54 0

Atoms and Molecules The term ‘atom’ was introduced by Ostward,

means indivisible. The first atomic theory was postulated by John

Dalton in 1808, a poor English School master. The term molecule was introduced by Avogadro. The nuclear model of Atom was first introduced

by J.J. Thomson. Mass Number is the sum of number of protons

and neutrons present in the nucleous of a of atom. Atomic Number is derived from Nuclear charge

of atom, hence it will be the number of protons. Electron is the fundamental particle of matter or

nature. Heaviest sub-atomic particle is Neutron Electrons and positrons have same mass and

opposite charges. Neutrinos and Antineutrons have to charge sad

no mass. The dual natureof electron was proposed by de-Broglie. The dual nature of elections was experimentally

provided by I.H. Germer. Nucleons are the sum of protons and Neutrons

presnt in an atom. The radius of nucleons of an atom varies in the

order 10–13 cm. The smallest atom known is Helium. The simplest atom is Hydrogen. The most abundant element in the Universe is

Hydrogen (2nd Helium) Isotopes are the different type of atoms of the

same element to having same atomic number anddifferent mass number.

Protium has no neutrons. Deuterium has one neutrons.

Tritium has two neutrons. Isobars are atoms of different elements having

same mass number and different atomic numbers.Eg: Argon - 40 and Calcium 40

Isotones : are atoms of different elements havingdifferent atomic number, and mass number, butthey should have same number of neutronseg: 3

1H and 42and 4

2He, both Contain twoneutrons.

Nuclear Isomers : Thes are the different types ofatoms of the same element having differentradioactivity constants.

The term ‘isotope’ was introduced by body. The element Tin (Sn) has largest variety atoms.

(Isotopes)

O r e Metal Chemical formula

Iron Pyrites Iron FeSCopper Pyrites Copper CuFeS2

Litharge Led PbOPyrolusite Manganese MnO2

Pitch blende Uranium U3O8

Monozite Thorium ThO2

Serusite Lead PbCO3

Gypsum Calcium CaSO4.2H2OLimestone Calcium CaCO3

Dolomite Calcium CaCO3MgCO3

Fluorspar Calcium CaF2

Copper glance Copper Cu2SMalachite Copper CuCO3 Cu(OH)2Zinc blende Zinc ZnS

Ores & Metals

CHEMISTRYIsotopes of hydrogen

54 1

Allotropes are the forms of the same element withdifferent physical appearances.eg: Red Phsophorus and white phosphorusoxygen and ozone.

The most complex atom available from with isUrsinium - 238

Valency is the combining capacity of one atom toanother.

Noble element have zero valency. Hydrogen shows univalency. Sodium and Potassium shows Univalency. The common valency of carbon is four. Hydrogen Producers largest number of

compounds (2nd - Carbon) Cathode rays are discovered by Julius Plucker.

Anode rays are discovered by Goldstein. Neutron was discovered by James Chadwick. Cathode rays are used in Television. The atomic size is about 105 times larger than the

nuclear size. Wavelength violet (VIBGYOR) is 3800 A0 - 4300 A0. Wavelength Red is 6500 A0 –

7600 A0

The most valid atomict heoryis ‘‘Wave mechanical modelofatom’’ suggested by MaxPlanck.

When gaseous atoms ormoelcules are heated they emitelectromagnetic radiations.

Some Important Elements

Barium ........................................ 56 .....................Sir Humphry Davy........................................ 1808Boron .......................................... 5 .....................Humphry Davy, J.L Gay Lussac, L.J.Thenard .... 1808Calcium ...................................... 20 .....................Sir Humphry Davy........................................ 1808Carbon ........................................ 6 .....................Known to ancientsChlorine ..................................... 17 .....................Carl Wilhelm Scheele .................................... 1774Copper ....................................... 29 .....................Known to ancientsFluorine ....................................... 9 .....................Henry Moissan ............................................ 1886Gold ........................................... 79 .....................Known to ancientsHelium ......................................... 2 .....................Sir William, Ramsay, Nils, Langlet, P.T. Clene ... 1895Hydrogen .................................... 1 .....................Henry Cavendish ......................................... 1766Iodine ........................................ 53 .....................Bernard Courtois .......................................... 1811Iron ............................................ 26 .....................Known to ancientsLead ........................................... 82 .....................Known to ancientsMagnesium ................................ 12 .....................Sir Humphry Davy........................................ 1808Mercury ..................................... 20 .....................Known to ancientsNitrogen ...................................... 7 .....................Daniel Rutherford ......................................... 1772Oxygen ....................................... 8 ..................... Joseph Priestly ............................................. 1774Potassium .................................. 19 .....................Sir Humphry Davy........................................ 1807Silicon ........................................ 14 ..................... Jons Berzelius .............................................. 1832Silver .......................................... 47 .....................Known to ancientsSodium ....................................... 11 .....................Sir Humphry Davy........................................ 1807Sulphur ...................................... 16 .....................Known to ancientsTin ............................................. 50 .....................Known to ancientsUranium ..................................... 92 .....................Martin Klaproth ........................................... 1789Zinc ........................................... 30 .................. Andreas Marggrat .......................................... 1746

Some important elements Atomic Number Discoverer Year of discovery

Max Planck

54 2

Spectroscope is an instrument which analyses thwavelength of emitted radiations.

