Chemical Reactions and Equations - Revision Notes
CBSE Class 10Science 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 2 M g + O 2 → 2 M g O 2 M g + O 2 → 2 M g O 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. Balanced Equation: A balanced equation is one in which the number of atoms on the reactant and product sides are equal. Balancing Equation : We balance a chemical equation so that no. of atoms o...