VI-CHEMISTRY

CHAPTER 1- INTRODUCTION TO CHEMISTRY SYLLABUS INTRODUCTION TO CHEMISTRY-BRANCHES OF CHEMISTRY-IMPORTANCE OF CHEMISTRY-SOME CHEMISTS AND THEIR DISCOVERIES-APPARATUS USED IN CHEMISTRY LABORATORY.

TOPICS COVERED: WHAT IS CHEMISTRY?

DIFFERENT BRANCHES OF CHEMISTRY

DEVELOPMENT OF CHEMISTRY-HISTORICAL PERSPECTIVES

IMPORTANCE OF CHEMISTRY

SOME CHEMISTS AND THEIR DISCOVERIES

APPARATUS USED IN CHEMISTRY LABORATORY

WHAT IS CHEMISTRY?

Chemistry is that branch of science which deals with the study of structure, composition and properties of substance and the changes which the substance undergoes.

It helps us to identify the substance on the basis of their physical properties like colour, state, taste, odour , solubility in water, combustibility etc.

It also helps us to know whether a substance dissolves in water or not.

DIFFERENT BRANCHES OF CHEMISTRY

ANALYTICAL CHEMISTRY It is a science of obtaining, processing, and communicating information about the composition and structure of matter. It is the art and science of determining what matter is made up of, its percentage and composition and how much of it exists. BIO-CHEMISTRY It deals with the study of chemical processes of living organisms. INORGANIC CHEMISTRY It deals with the study of synthesis, reactions, structure and properties of compounds of elements in non living material like rocks, soil, atmosphere etc. ORGANIC CHEMISTRY It deals with the study of the structure, properties, composition, reaction and preparation of carbon containing compounds which are present mainly in living things. PHYSICAL CHEMISTRY It is the branch of chemistry that deals with the relations between the physical properties of substances and their chemical composition and transformation CLICK THE LINK BELOW TO HAVE BETTER UNDERSTANDING TO THE TOPIC DIFFERENT BRANCHES OF CHEMISTRY https://youtu.be/4ekf0J-W5k0

CHEMISTRY

ANALYTICAL CHEMISTRY

BIO-CHEMITRY

INORGANIC CHEMISTRY

ORGANIC CHEMISTRY

PHYSICAL CHEMISTRY• ELECTRO CHEMISTRY• PHOTO CHEMISTRY• SURFACE CHEMISTRY• CHEMICAL KINETICS• QUANTUM CHEMISTRY• THERMO CHEMISTRY/

THERMODYNAMICS

DEVELOPMENT OF CHEMISTRY- HISTORICAL PERSPECTIVES

Humans have always sought to identify, use and change the materials in our environment. Early Potter's found beautiful glazes to decorate and preserve their wares. Herdsman, brewers and vintners used fermentation technique to make cheese, beer and wine. Housewife leached the Lye from wood ash to make soap. Smiths learned to combine Copper and Tin to make bronze. Crafters learned to make glass. Leather workers tanned hides. Alchemist believed they could refine base metals such as iron into precious metals such as gold if they could just find the mythical substance they called Philosopher's Stone. The Philosopher's Stone they searched for wasn't an actual rock instead it was supposedly a magical wax, liquid or powder that could heal ailments and prolong life, as well as change base metals into precious metals. Alchemists believed everything in the world was made up of four elements: air, fire, earth and water. For example, sulphur in the earth crust burns in with oxygen of air to form new substance i.e. sulphur dioxide. The Iron Pillar near the Qutub Minar in New Delhi was made around 400 BC by the iron workers in India, they had developed a process which prevented wrought iron from rusting

IMPORTANCE OF CHEMISTRY 1 AGRICULTURE Chemistry has helped agriculture in various ways by the use of chemical compounds that are as follows: • FERTILISERS Fertilisers are added to the soil to improve the fertility of the soil. Examples Superphosphate, Urea, Potassium Sulphate, NPK fertilizers, etc. • INSECTICIDES Insecticides are used for killing insects that infect and destroy crops examples BHC, DDT, Nicotine etc. • HERBICIDES Herbicides are used for killing weeds which grow along with the crops examples Glyphosate and Simazine. 2. FOOD Everybody is familiar with the properties of food such as flavor, smell, colour, preservatives and processing. Most of the food are also obtained through various chemical processes, refined oil butter, cheese etc. Some methods of food preservatives and Canning, freezing drying, fermenting pickling, sealing, etc.