The radioactive liquid element is Francium. The radioactive gaseous element is Radio. In stationery state, the energy associated with

an electron remains constant. The atomic number is first calculate by Moseley. The most reactive element - Floruned The densest element - Osmium The lightest element - Hydrogen The lightest metal - Lithium

Properties of Compounds The common refrigerents are Ammonia and Freon. Non stick Kitchenwaves are coated with Teflon. Teflon is chemically Tetra flouroethylene Photographic films are coated with Silver Bromide. Seeding of Cloud is done by using Silver Iodine. Phosphine (PH3) has the smell of rother eggs Bleaching Powder is chemically calcium chloride

hypo chlorite (CaOCl3) Bleaching Powder is a mixed salt. Egg shell, Marble, Limestone etc contains Calcium

Carbonate. Green house effect is created by Carbodioxide,

methene, watervapour etc. Dry kold is Dry ice, which is solid Carbondioxide. Zinc Phosphide and Arsenic sulphide are used

as Rat poison (rodenticide) Laughing gas is Nitrous Oxide. Benzyl chloride era be used as tear gas. Sodium peroxide is used as airpurifier in

Submarines. Tin Amalgrm (Sn + Hg) is used to coat on mirror.

Paper is cheically cellulose. The most abundant carbohydrae (organic

compound) present in nature is cellulose. Cellulose is not absorbedby humanbody, due to

the absence of cellulose in body. Rust is chemically hydrated ferric oxide. (Fe2O3.

x. H2O) Freezing mixture contains Calcium chloride and

sodium chloride. Flourosis is due to the excess intake of Fluoride

salts along with drinking water. Flourosis is first reported in India in 1938 on

Nelore Distt of AP. Calcium oxychloride is used as fungicide in pepper Aluminium is used to make CDs. Aluminium and its Compounds are amphoteric. Amphoteric means shows the properties of Acid

and Base. Oxides are binary compound of Oxygen and

metals or non metals. Acidic oxides show the properties of Acids.

eg: Carbon dioxide, sulphur dis oxide, phosphorusPentoxide etc.

Basic oxides are generally metallic oxides.eg: Calcium oxide, Sodium, peroxide, magnesium,oxide, etc.

Neutral oxides are neither acidic nor basic.

Euriched Uranium is Uranium - 235

Bhopal Gas Tragedy was due to the leakage ofMIC (Methyl Isocyanate)

54 3

eg: 1. Nictrous oxide (N2O)2. Carbon Monoxide (Co)

Amphoteric oxides are showing both theproperties of acids and bases.eg: Aluminiumoxide

Zinc oxideBerylym oxide

Aspirin is calledWonder Drug.

Aspirin ischemically AcetylSalicyclic Acid.

Ordinary Portlandcement (OPC) contains the major componentCalcium oxide.

While paints are made by using Titanium dioxide. The whitest compound ever known is Titsnium

dioxide. Titanium is referred as

wondermetal. Tranquilizers are

chemicals used asmedicine for mentaldisorderness.

Barbiutric Acid and itssalts are used aTranquilizers.

Sweetest sugar isFructose present inFruits.

Honey containsglucose and Fructose

Rocket propellentcontains fuel andoxidiser.

Rocket fuel is liquidHydrogen.

Fund of the future isliquid Hydrogen.

Analgesics are thedrugs used for relievingpain.eg: Aspirin

Antipyretics are the chemicals used to bring downbody temperature.eg: Paracetsmol, Aspirin

Disinfectnants : Chemical used to kill micro-organisms.eg: Phenol

Antibir tics : Chemicals extracted frommicroorganisms (fangi, mold, bacteria) and canbe used to distroy some other micro-organisms.eg: Streptomycin, Penicillin, Chloroamphenicol.

Antiseptics : Chemicals that can be applied toliving tissues to destroy micro-organisms.eg: Dettol

The element which is used to coat thephotocopying drum of Xerox is selenium.

Silicon, Germanium etc used in the manufactureof transistors and IC chips due to their semiconductivity.

Invar Iron, Nickel To make clock pendulam

Nichrome Nickel, Chromium, To make heatingIron elements

Phospher Bronze Copper, Tin (Sn) To make springs andPhosphorus (P) suspension filaments

in electrical instruments

Type metal Copper (Cu),Lead (Pb), To make typesTin (Sn),Antimony (Sb)

Sterling Silver Copper, Silver To make silver coins

Coinage Silver Copper, Nickel To make coins

Gun metal Copper, Zinc (Zn), To make barrels of GunTin (Sn)

Constantan Copper (Cu), To make electricalNickel (Ni) instruments

German silver Copper (Cu), To make utensils,Nickel (Ni), resistance wire etc.Zinc (Zn)

Alloys Alloys (teml-k-¦-c-w) Components Uses

Felix Hoffman

54 4

Watarges is a mixture of Carbon monoxide sadHydrogen used as Industrial fuel.

