Applied Chemistry–I

RAVI SAINIM.Sc.Lecturer

Department of ChemistryGovt. Polytechnic, Faridabad

(An ISO 9001:2008 Certified Company)

Vayu Education of India2/25, Ansari Road, Darya Ganj, New Delhi-110 002

Applied Chemistry–I

Copyright ©VAYU EDUCATION OF INDIA

ISBN: 978-93-82174-36-3

First Edition: 2013

Price: 150.00

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Dedicatedt o

My Loving ParentsShri. Indraj Singh Saini

andSmt. Geeta Devi Saini

andAll those who supported me during journey of life

Syllabus

DETAILED CONTENTS1. Basic Concepts of Chemistry (07 hrs)

1.1 Definition of chemistry and its importance1.2 S.I. Units of pressure, volume, density, specific gravity, surface tension and viscosity1.3 Matter, element, compound and mixtures, atoms, molecules, ions, symbols and formulae

(recapitulation only)1.4 Writing chemical formulae of simple chemical compounds and calculation of percentage

composition of chemical compounds1.5 Chemical equations, thermo-chemical equations, balancing of chemical equations by HIT

and TRIAL method2. Atomic Structure and Chemical Bonding (11 hrs)

2.1 Introduction to atom and its constituent particles, Dalton’s atomic theory, Rutherford’sand Bohr’s model of atom (overview only)

2.2 Atomic number, mass number, isotopes, isobars and isotones2.3 Concept of atomic orbitals, shapes of s and p- orbitals, quantum numbers2.4 Aufbau principle, Pauli’s exclusion principle, Hund’s rule and electronic configuration of

elements (upto Z=30)2.5 Chemical bond, types of chemical bonding: ionic and covalent (sigma and pie bonds) with

suitable examples.3. Water (10 hrs)

3.1 Sources of water3.2 Types of water based on dissolved salts.

3.2.1 Hard water, soft water

viii Applied Chemistry–I

3.2.2 Units to measure water hardness in ppm (mg/l) and simple numericals, degreeClark & degree French

3.3 Disadvantages of use of hard water in domestic and industrial applications (mainly boilerfeed water)

3.4 Methods to remove water hardness by3.4.1 Ion exchange process3.4.2 Lime-soda process3.4.3 Reverse Osmosis method

3.5 Quality criteria of drinking water as per BIS. (with special emphasis on hardness, totaldissolved solids (TDS), Chloride, alkalinity present in water)

4. Solutions (07 hrs) 4.1 Concept of homogenous solution, brief introduction of the terms (i) Ionization

(ii) Acidity (iii) Basicity (iv) equivalent weight and gram equivalent weight with suitable examples 4.2 Strength of a solution (i) Normality (ii) Molarity (iii) Molality as applied in relation

to a solution. 4.3 Definition of pH, simple numericals and different industrial applications of pH. 4.4 Buffer solution and applications of buffer.

5. Electrolysis (08 hrs)5.1 Electronic concept of oxidation and reduction5.2 Definition of the terms: Electrolytes, Non-electrolytes with suitable examples5.3 Faraday’s Laws of Electrolysis and simple numericals5.4 Different industrial applications of ‘Electrolysis’5.5 Applications of redox-reactions in battery technology such as (i) Dry cell (ii) lead

acid battery and (iii) Ni-Cd battery6. Environmental Chemistry (05 hrs)

6.1 Brief introduction to Environmental Chemistry and Pollution6.2 Causes and effects of air, water and soil pollutions6.3 Role of chemistry in controlling air, water and soil pollutions6.4 General idea of ozone depletion, global warming

LIST OF PRACTICALS1. Volumetric analysis and study of apparatus used therein. Simple problems on volumetric

analysis equation2. Preparation of standard solution of oxalic acid or potassium dichromate3. Determine the strength of solution of HCl with the help of a solution of NaOH and an

intermediate solution of standard oxalic acid4. Estimation of total dissolved solids (TDS) in water sample gravimetrically5. Estimation of total alkalinity of water volumetrically

Contents ix

6. Determine the pH of given sample using pH meter7. Determine the percentage purity of commercial sample like blue vitriol, 12.5 g. of which

have been dissolved per litre. Given M/20 Na2S2O3.8. Determination of solubility of a solid at room temperature9. To verify the first law of electrolysis (electrolysis of copper sulphate solution using copper

electrode).SUGGESTED DISTRIBUTION OF MARKS

Topic No. Time Allotted (Hrs) Marks Allotted (%) 1 07 14 2 11 20 3 10 20 4 07 16 5 08 16 6 05 14

Total 48 100

Preface

Basic Concepts: The first chapter of the book introduces the student to the basic concepts ofchemistry, viz Elements, compounds, mixtures, symbol of elements of the periodic Table, the

atoms, molecules, ions, valency of elements, writing of chemical formula and balancing of chemicalequations.