3. MEDICINES In hospitals, medicines, antiseptic and disinfectants made of chemical are used for curing patients. For example medicines like penicillin, tetracycline, ampicillin, Paracetamol, aspirin etc are used to treat infection. Chemicals are also used to perform various diagnostic tests such as blood tests urine tests, etc. Chemicals like Aspartame are the most successful and also the most widely used artificial sweetener by diabetic patients which is hundred times as sweet as Cane sugar. 4. COSMETICS Cosmetics are substance or products used to enhance or alter the appearance or fragrance of the body. Example: Talcum powder is made from mineral called talc, which is composed of magnesium, silicon and oxygen. 5. PETROLEUM The petroleum industry uses knowledge of chemistry not only for mining and refining of Petroleum to produce petrol, but also produces kerosene, wax and perfumes. 6.CLOTHING The knowledge of chemistry has enabled us to make better and more clothing materials, bleached, dyed and printed natural fibres like cotton, wool silk etc. Synthetic fibres like rayon, nylon, orlon, terylene and flame-proof textiles are the gifts of chemistry. 7. RECREATION Cinema films and the items used in Fireworks are the products of chemistry. Almost all sports goods are made up of chemical products. Records of popular songs, which are played on cassettes, video- tapes, CDs and other products like Table Tennis balls, etc. are also gifts of chemistry. 8. TRANSPORT Trains, aeroplanes, ships, jets, buses, cars, scooter are common means of transport. To keep these modes of transport into motion, fuel obtained from organic substance is required and their bodies are made up of carbon fiber which is as strong as steel. 9. COMMUNICATION Synthetic chemicals, metals, plastics, copper wires, silicon chips , enamels ,PVC, Cellphones computers laptops television sets audio and video equipment are all gifts of chemistry. 10. INDUSTRY The Knowledge of chemistry has helped a great deal in the growth and improved efficiency of industrial processes. CLICK THE LINK BELOW TO HAVE BETTER UNDERSTANDING TO THE TOPIC IMPORTANCE OF CHEMISTRY https://youtu.be/rrxr01gi4WM

SOME CHEMISTS AND THEIR DISCOVERIES

JOHN DALTON- (1766-1844) He was a British chemist. He is best known for the atomic theory of Matter.He Believed that substance are made up of particles that cannot be divided. He called the particles atoms. He stated that all the atoms of an element are exactly the same ,also suggested that all compounds are made up of atoms that are combined in simple numerical proportions.

JOSEPH PRIESTLEY (1733-1804) Published his discovery of oxygen in 1775.He called the gas dephlogisticated air. He named it Oxygen.He was the first person to dissolve in the gas carbon dioxide in water. He also investigated the gases hydrogen chloride, nitric oxide, nitrogen dioxide, nitrous oxide sulphur oxide, silicon, tetrafluoride, nitrogen and ammonia.

LOUIS PASTEUR (1822 - 1895)Discovered that microbes cause milk to become sour, the butter to turn rancid and wine to turn into vinegar. He developed the process of pasteurization, in which food is preserved by heating it, to kill the bacteria in them. Also developed the vaccine for rabies and Anthrax. In 1885, he founded the pasteur Institute which is a Centre for Medical Research

JONS JACOB BERZELIUS (1779-1848) was one of the many medical doctors who become interested in chemistry and contributed greatly to its progress. He developed a system of nomenclature which is present system of symbols and formulae. He also discovered several new elements including Selenium, silicon and Thorium.

ANTONIE LAVOISIER(1743-1794) Made so many important discoveries and is known as the Father of Modern Chemistry. Lavoisier stated that air contains two gases. He said that one, called, Oxygen that helps in combustion and breathing where as the other gas does not. He called the second gas azote (lifeless). Now it is called nitrogen. He determined what a chemical reaction really was. His system of naming chemical compounds is still used today. WILLIAM RAMSAY AND LORD RAYLEIGH(1842-1919)

founded that the air contains inert gases . William Ramsay won the Nobel Prize for Chemistry in 1904. Inert gases find application in neon lights, argon bulbs and in medical fields. HENRY CAVENDISH(1731-1810) discovered hydrogen gas. He called it as inflammable air. He noticed that when metals were dissolved in dilute acids, a colourless gas was evolved, this gas was combustible. He also showed that when the gas was burnt in oxygen, it gives rise to water. ERNEST RUTHERFORD(1871-1937) He was an English physicist,studied the atomic models and through his experiment discovered the atomic nucleus. In 1921 he predicted the existence of nucleus. His model of the nuclear atom become the basis of modern concepts of atomic structure. MARIE CURIE(1867-1934) Marie Curie discovered Radium and Polonium. Marie Curie received the Nobel Prize in chemistry in 1911 for her discovery of Radium and polonium. She was able to isolate and study compound and the nature of Radium. HENRY MOSELEY(1877-1915)

In 1912 arranged the elements in the increasing order of their atomic number known as the Modern Periodic Table and modified the periodic law as” the physical and chemical properties of elements are periodic function of their atomic numbers”, the Modern Periodic Law. This classification removed most of the defects of Mendeleev’s periodic table.

DMITRI MENDELLEV In 1869, propounded that “properties of elements are periodic function of their atomic weights” the Periodic Law and arranged the elements in increasing order of their atomic weight in the form of table known as Mendeleev’s Periodic Table.This classification had many defects and were later modified by Henry Moseley.

APPARATUS USED IN CHIEMISTRY LABORATORY

TEST TUBE is a small tube made of glass, it is used to heat small quantities of liquid or mix different liquids while heating liquid in a test tube keep the mouth of the test tube away from your face.

Test tube stand is a wooden or plastics stand it has holes and pegs. Holes are used to hold several test tube and pegs are used to place the washed test tube away for the water to drain out.