Producer gas is a mixture of Carbon-monoxideand Nitrogen used as ‘Industrial Fuel’.

Coke is the refined form of coal (contains theelement carbon)

Bathing salt is sodium carbonate used to reducethe hardness of water.

Baking Powder is mixture of sodiumbicarbonateand Paratric Acid salt.

Perodic Table There are 118 elements known today, out by

which 90 are naturally existing. The first man-made element is Technicium (atomic

no: 43) Promethium is also a men made element (atomic

no: 63) Modern Periodic Table is based on atomic

numbers of elements. Menoeleev’s periodic Table is based on atomic

weights. The father of periodic table is mendeleev. The most ironic compound is caessium flouride. Most electronegative element is Flourine. Most electropositive element is Francium or

Caessium. The element which shows hights electrons-

affinity is chloride.

Noble gas are listed in group 18 of modernperiodic table.

Enemy of copper is Sulphur. Non-ferrous metal is Aluminium. The most abundant metal in earths crust is

Aluminium The most abundant element present is earth’s

crust’s oxgyen. The metal which regulates Blood Pressure in

human beings is sodium. The metal related to arthertis is Potassium. The metal present in Insulin is zinc. Zinc is concentrated on the eyes of human beings. The most abundant helide present on earth’s crust

in Flouride. Liquid metals at Room Temperature are

Mercury, Gallium, Caessium,Francium, Eka Mercury

Liquid non-metal at room-temperature is Bromine.

The non-metal, which showselectric conductivity Graphite(Carbon)

Some important compounds andits discoverers

Carbondioxide ............................ Joseph BlackBenzene ................................ Michael FaradayMorphine ... Friderich Sertumer (Germany, 1805)Aspirin ........................ Dreser (Germany, 1889)Dichloro Diphenyl Trichloro Ethane (DDT) ......

Paul Muller (Germany, 1939)Carbon tetra chloride ............ Michael FaradayCarbon hexa chloride ............ Michael FaradayOzone .... Christian Friedrich Schonbein (1840)Carbon Monoxide (first prepared) ...................

JMF de Lassone (France, 1778)Carbon monoxide (first identified the composition)

William Cruikshank (England, 1800)Nitrous Oxide .......................... Humphry Davy

CFCs are called miracel chemicals, which destroyozone layer.

Mendeleev

54 5

The element with highest melting point is Carbon(diamond) (4000k)

The metal with highest melting point is Tungston.(3868K)

The most harmful metal to humanbeings is Lead. Lead has poorest electrical conductivity silver

has highest electrical sad Thermal conductivity. Metals kept under kerosene are sodium,

Potassium, Caessium etc. Iodine is also kept under kersone. Lithium is kept by coverng with paraffin wave. Metallurgy is the verious process involved in

the extraction of metal from its ores. Ore is the mineral from which the metal is

conveniently and economically extracted Ore has definite composition (formula) Clay is the mineral of Aluminium. Bauxite and cryolite are the main ores of

Aluminium. Sulphide ores are purified by Froth-floatation

process. Tinstone, Pyrolusite etc are purified by magnetic

separation. Calcination is the process of heating the ore

below its melting point in abscence fair to removevolatile impurities like , Arsenic etc.

Roasting is the process in which the ore is heated

below its melting point in prescence of air oxidisethe impurities.eg: Carbon, Sulphur etc removed as their gaseousoxides.

Gongue is the impurity present in the ore. Generally gangue is silica. Flux is the substance used to neutralise and

remove gangue a slag. Acidic flux is silica. Basic flux is limestone. Thomas slag is calcium phosphate. Metals extracted from sea-water are magnesium

adn sodium. Metals generally accumulated in Living

Organisms -------- Vanedium, Potassium. Most abundant metal present in developed

animals ......... Calcium. Most abundant element presence in our body

..................... oxygen. Most abundant compound present in animals

..................... Water. Magnesium is concentrated in chloroplast. Major metals present in chloroplast are

magnesium, manganese, copper and Iron. Major elements present in sea-water are chlorine,

sodium, magnesium, sulphur, calcium, potassium,carbon etc.

Biochemistry is the study of the substancesand chemical process which occur in living or-ganisms.

Histochemistry is a science that providesinformation about the distr ibution andactivities of chemical components in tissues.

Organic chemistry is the branch ofchemistry which deals with the study ofcarbon compounds.

Inorganic chemistry deals with thestudy of compounds other than carboncompounds.

Polymer chemistry deals with chain like mol-ecules formed by linking smaller molecules andwith plastics which consist of chainlink mol-ecules often combined with other materials.

Branches of Chemistry Synthetic chemistry involves combining

chemical elements and compounds to dupli-cate naturally occuring substances or to pro-duce compounds that do not occur naturally.

Radio chemistry involves the identificationand production of radioactive elements andtheir use in the study of chemical processes.

