94



Unit 5 CHEMICAL BONDS 103

5.1 Covalent bonds 104

Exercise 8 105

5.2 Ionic bonds 106

5.3 Metallic bonds 107


Exercise 9 108


Unit 6 MATTER IS COMPOSED OF PARTICLES 111

Experiment 5 112


6.1 Chemical bonds 114

6.1.1 Covalent bonds 114

6.1.1.1 Covalent molecular structures 114

Case study: The buckyball or buckminsterfullerene 114

6.1.1.2 Covalent network structures (macromolecules) 116

6.1.2 Ionic bonds 116

6.1.3 Metallic bonds 117

6.2 Different types of formulae 117

6.2.1 Molecular formulae 117

6.2.2 Empirical formulae 117


6.3 Models of molecules 118

Activity 9 119

Exercise 10 121



Question paper 124

KNOWLEDGE AREA CHEMICAL CHANGE 131

Unit 1 PHYSICAL AND CHEMICAL CHANGE 131

SAMPLE

1.1 Separation of particles 131

1.1.1 Physical change 131

1.1.1.1 Change of condition (state) 132


1.1.1.2 Change of shape 135

1.1.1.3 Colour change 136

Exercise 11 136

1.1.2 Chemical change 138


1.1.3 Change in particles and mass 140

Experiment 6 140

Experiment 7 (demonstration) 141

Exercise 12 143

1.2 Laws 144

1.2.1 Law of constant composition 144


1.2.2 Law of conservation of mass 146

1.2.3 Law of volume relationships in gas reactions 146


Experiment 8 148

Experiment 9 148

Exercise 13 150



Unit 2 WRITING AND BALANCING CHEMICAL EQUATIONS 155

2.1 Balancing of chemical reactions 155

Exercise 14 158

2.2 Energy changes 159

Exercise 15 160



Unit 3 REACTIONS IN AQUEOUS SOLUTIONS 163

3.1 Ions in aqueous solutions 163

3.1.1 Dissociation and ionisation 164

3.1.2 Hydration 165

3.1.3 Chemical equation for the dissolution process 165


Case study: Hard and soft water 167

Case study: Acid rain 168

Exercise 16 170

3.2 Electrolysis and the extent of ionisation as a measure of conductivity 171

Experiment 10 172

Exercise 17 173

3.3 Precipitation reactions 174

3.3.1 What is a precipitation reaction? 174

3.3.2 Method of writing equations for the precipitate reactions

175

3.3.3 Tests for anions 175

Experiment 11 176

SAMPLE

Exercise 18 178

3.4 Other chemical reactions in aqueous solutions 181

3.4.1 Ion exchange reactions 181

A. Precipitation reactions 181

B. Gas formation 181

C. Acid base reactions (transfer of protons) 182

3.4.2 Redox reactions 184

Experiment 12 185

Exercise 19 187



Unit 4 QUANTITATIVE ASPECTS OF CHEMICAL CHANGE 193

4.1 The mole concept 193

4.1.1 Atomic mass 196

4.1.2 Molar mass and formula mass 196

Exercise 20 198

4.2.1 The relationship between mole, mass and molar mass 199

4.2.2 Empirical formula 200

Exercise 21 202

4.3 Determining the composition of compounds 204

4.3.1 Determine the amount of mol water of crystallisation in copper(II)sulphate 204

4.3.2 Percentage composition of a compound 204

Exercise 22 205

4.4 Molar gas volume and concentration 206

4.4.1 Molar gas volume 206

Exercise 23 207

4.4.2 Concentration 210

Exercise 24 211

4.5 Stoichiometric calculations 212

4.5.1 Calculations based on balanced equations 212

Exercise 25 215



Question paper 221

KNOWLEDGE AREA CHEMICAL SYSTEMS 227

HYDROSPHERE 227

1. Why is water important? 228

2. The water cycle is necessary because... 228

3. Processes in a hydrosphere 230

4. The distribution of water 231

Exercise 26 232

5. Systems on earth 235

6. How does sunlight influence the water cycle? 237

7 The hydrosphere’s interaction with 238

SAMPLE

7.1 Atmosphere 238

7.2 Biosphere 238

7.3 Lithosphere 239

8. Influence of dams on the environment 240

Activity 10 241

Project: Quality and purity of water 242

Exercise 27 243

Summary of Knowledge Area 248

Mind maps of Knowledge Area 250

Question paper 253