BEAKER is a glass container made of glass. It is used for holding a measuring small quantity of liquids.

FLASK is a glass container to store or heat liquid substances. Flask may be flat bottom (used to store) or round bottom (for heating). A conical flask is used for mixing of different solutions. Tripod stand is made up of iron. It is used for supporting a glass apparatus while heating liquids and solids on them

WIRE GAUEZ is often placed on a tripod stand while heating substance.

Funnel is made of glass or plastic. It is used for filtering liquids and pouring liquid from one vessel to another.

FILTER PAPER is similar to bloating paper. It contains tiny pores to allow water to pass through. These pores do not allow particles of insoluble substance to go through them.

CAPILLARY TUBE IS a narrow tube made up of Glass. It is used for transferring counted drops of liquids from one container to another. MEASURING CYLINDER is a glass cylinder used for measuring volume of liquid to get an accurate reading of the volume of the liquid in the cylinder, it needs to be held at the eye level BUNSEN BURNER is used to heat substance in a laboratory it is connected to a gas supply unit. It consists of three parts the base, the burner tube and the air regulator.

WATCH GLASS is used to evaporate a liquid from its solution or to keep Chemicals for use during experiments. THISTLE FUNNEL is the long glass tube with broad inlet at the top. It is used to allow the entry of reactants into a flask. It is different from a funnel because its neck is longer and thinner than that of a funnel.

THERMOMETER is used to measure the temperature of a body. It is made of glass and has markings. We have laboratory thermometer and clinical thermometer. A clinical thermometer is smaller. It is used to measure the temperature of the human body.

SPIRIT LAMP has a glass or metallic base with spirit in it and a wick. It is used for heating substances on a tripod stand.

BEEHIVE SHELL is a clay vessel. it is used for collecting gases by the download displacement of water.

TONGS are made of steel or iron. They are used to hold hot apparatus.

RETORT is a a glass apparatus it is used in in distillation experiment.

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CHINA DISH is made of porcelain material and is called porcelain dish. It is used to heat or evaporate liquid substance.

CHAPTER -1 INTRODUCTION TO CHEMISTRY

WORKSHEET -1 1. Which of these scientist is responsible for developing a vaccine against rabies? (a) Louis Pasteur (b) John Dalton (c) Henry Cavendish (d) Dmitri Mendeleev 2. Which of the following is well known for his work ok on the periodic table? (a) John Dalton (b) Henry Cavendish (c) Dmitri Mendeleev (d) Louis Pasteur 3. A tripod stand is made of: (a) wood (b) Plastic (c) Iron (d) Glass 4. While heating a liquid in a test tube, the mouth of the test tube should be: (a) away from you (b) towards you (c) in the sink (d) towards your neighbour 5. Which of the following is used to stir a mixture of solution in the laboratory? (a) Glass rod (b) Glass tube (c) Pipette (d) Capillary tube 6.DDT and BHC are examples of? (a) Insecticides (b) Herbicide (c) Fertilizer (d) Pesticides

7. Oxygen and nitrogen was discovered by (a)Joseph priestley (b)Henry Cavendish (c)John Dalton (d)William Ramsay 8. A ____ is used for transferring solids from one container to another. (a) Spatula (b) Wire gauze (c) Watch glass (d) Spirit lamp 9.____deals with the study of chemical processes of Living Organism. (a) Biochemistry (b) Inorganic chemistry (c) Organic chemistry (d) Physical chemistry 10.____ is added to improve the fertility of soil. (a) Urea (b) Nicotine (c) Copper Sulphate (d) Simazine. 11____ is used to hold flask and other equipments firmly during experiment. (a) Clamp Stand (b) Retort (c)Tripod (d) Delivery Tube 12. Which Scientist discovered radium and polonium? (a) Henry Cavendish (b) Marie Curie (c)Henry Moseley (d) Ernest Rutherford DEFINE 1.Organic Chemistry Deals with the study of the structure, property,composition, reaction and preparation of carbon containing compounds which are present mainly in living things.

2.Preservatives Substance that are added to food to slow down or prevent the growth of microorganisms are called Preservatives ANSWER THE FOLLOWING QUESTION IN SHORT. 1. What is chemistry? Ans-It is a branch of science which deals with the study of substance their structure composition and properties. 2. Name four items of daily use which have been made using the knowledge of chemistry. Ans- Paper, Soap, Rubber, Cosmetics. 3. Give two examples: (a) Fertilizer - urea , Potassium Sulphate. (b) Insecticides- Nicotine , BHC. (c) Herbicides- Glyphosate, Simazine. 4.Write the full form of: DDT -Dichloro-Diphenyl-trichloro ethane BHC- Benzene Hexa Chloride 5.Who is known as Father of Modern Chemistry? Ans- Antoine Lavoisier is known as Father of Modern Chemistry

ANSWERS 1.LOUIS PASTEUR 2.DMITRI MENDELEEV 3.IRON 4 AWAY FROM YOU 5.GLASS ROD 6.INSECTICIDES 7.JOSEPH PRIESTLEY 8.SPATULA 9.BIOCHEMISTRY 10.UREA 11. CLAMP STAND 12.MARIE CURIE