Physical chemistry interprets chemical pro-cesses in terms of pysical properties of mattersuch as mass, motion, heat, electricity and ra-diation.

Radiation chemistry concerns the chemicaleffects of high energy radiation on substances.

Stereo chemistry studies the arrangement ofatoms in molecules and the properties that fol-low from such arrangements.

54 6

The halogens extracted from sea-water arechlorine and Bromine.

Metals extracted by self-oxidation and raductionmethod.1. Mercury 2. Copper 3. Lead

The atmosphere mainly consists of Nitrogen(78.09%) and oxygen(20.95%)

Lithosphere is the solid phaseof the earth saidin made of different types of rocks.

Lithosphere is the major source of metals. Most abundant eliments of earth’s crust are

silicon and oxygen - (about 75%) Core is the central portion of earth. Metallic Core valuable metals like manganese,

Iron, Coballo, Nickel, Copper, Irdium, Platinum,gold etc.

Sulphide Layer contains phsophorus, sulphur,zinc, cadmium, Tin, Antimony, Bismuth, Lead,Mercury etc.

High purity metal is prepared by1. Ven-Arked Process (Titanium)2. Zone- Refining (Germanium, Silicon)

Some important minerals and their major places ofoccurence in India.1. Nitre (Potassium) - Bengal & Haryana2. Magnesite, Dolomite (Megnesium) – Tamil Nadu3. Gypsum, Limestone (Calcium) – Rajasthan, Tamil

Nadu, J & K, M.P.

4. Bauxite (Aluminium) – Orissa, Tamil Nadu, J & K5. Tinstone (Tin) – Bihar, Orissa6. Chromite (Chromium) – Bihar, Karnataka, Orissa,

Tamil Nadu.7. Pyrolusite (Manganese) – Bihar, Maharashtra,

Karnataka.8. Haematite (Iron) – Bihar, Karnataka9. Cobaltite (Cobalt) – Rajasthan10. Copper pyrities – Bihar, M.P, Orissa11. Native Gold (Gold) – Karnataka, A.P12. Zinc Blende (Zinc) – Rajasthan

Acids The acid present in vinegar is acetic acid. Oranges and lemons contain citric acid. Curd contains lactic acid. Old name of hydrochloric acid (HCl) is Muriatic acid. Tamarind contains tartaric acid. Tea contains tannic acid. Urine contains uric acid. Ants contain formic acid in their body. Sulphuric acid is called the 'King of Chemicals.' Sulphuric acid is mainly manufactured by con-

tact process. The chemical name of aspirin is acetylsalicylic

acid. Oil of Vitriol is sulphuric acid. The acid used in lead storage batteries is

sulphuric acid. Earliest known acid is acetic acid. Aqua fortis is Neitric Acid. To purify gold, it should be treated with conc

entrated Nitric acid. The acid that can be used as a hypnotic is : Vitamin C is chemically ascorbic acid Dilute phenol is called Carbolic Acid. Strongest inorganic) acid is Perchloric acid. Weakest (inorganic) acid is Hydrocysnic Acid. The acid functions as digesting agent in our body

is hydrochloric acid. Apple contains ascorbic acid and malic acid. Pure milk contains no acid but sour milk con-

tains Lactic acid. Boric Acid is a mild antiseptic, used a eye-lotion Cola contains phosphoric acid. Ordinary soda water id chemically Cabonic Acid.

Zone- Refining (Germanium, Silicon)

54 7

pH values The pH scale is introduced by Sorreenson pH value generally starts from 0 and ends at 14 Project Neutral solutions are having pH exactly 7. pH value greater 7 and upto 14 isbasic. pH value 0 to 6.9 is acidic. Human Blood has pH value 7.3 or 7.4 (slight Basic) Generally other human secretions have pH 6.1 to 6.9 Acid rain has pH 3.00 to 4.5 Sea water has pH 8.5 pH of human stomach is about 3.5

Organic Chemistry Hydrocarbons and their

derivations are calledOrganic Compounds

Compounds of Carbonand hydrogen are calledhydrocarbons.eg: Fuels,

Compounds of carbon,Hydrogen and oxygen(H4 O – 2:1) are calledcarbohydrates.eg: Sucrose, glucose,cellulose

LPG means Liquifiedpetroleum gas, majorcomponent present in itsButane.

Leakage of LPG can beidentified by mixing itswith Ethyl Mercaptan.

CNG meanscompressed natural Gas,major component ismethane

Bilt, LPG & CNG containtraces of propane.

CFCs are also known asOzone Depleting Sub-stances (ODS) for itcauses depletion of theOzone layer.

The domestic cooking gas consists mostly of liq-uefied butane and isobutane.

RDX and Nitroglycerine are explosives. The chemical commonly used for preserving bio-

logical specimens is formaldehyde. Alcoholic beverages contain

ethyl alcohol. Protein is composed of car-

bon, hydrogen, nitrogen andoxygen.

