Here is your sample essay on Chemistry

Chemistry is a branch of science which deals with the structure and properties of the matters.

Matter-Matter is defined as anything which occupies space and mass. It can neither be created nor be destroyed. Matter is divided into three types-compound, mixture and element.

Compound-A compound is a substance which contains two or more elements combined in a fixed proportion by weight in such a way that their properties are changed.

Mixture-A mixture is a simple collection of two or more substances which retain their original properties and which may be present in any desired proportion. Components of a mixture can be separated by simple mechanical means. Generally, it is made up of elements or compounds.

Element-

An element is a substance which cannot be split up into two or more simpler substances by any physical or chemical means. It is the simplest form of matter.

Types of elements:

(i) Metals–

Metals are the elements which form positive ions by losing electrons. The metals are good conductors of heat and electricity. They are malleable and ductile and possess high density. The oxides of metals are basic in nature.

(ii) Non-metals-

Non-metals are the elements which form negative ions by gaining electrons. Non-metals are poor conductors of heat and electricity. They are brittle. The oxides of non-metals are acidic or neutral in nature.

Atom-

Atom is the ultimate particle of an element which does not exist in free state but takes part in chemical reactions.

Molecule–

Molecule is the ultimate particle of an element or a compound which exists in a free state but does not take part in chemical reactions.

Oxidation-

Oxidation is a process of gaining oxygen (or any other electronegative element) or removal of hydrogen (or electro positive element). Non-metals are reducing agents.

Reduction-

Reduction is the addition of hydrogen (or any other electropositive element) or removal of oxygen (or any electronegative element).

Radioactivity-

Radioactivity is the spontaneous disintegration of an atomic nucleus to produce stable nuclei with continuous emission of radiations. During radioactivity process three types of rays-a, 3 and Y are emitted from the elements.

Isotopes–

Isotopes are atoms of the same element having the same atomic number but different mass numbers.

Isobars-

Isobars are atom having the same mass number but different atomic numbers.

Atomic Structure-

An atom is made up of three fundamental particles known as electron, proton and neutron.

Nucleus-

The whole mass of an atom is concentrated into a very small space situated in the middle of an atom is known as nucleus.

Orbit-

An orbit is a circular path round the nucleus.

Electron–

Electron is one of the fundamental particles of an atom which has negative charge but negligible mass. It moves in different orbits around the nucleus.

Proton–

Proton is one of the fundamental particles of an atom which is positively charged and having the mass equal to one atom of hydrogen. Protons reside inside the nucleus. The number of protons and electrons in a neutral atom is always the same.

Neutron–

Neutrons are the fundamental particles of an atom which reside in nucleus with protons. Neutrons have no charge but equal mass to that of protons.

Charge on one electron or proton = 1-9 x 10 19 coulomb and mass of one proton or neutron = 91 x 10 kg.

Atomic Number–

The number of total positive charge in an atom is called the atomic number of the atom. The total number of protons of an atom is called atomic number of that atom, which is denoted by Z.

Atomic Mass–

The total number of protons and neutrons of an atom is called atomic mass of that atom. It is donated by A.

Valency of an element–

The combining capacity of an element ^is called valency. The Valency of calcium is 2, i.e. the combining opacity of calcium is 2.

Electrovalence-

The reaction in which there is a complete transference of electron or electrons from one atom to another is called electrovalence. The compound thus formed is known as electrovalent compound.

Covalency-

The chemical reaction in which there is a sharing of electron or electrons between two or more atoms is called covalence and compound thus formed is known as covalent compound.

Fuels-

The materials which are burnt to produce heat energy are known as fuels.

Biomass–

The waste material of living objects (like cattle dung) and the dead parts of living objects (like plants, trees and animals) is called biomass. Biomass contains carbon compounds.

Biogas-

Biogas is a mixture of methane, carbon dioxide, hydrogen and hydrogen sulphide. The major constituent of biogas, is methane. Biogas is obtained by the anaerobic fermentation of animal wastes.

Fossil Fuels–

Fossil fuels are the remains of the pre-historic animals or plants, buried under the earth million of years ago. Coal, petroleum and natural gas are the fossil fuels.

Coal Gas–

Coal gas is a mixture of hydrogen, methane and carbon monoxide (H2 + CH4 + CO).

Liquified Petroleum Gas (LPG)-Liquified

Petroleum gas is a mixture of three hydrocarbon?-butane, propane and ethane. The main constituent of petroleum gas is butane.

Natural Gas–

Natural gas is a domestic and industrial fuel. Natural gas consists mainly of methane with small amount of ethane and propane.

Rusting of Iron–

Rusting of iron is the formation of a red- brown flaky coating of a mixture of ferric oxide and ferric hydroxide This mixture is called rust.

Galvanisation-

Rusting of iron can be prevented by galvanisation. The process of depositing a thin layer (coating) of zinc metal on articles is called galvanisation.

Alloy-

An alloy is a uniform mixture of one metal with one °^r more other metals (or non-metals).

Allotropy-

Allotropy is a phenomenon in which two or substances have different physical properties but same chemical. Properties. Diamond and Graphite are two allotrpes of carbon. Diamond _the hardest natural substance known.

Organic Chemistry–

Organic chemistry is the study of carbon compounds.

Organic Compounds–

The compounds of carbon are known as organic compounds.

