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Basic Chemistry

Facts about Elements

An element is defined by the IUPAC as a pure chemical substance composed of atoms with the same number of protons in the atomic nucleus. All atoms of an element have the same number of protons. Atoms of elements can have different number of electrons and neutrons.

  • A variant of an element with different number of neutrons is known as its​​ Isotope

  • Different physical form of an element is known as​​ its (e.g. graphite and diamond)​​ Allotrope

  • Element most abundant in the Universe -​​ Hydrogen

  • Element most abundant in​​ the human body -​​ Oxygen

  • Element which forms more than 10 million compounds -​​ Carbon

  • Element with the lowest melting and boiling point -​​ Helium

  • Element with the​​ highest melting point -​​ Carbon

  • Element with the highest boiling point -​​ Tungsten

  • Element with highest density -​​ Osmium

  • Element with lowest density -​​ Hydrogen

  • Element with​​ highest​​ electronegativity Flourine

  • Element with lowest electronegativity (highest electropositivity) -​​ Francium

  • The first element to be produced artificially -​​ Technitium

  • The most corrosion resistant element (which cannot be affected by water, chemicals or acids) -​​ Iridium

  • The element which was discovered on the Sun before it was found on the Earth -​​ Helium

  • The​​ non-metallic element which is liquid at room temperature -​​ Bromine

  • The metallic element which is liquid at room temperature -​​ Mercury

  • The most reactive element -​​ Flourine

Facts about Periodic Table

  • The Periodic Table was created​​ by​​ Dmitry Mendeleyev, a Russian chemist and professor in​​ 1869.

  • The Periodic Table has​​ seven​​ rows or​​ periods.

  • The present Periodic Table has room only for​​ 118​​ elements.

  • Lanthanides​​ is a group of​​ 15 elements from atomic number 57 to 71. Together with Scandium and​​ Yttrium they are known as rare earth​​ elements.

  • Rare​​ earth​​ elements​​ which​​ are​​ 17​​ in​​ number​​ are​​ actally​​ not​​ rare.​​ Most​​ of​​ them are​​ commonly​​ found

  • Actinides​​ is a group of 15 elements from atomic number 89 to 103. All actinides are​​ radioactive.

  • The Periodic Table has 18 columns or groups. Some important groups are listed​​ below.

  • Group 1 -​​ Alkali metals​​ or Lithium group consists of Lithium, Sodium, Potassium, Rubidium, Cesium​​ and Francium. Hydrogen is not an alkali metal even though it is listed in the first​​ column.

  • Group 2 -​​ Alkaline earth metals​​ or Beryllium group consists of Beryllium, Magnesium, Calcium, Strontium, Barium and​​ Radium.

  • Group 15 -​​ Pnictogens​​ or Nitrogen group consists of Nitrogen, Phosphorus, Arsenic, Antimony, Bismuth and​​ Moscovium.

  • Group 16 -​​ Chalcogens​​ or Oxygen group consists of Oxygen, Sulphur, Selenium, Tellurium, Polonium and Livermorium.

  • Group 17 -​​ Halogens​​ or Flourine group consists of Flourine, Chlorine, Bromine, Iodine, Astatine and Tennessine.

  • Group 18 -​​ Noble gases​​ or Helium or Neon group consists of​​ Helium, Neon, Argon, Krypton, Xenon, Radon and Oganesson.

Common and Scientific Names of Chemicals

Sodium Compounds

 

Common Name

Chemical Name

Formula

Washing soda

Sodium carbonate

Na2CO3

Baking soda

Sodium bicarbonate

NaHCO3

Borax

Sodium tetraborate decahydrate

Na2B4O7·10H2O

Brine

Aqueous sodium chloride solution

NaCl

Caustic soda

Sodium hydroxide

NaOH

Hypo

Sodium thiosulfate

Na2S2O3

 

 

 

 

 

 

 

 

 

 

 

Calcium Compounds

 