The solution used to detectglucose in urine is BenedictSolution (Alkaline Solution ofCopper Sulphate and sodiumcitrate).

Alloys (teml-k-¦-c-w) Components Uses

Aluminium Bronze Copper (Cu) To make coins, statuesAluminium (Al)

Aluminium (Al)Alnico Nickel (Ni) To make magnets

Cobalt (Co)Iron (Fe)

Aluminium (Al),Duralumin Copper (Cu), To make aircrafts

Magnesium (Mg),Manganese (Mn)

Magnelium Aluminium (Al), To make external partsMagnesium (Mg) of troller, steamer etc.

Silumin Aluminium, To make engine partsSilicon

Nickel Steel Iron (Fe), To make drils, crankshaftNickel (Ni) bearings

Chrome Steel Iron (Fe), To make springs, tools etc.Chromium (Cr)

Chrome vanadium steel Iron (Fe) To make axils of motor carsChromium (Cr)Vanadium (V)

Manganese Steel Iron (Fe) To make rock driller,Manganese (Mn) plates, rails, protecting

shields etc.

AlloysFormaldehyde

54 8

Bio-energy is a renewable source of energy. Crude petroleum is converted into petrol through

a process called fractional distillation. Lead is added to petrol as an octane booster to

prevent knocking. Mercury is generally used as a thermometric fluid

rather than water because it has greater visibilitythan water.

Cooking oil can be converted into vegetable gheeby the process of hydrogenation.

To make rubber strong and bounceable, sulphuris added. This process is called ‘Vulcanisation.’

Ethanol is also called ‘grain alcohol’. The commonly used refrigerant in fridges is Freon

(dichloro difluoro methane). Freshly passed urine has no smell, but when it is

allowed to stand, it develops a strong ammoniaodour owing to conversion of urea to ammonia bybacteria.

Cheese and vinegar are made by fermentation. Non-stick kitchenware are coated with teflon and

pottassium hydrogen tartarate. Teflon is a polymer named ‘poly tetrafluoro-

ethylene (PTFE). The main constituent of dynamite is T.N.T. Anthracite is the purest form of mineral coal. The chemical name of aspirin is acetyl salicylic

acid. Gelatine is used in the manufacture of icecream

to prevent crystal growth. Soaps are produced by the saponification of fats

with alkali solution. Alcoholic beverages contain ethyl alcohol. Natural gas predominantly is methane. The chief chemical constituent of petroleum is

hydrocarbons. Among the fertilizers, urea has the maximum ni-

trogen content. Wood heated in an enclosed container will pro-

duce charcol. Petrol is otherwise known as gasoline. Enzymes are substances that convert organic

substances into simpler substances. Chemically enzyme is protein. Gas oil is same as the diesel oil. Interferone is a substance produced by cells in

response to virus infections. It usually preventsother viruses from infecting simultaneously.

Chemically interferon is a glycoprotein. The sweetest among the sugars is fructose

(C6H12O6). Artificial silk is also called rayon. Gober gas is a natural gas obtained from cow

dung and it has higher fuel value and commercialvalue. It is used as an alternative fuel to LPG.

Chiefly biogas contains methane while LPG (Liq-uefied petroleum gas) contains butane.

Marsh gas is Methane. Coal gas is a mixture of hydrogen (48%), meth-

ane (35%), carbon monoxide (6%), nitrogen (6%),carbon dioxide (1%)

Methane causes about 38% of the warming ofthe globe through the green house effect.

Radioactivity Neutral radioactivity was discovered by Henry

Bacqurrel. Artificial Radioactivty was discovered Irene curie

& F. Juliot. Simplest Radioactive atom is 13H (Tritium) Tritium is a beeta emitter. The daughter element of Tritium is Helium - 3

(23He)

Age of fossil can be calculated by Radio - Carbon- Dating, using carbon - 14.

Wine Dating can be done by using Tritium. Rock-Dating (Age of planet) can be calculated

by Uranium datingby using U-238 and Pb - 206.

54 9

Radioactive Iodine (Iodine -131) is used for thetreatment of Hyper Thyroidism.

Cobalt - 60 isotope is used for cancer treatment. Deficit in blood-circulation is identified by using

phosphorus - 32 Gold - 198 is used for the treatment of Leukaemia. Angrogram Test is done by using sodium - 24 Bone Cancer can be diagonised by using

phosphorus - 32. Highest velocity is shown by grama rays (same

as light) Hightest pentrating power also shown by gamma

rays due to very high energy (very shortwavelength)

During beeta emission isobars are produced. Controlled fission reaction is done in Nuclear

Reactor. The collen used in Nuclear Reactor is Liquid

Sodium. Graphite Rods and Cadmium Rods are used as

moderator in Nuclear Reactor. Five research reactor of India at BAARC are

Purnima, Zerlina, Dhruva, Circus and Apsara. Important Power stations in India are

1. Tarapur Atomic Power Station - Maharashtra2. Rajasthan Atomic Powerstation - Kota3. Narora Atomic power station - U.P4. Indira Gandhi Centre of Research - Kalpakkam(Chennai)

Nuclear Fusion reaction takesplace in HydrogenBomb.

