DIGITAL LIBRARY OF GLT SARASWATI BAL MANDIR, NEHRU NAGAR. BRIJESH SHARMA X-D

3.  Chemical Reactions
 Chemical Equations
 Balanced And Unbalanced Chemical Equation
 Type of chemical reactions
1. Combination Reactions
2. Decomposition Reactions
3. Displacement Reactions
4. Double Displacement reactions
5. Oxidation Reaction And reduction reactions
 Effect of Oxidation Reactions in everyday life

4. Chemical reaction are the processes in which new
substance with new properties are formed.

5. The method of representing a chemical reaction with theThe method of representing a chemical reaction with the
help of symbols and formulae of the substance involvedhelp of symbols and formulae of the substance involved
in it is known as chemical equation.in it is known as chemical equation.
The new substance produced in a reaction are known asThe new substance produced in a reaction are known as
products.products.
The substances which combine or react are known asThe substances which combine or react are known as
reactants.reactants.
Zn + H2SO4 ZnSO4 + H2

6. The process of making the number of different types of
atoms equal on both the sides of equation is called
balancing of equation.
The process of making the number of atoms on
different elements(one or more)is not equal on two
sides of the equation is called unbalance equation .
H2+O2 2H2O
H2+O2 H2O

7. The reactions in which to or more
substances combine to form A
single substances is called as
combination reaction
C+O2 CO2

8. The reactions in which a single
compound break down to gives
two or more substances are
called decomposition reactions.
2H2O 2H2+O2

9. The rections in which more
active elements displace a less
active elements its compound is
called displacement reaction.
CuSO4 + Zn ZnSO4 + Cu

10. The reactions in which two
compound react by an exchange ions
to form two new compound is called
double displacement reaction.
AgNO3+NaCl AgCl+NaNO3

11.  Oxidation=The reactions in which
gains Oxygen and loss hydrogen is
called oxidation reactions
 Reduction=The reaction in which
gains hydrogen and loss oxygen is
called Reduction reaction.

12. There are two common effects of oxidation reactions
there are;
i.Corrosion of metals
ii.Rancidity of food
Corrosion is the process in which metals are eaten up
gradually by the action of air, moisture or a chemical (Such as
an acid.) on the surface.
The oxidation of a oils or fats in a food resulting into a
bad small and bad taste is called rancidity.