Common Name

Chemical Name

Formula

Bleaching powder

Calcium hypochlorite

Ca(ClO)2

Quick Lime

Calcium oxide

CaO

Marble

Calcium carbonate

CaCO3

Plaster of paris

Calcium sulfate

CaSO4

Chalk

Calcium carbonate

CaCO3

Gypsum

natural Calcium sulfate

CaSO4·2H2O

Other Compounds

 

Common Name

Chemical Name

Formula

Alum

Aluminium potassium sulfate

KAl(SO4)2.12H2O

Aqua regia

Nitrohydrochloric acid

HNO3​​ ​​ + 3 HCl

Aspirin

Acetylsalicylic acid

C9H8O4

Corundum (ruby, sapphire)

Aluminium oxide

Al2O3

Dry ice

Solid Carbondioxide

CO2

Epsom salts

Magnesium sulfate

MgSO4·7H2O

Heavy Water

Deutrium oxide

2H2O​​ or​​ D2O

Pearl Ash

Potassium carbonate

K2CO3

Plumbago

Graphite

C

Prussic acid

Hydrogen cyanide

HCN

Important and Useful Chemicals

  • Chemical with which​​ flourescent lamps are coated for providing illumination -​​ Phosphor

  • Chemical used to remove rust stains from clothes - Oxalic​​ acid

  • Chemical with which photographic films are coated - Silver​​ Bromide

  • Chemical in which​​ gold dissolves - Aqua​​ Regia

  • Chemical with which non-stick cookware is coated -​​ Teflon

  • Chemical used in the manufacture of matches -​​ Phosphorus

  • Chemical used to purify water (as a disinfectant) -​​ Chlorine

  • Chemical used as an antiseptic in mouth freshner, toothpastes etc. - Hydrogen​​ Peroxide

  • Chemicals used in the​​ breath test to check drunken driving - Potassium dichromate and Sulphuric​​ acid

  • Chemical used as a purgative - Magnesium​​ Sulphide

  • Chemical used in cloud seeding - Silver​​ Iodide

  • Chemical​​ used​​ as​​ a​​ fixing​​ agent​​ in​​ photography​​ and​​ also​​ for​​ washing​​ as​​ a​​ germicide​​ -​​ Sodium​​ thiosulphate

  • Chemical commonly used in explosive devices as well as fertilisers - Ammonium​​ Nitrate

  • The substance which is used to make capsule shells in pharmaceutical industry. The substance is also used as gelling agent in cooking. -​​ Gelatin

  • The sugarcane industry product being blended with petrol to reduce pollution and also to reduce the import burden of petrol in India -​​ Ethanol

  • The organic compound widely used as a cleaning agent in dry cleaning - Tetrachloroethylene (perchloroethylene)

  • The chemical commonly used in baby diapers for its super absorbent properties - Sodium​​ polyacrylate

  • The chemical used for embalming bodies and preservation of animal specimens and tissue samples - Formalin (aqeous solution of​​ formaldehyde)

  • The compound which is used in moisturing creams and soaps because of its hygroscopic properties - Glycerol

  • The chemicals used to produce fog/smoke on theatrical stages​​ or​​ studios - 1. Dry ice 2. Glycol and water mix

  • The chemical used as anticoagulant in blood collection tubes and for the preservation of blood in blood banks - Sodium​​ Citrate

  • The chemical commonly used as rodenticide - Zinc​​ Phosphide

  • The chemical commonly used in sunscreen lotions, cigarette filters, ceramic industry - Zinc​​ Oxide

Precious Stones - Chemical Composition and Colours

 

Stone

Colour

Chemical Composition

Diamond

Transparent

Carbon

Ruby

Pink to Red

Corundum (Aluminium oxide​​ Al2O3)

Emerald

Green

Beryl​​ (Be3Al2(SiO3)6)

Sapphire

Blue

Corundum​​ (α-Al2O3)

Amethyst

Violet

Quartz​​ (Silicon​​ dioxide​​ SiO2)

Opal

Variety of colours

Hydrated​​ silica​​ (SiO2·nH2O)

 

Turquoise

Blue to greenish

Hydrated copper and aluminium phosphate​​ [CuAl6(PO4)4(OH)8·4H2O]

