10 sc chem chemicalreaction

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Finish Line & Beyond

CHEMICAL REACTIONS AND

EQUATIONS

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Writing a Chemical ReactionTypes of Chemical ReactionOxidation & Reduction
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There are two types of reactions

(I) CHEMICAL REACTION

(II) PHYSICAL REACTION

CHEMICAL REACTION: In a reaction when the original state of the particle changesand it cannot be reversed by simple physical means, this type of reaction is known

as chemical reaction. Example :- Fermentation of grapes, burning of wood etc. Inthis reaction we have seen that after burning of wood, coal is formed and we cannot

make wood from coal.

PHYSICAL REACTION: In a reaction when original state of the particle can berecovered by any means then this type of reaction is known as physical reaction.

Example :- Evaporation of water is the example of physical reaction because we can

turn vapour into water againWRITING A CHEMICAL RECTION

When we are going to write a chemical equation then there will be reactant andproduct. Left hand side of the equation is called reactant and the right hand side of

the equation is called product.

2H2+ O2 = 2H20

Reactant Product

Balanced Chemical Equations

According to the Law of conservation of energy we know that energy can neither becreated nor destroyed. So while writing a chemical equations we should keep in mind

that number of atoms in L.H.S and R.H.S of an equation should me balanced.

TYPES OF CHEMICAL REACTION

COMBINATION REACTION:-In a combination reaction two or more substancescombine to form a new single substance.

DECOMPOSITION REACTION :-- Decomposition reactions are opposite to

combination reactions. In a decomposition reaction, a single substance decomposes

to give two or more substances.


Example: CaO + H2O = Ca(OH)2Quick Lime Slaked Lime

2H2 + O2 = 2H2O

Hydrogen Oxygen Water


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DISPALCEMENT REACTION :- When an element displaces another element fromits compound, a displacement reaction occurs.

DOUBLE DISPLACEMENT REACTION:-- Two different atoms or groups of atoms

(ions) are exchanged in double displacement reactions.

EXOTHERMIC REACTION:-- Reaction in which heat generated is called exothermic

reaction.

ENDOTHERMIC REACTION :-- Reaction in which energy is absorbed is known as

endothermic reaction.

Oxidation and Reduction

OXIDATION :-- Oxidation is the gain of oxygen or loss of hydrogen.

If a substance gains oxygen during a reaction, it is said to be oxidized.

REDUCTION:-- Reduction is the loss of oxygen or gain of hydrogen.If a substance loses oxygen during a reaction it is said to be reduced.

Corrosion

We must have observed that iron particles are shiny when new, but get coated with areddish brown powder when left for some time. This process is commonly known as

rusting of iron.

When a metal is attacked by substances around it such as moisture, acids, etc., it is


Example: 2Cu + O2 = 2CuO Copper is getting oxidised

CuO + H2

= Cu + H2

O Copper Oxide is reduced

Example: Na2SO4 + BaCl2 = BaSO4 + 2NaCl Sodium Sulphate + Barium Chloride = Barium Sulphate + Sodium Chloride

Example : Fe + CuSO4 = FeSO4 + Cu Copper Sulphate Iron Sulphate

Example: 2Fe SO4 = Fe2O3 + SO2 + SO3Ferrous Sulphate Ferric Oxide


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said to corrode and this process is called corrosion.

Corrosion is harmful for many things, like car body, electric poles,etc. To preventcorrosion most of the things made of metal are given a thick coat of paint.

Example :- The black coating on silver and the green coating on copper are commonexamples of corrosion.


10 sc chem chemicalreaction

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