Hydrocarbons–

A compound made up of hydrogen and carbon only is called hydrocarbons.

Alkane-

It is also known as saturated hydrocarbons. A 1 hydrocarbon in which the carbon atoms are connected by only single bond is called an alkane or saturated hydrocarbon.

Alkene–

A hydrocarbon in which the two carbon atoms are connected by double bond is called alkene. It is also known as unsaturated I hydrocarbon.

Alkyne-

A hydrocarbon in which two carbon atoms are connected I by triple bond is called alkyne. This is also an unsaturated hydrocarbon.

Isomerism–

The organic compounds having the same molecular formula but different structural formula are known as isomers and this phenomenon is called isomerism. –

Cracking–

The breaking down of a big alkane molecule containing ‘a large number of carbon atoms into smaller hydrocarbon molecules by the action of heat is called cracking.

Alcohols–

Alcohols are the organic compounds containing I hydroxyl group (-OH) attached to a carbon atom.

Fermentation–

The slow chemical change produced in an organic compound by the action of enzymes, leading to the formation of smaller molecules is called fermentation.

Aldehydes-

Aldehydes are the organic compounds containing Aldehyde group (-CHO) attached to a carbon atom,

Organic Acids (Carboxylic Acids)-

Organic acids are compounds containing carboxyl group or carboxylic acid group -(COOH). These acids are also known as fatty acids.

Synthetic Fibres–

Synthetic fibre is a man-made fibre. A fibre is a kind of thread which is strong enough to make clothes, nets, ropes, I etc. Rayon, nylon and polyester (terylene) are synthetic fibres.

Rayon-

Rayon is a man made fibre prepared from a natural raw Material called cellulose.

Nylon–

Nylon is a synthetic fibre. It is a synthetic polyamide Neoprene-Neoprene is an important synthetic rubber and it is fibre. It is a polyamide of a dicarboxylic acid called adipic acid and a polymer of chloroprene (or 2-chlorobutadiene). Neoprene is prepared

Polyester–

Polyester is a synthetic fibre which contains many

Polymerization-

Polymerization is a process in which two or more smeller

Monomers-

A monomer is a small organic compound which can be polymerized.

Saponification-The process of making soap by the hydrolysis

Polymers-

A polymer is a big molecule formed by the combination of a large number of small molecules called monomers.

Detergent-Any substance which has cleansing action in water

Plastics–

A plastic is a synthetic material which can be moulded detergent, or set into any desired shape when soft and then hardened to produce Synthetic detergent-A synthetic detergent is the sodium salt a durable article. Bakelite, Polythene, Poly Venyl Chloride (PVC) are of a long chain benzene sulphonic acid or the sodium salt of a long the examples of plastics. Plastics are of two types:

Thermoplastic–

A plastic substance which can be melted Solutions-A solution is a homogeneous mixture of two or repeatedly by heating and can be moulded again and again into more substances. Salt solution and sugar solution are the examples of different shapes is called a thermoplastic substance. Polythene, Poly solutions. Venyl Chloride (PVC), Polystyrene and Nylon are thermoplastics.

Colloidal solutions (or Colloids)-A colloidal is a kind of

Thermosetting Plastic–

A plastic substance which once set solution in which the size of solute particles is bigger than that of a true does not become soft on heating and cannot be moulded a second time is called a thermosetting plastic. Bakelite, melamine is the soap solutions are the examples of colloidal solutions, examples of thermosetting plastic.

solution but smaller than that of a suspension. Milk, blood, ink, jelly,

Suspensions-A suspension is a heterogeneous mixture in which

Natural Rubber–

Natural Rubber is one of the most important he small particles of solid are spread throughout a liquid without natural polymers. It is also known as plantation rubber. Rubber is Solving in it. Muddy water and chalk water mixture are the examples obtained as latex from rubber trees suspensions.

Latex-

Latex is the white, milky kind obtained by making a cut Composition of air-Air is a mixture and near the surface of in the rubber tree. Latex contains about 30% to 40% of rubber in the earth.

Air contains mainly two gases-Nitrogen and Oxygen. The form of a colloidal solution in water components of air are as follows-Nitrogen-78 084%,

Vulcanisation of Rubber-

The quality of raw natural rubber Sgen-20-946%, Argon-Q.934%, Carbon dioxide 0-033%. can be improved by vulcanisation. The process of heating natural Nuclear Fusion-The process in which two light nuclei meet to rubber with sulphur to improve its properties is called vulcanisation- a bigger nucleus with a release of tremendous amount of energy For hardening the natural rubber carbon black is added to it during th^e Called the nuclear fusion. Nuclear fusion is the source of suns vulcanisation process. Hydrogen bomb is based on the principle of nuclear fusion.

Synthetic Rubber–

Synthetic Rubber means artificial rubber Nuclear Fission-The process of splitting of a heavy nucleus

Thiokol:Thiokol is an important synthetic rubber. It is a polymer ester groups. A polyester fibre is prepared by reacting a dicarboxyli_c of ethylene polysulphide. rubber is prepared by the condensation acid with dihydric alcohol. of 1, 2 dichloroethane with sodium polysulphide.

Soap-

A soap is the sodium salt of a long chain carboxylic acid (fatty acid) which has cleansing properties in water. Sodium stearate, molecu_; sodium oleate and sodium palmitate are such sodium salts from which soaps are prepared.