Topaz

Variety of colours

Aluminum silicate containing​​ fluorine (Al2(F,OH)2SiO4)

 

Lapis Lazuli

 

Deep blue

Metamorphic rock with mineral lazurite as its chief constituent

Aquamarine

Pale greenish blue or bluish green

Beryl​​ (Be3Al2(SiO3)6)

Morganite

Pink to orange-pink

Beryl​​ (Be3Al2(SiO3)6)


Other Precious​​ Materials

 

Material

Colour

Chemical Composition

 

Pearl

White (other​​ colours​​ are also possible but rare)

Argonite (Calcium​​ Carbonate CaCO3))

Ivory

White

Dentine​​ (Ca10(PO4)6(CO3)·H2O))

Important Organic​​ Acids

 

Name

Chiefly found in

Lactic acid

Sour milk

Acetic acid

Vinegar

Formic acid

Ant venom

Citric acid

Citrus fruits like lemon, lime, orange

Oxalic acid

Rhubarb, spinach

Butyric acid

Milk, butter

Lauric acid

Coconut oil

Malic acid

Sour apples, sour grapes

Tartaric acid

Grapes, tamarinds, pineapples

Erucic acid

Rapeseed oil, Mustard oil

Properties of Acids

  • Acids have pH less than​​ 7.

  • Acids turn blue litmus to​​ red.

  • Acids have sour​​ taste.

 

Reactions :

  • With bases - Acids react with bases to produce a salt and​​ water.

  • With​​ carbonates - Acids react with carbonates to produce salt, water and carbon​​ dioxide.

  • With metals - Acids react with metals to produce a salt and​​ hydrogen.

Important Inorganic Acids

 

Name

Formula

Common​​ Use

Also remember

Hydrochloric acid

 

HCl

Pickling of steel

Gastric acid secreted by stomach mainly contains HCl.

Nitric acid

HNO3

Production of fertilisers

Nitric acid is produced by electric discharge in the atmosphere such as lightning. Known as Aqua Fortis in ancient times.

 

Sulphuric acid

 

H2SO4

As an electrolyte in lead-acid batteries.

Known as Oil of Vitriol in​​ ancient​​ times.

Phosphoric acid

H3PO4

Used in beverages like colas to give a tangy taste.

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Hydroflouric acid

 

HF

Etching (writing or marking) of glass

 

Stored in plastic containers.

Carbonic acid

H2CO3

Making of soft drinks and other bubbly drinks

CO2 ​​ in air combines​​ with water in the ocean to form carbonic acid. Ocean acidification thus caused is of grave environmental concern.

 

 

Boric acid

 

 

H3BO3

  • Antiseptic

  • Eye wash

  • Socks​​ and​​ shoes to prevent athlete's​​ foot

 

 

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Chemical Processes

  • Electrolysis

It is a process in which electric current is passed through a substance to effect a chemical change. Usage : Electroplating, Production of pure form of some metals

  • Saponification

It is a process of converting fat into soap by treating it with an alkali. Usage : Manufacture of soaps

  • Fermentation

It is a metabolic process in which sugar or carbohydrate is converted to acid, gas or alcohol. Usage : Making of wine, liqour, curd etc.

  • Vulcanisation

It is a process in which natural rubber is treated with sulphur to make it more durable and elastic. Usage : Manufacture of tyres

  • Emulsification

It is a process in which large fat globules are broken down into tiny droplets. The tiny droplets are uniformly distributed in an immiscible liquid to form emulsion.

Usage : Emulsions are used in paints, cosmetics, medicines etc.

  • Sublimation

It is the transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase.

Usage : Used in frost-free refrigerators

  • Pasteurisation

It is a heat treatment process to kill bacteria in liquid food or beverages. Usage : Preservation of milk

  • Carbonation

It is a process of mixing carbondioxide in liquids under high pressure. Usage : Making of soft drinks

  • Distillation

It is a process of separating the component substances from a liquid mixture by selective evaporation and condensation.

Usage : Separation of gasoline etc. from crude petroleum.