Strongest Radioactive element is RADIUM. Liquid Radioactive metal is FRANCIUM Gaseous Radioactive element is RADON Unit of Radioactivity is Bacqurrel (Bq) (1Bq = 1

disintegrestion per second)1 curie = 3.7 × 1010 Bq

Photographic film is very strongly affected bybeeta rays.

Fats and Oils are esters of glycerol and organic acid. Neoprene is synthetic rubber used for insulation

of electric cables. SBR is styrene butadiene which is an artificial

rubber used for making tyre, chappals etc. Rayon Silks are synthetic fibres. Synthetic fibres

are polymers. Sodium/Potassium salt of stearic acid, palmitic

acid, and oleic acid is called soap. Synthetic Rubber used for making hoses is

Thiokol. Tyres filled with air are called pneumatic. Vinyl plastics are used as adhesive. Aqua regia is a mixture of concentrated nitric acid

and hydrochloric acid. It can dissolve gold andplatinum.

The standard Oral Rehydration Salt (ORS) con-tains sodium chloride, potassium chloride andanhydrous glucose.

D.D.T. and Gammexine are insecticides. Synthetic detergents are a mixture of sodium salts

of aromatic and aliphatic sulphonic acids. Hypo, used in photography, is chemically sodium

thiosulphate. Mordants are substances that fix colours of

fabrics. Gypsm is also used in the production of cement

for controlling the setting time of cement. Biogas is the appropriate technology to be

adopted for rural electrification and cooking. The tapes in the tape recorder are made of plastic

coated with iron oxide. The combination of PETN (Penta Erythritol Tetra

Nitrate) and TNT (trinitrotoluene) is calledpentolite. Doctors also use PETN in treating cer-tain heart disorders.

55 0

Halon is a gas for extinguishing fire.

Glasses Glass is a super cooled liquid.1. Ferric salts yellow2. Ferrous salts – Green3. Cobalt salts – Blue4. Manganese dioxide – Purple5. Nickel salt – Red6. Cupric oxide – Red7. Cadmium sulphide – Lemon Yellow8. Uraniumoxide - Greenish Yellow9. Cryolite - Milkay10. Calcium phosphate - Milkey (opaque)

Explosives TNT is trinitrotoluene. It is highly explosive sub-

stance. It is manufactured by the action of con-centrated nitric acid on toluene.

Explosive power is measured in terms of TNT. RDX - Research and Development Explosive is

a highly explosive substance. PETN-Penta Erythritol Tetra Nitrate is more le-

thal and deadly explosive than RDX; Gun cotton (nitro cellulose) is a powerful explo-

sive formed by the action of nitric acid on cellu-lose, used in the manufacture of gunpowder.

Instruments Eudiometer is to measure volume changes in

chemical reactions between gases. Manometer is an instrument to determine the

pressure of the gas. Saccharimeter is an instrument for determining

the amount of sugar in a solution.

Chemists The name 'Hydrogen' and 'Oxygen' was given by

Antoine Lavoisier. Joseph Black (1728-1799) a scottish chemist, dis-

c o v e r e dcarbondioxide asdistinct gas,showed that gasescould appear insolid, developedthe theory of latentheat.

Aluminium was first isolated by Hans Oested. Electron was discovered by J.J. Thomson. Neutron was discovered by James Chadwick. Nucleus and Proton was discovered by Ernest

Rutherford. W. George discovered titanium in 1791. Pierre & Marie Curie discovered Radium in

1898. Henry Cavendish discovered hydrogen in 1766.

Chemical Processes CHROMATOGRAPHY: The modern and most

effecive method to seperate different componentsof a mixture.

SUBLIMATION:The conversion of substancedirectly from solid to vapour state.Camphor, Iodine etc. undergoes sublimaton.

OXIDATION:The process of loss of electrons ina chemical reaction.

ELECTROPLATING:The deposition of the metalon another by electric current .

PASTEURIZATION of milk is the process bywhich milk is exposed to a high temperature from62.80C - 65.50C for 30 minutes to destroy certainmicro - organisms and to prevent or arrest fer-mentation.

The method used to obtain alcohol from molas-ses is called fermentation.

Bessemer Process : Removal of impurities frommolten metal by blowing air through the moltencharge in a Bessemer converter. Used to removecarbon and phosphorous from steel; sulphur andiron from copper.

Bosch Process : Production of hydrogen by thecatalytic reduction of steam with carbon monox-ide at 500

0C

Haber Process : The process in which Ammo-nia is prepared by combining nitrogen and hy-drogen.

Contact process:Preparation of sulphuric acid. Alumino thermic process : Preparation of chro-

mium and manganese. Cyanide process : used for the extraction of

silver and gold.J.J. ThomsonJames Chadwick

55 1

Phenomena and Reasons In cold countries, alcohol is preferred to mer-

cury as a thermometer liquid because alcohol hasa very low freezing point than that of mercury.