Information sheets 257

Work cited 259

SAMPLE

Name

Teacher

Class/Combination

Assessment

Term Activity Mark Parent

Term 1 Control test

Experiment

Term 2 Class test

Experiment

Exam

Term 3 Control test

Project

Term 4 Class test

PROGRAM OF FORMAL ASSESSMENT FOR GRADE 10ASSESSMENT TASKS (25%) END-OF-YEAR

ASSESSMENT (75%)TERM 1 TERM 2 TERM 3 TERM 4

20% Experiment

10% Control test

20% Experiment

20% Mid-year Examination (1½ hours)

20% Project 10% Control test

2 × Final Examinations –Paper 1 and 2(2 × 150 marks = 300 marks)

Total: 30 marks Total: 40 marks Total: 30 marks Total: 300 marksTotal = 400 marksFinal mark = 25% Assessment tasks + 75% Final examSAMPLE

Doc Scientia CHEMISTRY textbook and workbook - Grade 10 13

KNOWLEDGE AREA: MATTER AND MATERIALS

Matter is everything that: has mass and occupies space.

Matter consists of three states, namely: solid, liquid and gas.All matter is made up of small particles of elements from the Periodic Table. These small particles determine the properties and reactivity of the substance.

UNIT 1 MACROSCOPIC PROPERTIES OF MATTER

Macroscopic properties of matter

States of matter and the kinetic molecular theory

The atom Periodic Table

Matter is composed of particles.

Chemical bonds

Matter and materials

Mixtures

Pure substances

Names and formulae Electrical conductors and insulators

Thermal conductors and insulators

Magnetic and non-magnetic materials

Properties

Macroscopic properties of matter

SAMPLE

matter and materials

14 Doc Scientia CHEMISTRY textbook and workbook - Grade 10

Matter is used to manufacture items essential to humans (food, clothes, accommodation, transport, security systems, etc.).

The properties of matter are determined by its composition.A substance is chosen for a purpose according to its properties. A few examples:• Steel is chosen for construction due to its strength.• Metals are ductile and can be pulled into wires, which are then used for:

- security systems. - conducting wires, since metals are good conductors of electricity.

• Metals are malleable. They can be reshaped into sheets, which are then used to produce pots and pans, for example.

• Substances that have magnetic properties are used to produce magnets and electromagnets. Iron and steel are examples of this.

• Handles of pots and pans are made out of wood or rubber as they are good thermal insulators.• Aluminium is light and does not rust, so it can be used for window frames and door frames.• Rubber is used to make wetsuits, as it is waterproof. A layer of air is trapped between the diver and

the suit, which acts as a good thermal insulator and keeps the diver warm.• Plastic is used for raincoats and umbrellas, as it is also waterproof.• Wool can trap air between its fibres and is therefore a good thermal insulator. Wool is used to

produce blankets, jerseys, jackets and other warm clothing.

The properties of matter can be divided as follows:

Examples• Strength of material• Thermal properties• Electrical properties• Magnetic properties• Solubility • Brittleness, ductility and malleability• Tensile strength• Melting and boiling points

Examples• Constituent atoms• Types of bonds• Intermolecular forces

Properties of matter

Microscopic properties

Cannot be experienced by your senses.

Macroscopic properties

Can be experienced by your senses.

SAMPLE



Activity 1 Date:Work in groups of two and look at the labels of five products, for example: instant coffee, potato crisps, tinned vegetables, apricot jam and packets of pasta and sauce.

Complete the following table.

