CBSE Class 10 Science
Revision Notes
CHAPTER- 01
CHEMICAL REACTION AND EQUATIONS
Chemical Reaction : Whenever a chemical change occurs we can say that a chemical
reaction (permanent change) has taken place which can be expressed symbolically by a
chemical equation.
e.g. Food gets digested in our body
Rusting of iron.
magnesium is burnt in air to form magnesium oxide. This chemical reaction can be
represented as
We can observe or recognise a chemical reaction by observing change in state, colour,
by evolution of gas or by change in temperature.
Physical state of the reactants and the products are mentioned to make chemical
reaction more informative. e.g. we use (g) for gas, (l) for liquid, (s) for solid and (aq)
for aqueous.
Baalanced Equation : A balacned equation is one in which the number of atoms on the
reactant and product sides are equal.
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, Balancing Equation : We balance a chemical equation so that no. of atoms of each element
involved in the reaction remains the same at the reactant and product side.
Types of Reaction
I. Combination Reaction :– The reaction in which two or more substances combine to form
a new single substance.
e.g.
slaked lime is used for white washing walls. It reacts with to form
Calcium Carbonate and gives a shiny finish to the walls
Calcium Hydroxide Calcium Carbonate
(ii) Burning of Coal
heat+ light
(iii) Formation of water
Exothermic Reactions : Reaction in which heat is released along with the formation of
products.
eg..
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Revision Notes
CHAPTER- 01
CHEMICAL REACTION AND EQUATIONS
Chemical Reaction : Whenever a chemical change occurs we can say that a chemical
reaction (permanent change) has taken place which can be expressed symbolically by a
chemical equation.
e.g. Food gets digested in our body
Rusting of iron.
magnesium is burnt in air to form magnesium oxide. This chemical reaction can be
represented as
We can observe or recognise a chemical reaction by observing change in state, colour,
by evolution of gas or by change in temperature.
Physical state of the reactants and the products are mentioned to make chemical
reaction more informative. e.g. we use (g) for gas, (l) for liquid, (s) for solid and (aq)
for aqueous.
Baalanced Equation : A balacned equation is one in which the number of atoms on the
reactant and product sides are equal.
Material downloaded from www.vidyakul.com. 1/7
, Balancing Equation : We balance a chemical equation so that no. of atoms of each element
involved in the reaction remains the same at the reactant and product side.
Types of Reaction
I. Combination Reaction :– The reaction in which two or more substances combine to form
a new single substance.
e.g.
slaked lime is used for white washing walls. It reacts with to form
Calcium Carbonate and gives a shiny finish to the walls
Calcium Hydroxide Calcium Carbonate
(ii) Burning of Coal
heat+ light
(iii) Formation of water
Exothermic Reactions : Reaction in which heat is released along with the formation of
products.
eg..
Material downloaded from www.vidyakul.com. 2/7
