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1. Introduction to Chemistry2. Changes3. Properties of matter4. Chemical Terminology5. Air6. Hydrogen7. Water8. Acids, Bases and Salts

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CHAPTER 1: INTRODUCTION TO CHEMISTRY Chemistry is the branch of science which deals with substances(matter)- theircomposition, properties and their interaction with other substances. Thematerial of which a physical body is made up of is called a substance.Substances may be found in nature or are man-made or synthesized.Minerals, sulphur, water, coal etc. are substances found in nature whereaspaper, fabric, paint, drugs etc. are man-made. Substances undergo physicalor chemical changes when subjected to an energy change about which we willstudy in chapter 2.

IMPORTANCE OF CHEMISTRY

Chemistry plays an important role in everyday life and helps to fulfil man’sbasic needs. Some major fields of contribution of chemistry are:

1. Medicine: Extensive research has led to the discovery of various drugslike sulfa drugs and antibiotics to combat various diseases.

2. Agriculture: Different fertilizers and insecticides have helped to yieldbetter crops.

3. Industries: Chemistry plays a vital role in the development of industrieswhich include dyes and drugs, paints, plastics, synthetic fibres andpetrochemical.

Some pictures of various products of chemistry has been given below.

Fig 1- Calcium Capsules (medicines)

Fig 2- Plastic Bags (Industries)

CHEMSITRY IN ANCIENT TIMES

1. Metals: Early mankind after they learnt of the usage of fire, begancooking food for which they needed vessels leading to the discovery of metals from their ores.

2. Salts: Particular salts were found to be useful as food preservatives.

3.  Yeasts: Simple distilleries sprouted up for preparing wine byfermentation.

4. Plant extracts: The extracts were used for dyeing and colouringclothes.

5. Glass: First made in Egypt around 3000 B.C. by fusing sand, soda andlime.

IMPORTANT DISCOVERIES BY CHEMISTS

1. In the 8th century, alchemists called nitric acid- aqua fortis.

2. In the 9th century, the first mention of sulphuric acid was noted.

3. In 1630, Van Helmont discovered existence of carbon dioxide.

4. In 1772, Daniel Rutherford discovered nitrogen gas.

5. In 1774, Joseph Priestly discovered oxygen and later ammonia.

6. In 1776, Henry Cavendish first prepared hydrogen.

7. In 1776, De Lassone first prepared carbon monoxide.8. In 1777, Lavoisier, recognized the elementary nature of sulphur.

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9. In 1807, John Dalton postulated the atomic theory.

10. By the end of the 19th century, the modern atomic theory wasestablished laying the foundation of all modern concepts of chemistry.

SOME BRANCHES OF CHEMISTRY

1. Inorganic Chemistry(study of elements and compounds)

2. Organic Chemistry(study of carbon and its compounds)3. Physical Chemistry(study of physical aspects of chemistry)4. Biochemistry(study of chemical process in living matter)

CHEMISTRY LABORATORY

Chemistry is the branch of science which deals with chemicals, theircomposition and properties and the changes which the chemicals undergo.

 The chemical reactions which include a large number of experiments arecarried out in the chemistry laboratory using different laboratory apparatus.

Fig 3- A typical chemistry lab

SIMPLE CHEMICAL APPARATUS USED IN THE CHEMISTRY

LABORATORY

 The apparatus used in the chemistry laboratory include:

1. Test Tubes: It is a glass tube made of hard glass or pyrex glass towithstand heat. It is used mainly for heating substances, preparing andidentifying gases and for conducting chemical reactions.

Fig 4- Test Tubes There is a test tube holder for holding the test tube and a test tube rack for keeping test tubes.

2. Beakers and flasks: They are glass apparatus of different shapes andsizes. Beakers are mainly used for holding substances, collectingsolutions and carrying out reactions. Flasks are mainly of three types –

i) Round Bottom Flask(for heating liquid reactants)ii) Flat Bottom Flask(for reactions not requiring heat)

iii) Conical Flask(for conducting reactions.

 Fig 5- Beakers Fig 7- Flat Bottom Flask

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 Fig 6- Round Bottom Flask

3. Funnels, evaporating dish and measuring cylinders: A funnel’smain function is transferring a liquid. Evaporating dish is used forevaporating liquids whereas, measuring cylinder helps in measuringliquids.

4. Tripod Stand: It is made of cast iron and supports the apparatus

placed on top of it for heating. Fig 7- Tripod Stand

5. Wire Gauze: It is made of wire mesh and asbestos and is placed ontop of the tripod stand. It prevents the glass apparatus from crackingand initiates even distribution of heat.

 Fig 8- Wire Gauze

6. Stand and clamp: The stand has a clamp or ring to hold the glassapparatus placed on the tripod stand.

Fig 9- Stand and Clamp7. Bunsen Burner:

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