When we dip in sea water and come out , we feelchilled due to evaporation of water on the body.

Mercury is used generally in thermometers be-cause mercury expands and contracts evenly whenheated or cooled. It also remains liquid over a widerange of temperatures and does not stick to glass.

Miscellaneous Kevlar is a material for making bullet proof dresses. The oil in water is an example of suspension. Catalyst in a chemical reaction generally helps to

accelerate a reaction. The main use of salt in the diet is to produce

hydrochloric acid to digest the food. Chlorination means the addition of a small quan-

tity of chlorine in water as a germicide. Hydrogen has the same atomic number and mass

number. The ultimate source of nitrogen is the atmosphere

but, plants and animals cannot assimilate atmo-spheric nitrogen directly.

The animals get their nitrogen supply in the formof proteins from plants which in turn get theirnitrogen supply from the soil in the form of ni-trates.

Ammonia (NH3) is a compound of nitrogen. It canbe manufactured by combining nitrogen and hy-drogen at low temperature under high pressure.

Air pollution caused by automobiles can be re-duced by using lead free petrol and design alter-nations in automobiles.

Carbon monoxide (CO) is most carcinogenic in na-ture.

Normal Oxygen (O2) and Ozone (O3) are allot-ropes of oxygen.

Diamond, corrundum and topaz are all very hard.A scale called Moh’s scale is used to indicate thedegree of hardness of minerals.

Pure water is obtained from sea water by the pro-cess of distillation

Terminology Absolute temperature Temperature reckoned on

a scale beginning with absolute zero (---273.160C). Acetone A colourless inflammable liquid used as

a solvent. Adenosine Tri Phosphate (ATP) A nucleotide

co-enzyme that takes part in several chemicalreactions in living organisms. It is an intermediateproduced in photosynthesis.

Alkali metal Any metal, such as sodium,potassium, or lithium, whose hydroxide is an alkali.

Alkaline Having the properties of an alkali. Alkaline earth metals The group of chemical

elements comprising calcium, strontium, bariumand magnesium.

Allotrophy The property by which certainchemical elements exist in two or more differentforms (as carbon in graphite, charcoal, diamond,lamp black, etc.).

Alum A double sulphate of ammonium, or a univalentmetal (sodium or potassium), or of a trivalent metal(aluminium, iron or chromium). It is used as anastringent, an emetic and in the manufacture ofbaking powder, dyes and paper. The commonestform is potash alum.

Amber A yellow or brownish-yellow translucentfossil resin. Found on some sea shores and usedin jewellery, pipe stems etc. It is hard, easilypolished and quickly electrified by friction.

Amino acids A group of nitrogenous organiccompounds that serve as units of structure ofproteins and enzymes and are essential to humanmetabolism.

Ammonia A colourless, pungent gas, compoundof nitrogen and hydrogen. Its compounds areused as fertilisers, in medicines etc.

Amphoteric Substances having both acidic andbasic properties, e.g. alumina.

Antidote Medicine used against a poison, or toprevent a disease from having effect.

Antipyretic A substance used to lower bodytemperature.

Antiseptic Prevents infections, decay etc. Itinhibits the action of micro organisms.

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Asbestos (Rock Cotton) A variety of fibroussilicate minerals, used as heat insulating materialand fireproof fabrics as they are nonconductorsof electricity.

Aspirin Acetyl salicylic acid, a white solid usedin medicine as an antipyretic and analgesic.

Avogadro’s hypothesis At constant temperatureand pressure, equal volumes of gases containequal number of molecules.

Avogadro’s number Number of molecules presentin one mole of a substance is constant and isequal to 6.023 x 1023..

Base metal Non-precious metal, the main metalconstituent of an alloy.

Bath salts Salts used to soften hard water. Beet sugar Sucrose (sugar) obtained from sugar

beet. Bell metal An alloy of copper and tin (30%). Benzaldehyde A clear, pleasant smelling liquid

found in the oil of bitter almonds. It is used inmaking dyes, perfumes and flavourings.

Benzene A clear, inflammable liquid obtained bythe fractional distillation of coaltar. It is used as asolvent and has carcinogenic properties.

Benzine A mixture of hydrocarbons, obtainedby the fractional distillation of petroleum and usedas a motor fuel and in dry cleaning.

Bleaching Decolourisation by means of chemicalsor by exposure to the sun’s rays.

Bleaching powder Calcium oxychloride, used asa bleaching agent.

Blue vitriol Crystalline copper sulphate. Boiling point The temperature at which a

particular liquid boils. Borax A white crystalline salt with an alkaline

nature used in the manufacture of glass solderingof metals, enamels, gems, soaps etc.

Carbohydrates Energy-producing organiccompounds, e.g. cane sugar, glucose, starch etc.

Carcinogenic Compounds capable of causingtumours and cancer (e.g. benzene).

Carvacrol A thick oil, extracted from the oil ofmint and used as an antiseptic and anaesthetic.

Catalysis The process by which the rate of achemical reaction may be altered.

Catalyst Any substance that changes the rate of areaction without undergoing any chemical change.