Atomic Structure and Chemical Bonding:In chapter-2, various models of atoms are discussed i.e., J.J. Thomson model, Rutherford model,

Bohr model, wave mechanics model and quantum number and how to make electronic configuration ofatoms is also included in this chapter, description of ionic and covalent bonding is also gives.

Chemical Bonding: In Chapter-2 are described different types of bonding, viz, ionic, covalentand coordinate. Therein is discussed the orbital concept of covalent bond and highlights the differencesbetween covalent and electrovalent compounds. Introduces the concept of bond length, bond angle,bond energy and bond order of compounds. Distinguishes between (sigma) and (Pi) bonds.Rationalizes the shapes of molecules in terms of valence Bond theory as well as by molecular orbitalmethods. A theoretical explanation has been put forth to understand the properties exhibited by metals.

Water: The sources of water are highlighted in Chapter-3. The water is contaminated with a widerange of impurities. The so called “Hard water” constitutes a nuisance when used for domestic purposesas well as in industry. There are methods available for its evaluation as well as for removing hardness(temporary and permanent). Parameters have been laid down by the World Health Organisation (WHO)for water to be used for human consumption.

Solutions: When a solid (Solute) is dissolved in a liquid (solvent), one gets a solution. The soluteand solvent may be either gas, liquid or solid, and different types of solutions are possible (Chapter-4).Introduction is made to the term ‘equivalent weight’ in relation to an acid/base or an oxidizing/ reducingagents. The determination of the above mentioned substances is effected by volumetric analysis. Inthis context the term ‘indicater’ ‘standard solution’, ‘normality’, ‘molarity’, ‘molality’, ‘mole fraction’and ‘mass fraction’ are discussed. The concept of pH has been introduced, including its application inEngineering and agriculture.

Electrolysis: The use of electricity to bring about a chemical change falls within the domain ofelectrolysis (Chapter 5). Thus, for example, the electrolysis of Aq. NaCl produces H2(g) at the cathode

and CI2(g) as the anode. The mechanism of the reaction has been described. Faraday’s 2 laws ofelectrolysis have been detailed in the chapter. The industrial applications of electrolysis have beendiscussed. Additionally, the details about electrochemical or galvanic cell have been highlighted.

Pollution: In this chapter we described about the various types of pollution i.e., air pollutions, soilpollutions, water pollution, their effects and the preventive meansures also included.

Practicals: The concluding chapter is devoted to the practical work which the students are requiredto carry out. The experimental details about the use of burette, pipette for carrying titrations (example,acid-base titration, or redox titration) and including preparation of standard solution are described indetail. Additionally the students have been given instructions for finding the pH of a solution, includingpreparation of buffer solutions.

A number of illustrative examples, plus the viva voce questions are appended towards the end ofthe chapter.

— Ravi Saini

Contents

Preface (vii)

1. Basic Concepts of Chemistry 11.0 Introduction 11.1 SI Unit 11.2 Derived Units 21.3 Matter, Elements, Compounds and Mixtures 31.4 Symbols 61.5 Atom, Molecule 71.6 Chemical Equation 121.7 Balancing Chemical Equations 121.8 Thermochemical Equations 13

Exercises 152. Atomic Structure and Chemical Bonding 20

2.1 Dalton’s Atomic Theory 202.2 Thomson’s Atomic Model 202.3 Rutherford’s Scattering Experiment 212.4 Rutherford’s Nuclear Model of Atom 222.5 Atomic Number and Mass Number 242.6 Isotopes and Isobars 252.7 Drawbacks of Rutherford’s Model 262.8 Bohr’s Model of Atom 262.9 Quantum Mechanical Model of Atom 282.10 Heisenberg’s Uncertainty Principle 282.11 Probability Picture of an Electron 282.12 Difference between Orbit and Orbital 292.13 Quantum Numbers 292.14 Principal Quantum Number (N). 292.15 Azimuthal or Secondary or Angular Quantum Number (I) 30

xiv Applied Chemistry–I

2.16 Magnetic Quantum Number (M) 302.17 Spin Quantum Number (s). 312.18 Problems Related to Quantum Numbers 312.19 Pauli’s Exclusion Principle 332.20 Shapes of s and p Orbitals 362.21 Electronic Configuration of Atoms 372.22 Ionic bonds or electrovalent bond 402.23 Factors favouring the formation of ionic bond 412.24 Covalent bonds or non-polar bond (shared electron pair) (First suggested by G.N. Lewis) 42 2.25 Bond Parameters 44 2.26 Bond angle 44 2.27 Sigma ( ) and Pi ( ) Bonds 45

