Chemical reactions and equations Notes for Class 10th CBSE

  CBSE Physical Change: Change in physical properties.
– Melting
– Boiling
– Condensation
– [Note- No change occurs in the identity of the substance].
  Chemical Change:
– Atoms in the reactants are rearranged to form one or more different substances.
– Old bonds are broken, new bonds are formed.
– Reactants lose their properties to form product of different properties.
4 Fe(s) + 3O2 →2Fe2O(rust). Iron Oxygen Ferric oxide
   Chemical equation:
The symbolic representation of a chemical reaction is called a
chemical equation.
Features of a chemical equation:

  •    The reactants are written on the left hand side with a plus sign between them.
  • The products are written on the right hand side with a plus sign between them.
  • An arrow separates the reactants from the products. The arrow head points towards the products and indicates the direction of the reaction.

Skeletal chemical equation:
 A chemical equation which simply represents the symbols and formulas of reactants and products taking part in the reaction is known as skeletal chemical equation for a reaction.
For example: For the burning of Magnesium in the air, Mg + O2 → MgO is the skeletal equation.