Product Ingredients

Instant coffee

Potato crisps

Tinned vegetables

Apricot jam

Packet of pasta and sauce

1. What do the different ingredients tell you about the product?

___________________________________________________________________________

2. Why are the ingredients mentioned on the label?

___________________________________________________________________________

___________________________________________________________________________SAMPLE



Case study Date:Mopani wormsRead the following passage and then answer the questions:

Certain indigenous South Africans use Mopani worms as a source of protein. This has developed into a profitable industry with low costs, few overheads and a protein-rich food source.Mopani worms are the edible species of the caterpillar Gonimbrasia belina. Other traditional names for the Mopani worm are: mashonja (Botswana: Kalanga), phane (Botswana: Setswana), mašotša (South Africa: Sepedi), mashonzha (South Africa: Tshivenda), finkubala (Zambia), mcimbi (Zimbabwe: Ndebele) and omagungu (Namibia).The worms are usually found in Mopani trees, which are predominately found in grassland and bushveld.

When the worms are collected, the tail is cut off and the slimy green innards are squeezed out like toothpaste.The worms can be preserved in the following ways:• Squashed flat and dried in the sun.• Smoked, which results in a very different flavour.• Industrially pickled and bottled.

The dried worms can be eaten just as they are. They do not have much flavour, and taste like dried leaves. They are often marinated and served with tomato or chilli sauce.

Quick factsAdditive: A substance that is added in small quantities to improve the flavour, e.g. MSG.

Preservative: Substance used to preserve and protect, e.g. sulfur dioxide.

Ingredients: The substances of which the product is composed.

SAMPLE



They can also be marinated and roasted until crisp. Nowadays they are served as a speciality dish in some upmarket restaurants.

Questions:1. Name and discuss three types of preservation that are mentioned in the case study.

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

2. Name and discuss two other types of preservation used in industry.

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

3 What is a preservative? _____________________________________________________________________

_____________________________________________________________________

4. Name one preservative mentioned in the case study.

_____________________________________________________________________

Matter can be classified as mixtures or pure substances (consists of a single element or compound). This is revision of work done in Grade 9.

1.1 MixturesMixtures are common in our everyday lives: we breathe a mixture of gases in the air; we eat fruit salad; boerewors is a mixture of meat, fat and spices.SAMPLE



What are the properties of a mixture?• The components are not in a fixed ratio.• The components keep their own properties.• The components can be separated easily by physical means.

There are two types of mixtures.

A homogeneous mixture is a mixture with a uniform composition (that will remain constant for a period of time).

This means that the components of a homogeneous mixture:• cannot be distinguished from each other. • are in the same state.

This means that the components of a heterogeneous mixture:• are not in the same state. Examples: mud, smoke from a fire• are easily distinguishable. Examples: cool drink and ice cubes, potjiekos (meat, vegetables and gravy)

A heterogeneous mixture is a mixture with a non-uniform composition. Particles can be distinguished.

Homogeneous mixture Heterogeneous mixture

Mixtures

Examples - Air is a mixture of different gases – all in the same state. - Alloys are mixtures of metals. - Cool drink concentrate in water consists of two liquids that are mixed.

Quick factsThe following alloys consist of:brass: mixture of copper and zincsteel: mixture of iron and carbonbronze: mixture of copper and tinstainless steel: mixture of iron, chrome and nickel

SAMPLE



Examples of mixtures:

Example Components Type of mixture

Air Nitrogen, oxygen, carbon dioxideHomogeneous mixture: Uniform composition (will remain constant for a period of time).

An alcoholic drink Alcohol in water

Brine Salt in water

Steel Carbon in iron

Smoke from a fire Soot and ash in air

Heterogeneous mixtures: - Particles are not uniform.- Can be distinguished.

Salad dressing Oil, vinegar, water and herbs

Mud Sand in water

Orange juice Fruit pulp in fruit juice

Dough Flour, eggs and milk

Carbonated (fizzy) cool drink

Carbon dioxide in cool drink

Examples

Quick factsBlood is a heterogeneous mixture because it consists of different particles (like platelets, plasma, etc.) that are not necessarily spread uniformly.

Practical activity 1 Date:Work in a small group and make the following mixtures:• Sand and water• Potassium dichromate crystals (K2Cr2O7) and water• Iodine and ethanol• Iodine and water

Complete the following table.

MixtureHeterogeneous or homogeneous?

Are the constituent particles distinguishable?