3. Water 613.1 Sources of Water 613.2 Surface of Water 613.3 Underground Water 613.4 Impurities in water 623.5 Hardness of water 623.6 Types of Hardness 633.7 Degree of Hardness 633.8 Units of Hardness 643.9 Disadvantages of Hard Water 703.10 Boiler Feed Water (Water for Steam Generation) 713.11 Softening of Hard Water or Removal of Hardness of Water 743.12 Domestic water treatment 823.13 Requisites of Drinking Water 823.14 Purification of Water 833.15 Alkalinity 873.16 Free Chlorine 883.17 Chlorides 883.18 Total Dissolved Solids (TDS) 89

4. Solution 984.1 Solution 984.2 Introduction of common terms 984.3 Equivalent weight 994.4 pH Scale-Representation of H3O

+ ion Concentration 1054.5 Application of pH in Engineering 1094.6 Buffer Solution 1114.7 Explanation of the Buffer action of different types of Buffers 1124.8 Industrial Applications of pH 118

Contents xv

5. Electrolysis 1265.1 Electrochemistry is a Branch in Chemistry which Deals with 1265.2 Introduction to the Concent of Oxidation and Reduction 1265.3 Electrolytic conduction 1275.4 First Law 1305.5 Faraday’s second law of Electrolysis 130 5.6 Industrial applications of Electrolysis 1325.7 Types of Commercial Cells 1355.8 Primary Cells 1355.8 Secondary Cells 135

6. Environmental Pollution 1496.1 Introduction 1496.2 Environmental Pollution (Definition and Scope) 1496.3 Pollutants 1506.4 Classification of Pollutants 150

Air Pollution or Atmospheric Pollution 1516.5 Introduction 1516.6 Definition of Air Pollution 1516.7 Preventive Measures or Source Correction Methods 155

Water Pollution 1566.8 Introduction 1566.9 Water Pollution 1566.10 Sources of Water Pollution 1576.11 Classification of Water Pollutants 1576.12 Effects of Water Pollution 1586.13 Control of Water Pollution 1586.14 Soil Pollution 1586.15 Sources/Causes of Soil Pollution 1596.16 Control of Soil Pollution 1606.17 Green Chemistry 161

Practical 169–190Glossary 191–195Index 197

Basic Conceptsof Chemistry

C H A P T E R 1

1.0 INTRODUCTION

The word science comes from the latin word “Scientia” meaning knowledge, science refers to asystem of acquiring knowledge. This system uses observation and experimentation to describe andexplain natural phenomena. The purpose of science is to produce useful models of reality.

Fields of science are commonly classified into two major lines.1. Natural Science: Which deals with the natural phenomena and processes occuring in nature2. Social Science: The systematic study of human behaviour and society.

As natural science is a very vast knowledge and can’t be studied under single head. So, it can bedivided into two types.

1. Biological Science: Deals with living things their interaction with living and non living things.2. Physical Science: Deals with the properties of matter and energy.

Physical science can be divided into three types:1. Chemistry2. Physics3. Astronomy.

In this book, we deal with chemistry.

ChemistryChemistry is a branch of science which deals with the properties of matter, and the transformation andinteraction of matter and energy. Chemistry primarily studies atoms and collection of atoms such asmolecules, crystals or metals that make up ordinary matter. The word chemistry is directly drived fromthe word alchemy. According to modern chemistry, chemistry is the structure of matter at the atomicscale which determines the nature of a material. As chemistry deals with the peparation, properties,structure and reaction of material substances. It has interfaes with all scientific disciplines and aknowledge of the subject is essential for understanding nature as well as for the progress of society.Chemistry can be subdivided into the following important branches.

1.1 SI UNIT

In earlier times, many different units of measurement were used example distance was expressed inmiles, Furlongs, feet etc., weight was measured in seers, pounds etc. These units are quite fediousbecause. There is no uniformity. It was also observed that most of the popular system were cumbersome.

2 Applied Chemistry-I

For example, 1 mile = 1760 yards, 1 yards = 3 feet, 1 foot = 12 inches. In 1979 French Academy ofScience derived a simple system called the metric system. Which was soon adopted by the scientiststhrough out the world. The metric system is decimal system in which the different units for a physicalquantity are related to each other as multiples of power of 10.