Catenation Property of atoms binding themselvesto atoms of the same element. This property isexhibited by carbon.

Celluloid A thin, inflammable substance madefrom pyroxylin and camphor. It is used for makingphotographic films.

Chemical warfare Warfare by means of chemicaldevices, e.g. gases, including bombs, smoke-screens etc.

Chemiluminescence Light produced duringcertain chemical reactions e.g. light emitted byfire flies.

Chemotherapy The treatment of diseases by theadministration of chemicals, e.g. sulphonamides(sulpha drugs).

Chrome green Chromic oxide, used as a greenpigment.

Coal gas Gas used as a fuel, manufactured by thedestructive distillation of coal in the absence ofair.

Coal tar Thick, black, sticky substance which isproduced when coal gas is made by thedestructive distillation of coal.

Cracking Decomposition of a chemicalsubstance into smaller molecules by heating. Thisprocess is used in the petroleum industry.

Cyanamide A colourless, crystalline and unstablesubstance used in the manufacture of fertilizers.

Cytochemistry The chemistry of living cells. Decantation The process of separating a solid

from a liquid by pouring off the liquid into anothercontainer.

Dehydration Elimination of water. Deliquescent Substances which have the

property of absorbing water molecules from theatmosphere, e.g. calcium chloride.

Denatured A substance that has been convertedinto a form that is not its natural form, for purposes

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of making them unfit for eating or drinking, e.g.making ethyl alcohol denatured by addingmethanol or naphtha.

Detergent A cleaning agent made of the sodiumslat of aliphatic or aromatic sulphonic acids.

Dewar flask A thermos flask used for keepingliquids at temperatures different from that of air.

Distillation A process involving both evaporationand condensation simultaneously, used forpurifying liquids.

Endothermic reaction Reactions in which heat isabsorbed.

Exothermic reaction Reactions in which heat isliberated.

Fermentation The chemical changes brought aboutby living organisms (yeasts, bacteria etc.) in whichbigger organic molecules are converted into smallermolecules, e.g. conversion of glucose and canesugar into alcohol and carbon dioxide.

Flash point The lowest temperature at which asubstance catches fire on being lighted with aflame.

Formaldehyde Also called formalin (40% aqueoussolution of the gas formal-dehyde). It is used as apreservative and disinfectant.

Freezing mixture Salts of metals (NaCl, MgSO4,etc.) when mixed with crushed ice, lower itstemperature below 00C.

Galvanization The process in which iron or steelarticles are coated with zinc by dipping them in abath of molten zinc, to protect them fromcorrosion.

Gasoline The same as petrol obtained by thedistillation of petroleum.

Glass wool A collection of very fine glass threads. Glycerine A colourless, thick, syrupy liquid

prepared by the hydrolysis of fats and oils. It isalso called glycerol.

Hydrolysis A chemical reaction in which asubstance reacts with water to form a weaklyacidic, weakly basic or neutral solution.

Hypertrophy Enlargement of organs due toexcessive nutrition or eating.

Ignition The heating of a compound or mixtureto the point of complete combustion.

Iodoform A yellow, crystalline compound. It isused as a bactericidal in dressings.

Isomer Different chemical compounds with samemolecular formula but having different structuralformula e.g. dimethyl ether (CH3OCH3) and

ethanol (CH3CH2CH) have the same molecularformula (C2H6O). This phenomenon is calledisomerism.

Lechatelier’s principle If some force is appliedto a system in equilibrium, the system adjustsitself to annual the effect of the applied force.

Lithophone A white pigment made from zincsulphide and barium sulphate. It is used in paints.

Litmus A purple-coloured substance used intesting whether a particular substance is acidicor basic.

Mordants Substances used for fixing colours anddyes on textiles during the process of dyeing.

Pasteurisation The partial sterilization of foodstuff by heating to a temperature below boiling(1000C normally). This process kills micro-organisms, but retains the taste, flavour andnutritive value of food. It is named after itspioneer, Louis Pasteur. For example, milk ispasteurised by heating to 600C.

Proof spirit Solution of ethyl alcohol containing49.28 percent alcohol by weight in water.

Pyrolysis Chemical decomposition by the actionof heat.

Quicksilver Another name given to mercury(because it is a liquid and looks like molten silver).

Saccharin A white crystalline solid which is 550times sweeter than sugar, but does not have anyfood value. It is given to diabetic patients.

Steroids Class of organic compounds present inanimals and plants. These are present as bileacids.

Turpentine Resinous oil from terebinth and othertrees. It is used in varnishes, paints and inmedicinal preparations.

Urea Crystalline solid which is the chiefconstituent of human and other urine. It is formedin the body by the decomposition of proteins.

Vulcanization This is a process of improving thequality and hardness of rubber by heating it withsulphur at about 1500C.

White bronze Bronze containing a highproportion of tin.

White heat Temperature at which bodies becomeincandescent.

White lead Lead carbonate which is used as apigment.

White spirit A mixture of petroleumhydrocarbons.