Sand and water

Potassium dichromate crystals (K2Cr2O7) and water

Iodine and ethanol

Iodine and waterSAMPLE



1. What is a homogeneous mixture?

_________________________________________________________________________

_________________________________________________________________________

2. What is a heterogeneous mixture? _________________________________________________________________________ _________________________________________________________________________

1.2 Pure substances

Pure substances can be elements or compounds. They are substances with one type of constituent particle.

ElementsExamples: Na, Fe, O2

CompoundsExamples: H2O, NaCℓ

Pure substances

Pure substancesComposed of only one type of particle. They can be elements or compounds (different elements bonded together by a chemical reaction).

Mixture

Elements Compounds

A pure substance consisting of only one type of atom.

A pure substance consisting of two or more types of atoms that are chemically bonded.

Composed of different elements and/or compounds.SA

MPLE



Pure substancesComposed of only one type of particle. They can be elements or compounds (different elements bonded together by a chemical reaction).

Mixture

Elements Compounds

A substance that cannot be broken down into simpler substances.

A substance that can be broken down into simpler particles.

Can be separated mechanically.

Particles cannot be broken down. Particles can only be broken down by chemical means.

Can be separated by physical means (hand sorting, separating funnel, distillation, evaporation, etc.).

Smallest particle is either an atom, a diatomic element (e.g. H2), a molecule of the same atom (e.g. S8) or a positive ion (metallic bond).

Smallest particle is amolecule (covalent bond) oran ion (ionic bond).

Particles are according to composition of mixture.

Examples:Mg, Cu, Zn, S, F2, S8

Examples:H2O, HCℓ, NaCℓ

Examples:Air, mixed vegetables, sugar solution

Activity 2 Date:1 Classify the following as pure substances or mixtures.

Substance Pure substance or mixture

1.1 Blood

1.2 Dyes

1.3 Self-raising flour

1.4 Muesli

1.5 Copper wire

1.6 Distilled water

1.7 Table salt

1.8 Milk

1.9 Bronze

1.10 Tea

1.11 Oxygen

1.12 AirSAMPLE



2 Classify the following as homogeneous or heterogeneous mixtures, or pure substances. If it is a pure substance, state whether it is an element or a compound.

SubstanceMixture:

homogeneous/heterogeneous

Pure substance:element/compound

2.1 Sugar

2.2 Magnesium ribbon

2.3 Vegetable soup

2.4 Bath oil

2.5 Tin of assorted biscuits

2.6 Peanuts and raisins

2.7 Copper wire

2.8 Bicarbonate of soda (Baking soda)

Practical activity 2 Date: Work in a small group. • Cut some filter paper into long thin strips.• Use four test tubes containing a small amount of water each.• Wet a red Smartie and make a mark with it on one strip of filter paper.• Place the strip in a test tube so that the bottom end of it just touches the water. The top end should

hang over the edge of the test tube. The mark should just be above the water level.• Repeat these steps with the brown, green and blue Smarties.• Allow the test tubes to stand for a while, allowing the filter paper to absorb some water.• Make observations. • This experiment can also be done with ink from non-permanent markers, e.g. koki’s.

red dot brown dot blue dotgreen dotSAMPLE



Observations:

________________________________________________________________________________

________________________________________________________________________________

Conclusions:

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

1.3 Names and formulae of substances

All matter consists of elements. Elements can be grouped as follows:

Interesting factsIn 1869 two scientists – the Russian, Dmitri Mendeleev and the German, Julius Lothar Meyer – arranged the elements in a Periodic Table. Mendeleev used chemical reactivity, and Meyer the physical properties. The two tables were suprisingly quite similar. These were the first versions of the Periodic Table that we use today.

Elements

Metals Metalloids Non-metals

Left of dividing line,e.g. Na, Mg, Zn, Pb

On either side adjacent to the dividing line, e.g. Si, Ge

Right of the line,e.g. S, O2, Cℓ2, Br2

SAMPLE



H

Li Be

Na Mg

K Ca

B C N O F Ne

He

Aℓ Si P S Cℓ Ar

Ge As

Sb

1 2 13 14 15 16 17 18

AtPo

Te

Description Example

Elements on the left of the Periodic Table are usually named first.