For example: 1 km = 103 m; 1 cm = 10–2 m etc.Centimeter is smaller unit. This system was found to be too convenient to scientist that all over the

world adopted this system. In 1960 the metric system was further improved by general conference onweight and measures called the International System of Units abbreviated as SI (from French name,System International). The SI system has seven basic units from which all other units are derived. Allthese basic units are given in table.

Table 1.1 The seven basic SI units

Quantity Symbol SI Unit SI UnitSymbol

Length l meter mMass m kilogram kgTime t second sElectric current I ampere ATemperature T kelvin KAmount of substance n mole molLuminous intensity Iv cardeld cd

1.2 DERIVED UNITS

The units for all other physical quantities like area, volume, pressure, velocity etc., are easily obtainedby defining the derived quantity in terms of the base quantities using the base units. These are calledderived units since they have been derived from the basic SI units.

For example: Speed (or velocity) is distance, time. So, the unit is m/s or ms–1.Some of the common derived units are given in Table 1.2.

Table 1.2 Some of the common derived units

Physical quantity Definition of quantity Unit SI unit

Area length square Square meter m2

Volume length cube Cubic meter m3

Density Mass/unit vol. Kilogram cubic kg m–3

per meterSpeed Distance/unit time meter/second ms–1

Acceleration Speed change/unit time Meter per second square ms–2

Force Mass × Acceleration Newton N = kg ms–2

Pressure Force/unit area Pascal (Newton per Pa = Nm–2

square meter) = kg m–1 s–2

Specific gravity Density of substance/ Diamention less —Density of reference — —

Surface tension Force/length Newton per meter N/MViscosity resistance to flow Pascal s NS/m2

Basic Concepts of Chemistry 3

1.3 MATTER, ELEMENTS, COMPOUNDS AND MIXTURES

1.3.1 MatterThe word matter is used to cover all the substances and material from which the universe is composed.

Matter is defined as anything that has mass and takes up space. There are three physical states ofmatter.

(i) Solid(ii) Liquid

(iii) Gas

Table 1.3 Differences in the properties of the three physical states of matter

Physical state Volume Density Shape Fluidity

Solid Has a fixed High Has a definite Does not flowvolume shape

Liquid Has a fixed volume Moderate to high No definite shape Generally flowseasily

Gas No fixed volume Low No definite shape Flows easily

Chemical Classification of Matter

1.3.2 Element and Compound

There are two types of pure substance:1. Element: Elements are substances that cannot be chemically broken down into simpler

substances. An element cannot be decomposed by passing an electric current through it.

4 Applied Chemistry-I

2. Compounds: Compounds are pure substances made from two or more elements chemicallycombined together.

Elements are the “building blocks” from which the universe is constructed. There are over ahundred known elements, but the majority of the universe consists of just two (i) Hydrogen (92%) and(ii) Helium (7%).

Make up most of the mass of the universe. Elements are the basic building units of the materialworld. They cannot be chemically broken down into simpler substances.

Elements are further classified into following types:

1. Metal: Metals are usually solids (except for mercury, which is a liquid) at room temperature.A metal is an element that conducts electricity and is malleable and ductile.

2. Non-metals: Non-metals are solid or gases (except for bromine, which is liquid) at roomtemperature. A non-metal is an element that does not conduct electricity well and is neithermalleable nor ductile.

3. Metalloids: Elements which have properties of both metals as well as non-metals are calledmetalloids. There are eight elements which are called metalloids. They often look like metals,but are brittle like non metals. They are neither conductors nor insulators, but make excellentsemiconductors.

1.3.3 Compounds

A substance which is obtained by the union of two or more elements in a definite proportion by weightswhich can be decomposed again by suitable chemical methods is known as compounds.

For example: Water, carbon dioxide.

(i) The properties of the compounds are quite different from those of the elements of which it iscomposed of.

For example: Water is a compound of H2 and O2 but its properties are different from those ofH2 and O2.

(ii) The compound cannot easily be separated into its element.

Compound may be classified into two types:

(i) Inorganic Compound: Inorganic compounds are obtained from minerals and rocks.

For example: NaCl, CaCO3 (marble).

(ii) Organic Compounds: Organic compounds are obtained from plants and from animals.

For example: Carbohydrated oil, fat, protein, wax etc.

1.3.4 Mixtures

A mixture may be defined as a combination of two or more elements or compounds in any proportionso that the constituents do not lose their identity.

(i) Milk is a mixture of fat, protein, lactose etc.(ii) Air we breath is not a single, pure substance, it is a gaseous mixture of O2, H2, N2, H2O, CO2

etc.

Applied Chemistry I

Publisher : Vayu Education ISBN : 9789382174363 Author : Ravi Saini

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