NaCℓ Sodium chloride

Names of elements on the right of the Periodic Table change by adding -ide at the end.

COCarbon monoxide = oxygen changed to oxide.

“Mono” means one, “di” means two and “tri” means three, showing the number of atoms of that element.

COcarbon monoxide – 1 OCO2

carbon dioxide – 2 OsNO2

nitrogen dioxide – 2 OsSO3

sulfur trioxide – 3 Os

Some substances have common names, too. H2O hydrogen oxide = waterHCℓ hydrogen chloride = hydrochloric acid = swimming pool acid

Polyatomic ions, which always consist of the same ratio of elements.

Na2SO4sodium sulphateCaSO4calcium sulphate MgSO4magnesium sulphate

Each element has a unique name. When compounds are formed, the name must reflect the components.The following table applies to the naming of compounds:

SAMPLE



• When there is a bracket then a subscript, the subscript refers to everything inside the bracket. (Polyatomic ions will be discussed in more detail later.) Example: magnesium nitrate is Mg(NO3)2. This indicates one magnesium (Mg) and two nitrate ions (NO3), in total giving two nitrogen atoms (N) and six oxygen atoms (O). If the brackets were left out it would have meant 32 oxygen atoms, which is impossible.

• The formula can represent a molecule, as in H2O (water), or it could be the empirical formula, as in NaCℓ, which represents the smallest ratio of the components in a crystal.

• Positive ions are written first and negative ions second.

To write a formula you need to take into account the constituents as well as the ratio in which they are combined.• Water consists of hydrogen and oxygen in the ratio 2:1. Therefore the formula is H2O. Two hydrogen

atoms and one oxygen atom.

2 H 1 O H2O

+

+

• The number written at the bottom (subscript) refers to the preceding element. Na2SO3 has two sodium, one sulfur and three oxygen atoms. Na:S:O are in the ratio 2:1:3

Na2SO3 2 Na S 3 O

+

+

+

+

Mg(NO3)2 Mg 2 N 6 O

+

+

+

+

H+ HCℓCℓ-

+

+SAMPLE



The following are names of ions that are used often.

Negative ions (anions)

Polyatomic ionsMonoatomic ions

(the suffix of the name changes to -ide)

OH- Hydroxide SO42- Sulphate F- Fluoride

NO3- Nitrate SO3

2- Sulphite Cℓ- Chloride

NO2- Nitrite S2O3

2- Thiosulphate Br- Bromide

MnO4- Permanganate O2

2- Peroxide I- Iodide

CℓO3- Chlorate MnO4

2- Manganate S2- Sulphide

HCO3- Hydrogen carbonate HPO4

2- Hydrogen phosphate N3- Nitride

HSO3- Hydrogen sulphite CrO4

2- Chromate O2- Oxide

HSO4- Hydrogen sulphate Cr2O7

2- Dichromate P3- Phosphide

H2PO4- Dihydrogen phosphate CO3

2- Carbonate

CℓO- Hypochlorite C2O42- Oxalate

CH3COO- Acetate PO43- Phosphate

Positive ions (cations)

Be careful of the spelling of the ions. It is important that if it ends in “te” or “de” this changes the composition of the ion. “-ate” and “-ite” refer to the different number of oxygen atoms present.

NH4+ Ammonium Cu2+ Copper(II) Aℓ3+ Aluminium

H+ Hydrogen Ca2+ Calcium Cr3+ Chromium(III)

K+ Potassium Be2+ Beryllium Fe3+ Iron(III)

H3O+ Hydronium/oxonium Ba2+ Barium Co3+ Cobalt(III)

Cu+ Copper(I) Sn2+ Tin(II) Cr6+ Chromium(VI)

Hg+ Mercury(I) Pb2+ Lead(II) Mn7+ Manganese(VII)

Na+ Sodium Zn2+ Zinc(II)

Ag+ Silver Mg2+ Magnesium

Li+ Lithium Cr2+ Chromium(II)

Mn2+ Manganese(II)

Fe2+ Iron(II)

Co2+ Cobalt(II)

Ni2+ Nickel(II)SAMPLE

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